BACKGROUND OF THE INVENTION
Field of the Invention
[0001] This invention pertains generally to a method and apparatus for metering fluid from
a fluid fountain from which fluid is delivered onto an associated roll as a film having
a controlled thickness profile, and more particularly to a system for adjusting individual
metering keys to regulate the thickness of the fluid film at individual zones across
the roll to maintain a desired fluid profile.
Description of the Prior Art
[0002] To produce high quality printed matter, it is essential that ink be consistently
delivered in a carefully controlled manner for deposition upon the paper or other
stock in the printing operation. A number of factors involved in the printing process
directly influence the application of the ink to the paper and thus the resulting
appearance of the finished product. For example, the composition, texture and finish
of the paper stock or other material to be printed, the color, composition and consistency
of the ink, the type of ink roll being used, and the nature of the printed image itself
are among the factors involved. For any particular set of operating conditions there
is, however, an optimum profile of ink film thickness across the ink roll which is
preferably created and maintained as the printing operation proceeds.
[0003] To control the thickness of the layer or film of ink on the ink roll and create areas
of differing thicknesses as desired along the length of the roll, printing presses
are conventionally provided with an ink fountain having a flexible blade in close
proximity to the ink roll. As disclosed in U.S. Patent No. 4,008,664, the spacing
of the flexible blade from the ink roll is adjustable at a plurality of lateral locations
along the roll to thereby control the amount of ink flowing from the fountain onto
the rotating ink roll through the gap therebetween in corresponding zones spaced along
the roll. A plurality of rotary adjusting devices, or keys, are provided along the
fountain, with means bearing against the blade at the various locations to maintain
and adjust the position of the blade relative to the roll in response to rotation
of the individual keys, and thereby to control the thickness profile of the ink layer.
[0004] The keys may be operated manually by turning a knurled head in response to a perceived
visual need to vary the thickness of the ink layer in a particular area. Likewise,
as disclosed in the aforementioned Patent No. 4,008,644, each key might be provided
with a bidirectional motor operated manually from a remote location or, for example,
operated in response to signals from a sensor scanning the plate for ink coverage
or from a color sensor scanning the printed material. Other systems for adjusting
the keys have included a travelling carriage with a relatively complex arrangement
of clutches and gears for meshing with gear teeth on the keys and thereby selectively
rotating the keys a slight amount upon passing in one or the other direction.
SUMMARY OF THE INVENTION
[0005] In accordance with the present invention, there is provided a fluid metering system
for adjusting the profile of fluid transferred from a fluid fountain to an associated
roll. The system is particularly useful in printing presses for adjusting the individual
keys of a printing press ink fountain from which ink is delivered to an ink roll.
A carriage or positioning unit is mounted upon rails so as to traverse back and forth
in a path along the ink keys. A key drive system affixed to the carriage includes
a stepping motor whose output shaft drives an idler gear. Each key includes a friction
driving wheel, and the idler gear is positioned to driveably engage the friction wheel
of each key in succession as the carriage moves. The carriage or positioning unit
drive and the key drive system operate in response to appropriate signals as from
a conventional storage and processing unit so that when adjustment of a particular
key is called for, the carriage moves along the rails and into position for rotating
that particular key. While the carriage is moving, the key drive system rotates the
idler gear in the direction and at a speed synchronized with the carriage movement
whereby the idler gear will engage the friction wheels of and move past those keys
not requiring adjustment without causing rotation of the friction wheels. When the
carriage or positioning unit arrives at a key to be adjusted, and with the idler gear
in engagement with the friction wheel of that key, the key drive system is instructed
to rotate the idler gear such that the friction wheel will, in turn, be rotated in
either a positive or a negative direction to make the appropriate change in key position.
[0006] Another feature of the invention is means to sense the position of each key. Each
key has an associated transducer coupled thereto such as a magnetic Hall transducer.
A sensor is carried by the carriage. When a key is being adjusted, its associated
transducer generates a signal in the sensor carried by the carriage thereby giving
an indication of the position of the key.
[0007] It is therefore an object of the invention to provide an improved system for remotely
controlling the ink keys of a printing press and for sensing the position of the keys.
[0008] Another object of the invention is to provide such a device employing a single actuator
for the entire fountain of keys.
[0009] Another object is to enable the actuation and sensing of ink keys that are closely
spaced in a straight line.
[0010] Another object of the invention .is to provide an ink key control system for printing
presses which is cost-efficient in construction and maintenance.
[0011] Still another object is to provide such a system utilizing a friction drive to thereby
simplify the system and eliminate the need for intermeshing gears and clutches.
[0012] Yet another object is to provide an ink key control system in which operation of
a single key actuator is synchronized with its movement along and into engagement
with each key of a plurality of keys so as to adjust only those keys requiring adjustment.
[0013] Other objects and advantages will become more apparent upon a reading of the following
description of preferred embodiments of the invention made with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In the drawings, wherein like numerals are employed to designate like parts throughout
the same:
Fig. 1 is a plan view, with the fountain base pivoted to the horizontal position,
showing the positioning unit, key actuator and ink fountain keys of a printing press
employing one embodiment of the invention;
Fig. 2 is a plan view of the drive unit for the positioning unit or carriage;
Fig. 3 is an end elevation, partially in section, of the apparatus of Fig. 1 and including
the ink fountain and ink roll;
Fig. 4 is a fragmentary plan view taken substantially along line 4-4 of Fig. 3;
Fig. 5 is an end elevation, partially in section, illustrating another embodiment
of the invention;
Fig. 6 is a fragmentary view, partially in section, taken substantially along line
6-6 of Fig. 5; and
Fig. 7 is a fragmentary plan view of the embodiment of Fig. 5, with the fountain base
pivoted downwardly to a horizontal position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] Referring now to the drawings, there is shown generally at 10 in Fig. 1 a mechanism
for adjusting the keys which regulate the flow of ink from the fountain to the ink
roll of a conventional printing press, symbolically shown by the box 11. More particularly,
and as further shown in Fig. 3, the system includes a travelling carriage or positioning
unit 12 upon which is mounted a key actuating unit 13 for engaging and selectively
rotating the individual rotating keys of a console 14 of such keys as the carriage
is caused to traverse back and forth along the console in either direction as indicated
by the arrow 15.
[0016] As will be readily apparent in Fig. 3, the inking system of the printing press 11
within which the key adjusting mechanism is incorporated includes an ink fountain
16 and associated ink roll 17 extending laterally across the width of the press in
the.conventional manner. The ink fountain comprises a base 18 from which a flexible
blade 19 is suspended with its lower edge 20 in close proximity to the ink roll 17.
The flexible blade 19 and adjacent curved roll surface thus form a cavity within which
is maintained a reservoir 21 of ink. During operation of the press, the ink roll 17
rotates in the direction indicated by the arrow 22, and ink from the reservoir 21
flows through the space between the lower edge 20 of the blade 19 and the roll 17
to create a film of ink upon the surface of the roll whose thickness is determined
by the spacing of the blade edge from the roll surface at any point along its length.
Thus, as is well known, by precisely controlling the profile of the edge 20 of the
flexible blade, an ink film having a desired thickness profile can be maintained across
the roll.
[0017] To that end, ink flow regulators or keys 23 are positioned at locations spaced laterally
along the ink fountain 16. Each of the keys includes a barrel 24 threaded through
the base 18, with a tip 25 projecting beyond the base to engage and support the rear
of the flexible blade 19 adjacent the lower edge 20 thereof. Each section of the lower
edge 20 is biased against its associated tip 25. Thus, by rotating the threaded barrel
24 of a selected key, the tip 25 of the selected key may be advanced or retracted
as desired to thereby control the spacing between the edge 20 of the associated section
of the blade-and the adjacent surface of the roll 17.
[0018] While the keys may obviously be manually adjusted as required, present day printing
technology makes remote automatic adjustment of the keys highly desirable. In the
aforementioned U.S. Patent No. 4,008,644 it is suggested that each key might be provided
with a small bidirectional motor for this purpose. While such a system is entirely
satisfactory, there are certain advantages in being able to employ a single actuating
unit for adjusting all of the keys. Thus, in the present device, the barrel 24 of
each of the keys 23 extend rearwardly from the base 18 and has affixed thereto a friction
wheel 26 by means of which the key is rotated by the key actuating unit 13 as will
be hereinafter described. To permit manual adjustment of the keys at such times as
necessary, each barrel 24 may have at its outer end a knurled hand wheel 27.
[0019] The carriage or positioning unit 12 is supported upon a framework carried by the
press 11 and includes a spaced pair of parallel track members 28 extending between
supports 29 at either side of the press. A base plate 30 is mounted upon the track
members 28 by bearing blocks 31 such as ball bushings so as to be readily movable
back and forth along the track members. Controlled movement of the carriage back and
forth along the track may be provided by means of a perforated metal drive tape 32
affixed to the bearing blocks 31 as by studs 33. The drive tape is entrained around
the drive sprocket 34 at one end of the framework and an idler wheel 35 at the other
end. As will be apparent in Fig. 2, the drive sprocket is carried by the shaft of
a stepping motor unit 36. To insure that movement of the carriage will be precisely
timed by suitably controlling operation of the stepping motor drive unit, the drive
sprocket includes teeth 37 which are received in mating perforations 38 in the drive
tape 32.
[0020] The key actuating unit 12 is mounted upon the base plate 30 and includes a key positioning
stepping motor 39 whose output shaft carries a pinion drum 40 provided with a surface
41 of a durable friction material. Also journalled upon a shaft 42 affixed to the
base plate is a rotatable idler gear or wheel 43, likewise having a surface 44 of
a durable friction material. The frictional surface 41 of the pinion drum 40 engages
the frictional surface 44 of the idler gear 43, and consequently operation of the
stepping motor causes rotation of the idler gear in a direction opposite that of the
pinion drum.
[0021] As shown in Figs. 3 and 4, the keys 23 are closely spaced laterally across the ink
fountain so as to permit precise positioning of the flexible blade in narrow segments
across the ink roll 17. To achieve this relatively close spacing, it may be necessary
to offset or stagger the position of alternate ones of the friction wheels 26 upon
the barrels 24 of the keys. As will be apparent in Figs. 3 and 4, the planes of the
adjacent offset friction wheels are closely spaced so that the idler gear 43 will
be of sufficient width to engage one after another of the friction wheels in both
rows as it is moved back and forth across the console 14 of keys by the carriage.
[0022] A position detector, shown generally at 45, is provided for monitoring the rotary
positions of the keys. A number of prior art devices are available which would be
suitable for this purpose. By way of example and as shown in Figs. 3 and 4, one such
device particularly well suited to this application is a so-called magnetic Hall effect
transducer utilizing a multipolar ring magnet 46 affixed on the barrel 24 of each
of the keys 23 behind the friction wheel 26. A sensor 47 is secured to the base plate
30 of the carriage so that when the key actuating unit 13 is in position to adjust
the key, the sensor will be opposite the ring magnet of the key. The sensor will thus
detect angular position or rotation of the key through the changing field of the rotating
ring magnet and produce a signal representative of the angular position or amount
by which the key is rotated. As will be apparent, a single sensor 47 will suffice
for indicating the positions of the entire console 14 of keys.
[0023] There is shown in Figs. 5, 6 and 7 an alternate embodiment of the invention utilizing
a somewhat different apparatus for mounting and driving the carriage or positioning
unit. In other respects, it is substantially identical to the aforedescribed embodiment
and, where appropriate, like numerals are used in identifying like parts.
[0024] As best shown in Fig. 5 a carriage or positioning unit, indicated generally at 48,
is mounted upon the track members 28 so as to be movable back and forth therealong
across the console 14 of keys. More particularly, the carriage comprises a box frame
49 slidably mounted upon the upper one of the track members by ball bushing supports
50 and upon the lower track member by yokes 51 affixed thereto. The carriage is moved
along the rails by means of a drive mechanism including a splined shaft 52 extending
across the press and journalled at the ends (not shown) as in the support members
29. The splined shaft is rotated in either direction in a controlled manner as by
a stepping motor 53, mounted upon a bracket 54 affixed to the press framework supports
29, through meshing bevel gears 55 and 56 affixed to the output shaft of the stepping
motor and the spline shaft, respectively.
[0025] A travelling helical gear 57 having a central aperture with mating slots for receiving
the splines of the shaft 52 is journalled upon the splined shaft as by an appropriate
ball bushing 58 so as to be freely movable along the shaft while being driven thereby.
The travelling helical gear engages a mating gear 59 affixed to a shaft 60 journaled
in bearings 61 carried by the box frame 49. Also affixed to the shaft 60 so as to
rotate therewith is a pinion gear 62. The pinion gear engages a rack 63 affixed to
and extending throughout the length of the fountain base 18. Thus, as will be readily
appreciated, operation of the motor 53 will rotate the splined shaft 52 and the travelling
helical gear 57 keyed thereto which, in turn, drives the mating gear 59. The shaft
60 thus rotates to drive the pinion gear 62 in meshing engagement with the rack 63
so that the carriage 48 is caused to move along the console 14 of ink keys on the
track members 28. Since the teeth of the travelling helical gear 57 are intermeshed
with the teeth of the mating gear 59, the travelling gear will move with the carriage
48 by sliding longitudinally along the splined shaft 52 on the ball bushing 58. It
will be understood that by selectively operating the stepping motor 53 in either direction
the carriage 12 may be caused to move back and forth across the console 14.
[0026] The key positioning stepping motor 39 of the key actuating unit 13 is mounted within
the box frame 49, with the pinion drum 40 and idler wheel 43 in position whereby the
idler wheel frictionally engages each of the friction wheels 26 in succession as the
carriage moves back and forth across the console 14. Key position detector means 45
is provided by a multipolar ring magnet 46 affixed to the barrel 24 of each key and
a sensor 47 carried by the box frame 49 so as to be adjacent the magnet of any particular
key when the key actuating unit 13 is in position to adjust that key.
[0027] In both embodiments of the invention the entire key adjusting mechanism and ink fountain
may be pivotally affixed to a shaft 64 carried by the press framework so that they
may be swung downwardly from the operative position shown in Figs. 3 and 5 to a horizontal
position for facilitating cleaning and maintenance of the ink fountain 16, ink roll
17 and flexible blade 19.
[0028] Briefly reviewing the operation of the invention and referring to the embodiments
of Figs. 1 to 3, during a printing run the thickness profile of the ink supplied to
the printed stock is monitored in a conventional manner, for example, as taught by
the aforementioned U.S. Patent No. 4,008,664, or by a roving on-press color sensor
or other suitable means. The resulting information may be utilized in a number of
ways, the details of which are not part of the present invention, for controlling
the key adjusting mechanism 10 of the invention. Thus, when it is determined that
adjustment.of the ink film thickness is required in one or more areas along the ink
roll, the stepping motor drive unit 36 is instructed to move the carriage 12 from
its present position to the key 23 controlling the ink film thickness in that area
or zone. As.the carriage moves, a signal is sent to the stepping motor 39 causing
it to drive the idler wheel 43 at a peripheral speed and in the direction synchronized
with the movement of the carriage so that as the idler wheel frictionally engages
the friction wheel 26 of any key not requiring adjustment in moving therepast, it
will merely roll over the friction wheel without causing it to rotate. When the adjusting
mechanism encounters a key requiring adjustment, the stepping motor 39 will receive
a command to rotate the friction wheel by a predetermined amount in the direction
appropriate to retract or advance the tip 25 of the key to thereby increase or decrease
the thickness of the ink film.
[0029] It is anticipated that the key adjusting mechanism of the invention may be controlled
as by a microprocessor wherein programs are stored to establish predetermined ink
thickness profiles for different jobs that may be run on the press.
[0030] It is to be understood that the forms of the invention herewith shown and described
are to be taken as illustrative embodiments only of the same and that various changes
in the shape, size and arrangement of parts, as well as various procedural-changes,
may be resorted to without departing from the spirit of the invention. For example,
the adjustment keys can be of the type that are lever actuated or cam actuated.
1. A fluid metering apparatus including a rotatable roll and a metering means extending
therealong for metering fluid on said roll, said metering means including a marginal
edge in close proximity to the surface of said roll, said roll and metering means
defining a fluid fountain, a plurality of independently adjustable keys disposed across
said fountain, a section of said marginal edge moving closer to said roll upon adjustment
of an associated key in one direction and moving farther from said roll upon adjustment
of said associated key in the other direction to thereby regulate the thickness profile
of the fluid deposited across the surface of said roll as said roll rotates, a carriage
mounted for movement back and forth along said keys, and key actuating means carried
by said carriage for selectively adjusting said keys, said key actuating means including
drive means for frictionally driving a selected key.
2. The fluid metering apparatus of claim 1 wherein each said key is rotatably adjustable
and includes a barrel to which is affixed a friction wheel positioned to be driveably
engaged by said drive means as said key actuating means moves therepast.
3. The fluid metering apparatus of claim 2 wherein said drive means includes a rotatable
drive member adapted to driveably engage each key separately and said apparatus further
includes means for rotating said drive member at a speed and in the direction synchronized
with the movement of said carriage whereby said drive member rolls over the friction
wheel of any of said keys not to be adjusted without causing rotation thereof and
said means for rotating said drive member rotates said drive member at a speed and
in a direction to rotate the friction wheel of a selected key in response to a command.
4. The fluid metering apparatus of claim 1 further including a position detector for
indicating the adjusted position of each of said keys.
5. The fluid metering apparatus of claim 4 wherein said position detector comprises
a magnetic field sensor affixed to said carriage and positioned opposite a key when
said key actuating means is in position to adjust that key, and means on each said
key for producing a magnetic field that varies at said sensor as said key is adjusted.
6. A fluid-metering apparatus including a rotatable roll and metering means extending
therealong for metering fluid on said roll, said metering means including a marginal
edge in close proximity to the surface of said roll, said roll and said metering means
defining a fluid fountain, a plurality of independently adjustable keys disposed across
said fountain, each of said keys being rotatable, a section of said marginal edge
moving closer to said roll upon rotation of an associated key in one direction and
moving farther from said roll upon rotation of said associated key in the other direction
to thereby regulate the thickness profile of said fluid daperited across the surface
of said roll as said roll rotates, a carriage mounted for movement back and forth
along said keys, key actuating means on said carriage for adjusting said keys, said
key actuating means including means driveably engaging each of said keys in succession
as said carriage moves along said keys, means for moving said carriage in response
to a command in either direction from a first position to a second position at one
of said keys to be adjusted, and means driving said key actuating means at a speed
synchronized with the rate of travel of said carriage as said carriage moves from
said first to said second position so that any of said keys engaged by said key actuating
means between said first and second position remains stationary.
7. The fluid metering apparatus of claim 6 wherein said carriage is mounted on track
members, said means for moving said carriage comprising an endless tape affixed to
said carriage and entrained about a sprocket and an idler wheel, and a stepping motor
driving said sprocket.
8. The fluid metering apparatus of claim 6 wherein each said key includes a friction
wheel, and said key actuating means comprises a stepping motor and means to couple
said stepping motor-to said friction wheel of each of said keys in succession as said
carriage moves along said line of keys and drive a selected friction wheel by frictional
contact therewith.
9. The fluid metering apparatus of claim 6 wherein each said key comprises a barrel
threaded through a support member with a tip projecting forwardly to bear against
said metering means, and a rearward extension to which is affixed a friction wheel
adapted to be driven by said key actuating means for rotating said barrel.
10. The fluid metering apparatus of claim 9 wherein said key actuating means comprises
a reversible stepping motor and an idler wheel driven thereby, said idler wheel being
positioned to engage in succession the friction wheel of each said key as said carriage
moves along the line of keys.