U.S. patent application number 10/892800 was filed with the patent office on 2004-12-30 for method of producing a variable format cylinder for a web-fed offset printing machine.
This patent application is currently assigned to Man Roland Druckmaschinen AG. Invention is credited to Dauer, Horst, Dilling, Peer, Weinberger, Martin.
Application Number | 20040261641 10/892800 |
Document ID | / |
Family ID | 7642285 |
Filed Date | 2004-12-30 |
United States Patent
Application |
20040261641 |
Kind Code |
A1 |
Dilling, Peer ; et
al. |
December 30, 2004 |
Method of producing a variable format cylinder for a web-fed offset
printing machine
Abstract
Variable-format web-fed offset printing machine having
printing-unit cylinders comprising core cylinders to which
compressed air can be applied and onto which intermediate sleeves
can be pushed axially and shrunk on radially. Each intermediate
sleeve includes a carrier layer whose inner face rests on the core
cylinder, a compressible intermediate layer, a transition layer,
and a variable-thickness bridging layer, which ends with a covering
layer to which a further surface like a printing plate or a rubber
blanket can be fitted.
Inventors: |
Dilling, Peer; (Friedberg,
DE) ; Dauer, Horst; (Rohrbach, DE) ;
Weinberger, Martin; (Augsburg, DE) |
Correspondence
Address: |
COHEN, PONTANI, LIEBERMAN & PAVANE
Suite 1210
551 Fifth Avenue
New York
NY
10176
US
|
Assignee: |
Man Roland Druckmaschinen
AG
|
Family ID: |
7642285 |
Appl. No.: |
10/892800 |
Filed: |
July 16, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10892800 |
Jul 16, 2004 |
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09860167 |
May 17, 2001 |
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6782821 |
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Current U.S.
Class: |
101/375 |
Current CPC
Class: |
B41F 13/10 20130101;
B41N 1/16 20130101; B29C 44/1242 20130101; B41F 27/105 20130101;
B41F 27/14 20130101 |
Class at
Publication: |
101/375 |
International
Class: |
B41F 030/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 17, 2000 |
DE |
100 24 001.1 |
Claims
1. (cancelled)
2. A method for producing a variable format cylinder for a web-fed
offset printing machine, said method comprising providing an
intermediate sleeve having an open interior with axial end
openings, an outer circumferential surface, and holes extending
between said open interior and said outer circumferential surface,
closing said open ends in an air-tight manner, supplying compressed
air to said interior so that air emerges from said holes on said
outer circumferential surface of said intermediate sleeve to form
an air pad, pushing a functional sleeve axially onto the outer
circumferential surface of said intermediate sleeve while said
compressed air is being supplied, switching off said compressed air
so that said functional sleeve shrinks radially onto said
intermediate sleeve, providing a core cylinder having an outer
circumferential surface and means for supplying compressed air to
said outer circumferential surface of said core cylinder, supplying
compressed air to said outer circumferential surface of said core
cylinder, pushing said intermediate sleeve with said functional
sleeve onto the outer circumferential surface of the core cylinder
while said compressed air is being supplied, and switching off said
compressed air so that said intermediate sleeve shrinks radially
onto said core cylinder.
3-4. (cancelled)
5. A method of producing a printing unit cylinder for a web-fed
offset printing machine, said method comprising providing a
prefabricated composite comprising a carrier layer, a compressible
intermediate layer over said carrier layer, and a transition layer
over said compressible intermediate layer, fixing said
prefabricated composite concentrically in a cylindrical mold,
inserting one of a functional into said cylindrical mold
concentrically about said composite, thereby forming an
intermediate space between said prefabricated composite and said
functional layer, and filling said intermediate space with a
plastic foam to form a bridging layer which inseparably joins said
transition layer to said functional layer.
6. A method of producing an intermediate sleeve for a printing unit
cylinder in a web-fed offset printing machine, said intermediate
sleeve comprising a carrier layer having an inner surface for
fitting to the surface of a core cylinder, a compressible
intermediate layer over said carrier layer, a transition layer over
said compressible intermediate layer, a variable thickness bridging
layer over said transition layer, and a rubber blanket which is
inseparably fitted to said bridging layer, said method comprising
fitting said rubber blanket layer to said bridging layer by one of
spraying and vulcanizing.
7-12. (cancelled)
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to variable-format web-fed offset
printing machines and a method of producing variable-format
surfaces.
[0003] 2. Description of the Related Art
[0004] U.S. Pat. No. 5,819,657 discloses the production of plastic
sleeves with various wall thicknesses, which are fitted to core
cylinders as intermediate sleeves and bear flexographic or gravure
printing plates with different circumferential lengths. The
intermediate sleeves are constructed from an inner layer which,
under air pressure, expands in the radial direction and compresses
a following compressible layer. The compressible layer is followed
by a solid transition layer which bears an incompressible bridge
layer of different thickness--depending on the format. A printing
sleeve with a printing plate may be fitted to a cylindrical
terminating layer over the bridge layer.
[0005] The intermediate sleeves can be pushed onto a core cylinder
by means of compressed air, and the printing sleeves can be pushed
onto the intermediate sleeves--likewise over an air pad produced
with compressed air. For mounting the intermediate sleeves, a
compressed-air connection is provided at the end of the core
cylinder, and holes in its circumferential surface. On the
intermediate sleeves, air channels are provided in the bridge
layer, parallel to the axis of rotation of the cylinder, and have
pressure connections at the end annular surface and lead to the
circumferential surface of the terminating layer via radial holes
which are spaced apart axially from one another.
[0006] In order to shrink the intermediate sleeves and the printing
sleeves on axially, and to remove them, it is disadvantageous to
have to provide two separate air supplies on the printing machine.
The air channels running axially in the bridge layer are
complicated to produce and require a minimum wall thickness of the
bridge layer.
[0007] U.S. Pat. No. 5,706,731 discloses flexography cylinders with
hollow supporting cylinders, which are provided with a central air
supply and, in the vicinity of the insertion end, have radial holes
on the circumference as connecting channels to the centre, to which
compressed air can be applied. Intermediate sleeves are pushed onto
these supporting cylinders and, at their one end, likewise have
radial holes, in order to be able to use the centrally supplied
compressed air to mount printing plates onto the circumferential
surface as well. In order that the operation of shrinking the
intermediate sleeves on axially is not disrupted as soon as their
air channels come into alignment with the air supplies of the
supporting cylinders, the intermediate sleeves are provided with
rotatable closure rings. By means of the latter, the air outlet at
the circumferential surface can be closed and, as soon as the
intermediate sleeve has been shrunk on completely, the path for the
compressed air to the circumferential surface of the intermediate
rings can be opened by rotating the closure rings, by which means a
printing plate can be shrunk onto the intermediate sleeve.
[0008] The switchable closure rings have to be produced precisely
and make the intermediate sleeves more expensive.
SUMMARY OF THE INVENTION
[0009] The object of the invention is to make economic,
variable-format printing with web-fed offset printing machine
possible by means of simply constructed and simply mounted sleeves
on the printing-unit cylinders.
[0010] According to a first aspect of the invention, each printing
unit cylinder includes
[0011] (a) a core cylinder having an outer circumferential surface
and means for supplying compressed air to the surface;
[0012] (b) a carrier layer having an inner surface which rests on
the surface of the core cylinder;
[0013] (c) a compressible intermediate layer over the carrier
layer;
[0014] (d) a transition layer over the compressible intermediate
layer;
[0015] (e) a variable thickness bridging layer over the transition
layer; and
[0016] (f) a covering layer on the variable thickness bridging
layer, which covering layer is suitable for receiving a functional
surface, such as a printing plate or a rubber blanket, which can be
pushed on axially and shrunk on radially.
[0017] According to a second aspect of the invention, each printing
unit cylinder includes the elements (a) to (e) above, however the
covering layer is deleted and the bridging layer is suitable for
receiving a functional layer which can be inseparably fitted to the
bridging layer.
[0018] According to a third aspect of the invention, a variable
format cylinder for a web-fed offset printing machine is produced
by the following steps
[0019] (a) providing an intermediate sleeve having an open interior
with axial end openings, an outer circumferential surface, and
holes extending between the open interior and the outer
circumferential surface;
[0020] (b) closing the open ends in an air-tight manner;
[0021] (c) supplying compressed air to the interior so that air
emerges from the holes on the outer circumferential surface of the
intermediate sleeve to form an air pad;
[0022] (d) pushing a functional sleeve axially onto the outer
circumferential surface of the intermediate sleeve while the said
compressed air is being supplied;
[0023] (e) switching off the compressed air so that the functional
sleeve shrinks radially onto the intermediate sleeve;
[0024] (f) providing a core cylinder having an outer
circumferential surface and means for supplying compressed air to
the outer circumferential surface of the core cylinder;
[0025] (g) supplying compressed air to the outer circumferential
surface of the core cylinder;
[0026] (h) pushing the intermediate sleeve with the functional
sleeve onto the outer circumferential surface of the core cylinder
while the compressed air is being supplied; and
[0027] (i) switching off the compressed air so that said
intermediate sleeve shrinks radially onto the core cylinder.
[0028] The invention makes a format change possible which can be
carried out quickly and simply by the printer himself.
[0029] By means of the invention, the investment costs involved in
procurement are advantageously reduced, since the plastic sleeves
for different formats can be bought in at any time.
[0030] It is also particularly advantageous that the users of
conventional and digital web-fed offset printing can print with
variable cut lengths in accordance with their specific
requirements, and are therefore able to run economic production,
matched to the job, with the respective optimum paper waste.
[0031] As a result of the advantageous configuration according to
the invention, the intermediate sleeves have a low weight, as a
result of which they can be replaced easily and ergonomically.
[0032] As a result of the beneficial choice of materials with a low
thermal conductivity and heat capacity, the sleeves according to
the invention are advantageously also suitable for
computer-to-press technologies, in which the printing plates have
images set on them within the printing machine and lead to heating
of the surfaces, such as in the case of the thermal transfer
processes.
[0033] The particularly advantageous shaping of the intermediate
sleeve, which forms a detachable shrunk seat on a core cylinder and
has a further detachable joint for the functional sleeve, means
that the printing plate or rubber-blanket sleeves can be replaced
cost-effectively as required.
[0034] By means of an advantageous production method for the
intermediate sleeves, which provides for the functional surface to
be inserted into a cylindrical mould and for the bridging layer to
be foam-filled directly, more accurate production tolerances can be
achieved, the cost can be reduced, and the omission of the
compressed-air holes in this method leads to a further
simplification of production.
[0035] Other objects and features of the present invention will
become apparent from the following detailed description considered
in conjunction with the accompanying drawings. It is to be
understood, however, that the drawings are designed solely for
purposes of illustration and not as a definition of the limits of
the invention, for which reference should be made to the appended
claims. It should be further understood that the drawings are not
necessarily drawn to scale and that, unless otherwise indicated,
they are merely intended to conceptually illustrate the structures
and procedures described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 shows the cross section of an intermediate sleeve
with air channels and two detachable joints,
[0037] FIG. 2 shows the mounting of a functional sleeve outside the
printing machine, and
[0038] FIG. 3 shows the cross section of an intermediate sleeve
with a detachable joint.
DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS
[0039] In variable-circumference web-fed offset printing machines
according to the invention, core cylinders are provided on a
machine base instead of the conventional fixed-format plate and
blanket cylinders, on which core cylinders various intermediate
sleeves with different wall thicknesses can be mounted, so that
variable-format surfaces are produced. These intermediate sleeves
can bear both printing plates and rubber blankets.
[0040] The more extensive equipment of such a machine base with
further printing equipment which can be adapted to the various
circumferential lengths, such as inking units, damping units or, if
appropriate, also in-press image-setting equipment, web guiding
systems or folding equipment, will not be discussed further.
[0041] FIG. 1 illustrates a cross section of an intermediate sleeve
(3) mounted on a core cylinder (1). The core cylinder (1) is
designed as a conventional air cylinder with compressed-air
channels (2) distributed over the circumference, which permit the
intermediate sleeves (3) to be pushed on axially and shrunk on
radially in a reversible manner. The diameter of the core cylinder
(1) is defined by the smallest sectional length within the range of
formats to be covered and the layer thickness of the functional
surface fitted. In order to cover a wide format range, it may be
necessary to provide various core cylinders (1) with increasing
diameters.
[0042] The intermediate sleeve (3) is constructed on a carrier
layer (5) which preferably consists of glass-fibre reinforced
plastic and, with its cylindrical inner face, forms a detachable
joint with the core cylinder (1), its diameter being dimensioned
such that a press fit is produced. The carrier layer (5) is a thin
layer with a thickness of, for example, about 1 millimetre.
[0043] The carrier layer (5) is followed by a compressible
intermediate layer (6) of preferably about 3 millimetres layer
thickness, which allows the carrier layer (5) a reversible
expansion and permits the intermediate sleeve (3) to be shrunk onto
the core cylinder (1). The intermediate layer (6) consists of
porous polyurethane, for example. Other compressible materials can
also be employed.
[0044] The intermediate layer (6) is closed off by a thin
transition layer (7)--for example about 1 millimetre
thick--preferably made of glass-fibre reinforced plastic, onto
which a bridging layer (8) with a variable wall thickness is
fitted.
[0045] The bridging layer (8) is preferably produced from porous
rigid polyurethane foam, and its layer thickness is selected in
accordance with the sectional length of the format for which the
respective intermediate sleeve (3) is provided. Because of the
continuously variable thickness of the bridging layer (8), in
principle any desired format length can be implemented. The maximum
thickness of the bridging layer (8) is about 35 millimetres. If
reinforcing structures are used, however, thicker layers are also
possible. As a result of the preferred material selection in
accordance with a low density, the intermediate sleeves (3) have a
low weight and may be handled very easily by hand and permit
ergonomic replacement within the printing machine. In addition,
because of a low thermal conductivity and low heat capacity, the
intermediate sleeves are also suitable for printing processes in
which printing plates are thermally loaded in the printing unit,
such as in the case of printing-plate production within the
printing machine (thermal transfer processes, computer-to-press
technologies).
[0046] The bridging layer (8) is surrounded by a thin covering
layer (9), preferably made of glass-fibre reinforced plastic. The
thickness of the covering layer (9) is about 1 millimetre, for
example, and its cylindrical circumferential surface is used as a
joint with the functional sleeve (4).
[0047] For the covering layer (9) and the carrying layer (5) which,
at their outer and inner surface, respectively, have detachable
joints so that functional sleeves (4) can be shrunk on reversibly
or, respectively, so that they can be mounted or dismantled from
the core cylinder (1), wear-resistant materials, such as
glass-fibre reinforced plastics, must be provided.
[0048] Close to one end of the intermediate sleeve (3), on the
circumference, compressed-air channels (10) are provided, which
lead from the hollow inner side, through all the layers, to the
outer surface. They are preferably distributed uniformly around the
circumference and oriented radially in relation to the axis of
rotation. In order to improve the air pad during the fitting of the
functional sleeve (4), further channels running radially (31', FIG.
2) could be provided, being arranged in an axially offset manner
approximately centrally between the end faces of the intermediate
sleeve (3). As a result of the particularly advantageous
arrangement of the compressed-air channels (10) in the radial
direction, it is possible to dispense with longitudinal
channels--running parallel to the cylinder axis--so that the
intermediate sleeves (3) can be produced very simply, and no
minimum thickness for the bridging layer (8) has to be taken into
account.
[0049] The functional sleeve (4) which can be mounted detachably on
the covering layer (9) may be a metal or plastic sleeve, which is
used as a printing surface or as a carrier for a rubber blanket
and, if required, can be replaced simply and cost-effectively.
[0050] FIG. 2 shows the operation of changing a functional sleeve
(34) outside the printing machine. For this purpose, one end face
of the intermediate sleeve (30) is closed by being set up on a
support (35), and the other end, in the vicinity of which the
compressed-air channels (31) running radially are arranged, is
sealed off with a cover (32). Via a compressed-air connection (33)
on the cover (32), the cavity in the intermediate sleeve (30) is
supplied with compressed air, which escapes through the
compressed-air channels (31) and possibly through
additional--centrally arranged--compressed-air channels (31') on
the outer surface of the intermediate sleeve (30). The cover (32)
is dimensioned such that the functional sleeve (34) can be put over
it onto the intermediate sleeve (30) and can be pushed on the air
pad which forms. After the sleeve has been positioned, the
compressed air is switched off and the cover (32) is removed. The
functional sleeve (34) produces a shrink fit on the intermediate
sleeve (30) and closes the compressed-air channels (31, possibly
also 31') on the outside. The intermediate sleeve (30) therefore
prepared as a plate or rubber-covered cylinder can then be fitted
to the corresponding core cylinder (designed as an air cylinder) in
the printing machine and, at any time, replaced for a different
intermediate sleeve (30) having a different format for the
production of a different section length.
[0051] As a result of this particularly advantageous method, it is
possible to manage with conventional air cylinders on the printing
machine, and it is not necessary for any additional air connections
or changeover valves to be provided, which reduces the investment
costs.
[0052] With a known applicator structure, a printing company can
tailor the necessary number of intermediate sleeves (30) in advance
with appropriate format as plate and rubber-covered cylinders, and
change over the machine base in an extremely short time.
[0053] FIG. 3 shows a further exemplary embodiment in which the
functional layer (21) is non-detachably joined to an intermediate
sleeve (20). This intermediate sleeve (20) likewise comprises a
carrier layer (5'), intermediate layer (6') and transition layer
(7'), which are followed by the variable-thickness bridging layer
(8') and the functional layer (21) being joined directly to the
bridging layer (8') without any covering layer (9, FIG. 1). Such
intermediate sleeves (20) have only a single detachable joint,
namely that between the carrier layer (5') and core cylinder (1),
and can therefore be designed particularly advantageously without
any air channels, which makes their production simpler and more
beneficial.
[0054] A rubber blanket can, for example, be adhesively bonded onto
the bridging layer (8'), sprayed on or vulcanized on. By means of
chemical or electroplated metallization of the circumferential
surface of the bridging layer (8'), an intermediate sleeve (20) can
be tailored as a printing plate.
[0055] A further production option provides for a printing plate or
a rubber blanket to be inserted into a cylindrical mould and,
concentrically with this, a composite of carrier layer (5'),
intermediate layer (6') and transition layer (7') to be arranged in
its interior. The intermediate space between transition layer (7')
and the printing plate or the rubber blanket is then filled with
plastic foam. After the plastic has cured, the finished
intermediate sleeve (20) tailored as a printing or rubber-covered
cylinder can be removed from the apparatus. Dispensing with the
second detachable joint means that more accurate production
tolerances can be achieved and, because of the integration of the
functional surface into the production process of the
variable-format intermediate sleeve (20), the costs can be
reduced.
[0056] In the case of this integrated production process, it is
also possible, instead of the functional surface, to fix a
conventional clamping channel for conventional printing plates or
rubber blankets in the mould and to join them to the intermediate
layer (7') by foam filling. For this purpose, the clamping channel
can be arranged in a housing, which is fixed in the bridging layer
(8') by anchoring parts surrounded by foam.
[0057] One advantageous embodiment of the invention illustrated in
FIGS. 1-3 is the application to a rubber-covered cylinder of an
offset printing machine.
[0058] List of Reference Symbols
[0059] 1 Core cylinder
[0060] 2 Compressed -air channel
[0061] 3 Intermediate sleeve
[0062] 4 Functional sleeve
[0063] 5,5' Carrier layer
[0064] 6,6' Intermediate layer
[0065] 7,7' Transition layer
[0066] 8,8' Bridging layer
[0067] 9 Covering layer
[0068] 10 Compressed-air channel
[0069] 20 Intermediate sleeve
[0070] 21 Functional layer
[0071] 30 Intermediate sleeve
[0072] 31, 31' Compressed-air channel
[0073] 32 Cover
[0074] 33 Compressed-air connection
[0075] 34 Functional sleeve
[0076] 35 Support
[0077] Thus, while there have shown and described and pointed out
fundamental novel features of the invention as applied to a
preferred embodiment thereof, it will be understood that various
omissions and substitutions and changes in the form and details of
the devices illustrated, and in their operation, may be made by
those skilled in the art without departing from the spirit of the
invention. For example, it is expressly intended that all
combinations of those elements and/or method steps which perform
substantially the same function in substantially the same way to
achieve the same results are within the scope of the invention.
Moreover, it should be recognized that structures and/or elements
and/or method steps shown and/or described in connection with any
disclosed form or embodiment of the invention may be incorporated
in any other disclosed or described or suggested form or embodiment
as a general matter of design choice. It is the intention,
therefore, to be limited only as indicated by the scope of the
claims appended hereto.
* * * * *