Field of the Invention
[0001] The invention refers to an arrangement of a flexographic printing press with central
impression drum which includes at least one unwind unit, printing unit, drying unit,
cooling unit and rewind unit, more specifically, mutual arrangement of individual
units of the flexographic machine.
Background of the Invention
[0002] The flexographic printing presses with central impression drum are used for printing
on materials of variable width using traditional solvent-based and water-based inks.
These machines are used for printing on rolls of paper, foil and laminate. From the
functional point of view the flexographic printing presses consist of at least the
following units: unwind unit which unwinds the printed material, printing unit which
prints on the material, drying unit which dries the print on the material, cooling
unit which cools down the material and rewind unit, which rewinds the printed material.
Currently all the flexographic printing presses equipped with central drum are known
to use the arrangement shown in Fig. 1. This known arrangement of the flexographic
printing press primarily reflects the shortest travel of the material through the
machine and, naturally, it respects the condition that the printed material must not
get into contact on its printed side with the guiding roller before it is dried and
cooled down, otherwise the printed motive would be damaged. In such an arrangement
is the unwind unit located as close as possible to the printing unit, and after the
last print deck there are the drying unit and cooling unit. Before the rewind unit
positioned at the end there are, sometimes, other units too, such as a cutting unit,
lacquering unit, laminating unit etc. Adding an intaglio unit, or any other additional
application unit, between the unwind unit and the printing unit of the machine in
standard arrangement of units is very complicated, and it technically requires rebuilding
a major part of the machine. In such instances, the requirement for application of
layers prior to printing is usually addressed by adding an operation, i.e. it is done
on a different machine prior to printing. A drawback of such technology lays in the
fact that the operation requires more time and extra production costs associated with
packing of finished products.
[0003] The above specified standard arrangement of flexographic printing press' units has
drawbacks described in detail in the following sections, and these drawbacks concern
primarily worse operability of the machine, limited variability and, in some cases,
they lead to increased dimensions of the machine;
- Working space for the machine operators - with the unwind unit located as close to
the printing unit as possible, space limitation occurs during loading of a roll of
material and the space for an access of operators to this part of printing unit is
partly, but most of the times completely, blocked off. This drawback has been eliminated,
for example, on machines by Fischer & Krecke (today BOBST) by turning the unwind unit
and loading the rolls of material from the direction of the rewind unit, which is
a so called "face-to-face" arrangement.
- Web path access - the material being processed on a flexographic printing press of
above described standard arrangement of units is guided over unwind unit towards the
printing unit. The machine operators have a rather complicated access to this section,
especially when introducing the material into the machine, e.g. in case it rips. This
drawback is usually compensated by the system of pulling the material mechanically
through the machine.
- Machine variability - placement of the unwind unit implies that any change of its
type, including mostly also the change of its dimensions, affects location of the
surrounding parts of the machine. At least, the frames of the machine have to be extended
or shortened, and other units have to be shifted. In some cases it is necessary to
place another unit for material pre-print processing between the unwind unit and the
printing unit (e.g. application of coats for better adhesion of print inks on printed
material), which may, depending on the dimensions of the given unit, require rebuilding
of a major part of the printing machine.
- Machine height - components of flexographic printing presses which have to be placed
into the path of material between the unwind unit and the printing unit because of
their function (see Fig. 1), e.g. web guiding system prior to print, corona treatment
unit etc., have to be, in a standard arrangement of units, placed above the unwind
unit, and this can increase the machine height more than it would be necessary in
a different arrangement.
Summary of the Invention
[0004] The invention relates to the arrangement of flexographic printing press with central
impression drum, which may simplify its operability and increase its variability.
[0005] The above specified drawbacks are removed and the specified goal is achieved by different
arrangement of the flexographic printing press with a central impression drum comprising
at least one unwind unit, printing unit, drying unit, cooling unit and rewind unit,
the principle of which lies in the fact that it comprises a printing part of the machine,
in which are arranged units directly related to printing, and the end part of the
machine, which comprises at least an unwind unit and a rewind unit, and the printing
part of the machine is spatially separated from the end part of the machine.
[0006] The printing part of the machine, in which are arranged units directly related to
printing, thus comprises a printing unit followed by a drying unit and a cooling unit.
The unwind unit and rewind unit may be made in a carousel-type arrangement. The roll
of printing material may be loaded from the side or from the front.
[0007] An advantage is that with the new concept of the unit arrangement, the flexographic
printing press with central impression drum may, in its variability and operability,
compete with machines with "inline" unit arrangement, which may be achieved thanks
to the fact that individual units of flexographic printing press are positioned in
a line.
[0008] Removal of units, of which type and form may often vary, from the printing part of
the machine, enables the height and length of the machine to be defined solely by
the requirements of its particular configuration. That brings an option to install
the machine into the premises (production halls), where it would not be normally possible.
[0009] The web path through the machine may be arranged so as to be accessible as fast and
best as possible for the operators without the need to use ladders, ramps and other
means.
[0010] Division of the machine into two above specified parts causes also the division of
work spaces for the machine operators. The work space, which is necessary for loading
and removing rolls of material into and out of the machine at the end part of the
machine, does not interfere with the work space which is necessary for operators of
printing part of the machine, where the printing unit is incorporated. That means
that the operation related activities regarding printing - preparation, settings etc.
are not limited by activities related to material - rolls exchange. Both activities
may thus proceed simultaneously which leads to higher efficiency of the machine.
[0011] Technical solution described in this invention will enable the use of various combinations
of unwind and rewind units, and addition of more units into the web path between these
units and the printing unit. The end part may therefore still contain units for further
processing of the printed material, e.g. units for further coating/printing past the
unwind unit or before the rewind unit, such as intaglio or flexographic printing unit
and the like. Moreover, it is easy to adopt these changes later, in the course of
service life of the machine.
[0012] The printing part and the end part are preferably functionally separated. In such
instance the individual function parts of the machine, i.e. units used in flexographic
printing press with central impression drum, have to be of adapted design so as to
meet the condition of operability in any combination with other units. That implies
that individual units must be mechanically, electrically, pneumatically etc. independent.
Under this condition, the units can be freely combined or replaced in particular arrangements
of the flexographic printing press. That practically means that each unit, if it is
required by its functions, has its independent control unit (PLC), independent electrical
installation, independent pneumatic circuits etc.
[0013] The units are mechanically linked in a standard manner using frames which serve also
for guiding rollers and for guiding the material through the machine between units.
Vertical frames of the end part of the machine are preferably the same for all unwind
and rewind unit versions. When the mutual position of unwind and rewind unit changes,
e.g. due to their embodiment, only the horizontal frame is changed.
[0014] From the control point of view, it is preferred to control the printing part of the
machine by one PLC unit and the end part units to have their own independent PLCs.
That makes the printing part and the end part of the machine mutually absolutely independent.
[0015] A function unit is replaced by a different function unit with the same basic function,
but in different embodiment, most often in case of unwind and rewind units, embodiment
of which may greatly differ from the basic embodiment for a single roll to carousel-type
embodiment with continuous replacement of rolls. This concept enables also easy replacement
of the printing part of the machine.
[0016] With the new machine concept the embodiment of the printing part is determined neither
by the unwind unit, nor by the units placed between the unwind unit and the printing
unit. Width and length of the printing part of the machine is determined only by the
arrangement of print decks in the printing unit and by the web path in the drying
unit. The web path in the printing part may be suitably adapted for easy and quick
access to the material for printing.
[0017] The new machine concept is designed so as to enable implementation of all the above
specified requirements. It is presumed that all alternations of the configuration
of the machine units will take place at the end part of the machine and the printing
part will not be affected by these changes.
[0018] Due to the variability of the machine's new concept, new technologies may be implemented
into the flexographic printing press, which would otherwise had to be performed on
different machines in additional operations, hence the production efficiency increases.
Specifically, this may relate to the application of primer, application of base color
on transparent materials, application of lacquers (to increase abrasion resistance,
to increase print gloss, to increase barrierity of package,...), application of adhesives
(coldseal), package customization, package perforation, rotation section cuts, etc.
[0019] The new concept of the machine is particularly suitable for machines designed for
higher operation efficiency for short orders. Not only does it allow configuring the
machine exactly according to the requirements of the customer, it also enhances ergonomic
features and speed of machine control.
[0020] The new concept of the machine is also ready for potential future changes in configuration
of units according to trends in package production.
Description of the Drawings
[0021] Exemplary embodiment of this technical solution is shown in drawings, where Fig.
1 shows the known embodiment of the flexographic printing press with central impression
drum with standard arrangement of units, Fig. 2 shows the new concept of the unit
arrangement of flexographic printing press with central impression drum, Fig. 3 shows
the option for incorporation of coating application units for flexographic printing
press with central impression drum, and Figs 4a to 4e show possible versions of embodiments
of flexographic printing press with central impression drum using various unwind/rewind
unit types in the end part.
Description of the Preferred Embodiments
[0022] Principle of unit arrangement of flexographic printing press with central impression
drum according to this technical solution will be further clarified, but not limited,
in the following examples.
[0023] Basic embodiment of the flexographic printing press with central impression drum
designed according to this new concept consists of two parts, as shown in Fig 2. The
first one is the printing part
A of the machine which includes the printing unit
2, drying unit
3 and cooling unit
4. The printing part
A of the machine remains unchanged for all the versions of the flexographic printing
press, i.e. it is not in any manner influenced by the arrangement of other units,
alternatively, it can be entirely replaced with another printing part
A1 with different parameters (e.g. different length of printing etc.) The second part
of the machine consists of the end part
B which comprises the unwind unit
1 and rewind unit
5 or other required units, for example, cutting unit, pre-printing coat application
unit, printing lacquering unit, reprint unit etc. Arrangement of the printing part
A and the end part
B is designed so that any change of type of the embodiment of any unit would have minimal
impact on other units incorporated in respective parts of the flexographic printing
press.
[0024] Exemplary combination of the flexographic printing press with central impression
drum with incorporated units for coating application is shown in fig 3. The flexographic
printing press in this embodiment has the printing part
A which includes printing unit
2, drying unit
3 and cooling unit
4, which are the same as in the described basic embodiment of the flexographic printing
press. The second part of the machine consists of the end part
B, where before the unwind unit
1 and rewind unit
5 there is an intaglio unit
8 for application of pre-print primer coats and intaglio unit
9 designed, for example, for print lacquering. It is clear that the above described
units do not necessarily have to be intaglio units, but they can be replaced by flexographic
units, alternatively by other technology of coating application or reprinting, which
is possible with the new concept of the machine.
[0025] Other versions of arrangement of the flexographic printing press with central impression
drum, including various types of unwind units
1 and rewind units
5, including their mutual combinations, are shown on Fig 4, wherein individual arrangement
versions are shown in figs. 4a to 4e and described below.
[0026] Fig. 4a shows a flexographic printing press containing rewind unit
5 and unwind unit
1 in shaft-less embodiment for a single roll. In this arrangement, the rolls of material
are loaded to unwind unit
1 using a forklift for rolls. The roll is fastened in the machine using cones. The
material first passes through the printing unit
2, then through the drying unit
3 and continues to cooling unit
4. At the end of the machine the material gets rewound onto a roll fastened in rewind
unit
5. The roll of rewound material is removed from the machine using a forklift.
[0027] Fig. 4b shows a flexographic printing press containing unwind unit
1 in a shaft-less embodiment for a single roll and a carousel rewind unit
51 for two rolls in continuous operation with side removing of the rolls. In this setup
the rolls of material are loaded to unwind unit
1 using a forklift for rolls. The roll is fastened in the machine using cones. The
material first passes through the printing unit
2, then through the drying unit
3 and continues to the cooling unit
4. At the end of the machine the material gets rewound onto a free fastening shaft
on the carousel rewind unit
51. The carousel rewind unit
51 can be in continuous operation, which means that the rewound rolls are removed without
stopping of the machine. The rolls are removed from the carousel rewind unit
51 using a built in lifting platform.
[0028] Fig. 4c shows a flexographic printing press containing carousel rewind unit
51 and carousel unwind unit
11 for two rolls in continuous operation with side removing or loading of the rolls.
In this setup the rolls of material are loaded to carousel unwind unit
11 using a built in lifting platform. The roll is fastened on a free fastening shaft.
[0029] The carousel rewind unit
11 can also be in continuous operation, which means that the rewound rolls are removed
without stopping of the machine. The material passes first through the printing unit
2, then through the drying unit
3 and continues to the cooling unit
4. At the end of the machine the material gets rewound onto a free fastening shaft
on the carousel rewind unit
51. The carousel rewind unit
11 can also be in continuous operation. The roll is removed from the carousel rewind
unit
51 using a built in lifting platform.
[0030] Fig. 4d shows a flexographic printing press containing unwind unit
1 in shaft-less embodiment for a single roll and a carousel rewind unit
52 for two rolls in continuous operation. In this setup the rolls of material are loaded
to unwind unit
1 using a forklift for rolls. The roll is fastened in the machine using cones. The
material passes first through the printing unit
2, then through the drying unit
3 and continues to the cooling unit
4. At the end of the machine the material gets rewound onto an inserted fastening shaft
in carousel rewind unit
52. The carousel rewind unit
52 can be in continuous operation, which means that the rewound rolls are removed without
stopping of the machine. The rolls are removed from the carousel rewind unit
52 with the fastening shaft using a built in lifting platform, or using a forklift.
[0031] Fig. 4e shows a flexographic printing press containing carousel unwind unit
12 and carousel rewind unit
52 for two rolls in continuous operation. In this setup are the rolls of material with
inserted shaft loaded into the carousel unwind unit
12 using a built in lifting platform, or using a forklift. The unwind unit may be in
continuous operation, which means that the unwound rolls are changed without stopping
of the machine. The material passes first through the printing unit
2, then through the drying unit
3 and continues to the cooling unit
4. At the end of the machine the material gets rewound onto an inserted fastening shaft
in carousel rewind unit
52. The carousel rewind unit
52 can be in continuous operation. The rolls are removed from the carousel rewind unit
52 with the fastening shaft using a built in lifting platform, or using a forklift.
[0032] The above described versions take into account an option of incorporating, behind
the unwind unit
5 or before rewind unit
1, a unit for application of coating using various printing technologies, for example,
flexographic unit or intaglio unit
8 and
9.
Industrial Applicability
[0033] Flexographic printing presses with central impression drum are used especially for
printing on flexible materials (PE, PP, BOPP, PET and the like). Besides that it is
also possible to print on paper, aluminum foils, laminates etc. Their rather broad
range of uses requires various configurations of the unwind units, rewind units and,
alternatively, also an addition of further units for pre-print or post-print processing
of the material.
List of Reference Signs
[0034]
- A
- printing part
- B
- end part
- 1
- unwind unit
- 11
- carousel unwind unit - front roll loading
- 12
- carousel unwind unit - side roll loading
- 2
- printing unit
- 3
- drying unit
- 4
- cooling unit
- 5
- rewind unit
- 51
- carousel rewind unit - front roll removing
- 52
- carousel rewind unit - side roll removing
- 6
- web guiding system prior to printing
- 7
- web surface finishing - corona unit
- 8
- unit for application/printing after unwind
- 9
- unit for application/printing before rewind
1. An arrangement of a flexographic printing press with central impression drum comprising
at least one unwind unit, printing unit, drying unit, cooling unit and rewind unit,
characterized in that, it consists of a printing part (A) of the machine, in which the units directly related to printing are arranged, and
an end part (B) of the machine which includes at least the unwind unit (1) and the rewind unit (5), wherein the printing part (A) of the machine is spatially detached from the end part (B) of the machine.
2. An arrangement of a flexographic printing press with central impression drum according
to claim 1, characterized in that the printing part (A) and the end part (B) are functionally separated.
3. An arrangement of a flexographic printing press with central impression drum according
to any of the claims 1 or 2, characterized in that the printing part (A) comprises a printing unit (2) followed by a drying unit (3) and a cooling unit (4).
4. An arrangement of a flexographic printing press with central impression drum according
to any of claims 1 to 3, characterized in that individual units of the printing part (A) and/or the end part (B) are connected together with frames.
5. An arrangement of a flexographic printing press with central impression drum according
to any of previous claims, characterized in that the printing part (A) of the machine remains identical for all versions of the machine.
6. An arrangement of a flexographic printing press with central impression drum according
to any of previous claims, characterized in that the end part (B) further comprises the units for further processing of printed material.
7. An arrangement of a flexographic printing press with central impression drum according
to any of previous claims, characterized in that the units of the end part (B) of the machine are mutually independent and may be freely combined.
8. An arrangement of a flexographic printing press with central impression drum according
to any of previous claims, characterized in that the individual units of the machine are arranged in a line.