Note: Descriptions are shown in the official language in which they were submitted.
2 ~ 4 9 2 7 ~
~ACKGR~p OF_THE INVEN~ION
The present invention relates to prlnting systems
for use in keyless lithographic printing pro~esses.
In the field of high ~peed lithographic prlnting,
ink 18 ~ontinuously conveyed from an ~nk ~ource by means
of a series of rollers to a planographi~ printing plate
on ~ plate cyl~nder in a lithographic printing press~
Image portion~ of the print~ng plate a~cept ink from on~
or more of the last of a ~eries of inking roller6 and
transfer a portion of that lnk to a blanket cylinder as
~ reverse image from which a portion of the ink is
trans~erred to form a correct-reading image on paper or
other materlals. It is also ~ssential in oonventional
lithographic printing processes that a dampening ~olution
containing water and proprietary additives be conveyed
continuously to tha printing plate whereby transferring
ln part to the non-image areas o~ the prlnting plate th2
water functions to keep those non-image areas free of
ink. Hereinafter, the terms "water" and "dampenins
solution" refer to water plus additives or to other
aqueous solutions used in the operation of lithographic
print~ng presses.
In ~onventional pr~nting press systems, the ink ~s
continuously made available in varying amounts determined
by ~ross-press column input control adjustments to all
parts of the printing plate, ~ncluding both image ~nd
2~ 27~
non-image areas. In the ab~ence o~ the dampening
~olu~ion, the prin~ing plate will accept ink ~n both the
image Rnd non-image areas of lt~ ~urfa~e.
Lithographl~ printing plate surfaces in the absence
of imaging materials have minute interstices and a
hydroph~lic or water-loving property to enhanoe retention
of water, that ~ the dampening solution, rather than ink
on the sur~ace of the plate. Imaging the plate creates
oleophilic or ink-loving are~s according to the imag~
that i8 to be printed. Consequently, when both ink and
dampening solution are presented to an imaged plate in
appropriate amount~, only the ink tending to reside in
non-image areas becomes disbonded from the plate~ In
general, this action accounts for the oontinuous ink and
dampening solution d~fferentiation on the printing plate
surface, which is essential and integral to the
lithographic printing prooess.
Controlling the correct amount of dampening solution
supplied during lithographic printing has been an
industry-wide problem ever since the advent of
lithography. It requires continual operator attentivn
since each column adjustment of ink input may require a
change in dampener input. Balancing the ink ~nput that
varies for each column across the width of the press with
a uniform dampening solution ~nput across the w~dth o~
the press is at best a oompromise. Consequently,
7 ~
dependin~ upon whic:h por~ion s:~ the ima~ the operator
has adopted as his ~tandard of print qual~ty at any giv~n
time during the printing run, the operator may need to
adju~t the ink lnput at correspond~ngly located cross-
pres~ posltions. A~ a resulk, the dampening ~olution to
ink rat~o a~ that posltion ~ay ~e~ome changed rom a
desired value. Conversely, the operator ~ay ad~ust a
dampener lnput ~or best ink and ~ampen~ng solution
balance at one ~nking column, which may adversely ~fect
the ink ~nd damp~nlng solution balance at one or ~ore
other cross-press lo~ations. Ad~ustments such as these
tend to occur repeatedly throughout the whole press run,
resulting in 61ight to 6ignlf~cant difference~ ln the
quallty of the printed ~mage throughout the run~ In
carrying out these ad~ustment operations~ the resultiny
images may or may not be commerc~ally acceptable, leading
to waste in manpower, materials, and printing machine
time.
C~rtain commercially ~uccessful newspaper printing
configurations rely on the inklng train roller~ to carry
dampening solution directly to the printing plate.
~otable among these are the Gos~ Hetro, ~oss Netroliner,
and the Goss Headliner Offset printing presses whlch are
manufactured by the Graphic Systems Division ~f Ro~kwell
International Corporation. In these alternative
~onf~gurations, the dampening solution is ccmbined with
' ": '' ,:
the ink on ~n inking os~illator drum ~u~h that both ink
~nd water .Ire subsequently and continuously transferred
to the inking for~ roller~ for deposition onto the
printl~g plate. In another varlat~on~ the dampening
801ution i applied ln a conv~ntional manner dir~ctly to
the printing plate by means of ~eparate dampening roller~
and a dampening solu~ion ~upply system. In ~y~tems of
either type, regardles~ of the method whereby the
dampen~ng 601ution ~s introduced, it is well known that
some of the dampening solution becomes mixed with the ink
and returns to the inking traln of rollers and may
ultimately be introduced into the ink ~upply system
itself. In any case, these conventional lithographic
ystems require considerable operator attention to
tend to
maintain ink and dampening solution balance and~produce
more product waste than desiredO
Prior art devices and methods for correcting this
inherent f~ult in conventional lithography utilize
keyless inkers. Certain of these methods a~so involve
~liminating the dampening sys~em or el~minating operator
control of the dampening system.
Reyless inking 6ystems have been d~sclosed that
purport to ellm~nate operator attention to column control
of inking by elimination of adjustable inking k~ys,
there~y ~vo~ding muoh of the aforementioned disadvantages
of conventional llthography. ~or keyless inking systems
.,.,.; , ~ .. .
2~L.~2
an in~ ~etering ~e',hod i~ re~uired that cont~nue~ to
~unction desplte ~ne presence of up to about 40%
dampening ~olut~cn in the ink without allowing any
temporarily free dampening solution to interfere with
the ink-metering function. Also, the unused or non-
uniform portion of the ink ~ilm that i6 ~einy
continuously presented to th~ printing plate ~ust be
continuously ~crapedo~ the return ~ide o~ the lnking.
system ~o enable continuous presentation of a uniform
ink film to the plate by the supply side of the inking
~ystem. This s~raped-off fllm i5 not uniform ~cross tha
width of the press in ink and dampening solution
compos~tlon. Since it would not be e~onomically feasible
to con~inuously discard the ~nk in the unu~ed portion o~
~he ink and dampening ~olution m~xture, this mixture must
either be renewed by selectively removing dampening
solution from the mixture and returntng the ink portion
to the inking system or by thoroughly intermixing the
unused ink and dampening solutlon mixture with fresh
replenishment ink and returning such mixture to the
inking system. U.S. Patent 4,690,055 discloses a keyless
~nking sy6te~ in which dampening ~olut~on removal is
unnecessary and which accommodates the dampening 801ution
that is naturally acquired in the unused ink during the
practice of lithography and for which, therefore, removal
of dampening solution is not required.
2~ 27~
In the keylesR inking ~y~tem di~clo~ed ~n U.S.
Patent No. 4,690,055 ~h~reb~ ~ncorporated by reference),
the locat~on of the dampenir-g ~y~tem ia not critical and
can be positioned either to supply dampening ~olution
directly to the plate cylinder or at ~ome other location
~uch a at an osclllator drum to which ink is al~o being
~upplied. An ink circulating and ~lxing ~ystem receives
new or replenishment ink, as well as ~he ink and
dampening solut1on combination that is con~inuously
returned from a doctor blade which 6crapes excess
printing fluid from a rotating metering roller. Such lnk
and dampening combinations ~re generally herein referred
to as print~ng fluids. The printing fluid oirculating
and mixing ~ystem functions to assure an inherantly
uniform cross-press input of printing fluid that remains
consistent throughout and consist~ of a printing flu~d
pan roller, pump and appropriate conduits, a pr~nting
fluid pan level controlling system, and a printing fluid
reservoir of such volume and design that it assures the
printing flu~d being fed to the metering roller is
un~form in compo~itlon at any given in~tant of time
despite the existe~ce of the continual cross-press
dampening solution to ink ratio d~fferences of the unused
or scraped return printlng fluld previously re~erred to.
The printing ~luid circulation system i~ designed to
continuously collect and di~tribute the printing 1uid
2 ~ 7 ~
~rom a reservoir through a plenum or ~eries o~ vxlfices
to uniorm1y r~distribute the printlng fluid ~cross the
pre s width to provide uniform composition of the
printing fluid that i~ being introduced to the metering
roller. The metering roller can be one of th~ types
shown ~nd de~crlbed in U.S. Patent Nu~ber~ 4,882,990,
4,537,127, 4,862,799, 4,567,827, or 4,601,242, ~all o~
which are hereby in~orporatea by reference) or any wear
re~istant oleophilic ~nd hydroph~b~ ~eterin~ roller s
sub~tantially therein defined.
Although the ~ystem disclosed in U.S. ~atent
4,690,055 provides great improvements in lithographic
print~ng presses, the technology requires a rather large
and cUmberBome ~n~ pan arrangement th~t iB more-or-less
open t~ the press room environment. It requires that the
pan be disposed beneath the metering roller/doctor blade
~onfluence 60 that scraped off ex~ess and return printing
~luid film will fall readily into the pan arrangeme~t.
Pan roller or metering roller replacement is inconvenient
and time consuming because of the large pan Bize and its
peripheral attachmentE. Additionally, the pan roll~r
requires a ~eparate motor to drive it nominally ~t a
speed slower than the press speed metering roller. Due
to the more-or-less open nature of the pan system, the
pan r~ller which dips into the pool of print~ng fluid
cannot be driven at press epeeds be~au~e pr~ntlng ~luid
2 ~ 7 7
would be propell~d from lt~ sur~ace ln many dlrectlons,
lncludlng outs~de of the pan reglon~ lnto th~ pre~room~
A1BO~ the 81~w ro~atlonal movement ~f the pan roller
~au~es undue and sever~ ~sar on the ~eterlng roller
~urface ~h~n th~ two ~re ln lndented rel~tlonsh~p~
Consequently, the pall roller/meterlng roller ~onfluence
mu~ e a gap. C!ontrol of that gap to avoid meter~ng
roll~r wear and yet ~lmultaneou~ly assure ~omplete
fllllng of the ~eterlng roller cells 1~ difficult to
englneer and to control over long period~ of runniny
tlm~. For instance, depending upon flow proper~esofthe
ink be~ng u~ed, the cells may or may not beoome
~ompletely filled when non-forclng ~ondlt~on~ such a~ ~
gap between the pan roller and the ~elled roller are u~ed
or when lnk lnput ~ystem~ not u~lng pan r~ller~ are
employed.
~ ependlng upon the parti~ular metering roller
technology belng employed, the ~low-mov~ng pan roller
runnlng ln ~ontact with the rap~dly turning meterlng
roller that 1~ rotating at press speed, may rapldly wear
away the h~rd but abradable oleophlli~ and hydrophob~c
metering roller ~urf~ce, thereby negatlng that element's
necessary contrlbutlon to succe~Eul keyle~ llthographlc
lnklng operation. Under ~everely worn cond~tlons, the
metering roller may become hydroph~l~o whloh all~ws the
2~ 27~
dampening water to lnterfere with uniform and ~f~icient
metering ~f ink into the sy~m or it may lose ~t~
capa~ity ~o retain ink by loss of the celled ~urf~ce
~orphology. Accordingly, there exists a need for a
lithographi~ keyle6s ink~ng or printing ~luid system that
e~braces all the required operational ~eatures d~sclosed
by U.S. Patent 4,690,Q55 but which overcomes the
perceived neg~t~ve features, namely large pan res~rvoir
size with the attendant large ink volume requirement
associated with use of the pan roller and reservoir, and
those associated with potentially rapid wear of metering
rollers or inefficient filling of metering roller cells
because o~ the gap with the pan roller. Obviously, these
may restrict the range o~ metering roller te~hnologies
which ~an be advantageously employed.
The present invention overcomes the af~rementiGned
problems, difficulties and in~onveniences, yet retalns
all o~ the prlnciples esæential to keyless lithographi~
6ystems as disclosed ~n U.S. Patent 4,690,055.
Accordingly, in this improvement thQ pan and pan roller
are eliminated and ~at least two transfer rollers ~re
~mployed between the metering roller and an ~n~lng drum
in the in~ing train of rollers.
2 ~
5UMMARy OF THE INVENTION
An ob~ ect of the present inventiorl i8 to pxov ~ de an
improved 3ceyle ~ lithograpllic printing ~ystem having more
transfer roller~ in the ink~ ng train than ar~ required
in prior art keyless l ~ thograph~c pr~nting ~ystems .
It 18 ~no'cher ob~ect to increase the u~e~ul li~et~e
of the ~etering roll~r by providing press ~peed inX
transfer roller6 in plaee of prior art slow moving pan
rollers.
It is a further object of the present invention to
provid~ a pair of transfer rollars operating on the
~etering roller for effecting printing having greater
uniformity of optical density than 1B achieved ~n pri~r
art keyless lithographic printing systems.
It ~s another object of the present inv~ntion to
provide an improved keyless lithographic printing system
which eliminates the pan roller of the inker disclosed
in U. .S. Patent 4,6909055, yet closely approximates the
advantageous attributes of this prior art pan roller
inker system.
It is another object of the pxesent invention to
provide simplified and 6tructurally ~maller ink input and
c~rculation $ystem components which function to assure
that the process-generated, natural water content of the
ink is maintained in a homogenized condit~on, thereby
avoiding buildup of free water anywhere in the inking
~ 2~92~7P~
system.
~ nother principle objec~ of the present invention
is to provide an improved keyless lithograph~c ~ystem
having greater latitude ln the sele~t~on of usePul
~etering roll2r technologie~.
The ob~ects are achieved by an improved keyless
printing ~ystem for use ~n a keyless lithographic
printing press of the type having a blanket cylinder and
a plate cylinder with printing plate mounted thereon.
The improved keyless printing system comprises: a means
for supplying dampening water to the plate cyllnder: at
least one form roller in rotat~onal ~ontact w~th the
plate cylinder: lnking drum in rotational contact with
the form roller: at least first and second ~ransfer
rollers in rotational contact with the inking drum:
etering rollex having at least an oleophilic 2nd
together with a coacting ink doctoring blade
hydrophobic surface which~retains a quantity of printing
fluid for transfer by means of rotational contact
with the first and second transfer rollers: and means for
supplying printing fluid to the metering roller. In a
preferred em~odi~ent the fir~t and ~econd tr~nsEer
rollers are ~rictionally driven by at least the metering
roller and have a 6urface velocity substantially the ~ame
as the 6urface velocity of t~e meter~ng roller.
,. :
7 ~
~IEF ~ESCRIPTION OF T~E~R~WINÇ5
The features of the present invention which are
believed to be novel, ~re ~et forth w~th parti~ularity
in the appended ~la~ms. The invention, together with
further ob~ects and advantages, ~ay best be understood
by reference tv the ~ollowing description taken in
~on~unction with the accompanying dxawings, ln the
several F~gures in which li~e reference numerals ~dentify
llke elements, and in which:
FIG. 1 is a schematic ~ide view of a keyless
lithographic printing press system in accordance with the
present invention:
~ IGS. 2 and 3 are plan and ~levat~on views,
respectively, of the printing fluid input apparatus of
the present inv~ntion and of ~ me~ering roller;
FIG. 4 i~ an end view of the printing fluid input
apparatus and th~ ~etering roller;
FIG. 5 is a partial plan view of the printing fluid
input apparatus;
FIG. 6 i6 an end view o~ the metering roller and
the printing flu~d input apparatus in an open servic$ng
po~ition:
FIGS. 7, 8 and 9 are a plan view, an elevation v~ew
and a side view of a gage assembly used in the present
invention:
2~27~
FIGS. 1~ and 11 ~r~ ~ pl~n vl~w ~nd ~n elev~tlon
~lew of ~ ~e~l oap ~semb1y ~ed ~s~ tlle present
lnventlon~
~ IGS. 12 ~nd 13 are schematic repreRentatlo~ of
pressurlzed pr~nting ~luld clrculat~on system~ used wlth
the present inventlon:
FIGS. 14-17 are ~hematl~ ~lde Ylew~ ~f embodlments
of the present lnventlo~ havlng 8 doct~r blade and return
in7c ~atch pan (FIG. 14), an ln~e~tor or extruder ink
inpu~ element (~IG. 15) t an gnk lnput shoe or ra11
Q~eme~t (~Ia. 16) and a doctor bl~de and return lnk catch
pan ~lth slngle form roller ~IG, 17)s
F~G. 18a i~ a s~hematic ~lde vlew of a prlor art
~y~em according to U.S. Patent 4,690,05~
~ 1~.. 18b illustrates an experimental configuration
similar to the previously clted ~055 patent but with the
pan roller moved just out of indented relation with the
meter~ng roller.
FIGS. 18c and lBd nre ~chema~l~ slde v~ews ~f
experlmental oonflrguratlons havlng added rlder rollers~
FIG. 18e ~ 8 a sohematlc s~de view o the preferred
e~bodlment of the pre3ent ~nvention havin~ two transfer
rol ler~ 7
FIG. 19 1~ a table o~ experi~en'cal ~esu1t~ of
prlntablllty ~o~nparlng the coniguratlon~ of F'It So 18a
through 18e and
FIG. 2~ 1~ 'carget plate format u~ed 1n te~tlrlg the
conlg~rat~on of ~IGS. 18~ through 18e.
14
2~d~27rl'
DESCRIPTION OF T~E~PREF~RRED ~MBODIMENT
A keyless inking ~ystem in¢orporating the present
invention is depicted in FIG. 1 in which a blanket
~ylinder 10 prints on a web traveling as indicated by ths
directional arrow 12. Referring first to the dampening
and inking ~ystems associated wlth blanket cylinder 10,
a plate cylinder 15 is contacted by two ink form rollers
16 which ~re in turn contacted by a ~etering roller 20
via drum 11, such as a copper d~um, and two trans~er
rollers 13. The ink ~etering roller 20 is preferably of
the type disclosed in U.S. Patent Numbers 4,862,79g,
4,882,990, 4,537,127, 4,567,827 or 4,601~242 which were
cited previously. In the dampening arrangement
associated with plate cylinder 15 there typically is
provided a rubb~r dampener form roller 19 and an
oscillating transfer roller 2~, which may be copper
covered or chrome covered. The water is contained in a
pan tray 23 and a pan roller 24 is used to pick up water
from the pan 23 to bring it into contact with, for
instance, a spiral brush roller 25 that is rotating at
a fipeed which is different relative to the speed of
rotation of pan rolier 24. It should be recognized that
virtually any known dampening system can be used with the
present invention.
With this or other arrangements dampening solution
is transferred onto the transfer roller 22 and from ther~
2~l~9~77
to t~e dampener form roller ~9. The ~orm roller 19 i5
typically position~d in a water-first sequence so that,
during each revolution o~ the press subsequent ~o
transferring ink to the blanket cylinder 10, plates ~re
~irst subjected to dampening solution from the dampener
form roller 19 before renewed printing fluid is applied
to the imaged Eurface of the plates by means of the
rubber covered ink ~orm roller6 16.
A significant part of the present invention is the
inking system that is used to supply printing fluid to
the plate and blanket cylinders 15, 10. This ~ystem9
makes it possible to supply a uniform mixture oP ink and
naturally occurring dampening ~olution to the plate
cylinder 15 and thereby maintain the high print quality
characteristic of conventional lithographyO In this ar-
rangement the printing fluid input and circulation system
is identified generally by the numeral 30 and is used to
deliver ink containing dampening solution, also rePerred
to as the printing fluid, to the metering roller 20.
Dampening solution in this system ~s not deliberately
added to the ink but rather result naturally ~rom ink
coming in cont~ct wi~h dampening solution on the printing
plate cylinder 15 and which, by means of the unused or
return portion oP printing fluid that passes or transfer~
ba~k down through the various rollers, in part eventually
enters the printing fluid input system 30.
2 ~ l~ 9 2 7 ~
The prir.ting fluid ~nput ~pparatu~ of the zystem 3~
of the pr~,e~t invention i8 depict~d in ~n open ~arvicing
position r~latlve to the metering roller 20 in FIGS. 2
and 3. An end view of the ~pparatus enyaged with the
~etering roller 2~ in ~ clo3ed operating position i~
depicted ~n FIG~ 4. The me~ering roller 20 ha~ ~irst
and ~econd ends 32 and 34 which rotate ln frame~ 36 and
38, respectively. The meterlng roller 20 hag a surface
40 intermediate the fir~t and second ends 32 and 34, the
surfa~e 40 capable of retalning a qu~ntity of printing
fluid. A housing 42 has an open rirst 6~de 46 which
mates with at lea~t a portion of the sur~ace 40 ~ the
metering roller 20. When the housing 42 is in the closed
operating position a ~hamber 44 is ~ormed which contains
the printing fluid under a predeterm~ned pressure.
At least first and second end ~eal assemblies 48 and
50 are mounted on first and second opposed ends 52 ~nd
54, respect~vely, of the housing 42. Each of the first
and second end seal assemblies 48 and 50 have at least
a first surface 56 for mating with first and second end
sections 58 and 60, respect~vely, of the metering roll~r
20.
Referring now also to FIGS. 4 ~nd 5 a reverRe angle
doctor blade 62 i~ attached to a 6econd side 64 of the
housing 42 and has an edge 66 for ~ontacting the surface
40 of the metering roller 20 and for removing exoess
2 ~ l~ 9 ~ 7 7
prlnting fluid adherir.g tD the surface 40 as the me ering
roller 20 rotate~ pas'. the printing fluid filled chamber
44. A ~ealing membex 68 is att~ched to a third ~ide 70
of the ~ousing 42 and has ~ Rurface srea 72 ~or
6ubstantially ~eallng tha chamb~r 44, at laast the
surface area 72 of the ~ealing member 68 being ad~acent
the sur~aoe ~0 of the metering roller 20 ~uch that ~n
edge 74 o~ the seal~ng memb~r 68 extends into the ~hamber
44. In a preferred embodiment the sealing member 68 is
~ubstantially longer and more flexible than the reverse
angle doctor blade 62.
Since the printing fluid in the ~hamber 44 is under
pressure it is a feature of the present invention that
the reverse anqle doctor blade 62 is held against the
surface 40 of the metering roller 20 at least in part by
this pressurized printing fluid in the chamber 44.
It is w~ll known in the art of printing presses to
provide devices which cause selected rollers or ~ylinders
to oscillate ~for example the roller oscillation drive
disclosed in Goss Metrol~ner Parts Catalog No. 280-PC,
Referring again to Figure 1,
Figure 280-56). ~ in ~the present invention such a means
~or oscillat~ng 76 can be attached to the metering roller
20, thus providing oscillat~on to the metering roller
20, while the housing 42 of the printing fluid input
apparatus 30 remains stationary. Th~ metering roller 20
i~ o~ the type having ~n oleophilic and hydrnphobic
18
2 ~ 7
urface.
Depending upon the applic~cion it may or may not be
necess~ry to prov~ds o~cl.l.la~ion to the metering roller
20. However, it i8 ~ novel fsature of the present
~nvention that ~n those ~ppll~ation~ where ~t i~
desirable to provide oscillat~on to the ~etering roller
20 it ~ fea~ible to accomplish this with the printing
fluid input apparatus of the present invention.
The sealing member 68 may, for instance, be formed
o~ steel or plast~ and have a width in the range of
approximately 1 to 2 inches and a thickness in the range
of approximately 0.004 to o.OI inch selected as a
function of the open f~rst side dimension of the housi~g
42 and of the diameter of the meterlng roller 20 which
mates w~th the open first side, ~uch that the sPaling
member 6~ properly seals the chamber 44. The reverse
angle doctor blade 62 may be formed of steel or plasti~
and in general have a width of approximately 1 inch and
a thickness in the range of approximately 0.004 to 0.01
inch, if steel, and 0.04 to 0.06 inch, if plastic.
As 6hown ln FIG. 6 the housing 42 is attached to a
~upport 80 which ~ 5 pivotable about axis 82 and thus
provides an open servicing position and a closed
operating position. The housing 42, as well as metering
roller 20, are shown in the open ~ervicing position in
FIGS. 2 and 3, FIG. 2 being a plan view and FIG. 3 being
19
2 ~ ~
elevation view.
The print~ng fluid ~nput apparatu~ ~urther ~nclude~
at lea6t one inlet mean~ 102 in the housing 42 for
inputt~ng prin~ing 1uid into t~e chamber ~4 and at least
on~ outlet means ~04 ~n ~he hous~ng 42 for ou~putting
printing fluid from the chamber 44. Since the chamber
44 i sealed by the ~etering roller 20, the first and
~econd end assemblies 48 and S0, the reverse ~ngle doctor
blade ~2 and the sealing member 68, lt is thus possible
to keep the printing fluid under a predetermined
pressure. In the preferred embodiment, as will be
discussed below, a circulating ~ystem ~s used to pump the
printing fluid through the housing 42. It ~s an
important fe~ture o the present lnvention that, ~ince
the printing fluid is under pressure, the printing fluid
circulation system is totally independent of the force
of gravity as opposed to prior ~rt systems that rely on
the printing ~luid falling into a reservoir or catch pan.
Therefore, the hous~ng 42 c~n be located anywhere around
the circumference the metering roller 20. This has
significant and ~mportant advantages in the art of
keyless lithographic printing pres~ design. It allows
for pr~ntlng couples of a press to be inverted thereby
shorting the length of the paper path between the
couples, as well as, provid~ng ~avings in space ~nd
materials of construct~on. Th~s freedom to locate the
2V~77
housing 42 anywhere around th~ oircumference of the
metering roller 20 provides a degree oP Preedom in design
of the printing press not ound in prior art keyless
printing pres6es.
Furthermore, the hous~ng 42 ~an ~e desi~ned to
extend the ~ull axial length of the surfa~e 40 oP the
~etering roll~r 20 or to extend only over ~ portion of
the ~urfaoe 40. For ~xample, a num~er of hou~ings, each
less than full press w~dth, can he located on one
metering roller. Also, the houslng 42 can be ~tructured
to wrap around the circumference o the ~etering roller
20 to greater or lesser extents depending upon the
criteria ~f the pre~s being deslgn.
Referring now to FIGS. 10 and 11, each of the end
~eal assemblies 48 and 50 shown in FIGS. 2 and 3 has a
seal 90 which is supported by a seal ~ap 92. As can be
seen in FIG. 5 the 6eal cap 92 i6 att~ched to an ~nd of
the housing 42, more specifically a ~eal cap assembly is
attached to each end of the housing 42.
Furthermore, the present invention can include a
gage assembly 94, AS ~hown in FIGS. 7, 8 and 9, which
engages the hou~ing 42 with ~ loc~tlng pln 96 when the
housing 42 iB pivoted into the ~lo~ed operating po~ltion
for ~ccurate positioning of the housing 42 relative to
the metering roller 20, see ~IG. 6. The gage asse~blies
94 are located adjacent the fir~t and ~e~ond end sections
.9 2 ~ ~
32 ~nd 34 of the ~etering roller 20. The gage assembly
94 has first and second section 81, 83 which 6urround
the ends 32, 34 of the ~etering roller 20.
In general a means 100 ~or press~rizing with the
printing fluid the chamber 44 ln the housing 42 is
connected to the hou6ing 42 via the lnlet means 102 and
the outlet ~eans 104 on the housing 42.
As ~hown in FI~. 12, the means 100 for pressurizing
is a clrculatlny ~ystem havlng a pump 106 with an output
108 and an ~nput 110. The output 108 ~f the pump 106 is
connected to a pressure regulating check valve 111 and
to the inlet means 102 of the housing 42. The input 110
of the pump 106 is ~onnected to an printing fluid
reservoir 112 which is also ~onnected to the outlet ~eans
104 of the housing 42. As shown in ~IG. 12 the pressure
regulatlng check valve 111 ~s alæo connected to the
printing fluld reservoir 112. In the preferred
embod~ment the pump 106 is driven by a constant speed
drive motor 114 which is connected t~ press/unit controls
116 of the printing press. The press~unit controls 116
may also receive siqnals from a sensor 118 ~ounted in the
housing 42 for 6enYing the pressure of the printing fluid
in the chamber 44 of the housing 42. In one embodiment
a pressure of 4-6 psi ls maintained in the ~hamber 44 to
enable smooth c~nsistent printing ~luld input to metering
roller 20. The pressure regulating ~heck valve 111
22
, 2~ 2~
functions to set the pressure o~ 4-6 p~i in the chamber
44 and allows a portion of the printing fluid to flow
back lnto the printing fluld reservoir 112, as nece~sary.
FIG. 13 depic~ an alternatlve mean~ 100 for
pre~surizing the ~hamber 44 wherein the pump 10~ i8
driven by a ~otor 120 which is operated ~t a speed
proport~onal to the Ppeed of the printing press via
varia~le ~peed drive 122. In thi~ embodiment the output
108 of the pump 106 is connected to the inlet means 102
of the housing 42 and the outlet means 104 of the housing
42 is oonnected to the printing fluid reservolr 112. The
input 106 of the pump is al o connected to the printing
fluid reservoir 112. Various means can be used to add
fresh replacement ink to the printing fluid reservoir 112
in either the FIGo 12 or FIG. 13 embodiments as needed.
For example, the means can include solenoid valve 124
which is connected to a press/unit controller 126, the
press/unit controller 126 receiving a signal from a
printing fluid level sensor 128 connected to the prlnt~ng
fluid reservo~r 112. It 16 a novel feature o~ the
present lnvention that the printing fluid reserv~$r 112
can be locatsd at any position relative to the ~hamber
44, higher or lower than the ~hamber 44, ~ince the
printing fluid flow i5 regulated by internal pres~ure
rather than by the ~orce of gravity.
2al~s~7;~
In addition the present invention can include a
means for ~ontrolling the temperature o~ the printlng
fluid in the cha~ber 44 of the housing 42 For exa~ple,
the ~eans for controlling the temperature can be
connected directly to the housing 42 or can be connacted
to the printing fluid reserYoir 112. The ~eans for
controlling the temperature can utilize resi~tance
element strip h~ater~ affixed to the huusing 42 (for
example, a Chromalox No. SL0515 flexible resistive
element heater). For the printing ~luid reservoir 112
an immersion heater such as ChromalGx No~ A~MT0-2155T2
can be used.
The present invention overcomes a number of
prob}ems, difficulties and restrictions in prior art
keyless lithographic printing systems. For instance, the
pan and pan roller of the cited prior art (U. S. Patent
No. 4,690,055) are replaced by a ~maller and less
complicated housing that together with the metering
roller surface form a completely enclosed housing.
The inks selected for use in the present invention
preferably have low values of vi~cosity ~t low rates of
shear ~o that the printing fluid flows readily ~s
compared to conventional lithographic inks. An ink
having this property readily flows into and, subsequent
to doctor blade metering as herein practiced, out of the
cell~ or interslices in the surface of the rapidly
24
2a~2'~
rotating metering roller 20 as it ~oves past the
pxessurized slowly circulating printing fluid in chamber
44.
An important ~eature when us~ng a low viscosity
printing fluid with the present inYention is that the ink
can be gormulated to have good printing fluid transfer
properties in the inking train of roller6 and yet have
any of a wide range of vi~cosity v~lues at low ~hear
rates, the ~ormulation being dependent upon the
configuration of the various rolleræ and cylinders used
in a particular printing press. This capability is not
possible with prior art pan roller printing fluid input
systems as the amount of fluid input to the metering
roller is dependent upon ~he pan roller force and not on
the printing fluid'~ mobility. T~is capabllity is also
not possible without the use of oleophilic and
hydrophobic metering rollers since water is ~ore readily
forced out of low viscosity printing fluids and in the
absence of the hydrophobic property will debond the fluid
from the metering roller, thereby negating control of ink
input.
In FIGS. 14 through 16, the paper web 12, blanket
cylinder 10, plate cylinder 15, form rollers 16,
dampening syste~ 14 and oleophilic inking drum 11 ~re all
configured substantially parallel axially ~nd are more-
or-less standard elements in the practice of lithographic
2 ~ 7 7
printing. Normally, and as conventionally practiced,
only one transfer roller ~3 i~ required to convey the ink
~e~ered by the coacting ~etering roller 20 and blade 18
~o the oleophilic inking drum 11 thence by ~eans of foxm
rollers 16; pr~nting plate 15, and printing blanket 10
to the paper 12. The preRent invention provides and
requires, in addition ~o ~he ~ir~t transfer roller 13 a
second transfer roller. 17 for reason~ hereinafter
explained. FIGS. 14 through 16 represent alternative
embodiments of the present invention and are similarly
configured except that different ink or pr~nting fluid
input means 30 and locations of different dampening
systems 14 are dep~cted to illustrate the ver~atillty of
the present invention. Preferably, the capaciti~s of the
input and circulation means 30 are manufactured to be
less than about five gallons of ink or printing fluido
Other combinations of ink input systems and dampening
systems can be visuali7ed by tho~e skilled in the art
based on the teachings of this disclosure, with~ut
departing from its general intent.
As also shown in FIG. 14 an auxiliary transfer
xoller 213 can be utllized in rotational contact with the
inking drum 11. The auxiliary trans~er roller 213
transfers printing fluid to an auxiliary inking drum 211.
further auxiliary form roller 216 is in rota~ion~l
contact with the auxiliary inking drum 211 ~nd the plate
~.92~J7
cylinder 15. Other variations of auxiliary rollers,
drums and cylinder~ are p~ssible for use with the present
invention.
During pract~ce oP the keyless inking technology
disclosed in U.S. Pat~nt ~,690,0~5, it became apparent
that should the need arise to ln~tall page-wide instead
o~ press-wlde keyless inking ~ytems, this ~epar~tely-
driven pan roller prior art would be particularly
difficult to engineer. The central pages of a four wide
newspaper press would re~uire mounting and coupling the
central two pan rollers to a separate drive ~ystem ~ithin
the restrict~on of about only 3/4" margin between ~ide-
by-side page locations of a typical newspaper web.
In pra~ticing the teachings of U.S. Patent 4,690,055
with newspaper presses four pages wide, one is compelled
to manufacture a heavy, relatively large-diametered pan
roller to avoid deflection or deformation in the
unsupported central region. Doing so requires, in turn,
a large size ink pan and reservoir assembly, which
together with ~ssorted pumps and hoses occupies
considerable space just under the printing ¢ouple.
Further, a minimum practical ink fluid level in the pan
reservoir results in a relatively large working lnX
volume of 5 to 10 gal. This is an inconveniently large
volume of ink to handle whenever an ink change is
required~
'
2 ~ ~92 '~7
It was also determ~ned, in practicing the ~echnology
of U.S. Patent 4,69~,055, that normal amounts of pan
roller to metering roller contact pressure, corresp~nding
to, for instance rom 1/8" to 3/16" flat portion at the
nip formed by ~he two rollers, can result in
foreshor~ened ~eterin~ roller l~fet~mes due to premature
wear of the metering roller surface coating6. Depending
upon the severity of the general print~ng conditions, the
metering roller technologies of UuS. Patent Numbers
4,537,127; 4,567,827, and 4,601,242 may ~eter ink
effectively for only 5 to 20 million printed copies
instead of the expscted 40 million copies or more, based
upon doctor blade wear testing in the absence of a low-
moving pan roller in contact with the ~etering roller.
These and other reasons motivated the present
invention leading to the present improved keyless inking
system, which ~ystem retains all o~ the functional
features necessary to practice trouble free lithographic
keyless inking previously taught by U.S. Patent
4,690,055.
FIG. 18a represents ~n general the prior art roller
configuxation technology o~ U.S. Patent 4,690,055. FIG.
18b is ~imilar but with pan roller 21 placed out o~
contact with the metering roller 20. FIGS. 18c, 18d and
18e represent similar keyless press roller configurations
without a pan roller but with an added rider roller 29
28
2~L~9277
in contact with meterin~ xoller 20. FIG. 18e,
however, represents a press #ystem having a second
transfer roller 17 according to the present invention.
All elements 10, 12, 15, 16 and 11 remained identical in
the FIGS. 18a-18e configurations while these systems were
evaluated for runnability and printability~ All o~ them
conveyed ink reasonably well to the paper substrate being
printed. However~ ~onfigurations uslng only one transfer
roller 13 and no pan roller 21, namely the configurations
of FIGS. 18c and 18d, resulted in measurably inferior
uniformity of cross-press optical density values when
running a critical format such as that shown in FIG. 20.
This similarly-poor result was obtained using the
configuration of FIG. 18b corresponding to the technology
disclosed in U.~. Patent 4,690,055 excepting with a
purposeful gap between the pan roller 21 and the metering
roller 20. U.S. Patent 4j690,055 teaches that
interference between the pan and metering rollers is
preferred. The above disclosed result seems to verify
this teaching. The instant result also verifies that a
frictionally-driven press-speed rider roller 29 in place
of the pr~or ~rt slow-speed pan roller, when riding
ayainst the metering roller, Figures 18c and 18d, does
not emulate the prior art performance quality. Certain
of these results are included for re~erence in the Table
depicted in FIG. 19.
29
,
~. , ,, . '
,~
;
2 ~ 7 ~
When a frictionally driven roller 17 as in FIG. 18e
was ~nstalled in contact with both the main inking drum
11 and the metering roller 20 and whe~l using the 6ame
non-uniform format of ~IG. 20, the printing ~ystem
closely approxi~ated the advantageous attributes of the
prior art pan roller inker ~s tauyht by U.S. Patent
4,690,055. Tha corresponding r~sults ~re also listed in
the Table of FIG. 19.
The frictionally driven, press speed, second
transfer roller of the present ~nvention avoids~ the
necessi~y ~or pressure indented contact of thè metering
roller with any inking roller operating at significantly
different surface speed than the metering roller ~tself.
We h~ve found the useful lifeti~es of the previously-
disclosed, advantageous, hard, oleophilic, hydrophobic
ink metering rollers may thereby be increased two-~old
to ten-fold over that when the 6eparately-driven pan
roller technology of U.S. Patent 4,690,055 ~s employed.
Reasons for the advantageous, more uniform optical
density effec~ are not clearly known. Cerkainly, i~ the
additional differently-diametered roller 17 merely
functioned to exchange and rearrange the ink in the cells
of the ink metering roller 20, it ~hould be expacted that
the FIG. 18c and 18d variations would function similarly
to the FIG. 18e configuration. The Table of FIG. 19
verifies this is not the case and the dual-contact, two-
- ~ .... ,;; ,.~.. .. . . .
2~9~7~
transfer roller configuration depicted in FIG. .~8e is
clearly superior.
Indep@ndent of the exact technical reasons, the
present invention hows that a ~low-moving ~nk-input pan-
roller r;ding agains~ the press~peed celled metering
roller of the prior ar~ i~ not ~he only conf~uration
that provides the process functions necessary to assure
minimum format dependence of optical density when
printing with a keyless lithographic printing press. The
slow-moving pan roller can be replaced by a second,
press-speed transer roller as herein disclo~ed and
thereby obtain fully equivalant printed guality, while
providing the new advantages of less circulating volume
of printiny fluid, smaller overall inker dimensions, less
wear of the ~elled metering roller during printing
operations and the opportunity to use any of several
printing fluid input devices.
The invention is not limited to the particular
details of the apparatus depicted and other modificat~ons
and applications are contemplated. Certain other changes
may be made in the above described apparatus without
departing from the true ~pirit and ~cope of the invention
herein involved. It i8 lntended, therefore, that the
subject matter in the above depiction chall be
interpreted as illustrative and not in a limiting sen~e.
31
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