U.S. patent number RE28,880 [Application Number 05/116,840] was granted by the patent office on 1976-06-29 for printing machines feed mechanism.
This patent grant is currently assigned to Colorflo Limited. Invention is credited to Harold Frederick Farrow.
United States Patent |
RE28,880 |
Farrow |
June 29, 1976 |
Printing machines feed mechanism
Abstract
The feed mechanism for a printing machine in which printing ink
is fed into the recessed design of an intaglio printing plate
includes a cylinder open at its upper end and communicating at its
bottom with the recessed designs. A piston is housed in the
cylinder, the lower end of which piston forms a chamber at the
bottom of the cylinder. The piston rod extends above the cylinder
and carries a support member at its upper end, the support member
carrying a head. A second cylinder rests upon the top of the first
cylinder and receives the head which is slidable therein within
limits. A spring is interposed between the head and the bottom of
the second cylinder. The piston and piston rod have a bore forming
a second chamber provided at its upper end with an ink supply
inlet. A hollow relief piston is slidable in the lower end of the
bore communicating with the second chamber and communicating
through inlet openings with the first chamber. A ball valve in the
lower end of the relief piston is normally spring-biased to close
the outlet passage of the relief piston, and a second spring in the
bore above the relief piston normally urges the relief piston into
position in which the ball valve closes communication between the
first chamber and the opening in the bottom of the first cylinder.
The piston rod is adapted to receive printing pressure whereby the
chambers will be contracted by the application of pressure on the
printing plate during printing, and will expand when such pressure
is released, the chamber expansion causing a further supply of ink
to be sucked into the chambers ready for the next printing
operation; and the ball valve being closed automatically by
application of said pressure.
Inventors: |
Farrow; Harold Frederick
(Hitchin, EN) |
Assignee: |
Colorflo Limited
(GB)
|
Family
ID: |
27259159 |
Appl.
No.: |
05/116,840 |
Filed: |
February 19, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
744068 |
Jul 11, 1968 |
03543682 |
Dec 1, 1970 |
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Foreign Application Priority Data
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Jul 21, 1967 [UK] |
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33735/67 |
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Current U.S.
Class: |
101/366; 91/422;
417/469; 417/495; 417/549; 417/466; 417/491 |
Current CPC
Class: |
B41F
9/00 (20130101) |
Current International
Class: |
B41F
9/00 (20060101); B41F 031/08 (); B41F 031/18 () |
Field of
Search: |
;101/366
;417/466,467,468,469,487,490,491,495,497,531,547,549,554,556,501,524,526-528
;91/422 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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6,701,075 |
|
Jul 1967 |
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NL |
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326,817 |
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Mar 1930 |
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UK |
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Primary Examiner: Coughenour; Clyde I.
Claims
I claim:
1. A feed mechanism for the type of printing machine in which
printing ink is fed into the recessed design of an intaglio
printing plate through the thickness of said plate, comprising a
cylinder open at its upper end and having its bottom adapted to
communicate with said recessed design; a piston in said cylinder
forming with the bottom of the cylinder an ink chamber; a piston
rod for the piston extending above the cylinder; a head carried by
the upper end of the piston rod; a second cylinder disposed upon
the first cylinder and slidably receiving said head; a spring
interposed between said head and the bottom of said second
cylinder; said piston and piston rod having a bore therein forming
a second ink chamber adapted to communicate with an ink supply; a
hollow relief piston slidable in the lower end of said bore
communicating at its top with the second chamber and also
communicating through lateral openings with the first chamber when
the relief piston is projected to expose said openings below the
first piston; a ball valve in the lower end of the relief piston
and cooperating with a valve seat and normally spring-biased to
close the lower end of the relief piston; and a second spring in
said bore above the relief piston normally urging the relief piston
into position in which the ball valve closes communication between
the first chamber and the opening in the bottom of the first
cylinder; said piston rod being adapted to receive printing
pressure, whereby said chambers will be contracted by the
application of pressure on the printing plate during printing, and
will expand when such pressure is released, thereby causing a
further supply of ink to be sucked into the chambers ready for the
next printing operation. .Iadd. 2. A feed mechanism for the type of
machine in which fluid is fed into the recessed design of an
intaglio plate through the thickness of said plate so that the
fluid is deposited on the material in the form of the design,
comprising a housing part having an outlet opening for
communication with said recessed design, a first piston movable in
said housing part and forming therewith a first chamber, means for
delivering fluid into said first chamber, said first chamber being
contracted during movement of said first piston in one direction
thereby increasing the fluid pressure in said first chamber, and an
outlet valve means carried by said first piston and movable
relative thereto by said fluid pressure in a direction opposite the
direction of movement of said first piston in contracting said
first chamber to effect opening of said outlet opening, said outlet
valve means having surface portions against which said fluid
pressure acts to effect said movement in said opposite direction,
said first piston having a bore therein forming a second chamber
adapted to communicate with a fluid supply, and said means for
delivering fluid into said first chamber includes means defining at
least one opening communicating said chambers, and further
including means for restricting fluid flow through said one opening
upon movement of said first piston relative to said housing part,
and a second piston in said bore and carrying said outlet valve,
and said second piston having said surface portion against which
the increase in the fluid pressure in said first chamber acts
causing movement of said second piston into said bore to effect
opening of said outlet opening. .Iaddend..Iadd. 3. A feed mechanism
as defined in claim 2 wherein said second piston comprises a hollow
member connected with said fluid supply, and said outlet valve
means comprises a relief valve member movable relative to said
second piston to communicate said recessed design with said second
chamber when the pressure of the fluid acting on said valve member
exceeds a predetermined pressure to thereby provide for pressure
relief. .Iaddend. .Iadd. 4. A feed mechanism as defined in claim 2
wherein said second piston is hollow, and said means defining at
least one opening communicating said chambers comprising a portion
of said second piston, and said means for restricting fluid flow
through said one opening comprises a portion of said first piston
which slides relative to said opening. .Iaddend. .Iadd. 5. A
mechanism for use in applying a fluid design onto material
comprising a plate having a recessed design therein in accordance
with the fluid design to be applied to the material and a passage
through the thickness of the plate communicating with said recessed
design, a fluid injector unit for delivering a charge of fluid
under pressure through said passage to said recessed design when
the plate and material are in sealing pressure relationship, said
injector unit including a main piston movable in a first chamber to
force fluid from said first chamber into said recessed design and
means for relieving said pressure of the fluid in said recessed
design, said means for relieving the pressure of the fluid in said
recessed design comprising a member supported by said piston for
yielding movement and having a surface portion exposed to the
pressure and which yields in response to a predetermined pressure
of the fluid acting thereon to thereby effect said pressure relief,
said main piston having a passage therein through which fluid
flows, an auxiliary piston located in said passage, said auxiliary
piston having a second chamber communicating with said passage in
said main piston and through which fluid flows, means communicating
said second chamber and said first chamber to provide for fluid
flow therebetween, and said member being carried by said auxiliary
piston. .Iaddend..Iadd. 6. A mechanism as defined in claim 5
wherein said member comprises a valve means movable in response to
said fluid pressure and which opens to communicate said recessed
design with said first chamber. .Iaddend..Iadd. 7. A mechanism as
defined in claim 5 wherein said injector unit comprises a housing
part having an outlet opening, and said member comprises an outlet
valve means for blocking flow of fluid through said outlet opening
and movable relative to said main piston to effect opening thereof.
.Iaddend.
Description
PRINTING MACHINES
This invention relates to intaglio printing plates and to printing
machines of the type in which printing ink is fed into the recessed
design or engraving of an intaglio printing plate through the
thickness of the plate.
A problem arises with such plates as it is difficult properly to
regulate the amount of ink fed through the plate in accordance with
the printing requirements. Clearly it is very undesirable for
either too much or too little ink to be fed and it is also
essential to control the point in the printing cycle at which ink
is fed to the plate.
These problems are satisfactorily solved by a printing machine in
accordance with the invention which has an ink feed mechanism
comprising one or more pump chambers arranged to be contracted by
the application of pressure on the printing plate during printing
and to expand when the printing pressure is released, each chamber
having an outlet which communicates, when printing is taking place,
with one or more ink passages extending through the printing plate
and an inlet which communicates with an ink supply the inlet being
controlled by a valve device which is closed automatically by the
application of printing pressure to the printing plate and outlet
being also controlled by a valve device which is normally closed
but which is opened automatically by the application of further
printing pressure for the printing plate after the inlet valve has
been closed.
The inlet valve device is preferably arranged to be actuated by the
displacement of the printing plate relatively to a support or the
like forming part of the printing machine and from which the
printing plate receives pressure preferably through the
intermediary of a spring or springs. The outlet valve may be
actuated by the hydraulic pressure of the printing ink generated by
increased pressure in the chamber after the inlet valve has been
closed.
With such a construction the initial application of printing
pressure of the inlet valve causes ink to be driven from the pump
chamber back to the supply but as the printing plate begins to
receive the full printing pressure the inlet valve is closed and
the outlet valve is open so that ink is forced through the printing
plate only when the printing plate is being pressed onto the
surface to be printed with a reasonable pressure. The printing
surface is then printed with ink under pressure. When sufficient
ink has been supplied to service the intaglio printing plate excess
ink is returned to the supply by the opening of a pressure relief
valve. The outlet valve closes as the plate is being lifted from
the surface.
The printing chamber then expands so as to cause a further supply
of printing ink to be sucked into the chamber ready for the next
printing operation.
Each pump chamber may have a piston attached to a press plate and
working in the chamber formed in a plate designed to carry the
intaglio printing surface. Each chamber has one or more inlet
openings adapted for connection to an ink supply and one or more
outlet openings which communicate with one or more ink passages
extending through the thickness of the printing plate and into the
recessed design or engraving in the printing surface thereof. The
printing plate has a limited movement towards and away from the
support under the control of one or more springs which constantly
tend to move the plate away from the support but allow the support
to approach the plate and thereby compress the pump chamber when
the pressure of the springs is overcome by the printing pressure
applied.
Each inlet opening for the supply of ink communicates with its pump
chamber through a port formed in an auxiliary "relief" piston which
works in a cylindrical bore in the main piston. One end of this
auxiliary piston carries a valve or valves which control the outlet
opening or openings leading from the pump chamber to the recesses
of the printing plate. The auxiliary piston is controlled by a
spring which constantly tends to press the auxiliary piston inwards
i.e. in a direction to close the outlet opening or openings.
An embodiment of one part of the ink feed mechanism of a printing
machine in accordance with the invention will now be described by
way of example with reference to the accompanying drawing which is
a cross section through the mechanism.
The mechanism comprises a cylinder 2 the interior chamber 4 of
which communicates with a recessed design or engraving on the
printing surface of an intaglio printing plate (not shown) through
a passage 6. A piston 8 works in the chamber 4 and is provided with
a sliding seal member 10 to provide a seal between the piston and
the chamber. The upper portion of the piston rod 12 is secured to a
support member 14 having a head 15 which is arranged for limited
sliding movement in a cylinder 16 which rests on the top of the
walls of the cylinder 2. As pressure is applied to the piston rod
during printing for example by means of a member secured at 18 to
the piston rod, the member 14 moves down within the cylinder 16
compressing a spring 20 which is located between the head 15 of the
member 14 and bottom wall 22 of the cylinder so as to apply
pressure to the cylinder 2 through the spring 20.
The piston 8 and its rod 12 are formed with an internal passage 24
communicating at the upper end with an opening 25 through the
member 14 for connection to a supply of printing ink. The lower
portion of the passage 24 is of larger diameter to provide a
cylinder 26 carrying a relief or auxiliary piston 28 which is
hollow and which communicates with the chamber 26 through an
opening 30 and with the chamber 4 through chamber inlet openings
32.
The piston 28 which is a sliding fit in the cylinder 26 carries a
ball valve 34 at its lower end which is normally biased by means of
a spring 36 within the piston to a position in which it closes the
outlet passage 38 from the piston. The piston itself is biased by
means of a spring 40, located within the cylinder 26 to a position
in which the ball valve 34 closes communication between the chamber
4 and its outlet passage 6.
During use of the mechanism, printing pressure is applied by
standard means (not shown) to the piston rod 12 and support member
14 causing through the spring 20 the printing plate 2 to be pressed
against the surface to be printed. Further, pressure is applied to
the printing ink in the chamber 4 by the piston 8 within the
chamber. During the initial movement, the outlet 6 remains closed
by the outlet valve 34 and the inlet valve 32 is open so that ink
within the chamber 4 can flow back through the relief piston 28 and
up through the passage 24 in the main piston to the ink supply.
However, as the pressure increases and the piston 8 moves downwards
in the chamber 4 over the relief piston 28, the head of the piston
8 acts as a valve device to close the ports 32 so that
communication between the chamber 4 and the ink supply is cut off.
By this time the printing plate is pressed firmly down on the
printing surface and when the pressure in the chamber 4 has built
up sufficiently the pressure acting on the tapered nose 42 of the
relief piston 28 causes this piston to move up into the cylinder 26
against the pressure of the spring 40 so as to open the passage 6
through the printing plate to the chamber 4 allowing printing ink
to reach the intaglio surface of the plate.
When sufficient ink has been supplied to service the intaglio plate
excess ink is returned to the supply the passage 38 on lifting of
the ball valve 34 from its seat by the excess pressure of the
ink.
As the printing pressure is relaxed the pressure on the relief
piston 28 within the chamber 4 is also relaxed allowing the spring
40 to move the piston back to the position in which the passage 6
is closed by the ball valve 34. In this position ink is no longer
fed to the intaglio recess thus avoiding the possibility of excess
ink being supplied as the plate is lifted from the surface which
has just been printed.
As the pressure is further relaxed the spring 20 moves the main
piston 8 upwardly within the chamber 4 to the position shown in the
drawings in which it abuts against the stop 44 and as the chamber 4
is expanded and as the ports 32 are now open ink is drawn through
the supply opening 25 the passage 24 the cylinder 26 and the
opening 30 into the chamber 4 ready for the next printing
operation.
Thus the ink required for printing is controlled automatically.
It will be appreciated that a number of chambers and pistons such
as that described and illustrated in the drawings would normally be
provided for a single printing plate.
The spring 20 which is used to apply pressure to the printing plate
could of course be replaced by subsidiary pistons and cylinders
coupled to a hydraulic accumulator.
The mechanism can be used for example to feed colored paint or the
like rather than colored ink into different parts of an intaglio
surface each chamber being supplied with paint of one particular
color so that colored patterns can be printed. Alternatively two or
more pump units such as that described can be connected to a common
outlet into an intaglio relief so that by using different colors of
ink or paint one for each pump unit, marbled effects can be
obtained.
Equally adhesives could be used instead of paint or colored
printing inks, as could thermoplastic material.
If a plate is supplied with more than one pump unit then the
outlets from the chambers of each unit can be made of different
cross sections so that the quantity of each colored ink or paint
can be regulated.
* * * * *