Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Ink Transfer Arrangement
Background of the Invention
In the prior art, ink has been transferred from the fountain to the
image plate by transferring ink from one roller to another along a roller
train. Inltially the ink is passed from the fountain to a fountain roller
and the thickness of the ink applied to the fountain roller ls determined
by the gap between a single fountain blade, or a segmented fountain blade,
and the fountain roller. As is well understood in the prior art, there is
a plurallty of keys, or screws, located on the underside of ~he fountain
blade. The keys come in contact with the fountain blade at different
height settings thereby providing different gap thicknesses between the
fountain blade and the fountain roller, along the length of the fountain
blade. The different gap thicknesses, of course, provide for different
amounts of ink to be applied to the fountain roller, along the length of
the fountain roller. The different amounts of ink being applled to the
fountain roller accommodate the different dlmenslons of the areas to be
inked on the image plate. In the prior art, a ductor roller is employed to
initially lift ink from the relatively slow speed fountain roller.
Thereafter, the ductor roller i9 physically moved to transfer the ink, that
it has received from the fountain roller, onto a high speed receiver
roller, in batches. As the ink is transferred from the receiver roller and
thereafter from one roller to another in the roller train, the batches are
smoothed out un~il finally ink is transferred to a form roller which
functions to apply the ink to the image plate. -~
The above described method of transferring ink from the reservoir ~o
the image plate has several disadvantages. Continuous blades, as opposed
to segmented blades, are difficult to ad~ust because the more flexible the
blade the more localized is the effect of the key and the more likely that
the hydrodynamic pressure of the ink in the gap will push the blade away
from the fountain roller in the areas between the keyR. While rigid blades
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reduce the bowing of the fountain blade between keys, such ri8id blades
make it difficult to obtain an ink feed profile that enables wldely diverse
ink feeds to correspond to the need~ of the plate image distribution.
Segmented blades have been developed to counter the problems related to
continuous blades as set forth above. However segmented blades have their
own problems which result because ink and solvents get between the segments
and cause mechanical malfunctions. In some prior art systems, which use
segmented blades, a plastic shield has been located be~ween the segmented
mechanism and the fountain roller but such a shield has incurred wear
problems causing the gap to change with time and use.
All of the foregoing prior art systems suffer from a serious problem
related to effecting a precision setting of the ink gap particularly when
the system requires low setting3. For instance, assume that the image
plate is comprised of a large area on one side of the plate to be inked,
while the other side has a small postage stamp sized area to be inked. The
dwell, or the sweep, of the ductor roller on the ink fountain roller must
be adequate to allow a practical opening (perhaps an openlng of .015
inches) of the keys which lie opposite the large area to be inked. On the
light coverage side the ink gap would likely be held down to perhaps .001
inches or less. It may be that the run-out of the fountain roller may be
.001 inches and there would be bowing of the roller and fountain blade from
the hydrodynamic pressure of the ink. The hydrodynamic pressure, in turn,
will vary with the ~peed of the press. It can be readily seen from the
foregoing conditions ~hat problems do re~ult if the user does attempt to
preset the fountain blade gap to accommodate different demands for ink on
the image plate. Another set of problems results, in the prior art
systems, from the inability to se~ a zone to a zero feed. When no feed is
required, i.e.~ at the non-printing areas of the plate, the key closure can
wear and bow the tountain roller ~hereby affectlng other key settings.
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Still another problem, that is inherent in the prior art arrangement,
is the problem of the varying momentum of the ductor roller. The ductor
roller in the prior art alternately runs in contact with the high surface
speed of the receiver roller and then run~ in contact with the relatively
slow speed of ~he fountain roller. When the ductor roller leaves ~he
receiver roller it is spinning at a very high speed and a~ it comes in
contact with the fountain roller it skids due to the deceleration it
experiences in adapting to the ~low speed of the fountain roller. Such
skidding results in an initial non-predictable transfer of ink. The
transfer of ink is different during the early contact between the fountain
roller and the ductor roller from that which takes place when the two
rollers, i.e., the fountain roller and the ductor roller, are rolling
together at the same speed. In the present system, the fountain gap is
maintained at a relatively fixed width and thereby many of the above
mentioned problems are eliminated.
Summary of the Invention
The present device is used in a printing press and employs a plurality
of doctor blades, each of which is mounted on a support and is designed to
be partially rotatable around such support. Each of the doctor blades is
connected to a source of motion, such as a solenoid, so thae it can be
partially rotated, clockwise and counterclockwise, into one of two
positions. The f~rst of the positions is in close proximity to the
fountain roller of the printing press, while the second position i~ in
close proximity to the receiver roller. When a doctor blade is close to
the fountain roller, it scrapes ink from the fountain roller and the amount
of ink ~hat it scrapes depends on how long a doctor blade is held against
the fountain roller. Since each doc~or blade is individually movable into
the first position, the amount of ink lifted, or scrapedt can vary from
doctor blade to doctor blade. When the assoclated solenoids are
deenergized, each doctor blade returns (the blades are spring loaded in a
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preferrecl embocliment) tG the second position ~hlch is a wiping
position. In the ~li.piny position, ink is wiped ~rom the doctor
blades by a ~eceiver roller and is carried therefrom, through a
roller trai.n, to the ima~e plate ~or inking the image plate. The
initial transfer of the ink from ~he reservoir to the fountain
roller provides the basis for the quantity of ink applied to the
image plate, in the prior art. In the present system the gap
bet~leen the fountain roller and the fountain blade is held
constant and the ink transfer, -that provides the basis for the
quantity of ink that is applied to the image plate, is effected
by the amount of time the doctor blades are held in the first
posi-tion, i.e., -the scrapin~ position.
In accordance with the present invention there is
provided in a printing press arrangement which has a means to
provide a layer of ink which receives ink from an ink source and
receiver roller means which delivers ink throucJh a roller train
to an image plate, a system to tranfer ink from said means to
provide a layer of ink to said receiver roller means, comprising
in combination:
doctor blade means formed to be movable in both first and second
direction, said doctor blade means disposed with respect to said
means to provide a layer of ink and said receiver roller means so
that when said doctor blade is moved in said first direction it
comes in sufficiently close proximity to said means to provide a
layer of ink to lift ink therefrom and so that when said doctor
blade means is moved in said second direction it comes in
sufficiently close proximity to said receiver roller means to
have at least part of the ink, which was scraped by said doctor
blade means, removed therefrom by said receiver roller means;
3~ means to move said doctor blade means in said first direction and
in said second direction, said means to move said doctor blade
formed to selectively move said doctor blade in said ~irst
direction for different time periods whereby when said means to
move said doctor blade means has selectively moved sai.cl doctor
blade means in said first direction for different time periods,
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and subsequently in said second direction, different amounts of
ink are transferred from said means to provide a layer of ink to
said receiver roller means which different amounts of ink are
commensurate with said different time periods.
In accordance with the present inven~ion there is also
provided in a printing press arrangement wherein the image plate
is divided into printing zones, a system to transfer ink from the
exit means of a reservoir of ink to an image plate, comprising in
combination: fountain roller means, having a length dimension and
located at said exit means of said reservoir of ink; fountain
plate means formed to be substantially as long as said fountain
roller means and located below said fountain roller means ~o form
a substantially fixed gap therebetween to permit ink to leave
said reservoir at an established thickness with said ink clinging
to said fountain roller means; a plurality of doctor blade means
aligned along the length of said fountain roller means; a
plurality of moving means with each respectively connected to an
associated different one of said doctor blade means whereby each
of said doctor blade means can be independently moved into a
first position for a different period of time, which first
position is in close proximity ~o said fountain roller means
whereby ink, which is clinging to said fountain roller means, is
scraped therefrom by each doctor blade in a volume which is
commensurate with the time period that said doctor blade .is held
in said first position and whereby each of said doctor blade
means is independently moved by its associated moving means into
~ a second position and whereby different amounts of ink can be
: ~ transferred uniformly in a given time period within a printing
zone; receiver roller means having a length dimension which is
substantially equal to the length of said fountain roller means,
said receiver roller means located in close proximity to said
plurality of doctor blade means whereby when each of said doctor
blade means i5 in said second position, ink which was scraped
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from said fountain roller means by said doctor blade means is
substantially wiped from said doctor blade means by said receiver
roller means; and roller train means disposed to rotationally
move in close proximity to said receiviny roller means and to
said image plate to receive ink from said receiving roller means
to be transferred ~,o an image plate.
The objects and features of the present invention will
be better understood in view of the following description taken
in cGnjunction with the drawings wherein:
Eiyure 1 is a schematic layout of the present device
operatiny in conjunction with the fountain roller and roller
train of a printing press;
Fiyure 2 is the front view of a doctor blade mounted on
a support device and coupled to an ac-tuator;
Figure 3 is a side view of Figure 2;
Figure 4 depicts three positions of the doctor blade
transferring ink; and
Figure 5 depicts an array of doctor blades as they are
aligned with the fountain roller and without the distribution
roller.
Consi~er Figure 1. In Figure 1 there is shown an ink
reservoir 11 and a fountain ~lade 13 located with the reservoir.
The fountain blade is located in close proximity to the fountain
roller 15 so that there is a gap 21 between the fountain blade 13
and the surface of the fountain roller 15. The gap 21 permits
lnk to be metered from the reservoir 11 onto the surface of the
fountain roller 15. The metered ink 16 can be seen clinging to
the fountain roller 15.
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Further a~ can be gleaned from Figure 1 the fountain bl~de 13 i9 held
either closer or farther away, from the fountain roller, depending upon the
position of the key 17. The key 17 is a threaded member which is threaded
into the key holder 19. As can be determined from an examlnation of Figure
1, when the key 17 i9 rotated upward the fountain blade 13 comes closer to
the fountaln roller 15 and hence less ink is metered out to the fountain
roller. On the other hand when the key 17 is moved downward then the gap
becomes larger and a larger amount of ink is offered to the fountain rollar
15. The key 17 is locked into position by the nut 18. It should be
understood that in a preferred embodiment the fountain blade is a fixed
blade and need not be varied by keys. In a preferred cmbodiment the gap 21
is held constant at approximately .Ol inches although other gap widths
could be used. There is no need, in the present system, to vary keys
because, as will be understood from this description, while the
determination of the amount of ink transferred is to some degree dependent
upon the width of the gap, it is controlled principally by the time tha~
the doctor blades are in the scraping po~itions.
As the ink 16, clinging to the fountain roller 15, is moved upward it
comes in contact, (as shown in Figure 1), with the doctor blade 25. As can
be seen in Figure 1, there is a build up of ink 27 on the doctor blade 25
as the ink 16 is scraped away from the fountain roller 15. The position of
the doctor blade 25 (in solid lines~ i~ the first position, or the scraping
position, while the doctor blade and the doctor blade holder are depicted
by the dashed line in the second position, or the w$pe off posltion of the
doctor blade. When the system is directed to remove ink from the fountain
roller 15 and transfer it to the receiver roller 29 (so that uleimately it
i transferred to the distribution roller 23) there is a signal genera~ed
at~the microproce~or 31. It should be noted, as dep~ceed by the dashed
line in Figure 1, that there is a number of rollers between the
dlstribution roller 23 and tbe form roller 24. The signal from the
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microprocessor 31 is transmitted to the driver 33 whereat its electrical
current value is amplified and hence the actuator or solenoid 35 i5
activated. When the solenoid 35 is energized, it pulls the doctor blade
holder 26 in a clockwise direction. The doctor blade holder 26 rotates on
the bearing 28 and moves the doctor blade 25 ln close proximity and, in a
preferred embodiment, in contact with the fountain roller 15. As explained
above, when the doctor blade 25 is in the position shown in Figure l, it is
lifting ink, or scraping ink, away from the fountain roller 15.
It should be understood that the amount of ink 27, which i9 lifted
onto the doctor blade, is directly proportional to the amount of time that
the doctor blade 25 is in the fir~t position (i.e., the position shown in
Figure l). The microprocessor 31 of course makes that time determination
through a program and provides a continuing signal for ~hat time which
signal is amplified to energize the solenoid 35. When the program in the
microprocessor has caused the solenoid to be energized for a sufficiently
long time, (30 that enough ink has been lifted), then the signal therefrom,
through the driver 33 to energize the solenoid 35, is terminated. When the
solenoid 35 is deenergized, the doctor blade holder is pulled to the left
by the spring 30 and hence the doctor blade 25 is moved to the right and is
located in the pocition shown by the dashed doctor blade 25a. When the
recsiver roller 29, which is moving counterclockwise, is ro~ated, i~ wipes
the ink build up 27 from the doctor blade 25a. As explained above, the ink
is loaded onto the receiver roller 29 in mounds. The receiver roller 29
transports the ink and comes in contact with the intermediate roller 32 and
34 which in turn transfer the ink to the distribution roller 23. The ink
is transferred from the distribution roller 23 to a train of rollers,
signified by the dashed line, which train ends in a form roller 24. The
microprocessor of a preferred embodiment is a model 2~0 manufactured by
Zilog Company and the driver can be any well known clrcuit which converts a
logic level signal to a higher voltage and current to meet the deslgn
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requirements of the solenoid used. Other microprocessors could be used and
the driver design depends on the solenoid employed.
It should be recognized that if the doctor blade 25 returns repeatedly
to lift ink from the fountain roller then the amount of ink applied to the
receiver roller would be subs~antial. Accordingly not only is the time
that the doctor blade is in contact with the ink on the fountain roller one
of parameters (that is employed by the microprocessor), but the repetition
rate of transferral of the doctor blade 25 between its 25a positlon and its
25 positlon i~ also a highly desirable factor ehat the microprocessor
employs. It can be noted in Figure 1 that the doctor blade 25 and the
doctor blade holder 26 are deplcted as belng operated by the solenoid 35
and the spring 30 by way of illustration. In the preferred embodiment the
doctor blade is arranged with its holder as shown in Figure 2.
In Figure 2 the doctor blade 25 is shown with the surface that comes
in contact wlth the fountain roller facing out from the dra~ing. Behind
the doctor blade is a stiffenin8 means 37 which can be seen in both Figure
2 and Flgure 3. The stiffening mean~l 37 i~ secured to the doctor blade by
two bolts 38 and 40 and located by pin 39. I have found that if the
stiffen-lng means 37 is not employed as shown, the doctor blade 25 (which is
necessarily quite flexible) will often cling to the ink 16 as the spring
returns the doctor blade 25 to the receiver roller 29. This delayed motion
results in an unsatisfactory transfer of ink and the delay is eliminated by
using the stiffening means 37.
The bolts 38 and 40 are threaded into an inverted "L" shaped holder 55
as can be seen from the po~ition of bolt 38 in Figure 3. The upper section
of the holder 55 has two apertures 43 and 45 formed therein. Each of the
apertures 43 and 45 is threaded to hold an internal nut, such as an Allen
nut. The nut in threaded aperture 43 secures the holder 55 to the rod 48
while the nut in aperture 45 secures the holder 55 to ~he rod 47. The rod
47 i~ held in ~he bearing 49 while the rod 48 i~ held in the bearing 51.
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The lever 53, which can be better seen in Figure 3, is secured to the
holder 55 and is designed to fit over the pin 57. The pin 57 is held by
the block 59. Secured to the block 59 i5 an internally threaded member 61
into which the rod 63 i8 threaded. As can be seen in Figure~ 2 and 3, the
rod 63 has a lower section 63a which is threaded and it i~ that portion of
the rod which i9 threaded into the threaded member 61. Tha threaded
section 63a i8 locked to the member 61 by the nut 62.
A~ can be further seen in Figures 2 and 3, there i9 secured to the rod
63 a washer-llke member, or flange, 65. The flange 65 serve3 a~ a travel
~top for the rod 63. The rod 63 pas~es through the core of ~he solenoid
67. When the solenold 67 is energized the rod 63 moves upward untll the
flange 65 comes in contact with the housing of the solenoid 67. The
movement upward by the rod 63 pulls the block 59 upward which in turn
partially rotates the lever 53. When the lever 53 moves clockwise the
block 55 moves clockwlse, thereby moving the doctor blade 25 clockwise to
the position shown at 25b in Figure 3. As long as the solenoid 67 is
energized, the doctor blade 25 will be held in the 25b position and will be
lifting ink from the fountain roller as explained above. The spring 69 ls
seated in a ring which surrounds and is fixed to the rod 63. When the
solenoid 67 is deeDergized, the spr$ng 69, will partially uncoil to push
the rod 63 downward to its home position. When the rod 63 moves downward
it pushes the block 59 downward. The downward movement of the block 59
causes the lever 53 to move counterclockwise thus causing the doctor blade
25 to move counterclockwise. The doctor blade 25 will return to the 25c
position which i~ the wipe-off position described earlier. When the doctor
blade is in the 25c position the receiver roller`wipes the ink from the
doctor blade 25 and that ink is transported through the roller train to the
form roller 24 of Figure 1.
Figure 4 depicts the actual transfer of the ink from the fountain
roller 15 to the receiver roller 29. Throughout the descriptlon I have
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referred to a fountain roller and a fountain as the qource of the layer of
ink but it should be understood that some other apparatus could well
provide a layer of ink and be within the spirit of the presen~ invention.
In Figure 4 the doctor blade 25 is in three positions 25d, 25e and 25f.
When the doctor blade 25 is ln position 25d, it is scraping the layer of
ink 16 from the fountain roller 15. Note the mound of ink 27d which is
bein8 lifted fro~ the layer of ink 16. The mound of ink 27d i9 shown in
the transfer state, as 27b, riding on the doctor blade in the 25e position.
Figure 4 further shows the doctor blade in the 25f position with the mound
of ink 27c ~oining the layer 20. Because there i$ a difference in the
speed of the roller 29 (which is at some positive value) and the at rest
value of the ink at the surface of the doctor blade, the ink will form the
mound 27c, even though the doctor blade i9 attempting to pu3h the mound of
ink into the layer. The mound of ink 27 eventually gets smoothed out in
the roller train.
Figure 5 depicts a plurality of doctor blades 73, 74, 75, 76, 77, 78,
79, 80, 81 and 82. In Figure 5 the distribution roller is not shown but it
should be understood that the blades with the lesser amounts of ink thereon
have left the fountain roller and are in the position where they would
normally be wiped by the distribution roller. The dashed lines between
doctor blades 77 and 78 is to indicate that there are many doctor blade~
therebetween. In a preferred embodiment each doctor blade would be about 1
1/2 inches wide and there would be as many doctor blades employed as would
be nece$sary to accommodate the width of the press. Each of the doctor
blades 73 through 82 is connected to an activating mechanism shown by the
blocks 83 through 92. It i~ to be understood that the activating
mechanisms 83 through 92 are of the kind depicted in Figures 2 and 3 and
described above. It should also be understood that the movement of the
doctor blades, in a preferred _ odi=ent, is synchronized ~ith the :peed of
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the printing press although other speeds could be provided by the
microprocessor if it were deemed advisable.
As can be further seen in Figure 5, the doctor blades 73 through 82
are lined up with the fountaln roller 15. Between the fountain blade 13
and the fountain roller 15 there is a gap 94 whose upper limit is shown by
the dashed line 93. The dashed line 93 is the lower edge of the fountain
roller 15. The ink is shown, in Figure 5, as leaving ehe reservoir through
the gap 94 and clinging to the fountain roller 15. The ink (e.g., mounds
of ink 95 and 97) i9 further shown as being scraped off on the doctor
blades. It should be understood that (in a preferred embodiment) all of
the doctor blade~ are transferred to the fountain roller at the same time
but they are, or can be, transferred therefrom at different times. In
Figure 5, for instance, there is shown a mound of ink 95 on the doctor
blade 75. Note that the mound of ink 95 is greater than the mound of ink
97 on doctor blade 81. In accordance with operations described earlier it
i8 evident that the doctor blade 75 has been held in its scraping position
for a longer period of time than the doctor blade 81. The present device,
as can be further seen in Figure 5, enables the doctor blades to lift and
meter out different amounts of ink to the roller train to accommodate
different demands for ink at the image plate. It should be understood that
these different amount of inks are very accurately metered out becauYe
there are not variations in key settings involved. The gap 94 is held
constant and the variatlon of the ink metered out is effected ~y varying
ehe times that the doctor blades are held in the scraping position.
One of the major advantages of the present system is the capability of
the present systPm to skip ink transfers. In the prior art, the ductor
roller i8 fixed (to transfer on each given occasion) by a gear train
arrangement. The fixed transfer leads to particular difficulty when
portion~ of the image plate require very little ink. When very little ink
is required, in the prior art, the gap between the fountain roller and the
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fountain blade is adjusted by the keys to be relatively small. However,
the gap must be large enough to provide ink to the fountain roller. As
mentioned earlier, these small settings give rise to problems and make a
basls for a difficult compromlse. Be that as it may, when a prior art
system is operatlng, the ductor roller transfers ink at a regular pace and
if le~s ink than is necess~ry is being supplied there is no simple way, in
the prior art, to remedy the situation. With the present system, if very
little ink is required, the doctor blade can be transferred for a
relatively long period (or alternatively for a short period) and thereafter
one, or two, or any number of ink transfers can be skipped until there is a
need for more ink to be transferred.
The many problems that are present in ink transfer systems in the
prior art which result from: setting key height to different values;
having segmented fountain blades; havlng rigid blades; hydrodynamic
pressure of the ink in the gap; bowing of the fountain roller, etc., as set
out earlier under the "Background" section of this description are
eliminated by using the present system.
