Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1 155~3~
1 This application is a divisional application of
Canadian patent application serial number 325,681 ~iled
on April 18, 1979.
BACKGROUND OF T~IE INVENTIO~l
Inkers for printing plates which have achieved
co~ercial acceptance generally comprise from two to four
form rollers which are positioned in rolling engagement with
a printing plate. Each of the form rollers is usually in
rolling engagement with one or more vibrator rollers to which
ink is applied by a multitude of rollers in a train of rol-
lers of varying diameters arranged in pyramid fashion. Ink
is delivered to the train of rollers over a ductor roller
which oscillates into and out of engagement with a film of
ink formed by a flexible doctor blade urged into engagement
with the hard surface of an ink fountain roller ~y a multi-
plicity of ink keys.
The lnk film formed on the ink fountain roller has
been too thick and too irregular for application directly
to a printing plate for quality printing. These inkers which
include a multiplicity of rollers are intended to reduce the
thickness of the ink film and to deliver a film of uniform
thickness to the printing plate. ~owever, since the ink film
on each of the rollers is not totally replenished on each
revolution on the form rollers; image ghosting and ink accum-
ulation ana starvation is not completely eliminated. Thus,
stripes and uneven ink distribution are produced on the pro-
duct due to the ghosting and ink accumulation.
The multiple roller inkers require complex drive
trains and are relatively expensive to purchase initially and
to maintain thereafter.
1 ~L55336
1 Other types of inkers which have attempted to
meter ink from a transfer roller to a form roller have util-
ized a doctor blade to remove all of the film of feedback
ink from the form roller prior to replenishing the ink film.
Since most form
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1 1~533~
1 rollers are resilient, the contact of the doctor blade to the
form roller surface scores the form roller and wears out the
blade and roller causing an uneven film of ink.
The invention described herein addresses the problem of
forming a thin filln of newsprint type printing ink of low
viscosity having substantially uniform thickness on a form
roller and moving the film of ink into engagement with the image
area on the printiny plate while eliminating the trains of rollers
in the inking system, eliminating the necessity for the consump-
tion of excessive power and further reducing and eliminatingnumexous adjustments and areas of ghosting and ink accumulation
which produce undesirable variations on th2 product being printed.
Devices of the type disclosed in U.S. Patent No.
3,926,114 were devised to remove all the unused portion of ink-
and dampening fluid from the form roller prior to forminy a new
fi].m of ink by metering the ink through a yap betwee~ the form
roller ancl a transfer roller. There is considerable wear on
the ink removal blade and the roller in this type o~ device.
Also, it is extremely difficult to form an ink film which is
sufficiently thin by using a doctor blade when metering newsprint
ink.
Inking devices of the type disclosed in U.S. Patent No.
2,240,762 employ rollers having cavities formed in the surface
to meter ink onto a form roller for application to a printing
plate.
A printing unit generally comprises two printing
couples ior applying ink to the web. If it is desired to
print on both sides of the web in a single printing unit, the
web is routed through the unit such that ink is applied to both
sides. How~vcr, if it is desired to print two colors in the same
1 ~5533~
1 unit on one side of the web, one o~ the printing couples must
be reversed, from the direction used to print on both siaes of
the web, and the web is routecl to print on one side. The
reversal of the printing couple requires reversal of the
rollers in the couple.
SUMMARY OF T~IE INVENTION
The impxoved inker construction comprises a metering
roller and a transfer roller, each having an oleophillic surface
urged into pressure indented relationship. The metering roller
is adapted to meter an excess of low viscosity ink at the nip
between the metering roller and the transfer roller such that a
uniform film is metered onto the surface of the transfer roller.
~n ink storage roller is positioned in pressure indented relation
with the transfer roller to further condition the film of ink
to assure that the film is substantially uniform and continuous.
The film of ink ic; then sheared and rnetered between the nip
between the transEer roller and a form roller. By controlling
the speed bet-~een the form roller and the transfer roller,
slippage occurs thus forming a thin, substantially uniform,
- 20 calendared, smooth layer of ink onto the form roller.
As an irregular film of ink moves from the printing
plate on the foxm roller, it marries with a fresh uniform film
of ink on the transfer roller to form a substantially uniform
film of ink on the form roller by removing ink from the transfer
roller to replen;sh the depleted areas on the form roller. The
transer roller continuously furnishes a uniform film of ink to
the form roller and the irregular feedback film, formed as the
form roller removes ink from Lhe transfer roller, moves back to
the flooded nip between the transfer roller and metering roller
to be rernetered.
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1 The film of in~ on the form roller is further conditioned
by a matcrial conditioning roller to produce a smooth matte finish
thereon. The material conditioning roller has essentially the
same affinity for ink as does the form roller and thus splits the
film causing a matte finish on the ink layer.
The matte finish is readily adapted to acceptincJ
dampening fluid for use in a lithographic printing system. A
darnpening system having a transfer roller with a hydrophillic
surface and a metering roller transfers dampening fluid to the
matte finish of the ink on the form roller prior to movement of
the ink and dampening fluid layer into engagement with the
printing plate~ The ink and water film is transferrea to image
areas on the printing plate and the dampening fluid to non-image
areas such that lithographic printing may be performed.
After the layer of ink on the form ro~er moves away
from the printing plate there will be ghosted or depleted areas
of ink which are reduced by an ink storage roller which
accumulates the ink and supplies it to the ghosted or areas
star~ed of ink prior to the layer of ink moving into the nip
between the form roller and the transfer roller to replenish the
depleted film of ink.
The inking and dampening units are particularly adapted
to be reversed, such that dampening fluid is applied to the form
roller and then ink applied there over. This permits reversal of
the entire unit when desired.
This type of inker is particularly adapted for applying
newsprint type ink in inking processes such as Di-Litho (regis-
tered trademark of American Newspaper Publishers Association/
Research Institute) for printing direct on a lithographic plate
with water, printing offset from a blanket with water, letterpress
_~ _
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1 s-tereotype, dry offset, and letterpress direct printing with
a letterpress plastic relief plate.
A primary object of the invention is to provide
an inker to continuously provide a substantially uniform
thickness of ink to a form roller for applying to a litho-
graphic printiny system.
A still further object of the invention is to
provide an inking system which affords precision control of
the thickness of the ink film to eliminate ghosting and a
resulting colour variation of printed images.
Another object of the invention is to afford an
inking system to use with low viscous ink which will provide
a su~stantially uniform thickness of ink which is readily
acceptable to receiving dampening fluid for application on
a printing plate and which may be reversed.
A further object of the invention is to provide
a simple and efficient inking system capable of forming a
thin, continuous and substantially uniform thickness of
ink which eliminates the necessity of power consuming tech-
niques.
A still further object of the invention is to
provide inking apparatus which has a single point of control
of the thickness of ink which eliminates streaks and imper-
fections from lint and paper fragments while minimizing lag
time of adjusting the ink film.
In one of i-ts aspects, the invention provides
an improved ~7eb fed printing press wherein ink is applied
to a printing plate on a plate cylinder which transfers an
image to liquid receptive material, wherein said improvement
comprises a single form roller having an ink receptive
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1 sur~ace; means rotatably supporting said form roller in
pressure indented relation with the printing plate; positive
drive means connected to said form roller; an ink transfer
ro:ller having an oleophilic ink receptive surface; means
rotatably supporting said ink transfer roller in pressure
in~ented relation with said form roller; means forminy a
film of ink on said transfer roller; reversible drive means
drivingly connected to said ink transfer roller, said rever-
sible drive means being adapted to permit reversing the dir-
ection of rotation of said ink transfer roller upon reversing
the direction of rotation of the form roller and the plate
cylinder; a-pair of ink storage rollers; and means rotatably
supporting said ink storage rollers such that the surface of
the form roller which is moving form pressure indented relation
with the printing plate moves adjacent to one of said ink
storage rollers before moving in pressure indented relation
with sai.d ink transfer roller upon rotation of the form roller
in a clockwise or a counter-clockwise direction
In another of its aspects, the invention provides
an improved printing press wherein ink is applied to a
printing plate on a plate cylinder which transfers an image
to a web, wherein the improvement comprises an ink metering
means; an ink transfer roller having an oleophilic ink re-
ceptive surface; a form roller in rotative contact with the
printing plate and having an ink receptive surface adapted
to be urged into pressure indented relation with said ink
transfer roller to form an ink transfer nip;.means support-
ing said ink metering means and said ink transfer roller in
pressure relationship to form an ink metering nip between
adjacent surEaces of the ink metering means and the ink
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9 transfer roller; means to supply ink to said ink metering
nip to produce a film of ink on the surface of said ink trans-
fer roller; a dampening fluid transfer roller adapted to
apply dampening fluid to the surface of the form roller; means
rotatably supporting said dampening fluid transfer roller in
pressure indented relation with said form roller to form a
dampeniny fluid transfer nip; dampening fluid metering means;
means to supply dampening fluid to said dampening fluid
transfer roller such that the dampening fluid metering means
produces a film of dampening fluid on the surface of the
dampening fluid transfer roller; and drive means associated
with said plate cylinder, said form roller, said dampening
fluid transfer roller, and said ink transfer roller to move
a point on the surface of the form roller sequentially from
indented relati.on with said printing plate where ink and
dampening flui.d contact the printing plate, to the dampening
fluid transfer nip where dampening fluid is applied to said
form roller, to the ink transfer nip where ink is applied to
said form roller and finally into indented relation with
2~ said printing plate, said drive means being adapted to rotate
said ink transfer roller such that its surface speed is less
than the surface speed of said form roller.
In yet another of its aspects, the invention
provides a method of metering a thin film of liquid news-
print type ink onto a printing plate comprising the steps of:
moving an irregular film of ink left on a form roller after
applying ink to the printing plate through a nip between the
form roller and a vibrator roller to replenish ink depleted
areas in the irregular film with ink removed by the vibrator
roller from heavily inked areas on the form roller; depositing
1 15S336
an excess of fluid newsprint type ink onto a transfer roller
surface; rotating the excess of newsprint type i.nk through
an ink metering nip to form a film of ink of controlled
thickness; rotating the film of ink of controlled thickness
into engagement with the surface of the form roller to
Eorm a film of ink on the form roller; slipping the transfer
roller relative to the form roller such that a thin, Gontin-
uous film of ink is produced on said form roller; rotating
a material conditioning roller on the surface of the film of
ink on the form roller to produce a matte finish on said
film of ink; and applying a braking force to said transfer
roller to maintain the surface speed of the transfer roller
less than the surface speed of the form roller.
In still another aspect, the invention providés
a method of converting a pair of printing couples to
print on two sides of a web into a pair of printinq couples
to print twice on one side of the web, wherein each print-
ing couple comprises a plate cylinder and a form roller driven
at substantially e~ual surface speeds; an ink metering roller
and an ink transfer roller urged together to form a flooded
ink metering nip having an excess of ink on one side of the
ink metering nip, the ink transfer roller being urged into
pressure idented relation with the form roller and driven
at a surface speed less than the surface speed of the form
roller; and a dampening fluid metering roller and a dampen-
ing fluid transfer roller urged together to form a flooded
dampening fluid metering nip having an excess of dampening
fluid on one side of the dampeniny fluid metering nip, the
dampening fluid transfer roller being urged into pressure
indented re:Lation with the form roller and driven at a
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1 surEace speed less than the surface speed of the form roller,
the improved method comprising the s-teps of: reversing
the direction of rotation of the plate cylinder and the form
rol:ler in one of the printing couples; reversing the direction
of rotation of the ink mctering roller and the ink transfer
roll.er to move the excess of ink to the opposite side of the
ink metering nip and to move the surfaces of the ink trans-
fer roller and the form roller in the same direction at
different surface speeds; and reversing the direction of
rotation of the dampening fluid metering roller and
the dampening fluid transfer roller to move the excess
dampening fluid to the opposite side of the dampening fluid
metering nip and to move the surfaces of the dampening
fluid transfer roller and the form roller in the same direc--
tion at different surface speeds, and such that dampening
fluid is applied at the dampening fluid transfer nip
to the surface of the form roller which is moving toward
the ink transfer nip
Other and further objects will become apparent
upon referring to the following detailed description and
the attached drawings.
BRIEF DESCRIPTION OF THE DR~WINGS
Drawings of a preferred embodiment of the
invention are annexed hereto so that the invention may be
better and more fully understood, in which:
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1 Figure 1 is a diagrammatic illustration of the ink-
ing system illustrating the various films of ink and dampening
fluid;
Fiyure 2 is a front elevational view illustrating
the meterinc3 and transfer rollers and support structure;
Figure 3 is a cross sectional view taken along line
3-3 of Figure 2;
E`igure 4 is a diagrammatic view of a standard
printing unit;
Figure 5 is a diagrammatic view of a reversed print-
ing unit;
Figure 6 is a diagrammatic view of the electrical
hookup of the motors of dampening ancl inking units.
Numeral references are employed to designate like
parts throughout the various figures of the drawings.
DESCRIPTION OF A PREFERRED EMBODIMENT
In Figure 1 of the drawings, the numeral 1 generally
designates an ink applicator apparatus for applying ink and
dampening fluid to a lithographic printing plate of a print-
ing press. The ~Jater applicator is a dampener 200 of the
type disclosed in United States Patent No. 3,937,141, entitled
"Dampener for Lithographic Printing Plates" which issued
February 10, 1976 to Harold P. Dahlgren.
As best illustrated in Figure 2, ink applicator 1
comprises spaced side frames 2 and 4 joined by tie bars (not
shown) forming a strong rigid structure for supporting form
roller 90, ink transfer roller 10, ink metering roller 12 and
ink pan 14. Side fra-mes 2 and 4 may be the side frames of a
press or may comprise inker side frames connectable to side
frames of a printing press.
~ 10 -
. .
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1 Throw-o~f links 16 and 18 axe pivotally secured by stub
shafts 20 and 22 to the respec-tive side frames 2 and 4. Throw-
o,f cylinders 24 and 26 are pivotally ~onnected between side
frarnes 2 and 4 and throw-of.! links 16 ana 18, respectively, for
pivoting throw-o:EE links 16 and 18 about stub shafts 20 and 22
for moving tr~nsfer cylinder 10 into position, as will be
hereinafter more fully explained, for delivering ink to a form
roner in a lithographic printing system.
A skew arm 28 is mountea for pivotal movement of one -
end of a metering roller 12 about the axis of ink transfer roller
10. As diagrammatically lllustrated in Figure 2, skew arm 28
is rotatably secured to stub shaft 30 extending between link 18
and skew arm 28 adjacent an end of ink transfer roller 10.
Skew arm 28 and throw-off link 16 have grooves 28a and
16a, respectively, formed in the inner surfaces thereof in which
blocks 36, carrying s~lf~alicjniny bearings 38, are slidably
disposed. B:Locks 35 are riyidly secured in the upper portion of
yrooves 28a and 16a by screws 37 to provide suitable support
for shafts 31 and 32 of the ink transfer roller 10. Suitable
means such as resilient springs 40 between blocks 35 and 36
urge blocks 36 longitudinally of skew arm 28 and throw-off link
16 in a direction away from the longitudinal axis of transEer
roller 10. A pressure adjustment screw 42 urges block 36
longitudinally of skew arm 28 and throw-off link 16 against the
bias of springs 40. Stub shafts 44 and 46, ex-tending out~7ardly
from opposite ends of metering roller 12, are received in
self-aligning beari.ngs 38 to rotatably secure metering roller 12
in pressure indented relation with transfer roller 10. Stub
shafts 31 and 32, extending out.wardly from oppos.ite ends o~
transfer roller 10, arc rcceived in bearings 39 in blocks 35.
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1 It sllould be readily apparent that rotati.on oE pressure
adjust:ment screws 42 will move opposite ends of metering roller
12 relative to the axis of transfer roller 10 ~or controlling
pressure between transfer roller 10 and metering roller 12.
~ s illustrated in ~iyure 3, suitable means is provided
for establishing and maintaining a desired angular relationship
be-tween throw-off link 18 and skew arm 28. In the form of the
invention illustrated in Figure 3, and adjusting screw 50 is
rotatably secured to skew arm 28 and extends through threaded
apertures in pivotal blocks 52a and 52b. Blocks 52a and 52b are
pivotally secured to lug 54 on arm 28 and lug 56 on link 18. By
adjusting screw 50, the spacing between lugs 54 and 56 is
adjusted to move skew arm 28 relative to link 18 about shaft 30.
Side frames 2 and 4 have suitable adjustable stop means
such as stop blocks 5 having set screws 5a extending therethrough
for en~gi.ny throw-off links 16 and 18 when rods of throw-off
cyli.nders 2~ and 26 are extended for establishing a desired
pressure relationship between the transfer cylinder 10 and an ink
coated form roller 90 arranged to transfer ink to a lithographic
or relief printing plate 112 on plate cylinder P, as will be
hereinafter more fully explained. Stop means such as stop
blocks 6 having set screws 6a secured thereto provide an off-
impressi.on limit when piston rods of throw-off cylinders 24 and
26 are retracted to move the transfer roller 10 away from the
surface of for'm roller 90. Stub shaft 32 has a brake disc 51
secured thereto and friction pads 53 are pivotally secured to
support 55 secured to arm 28 to control the speed of transfer
roller 10 when it is driven by rictional engagement with form
roller 90.
Slllb-shaft 31, extending outwardly from the end of
transfer ro:l..ler 10, has a gear 60 rigidly secured thereto by
1 15533G
1 screw 61 which is in meshincJ relation with a gear 62 rota-tably
secured by a bearing 45 disposed on shaft 44.
Gear 62 is secured in meshing relation with gear 64 on.
shaft 58 rotatably sccured to sicle frame 2 through a clutch
assembly 66 of a type such as a Morse one-way clutch. Shaft 58
i5 secuxed to the shaft of a reversible var.iable speed drive
drive means such as a reversible variable speed electric gear-
n.otor 69. It should be appreciated that gear-motor 69 may be
replaced by other drive means such as gears, sprockets, or pulleys
arranged to be driven from the printing press drive, preferably
through a gear box or similar variable speed control apparatus.
Shaft 44, extending outwardly from the end of metering
roller 12, has a year 70 secured thereto in meshing relation with
a gear 71 secured to anddriven by shaf~ 53.
Power supply line-80 is connected through a variable
xheosta;t 84 to the terminals of motor 69 so that motor may be
run at vari.ab].e ~pe~ds to control the speed of rotat.ion, and,
consequently, surface speeds of transfer roll~r 10 and metering
roller 12 independently of the press drive. If it is deemed
expendient to do so motor 60 could be replaced by a speed-variable
coupling which connects shaft 5~ to the press drive means, as
hereinbefore described.
Clu-tcll assembly 66 allows transfer roller 10 to be
driven by gear-motor 69 at a minimum speedra~o relative to
metering roller ].2, for example 1:1, and allows transfer roller 10
to be over-clriven by form roller 90 at higher speeds without
driving the metering roller 12 at a faster speed which may tend
to sling ink 14a out. of pan 1~. -
It should be appreci.ated that clutch 66 can be deleted
and replaced by a gear to allow drive of the transfer roller 10
- 13 - .
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1 positively from -the gear-motor 69 or clu-tch 66 may be locked
to permit reversiny of inker transfer roller 10. Clutch 66 may
be reversed by removing same and reversing it on shaft 58 if so
desired.
Ink storage rollers 82 and 82', illustrated in Figure 1
are preLerably vibrator rollers. Ink storage rollers 82 and
~2' are adapted to equalize areas of excess ink on transfer roller
10 in a manner to be more fully explained hereinafter. Rollers
82 and 82' are preferably driven positively by roller 10, i.e.,
by gears driven by a gear on roller 10.
Suitable means are provided for delivering an abundant
supply of ink to the ink metering nip N between adjacent surfaces
of transfer roller 10 and metering roller 12. In the particular
embodiment of the invention illustrated in Figure 1, a portion of
the surface of metcring roller 12 is submerged in ink 14a in
ink pan 1~.
Ink 14a preferably comprises a low viscosity ink such
as the type employed for inking raised image areas in letter press
printing or the type used in direct or offset lithographic
printing such as type ink.
- The transfer roller 10 is preferably hard and has an
exterior surface which may be smooth or textured and which is ink
receptive or oleophillic. Ink transfer roller 10 may, therefore,
have an exterior surface of materials such as copper, or plastic.
The surEace oErtransfer roller 10 may be either hard or resilient,
depending upon the characteristics of the surface of form roller
90. If form roller 90 has a hard surface, the surface of
transfer roller I~ is preferably hard.
Meteriny roller 12 preferably comprises a hollow tubular
sleeve havi lly stub shafts 44 and 46 formed thereon. A resilient
- 14 -
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1 cover 12c is secured about the outer surface of the sleeve. The
material of metering roller 12 is selec-ted so as to be oleophillic
and the surface may be smooth or textured.
To reduce the tendency of ink to accumulate adjacent the
cnds of transfer roller 10, meteriny roller 12 is l.onger than
transfer roller 10 such that ends of the metering roller 12 extend
beyond the ends oftransfer roller 10. The transfer roller 10 is
preferably longer than form roller 90 to minimize accumulation
of excess ink adjacent ends of form roller 90.
- It should be readily apparent that, if desired, the
material of transfer roller 10 and metering roller 12 may be
reversed such that metering roller 12 has a hard surface and
transfer roller 10 has a resilient cover, or both could be
resilient.
Form roller 90 is preferably cut to be the same length
as the.printing plate to also eliminaté accurnulation of excess
ink which will tend to build on the form ro~eris longer than the
printing pl~te.
Referring to Figure 1 of the drawing, transfer roller
2~ 10 is preferably positioned in pressure indented relation with a
form roller 90, having a metal tubular core 91 to the ends of
which are secured stub shafts e~.tending outwardly therefrom and
rotatably journaled in bearings 92 carried by the side frames 2
and 4.
Form roller 90 has a smooth outer cover 96 which may be
non-absorbent or absorbent, hard or soft, depending upon the
nature and construc-tion of printing p].ate 112.
In one embodiment, form roller 90 may have a resilient
non-absorberlt surface. ~nother embodimellt oE forrn roller 90
includes a resilient surEace and has a molleton type cover which
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1 absorbs ink and will reject dampening fluid. However, if plate
112 has raised image areas and is constructed of resilient
materi.al, form roller 90 could be provided with a hard surface
of, for example, copper or a hard thin plastic covering.
~ n ink storage roller 94, preferably a vibrator roller,
is adapted to remove ink from areas 128" from ink film 128 on the
. surface of form roller 90 and add the ink to the depleted areas
128' thereby creating a more uniform film of ink on the surface
of roller 90 moving from the nip 120 to~ard nip 108
.A second ink stora~e roller 94', similar to roller 94,
is positioned between plate cylinder P and dampener 200 to
smooth the ink film.upon reversal of form roller 90 as will be
more fully explained hereinafter.
A material conditioning roller 86, preferably a vibrator
roller, is rotatably supported on shaft 86a in blocks 86d and is
adapted to condition and smooth the surface of ink film 100 to
make the film more receptive to accepti~g dampening fluid. Screws
86b and 86c are adapted to urge blocks 86d and roller 86 into
pressure indented relation with form roller 90. The surface of
material conditioning roller 86 is preferably of similar material
to that of form roller 90 such that the surface has the same
affinity for ink as does the surface of form roller gO.
As the ink fi~m 100 emerges from the nip 106 between
form roller 90 and transfer roller 10, it is slick, and cal.endared.
slick film ~f ink is not particularly receptive to dampening
fluid since the surface tension of the molecules of ink may
reject the thin layer dampeniny fluid to be applied by
dampener 200. Material conditioning roller 86 will receive a
portion of the film 100 of ink thus splitting the film 100 of
ink and producing a film 100' on roller 86 thus leaving film lOOa
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1 . with a matte finis}l havirlcl microscopic indentations. The matte
finish on f.ilm lOOa will more readily accep-t the thin layer o~
dampen:ing fluid due to molecular attr~ction which is now greater
than the surface tension of the darnpening fluid forming a film
Z17.
Material conditioning roller 86 and ink s-torage rollers
9~ and 82 are preferably constructed of diameters such that as
they rotate ink will be properly applied or extracted and
redistributed on the surface of roller 90.
Vibrator rollers 82, 86 and 94 are preferably provided
with drive means (not shown) to oscillate the rollers in a
longitudinal direction. Suitable oscillator drive means is well
known to persons skilled in the printing art and further descrip-
tion is not deemed necessary. Rotation is provided through
friction contact w.ith aAjacent surfaces.
Dampener 200 is di.agrammatically illustrated in Fiyure
1 and comprises a hydrophill.ic transfer roller 210 on shaft 210a
and a resilient metering roller 212 on shaft 212a, mounted in a
similar manner to inker 1, as described in Patent ~o, 3,937,141.
Metering roller 212 meters dampen.ing fluid 214a from pan 214 onto
transfer roller 210 through flooded nip Na. Water film controlled
by'pressure between rollers 210 and 212 forms a thin layer of
dampening fluid 204 which is metered through dampening fluid
transfer nip 106a onto the matte finish of ink,film lOOa on the
sur:Eace of form roller 90.
Dampener metering roller 212 is driven by a variable
speed reversible motor 269. As illustrated in Figure 6,
rheostats 84 and 284 are connected to a suitable electrical
supp]y and are connected to a pa:ir of yained double pole, double
throw switches 81a and 81b to control the direction of motors
69 and 269.
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1 The operat:on and fuction of the apparatus herein-
before described is as follows:
Pressure between ends of transfer roller 10 and metering
roller 12 is adjusted by rotating pressure adjustment screws 42
Si.nce long rollers urged toyether in pressure relation-
tend to de1ect or bend, pressure adjacent centers of such rollers
is less than pressure adjacent ends thereof. Pressure
longitudinally of rollers 10 and 12 is adjusted by rotating
screw 50 and rotating skew arm 28 about the axis of transfer
roller 10 to a position wherein a desired pressure distribution
longitudinally of rollers 10 and 12 is obtained.
Adjustment screw 5a is positioned to engage throw-off
links 16 and 18 for establishing a desired pressure between
transfer roller 10 and form roller 90.
The surface speeds of rollers 10 and 12 are reyulatable
by manipulatiny rheostat 84 as has been hereinbefore explained.
Dampener 200 is adjusted in a similar manner as inker 1.
For the purpose of graphically illustratin~ the novel
function and results of the process of the mechanism hereinbefore
illustrated and described, a diagrammatic view of the metering
roller 12 r the transfer roller 10 and the form roller 90 is
shown in Figure 1. Ink and water films shown are exaggerated
for clarity. - .
As shown in Figure 1, metering roller 12, when employed
to deliver inkl to a printing plate 112, is preferably a
" .
resilient surfaced roller having a smooth surface 12c thereon
. and has the lower side thereof immersed in ink 14a in pan 14. The
metering roller 12 is rotatably mounted in pressure indented
relation with transfer roller 10, and the pressure between
adjacent rol.ler surfaces is adjusted by screw ~2, as hereinbefore
- 11SS33~ (,
1 descrlbed, 50 that the s~lrface of transEer roller 10 is actually
impressed into the surface of roller 12 at ink metering nip N.
As th~ surface of roller 12 rotates toward the ink
m~tering nip N between rollers 10 and 12, a relatively heavy
layer 101 of ink is picked up and lifted on the surface of roller
12. At the point of tangency, or cusp area at the ink metering
nip N, between the rollers 10 and 12, a bead 102 of ink is piled
up forr,ling an excess of ink. The greatness of the excess of
ink forming bead 102 is regulated by virtue of the fact that
excess of ink wil]. fall back into the pan 14 by gravity, thus,
virtually creatin~ a waterfall, and by the surface speed of
metering roller 12. The bead 102 becomes a.reservoir from which.
ink is drawn by transfer roller 10. As roll~rs 10 and 12 rotate in
pressure indented relation, a layer of ink is sheared and/or
metered between adjacent surfaces of the two rollers separated by
a thin lllbr.icatiny la~er o:E ink 103. Since the transfer roller
10 has a smooth, oleophilli.c surface thereon, a portion of the
film 103 adheres to the surface of roller 10 to form a film 104a,
the remaining portion 105 thereof beinc~ rotated back or fed back
in the pan 1~. The film of ink 104a is distrihuted on the
surface of roller 10 by reason of the rotating, squeezing action
between rollers 10 and 12 at their tangent point at ink metering
nip N. Ink storage roller 82 splits film 104a and receives a
film 104' which is added to film 104a again to further assure
smooth uniform thickness of film 104 on transfer roller 10.
The film of ink 10~ rides on the surface of roller 10
and comes in contact with the Eilm 130 o:E ink on form roller 90
at the tanyent point or ink trallsfer nip 106 between transfer
roller 10 and form roller 90.
~t ink transfer nip 106, it will be observed that
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115$33G ~,
1 transfer roller 10 is impressed into the resilient surface of form
roller 90 and that thc film of ink 104 has an outer surface 108,
contac-ting ink film 130, and an inner surface 110 adhering to
the surface o rolier 10. The outer surface 108 of film 104 and
the outer surace 131 oE the film of ink 130 on form roller 90
are uryed toyether to create a hydraulic connection between
roller 10 and 90 as they rotate in close relationship, but there
is no physical contact between the roller surfaces.
It is an important fact to note that the relative
thick film of ink 104 permits rollers 10 and 90 to be rotated at
different surface speeds as will be hereinafter explained.
Preferably, the form roller 90, which is normally rotated at the
same surface speed as the pintiny plate 112, and press driven,
is rotatea at a greater surface speed than the surface speed of
roller 10. By regulating the differential surface speed between
transfer roller 10 and applicator roller 90 the amount of ink
applied to the plate 112 may be regulated.
~ ithin limits, as will be hereinafter more fully
explained, if the surface speed of transfer roller 10 is increased
the in~ film 104 is presented at th~ ink transfer nip 106 at a
faster rate and more ink is transferred by the surface of rollcr
90 to lithographic printing plate 112, and the opposite is true,
if the surface speed of roller 10 is decreased.
The film of ink 104, existent between adjacent surfaces
of rollers 10 and 90, permits rollers 10 and 90 to be rotated
at different surface speeds in sliding relationship, because the
film of ink 104 actually provides lubrication which permits
slippaye between adjacent surfaces of rollers 10 and 90 without
frictional deterioration. By reason of the slippaye between
rollers 10 cllld 90, the ink film 104 is calendared, smoothed out,
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~15533~ ~,
1 metered and distributed by shearirly the ink between adjacent
surfaces of roller 10 and the ink film 130 on form roller 90,
to create ink filrn 100. The thickness of ink film 100 is con-
trolled by pressure between metering roller 12 and transfe
roller 10 and the speed of transfer roller 10.
Transfer roller 10 preferably is driven at a surface
speed which is within a range of for example, several hundred
feet per minute slower than the surface speed of form roller 90.
For example, if a printing press has paper travellincJ therethrough
at a surface speed o 1200 feet per minute the surfaces of
printing plate 112 and form roller 90 will ordinarily have
surface speeds of 1200 feet per minute. The surface speed of
transfer roller 10 would preferably ro-tate at a surface speed
in a range between 50 feet per minute and 100 feet per minute.
Ink films 104 and 130 will be combined at ink transfer
nip 106 and will split when sheared as rollers 10 and 90 rotate
away from ink transfer nip 106. The fresh film 100 of ink
adheres to the surface of form roller 90. Ink rejected by form
roller 90 forms a feed~ack film 116 of ink which may be slightly
irregular which adheres, to the surface of the transfer roller
10 and is conveyed back to the bead 102 of ink adjacent ink
metering nip N to be remetered. Feedback film 116 is not uniform
because the starved areas on form roller 90, from which ink was
removed by image areas on the plate 112, removed diEferent
~uantities of ink from film 104 in order to remeter film 128 on
form roller 90. Film 128 has starved areas 128' from ink
- removed by image areas 122 on p:klte 112, thus rendering film 128
irregular.
As the film 100 of ink on the surface of form roller 90
moves froln ink meterincJ nip 106 adjacen-t transEer roller 10, the
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11S~33~ ~
1film 100 is substantially uniform as non-uniform ~ilm 130 is
combi]ned with the uniform film 104 carried on transfer roller
10. Filrn 1.30 accepts ink from film 10~ in the starved or
depleted areas 128'. The transfer roller 10 is caused to
rotate at a speed which satisfies the need for inX by form
roller 90 by overridding clutch 66. The deple~ed portion or
feedback fi~m 116 is returned to the abundant or excess supply
of-ink at bead 102 between metering roller 12 and transfer
roller 10 to rep].enish the ink film 104.
10It has already been explained that the ink film 130
is smoothed out, distributed, metered, and regulated at the ink
transfer n.ip 106 between transfer roller 10 and form roller 90.
Material conditioning roller 86 splits film 100, taking on a
film 100' to produce a matte finish on ink film lOOa. Any
irregularities or streaks in film 100 will be spread and
equalized to form film lOOa of very uniform thickness.
The interface tension between the outer surface of the
less viscous dampening fluid film 204, by reason of molecular
attraction between the surface of the more visocus ink film lOOa,
causes a portion 216 of the smooth and regulated film 204 of
dampeniny flui~ to be added to the surface of ink film lOOa,
which in turn is transferred to the plate at the tangent point
between the plate 112 and-form roller 90 at inking nip 120.
The lithographic printing plate 112 has hydrophillic,
or water liking, non-image areas 121 and oleophillic, or ink
receptive, image areas 122 formed on the surface thereof. If
printiny plate 112 is provided with raised image areas, the
dampener 200 would not be required to prevent transfer of ink
to non-imaye areas.
30 ~ the nip 120 between applicator roller 90 and printinc3
1 15533~
1 platc 112, the ink film 100 ic; split, forming thin films 125 of
ink and water ove.r ole-ophillic surfaces 122 on the printing
plate. ~he layer 216 oE dampening fluid, if dampening fluid i5
employed, is carried on and in the film 100 of ink and is also
di~ribut~d to form a thin film ~26 o:E dampeniny fluid over
hydrophillic areas 121 of the printing plate.
No apprec.iable amount of dam~ening fluid remains on the
surface of form roller 90 which is moving away from the nip 120,
but such dampening fluid as does remain thereon is transferred
with the ink film 128 to the ink film 130a on the ink storage
roller 94 where the dampening fluid can be dissipated and/or -
evaporated to such an extent as to be of no consequence in the
inking system.
Ink of film 128 remaininy on form roller 90 is
combined with film 130a on ink storage roller 9~ and split and
co:L:Lected on roller 9~. Ink on roller 94 is added to depleted
areas 128' in film 128 thus reduciny the effect of ghosted and
areas in film 128 ~y forming a more uniform film 130 before
re-entering nip 106.
The layer oi dampening fluid 216 is applied in
substantially the same manner. An excess of dampening fluid 201
is supplied to bead 202 to form a film 204 of dampening fluid
ich is applied to ink film lOOa on forrn roller 90 at nip 106a.
The film 217 of dampening fluid is returned to bead 202 to be
re-metered at nip Na.
From the foregoing it should be readily apparent tha-t
the improved apparatus for applyirly ink to printing systems offers
control of metering at ink meteriny nip N to provide a film 104
of ink of precisely controlled tllickness by adjusting pressure
between transfer roller 10 and metering ro:Ller 12 and further by
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1 ~5~33~ ~ `
1 controlling surface speeds of the rollers relative to each other.
The rate at which the me-tered film 104 of ink is offered to film
130 of ink on form roller 90 at ink transfer nip N an~ also the
hydraulic force for obtaining the desired film split is
controlled.
To eliminate conditions which could cause accumulation
of inlc renderiny it impossible to form a film 104 of precisely
controlled thickness the specific roller arrangement provides for
elimination of ink which is fed back in the form of ink film 116
on transfer roller 10 moving away from the ink transfer nip 106.
Thus, the effect of the unused depleted film of ink not accepted
by form roller 90 is eliminated from the inking system by
returning film 116 to the flooded ink metering nip N and is not
left to accumulate on transfer roller lO as in prior art devices.
While a preferred embodiment of the invention has been
hereinbefore described and illustrated in the attached drawings
it should be appreciated that other and further forms of the
apparatus can be devised without departing from the basic concept
thereof.
It should further be appreciated that either the transfer
roller 10 or metering roller 12 could be geared to the press
drive, or driven by an independent drive means, for e5tablishing
the conditions hereinbefore described for a specified speed range.
It should be appreciated that transfer roller 10 may be
oscillated l,at!erally along its axis to further smooth ink films
130 and 100.
Figure 4 illustrates a pair of inkers 1 used in the
standard configuration to print on both sides of a web W. A
printing unit U generally has a pair of printing couples C each
of which cc~ r~rise an inker unit 1 and dampener unit 200. If it
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1 15533~
1 is necessary to print t~o colors on one side of web W, then the
ric~ht hana couple C as viewed in I~ ure 5 must be reversed such
that the web W may be routed for printing on a single side. In
reversing the direction o:E the form roller 90, dampening fluid
will be applicd over the thin ghosted film of ink leaviny the
plate 112 after inlc storage roller 9~' cvens the ink film to
some extent. A fresh supply of ink will be added to the dampening
fluid and ink on roller 90 as the roller 90 moves through nip
106. Thus, the couple C may be reversed by simply reversing the
drive to the coup]e and motors 69 and 269.
Since friction on the drive will be altered by reversing
the inker 1, brake 51 should be adjusted to control the speed
ratio between form roller 90 and transfer roller.10.
It should be readily apparent that the films of ink and
dampening f].uid illustrated i.n FicJure 1 repre~en-t a standard
pri.nting couple moving in the normal or stand~rd direc-tion and
that their films would change in location from those illustrated
should the couple be reversed to apply darnpening fluid first ~nd
in)c on the dampeninc3 fluid.
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