Title: Method and device for generating an air stream in a duplicating machine
Abstract: A device for generating an air stream in a duplicating machine, in particular in a printing machine, has at least one fan unit, which includes at least one ionic fan. Methods for guiding and depositing flat products, in particular print carriers, in duplicating machines are also provided. Further, a method for the zonal powdering of print carriers in duplicating machines is provided. A delivery configuration, in particular for printing machines, is also provided.
Patent Number: 6,889,609 Issued on 05/10/2005 to Braun, et al.
| Inventors:
|
Braun; Helmut (Rauenberg, DE);
Heller; Bernd (Neckargemünd, DE);
Wolf; Thomas (Karlsruhe, DE)
|
| Assignee:
|
Heidelberger Druckmaschinen AG (Heidelberg, DE)
|
| Appl. No.:
|
927555 |
| Filed:
|
August 9, 2001 |
Foreign Application Priority Data
| Aug 09, 2000[DE] | 100 38 774 |
| Current U.S. Class: |
101/483; 101/424.1 |
| Intern'l Class: |
B41M 000/00 |
| Field of Search: |
101/4241,424.2,416.1,483,488,487
271/211,208
315/111.91
|
References Cited [Referenced By]
U.S. Patent Documents
| 3751715 | Aug., 1973 | Edwards.
| |
| 4210847 | Jul., 1980 | Shannon et al.
| |
| 4463363 | Jul., 1984 | Gundlach et al.
| |
| 4524371 | Jun., 1985 | Sheridon et al.
| |
| 4593994 | Jun., 1986 | Tamura et al.
| |
| 4643414 | Feb., 1987 | Weisgerber.
| |
| 5006761 | Apr., 1991 | Török et al.
| |
| 5153618 | Oct., 1992 | Frank et al.
| |
| 5497987 | Mar., 1996 | Henn et al.
| |
| 6038998 | Mar., 2000 | Platsch.
| |
| Foreign Patent Documents |
| 1 286 051 | Jan., 1969 | DE.
| |
| 24 46 798 | Apr., 1978 | DE.
| |
| 34 13 179 | Oct., 1985 | DE.
| |
| 43 08 276 | Sep., 1994 | DE.
| |
| 197 33 691 | Jun., 1998 | DE.
| |
| 1085743 | Oct., 1967 | GB.
| |
| PCTEP99/04864 | Feb., 2000 | WO.
| |
Primary Examiner: Nguyen; Anthony H.
Attorney, Agent or Firm: Greenberg; Laurence A., Stemer; Werner H., Mayback; Gregory L.
Claims
1. In combination with a duplicating machine, a device for generating an air
stream in the duplicating machine, comprising:
at least one fan unit having one of a sequence of ionic fans and a matrix configuration
of ionic fans, said ionic fans being supplied with a voltage for generating and
accelerating gas ions by a discharge for accelerating non-ionized gas by pulse
transmission and generating the air stream, said ionic fans being one of individually
controlled and individually regulated by the voltage in order to generate one of
a desired flow profile and a desired flow field.
2. The device according to claim 1, wherein said ionic fans are disposed substantially
adjacent one another along a given apace curve.
3. The device according to claim 1, wherein said ionic fans are disposed substantially
adjacent one another along a straight line.
4. The device according to claim 1, wherein said ionic fans are disposed substantially
adjacent one another and spread over a given area.
5. The device according to claim 1, wherein said at least one fan unit is configured
to be disposed adjacent a transport path for flat products.
6. The device according to claim 1, wherein said at least one fan unit is configured
to be disposed adjacent a transport path for print carriers.
7. The device according to claim 1, wherein said at least one fan unit is configured
to be disposed adjacent a transport path for flat products selected from the group
consisting of paper sheets and cardboard sheets.
8. The device according to claim 1, wherein said at least one fan unit is configured
to be disposed adjacent a transport path for a flat product and said at least one
fan unit is configured to act upon at least a part of a region surrounding the
flat product with a pressure for guiding the flat product, the pressure is selected
from the group consisting of an overpressure as compared to an ambient pressure
and an underpressure as compared to the ambient pressure.
9. The device according to claim 1, including:
a powder container for holding powder; and
at least one feed unit connected to said powder container and transporting the
powder from said powder container into the air stream of said ionic fans.
10. The device according to claim 9, wherein said powder container, said at least
on feed unit and said ionic fans are configured to apply the powder to flat products.
11. The device according to claim 9, wherein said powder container, said at least
one feed unit and said ionic fans are configured to apply the powder to print carriers
selected from the group consisting of paper sheets and cardboard sheets.
12. The device according to claim 10, wherein said ionic fans are configured
to be controlled for a zonal powdering of the flat products.
13. The device according to claim 12, wherein the flat products define a transport
direction and said ionic fans are configured to be controlled in a direction transverse
to the transport direction.
14. The device according to claim 10, wherein said at least one feed unit is
a plurality of individually controllable feed units configured to be controlled
for a zonal powdering of the flat products.
15. The device according to claim 14, wherein the flat products define a transport
direction and said plurality of individually controllable feed units are configured
to be controlled in a direction transverse to the transport direction.
16. The device according to claim 10, including at least one further fan unit
configured to suck away excess powder from a region surrounding the flat products.
17. The device according to claim 1, wherein the duplicating machine is a printing machine.
18. A duplicating machine configuration, comprising:
a duplicating machine including an air stream generator for generating an air
stream; and
said air stream generator for generating the air stream including at least one
fan unit having one of a sequence of ionic fans and a matrix configuration of ionic
fans, said ionic fans being supplied with a voltage for generating and accelerating
gas ions by a discharge for accelerating non-ionized gas by pulse transmission
and generating the air stream, said ionic fans being one of individually controlled
and individually regulated by the voltage in order to generate one of a desired
flow profile and a desired flow field.
19. A printing machine configuration, comprising:
a rotary offset printing machine including an air stream generator for generating
an air stream; and
said air stream generator for generating the air stream including at least one
fan unit having one of a sequence of ionic fans and a matrix configuration of ionic
fans, said ionic fans being supplied with a voltage for generating and accelerating
gas ions by a discharge for accelerating non-ionized gas by pulse transmission
and generating the air stream, said ionic fans being one of individually controlled
and individually regulated by the voltage in order to generate one of a desired
flow profile and a desired flow field.
20. A delivery configuration for a duplicating machine, comprising:
a delivery including an air stream generator for generating an air stream; and
said air stream generator including at least one fan unit having one of a sequence
of ionic fans and a matrix configuration of ionic fans, said ionic fans being supplied
with a voltage for generating and accelerating gas ions by a discharge for accelerating
non-ionized gas by pulse transmission and generating the air stream, said ionic
fans being one of individually controlled and individually regulated by the voltage
in order to generate one of a desired flow profile and a desired flow field.
21. In combination with a duplicating machine, a cylinder configuration, comprising:
a cylinder disposed in the duplicating machine, said cylinder having an interior
region;
an air stream generator for generating an air stream disposed in said interior
region of said cylinder; and
said air stream generator including at least one fan unit having one of a sequence
of ionic fans and a matrix configuration of ionic fans, said ionic fans being supplied
with a voltage for generating and accelerating gas ions by a discharge for accelerating
non-ionized gas by pulse transmission and generating the air stream, said ionic
fans being one of individually controlled and individually regulated by the voltage
in order to generate one of a desired flow profile and a desired flow field.
22. The cylinder configuration according to claim 21, wherein the duplicating
machine is a rotary offset printing machine.
23. A method for guiding flat products in a duplicating machine, the method which comprises:
generating a flow field of air streams with at least one fan unit having one
of a sequence of ionic fans and a matrix configuration of ionic fans, the ionic
fans being supplied with a voltage for generating and accelerating gas ions by
a discharge for accelerating non-ionized gas by pulse transmission and generating
an air stream, the ionic fans being one of individually controlled and individually
regulated by the voltage in order to generate one of a desired flow profile and
a desired flow field; and
guiding flat products, at least in given sections of a duplicating machine, with
the flow field of air streams.
24. The method according to claim 23, which comprises guiding print carrier as
the flat products.
25. The method according to claim 23, which comprises providing individually
controllable ionic fans as the controllable ionic fans.
26. A method of depositing flat products in a duplicating machine, the method
which comprises:
generating a flow field of air streams with at least one fan, unit having one
of a sequence of ionic fans and a matrix configuration of ionic fans, the ionic
fans being supplied with a voltage for generating and accelerating gas ions by
a discharge for accelerating non-ionized gas by pulse transmission and generating
an air stream, the ionic fans being one of individually controlled and individually
regulated by the voltage in order to generate one of a desired flow profile and
a desired flow field; and
at least supporting a depositing of flat products with the flow field of air
streams in a duplicating machine.
27. The method according to claim 26, which comprises providing print carriers
as the flat products.
28. The method according to claim 26, which comprises providing individually
controllable ionic fans as the controllable ionic fans.
29. A method of powdering print carriers in a duplicating machine, the method
which comprises:
generating a flow field of air streams with at least one fan unit having one
of a sequence of ionic fans and a matrix configuration of ionic fans, the ionic
fans being supplied with a voltage for generating and accelerating gas ions by
a discharge for accelerating non-ionized gas by pulse transmission and generating
an air stream, the ionic fans being one of individually controlled and individually
regulated by the voltage in order to generate one of a desired flow profile and
a desired flow field; and
feeding powder to print carriers in a duplicating machine by using the flow field
of air streams for performing a zonal powdering of the print carriers.
30. The method according to claim 29, which comprises providing individually
controllable ionic fans as the controllable ionic fans.
31. A method of transporting print carriers in a duplicating machine, the method
which comprises:
generating blast air with at least one fan unit having one of a sequence of ionic
fans and a matrix configuration of ionic fans, the ionic fans being supplied with
a voltage for generating and accelerating gas ions by a discharge for accelerating
non-ionized gas by pulse transmission and generating an air stream, the ionic fans
being one of individually controlled and individually regulated by the voltage
in order to generate one of a desired flow profile and a desired flow field; and
using the blast air for one of transporting and assisting a transport of print
carriers at least in one section of a duplicating machine.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a device for generating an air stream in a duplicating
machine, in particular in a printing machine. The invention relates, furthermore,
to methods for guiding and depositing flat products, in particular print carriers,
in duplicating machines. The invention also relates to a method for the zonal powdering
of print carriers in duplicating machines. The invention also relates to a delivery
configuration and to a method of guiding and/or transporting flat products.
It is known, in duplicating machines, for example in printing machines, which
process sheetlike or weblike flat products, in particular print carriers, to assist
the transport of the flat products through the use of an air stream.
In this way, for example, in rotary printing machines paper sheets are guided
by transport grippers at a front edge of the sheets and, in addition, their trailing
sheet surface is supported by an air cushion. Thus a situation can be prevented
where the sheet touches components of the printing machine and is damaged or where
smudging of the freshly printed-on printing ink occurs.
Such a guide device for a sheet with an air flow between the sheet and a sheet
guide surface is known from Published, Non-Prosecuted German Patent Application
No. DE 43 08 276 A1 corresponding to U.S. Pat. No. 5,497,987. A respective sheet
is exposed to an air flow generated through the use of a plurality of air jets
which emerge from flow ducts provided in the sheet guide surface, the flow ducts
having the form of perforations at the sheet guide surface. These perforations
are provided with blowing nozzles which are connected to a compressed-air source
via blowing-air lines, and, where appropriate, the blowing-air lines can be opened
and closed individually or in functional groups through the use of adjustable valves.
A guide device of the type described above has the disadvantage that it is not
possible to set the air flow accurately, since the strength of the individual air
jets cannot be regulated in a continuous manner. Moreover, in order to modify the
generated flow profile, it would be necessary to exchange the guide device for
a second guide device having a modified nozzle configuration.
Further, fans may be used in deliveries of printing machines. Through the
use of such fans, the printed sheets, which are released by the transport grippers,
are pressed downward onto a depositing pile. German Patent No. DE 34 13 179 C2,
corresponding to U.S. Pat. No. 4,643,414, describes a control and regulating device
of a sheet delivery for sheet-processing machines. In this case, the sheets are
supported, during depositing, by an air flow which is caused by blowing fans provided
above the transport path of the sheets. The fans may be driven individually, in
longitudinal or transverse rows, in a diagonal row or in any combination at a higher
or lower rotational speed or else switched off completely.
However, since the fans have very large dimensions, only a small number
can be provided adjacently to the sheet transport path, and therefore it is not
possible to generate a desired flow field with a high degree of inaccuracy.
Furthermore, blower units are also used during the powdering of freshly
printed sheets in the delivery of a printing machine. Published, Non-Prosecuted
German Patent Application No. DE 197 33 691 A1, corresponding to U.S. Pat. No.
6,038,998, shows a sheet-processing rotary printing machine, in which the sheets
are guided over an air cushion. In this case, above the transport path, powder
nozzles are provided, through the use of which the powder is applied to the sheets
in an air/powder mixture. Powder nozzles which are acted upon by powdering gas
may also be provided in guide plates provided below the sheet transport path.
In the described device for the powdering of sheets, undesirable turbulences
of
the air/powder mixture may occur, with the result that the powder settles on components
of the printing machine, so that these have to be cleaned regularly. Accurate zonal
powder application is not possible with the aid of the device described.
Moreover, the prior art, such as, for example, U.S. Pat. No. 5,006,761
and U.S. Pat. No. 4,210,847, discloses fans which, instead of using a rotating
propeller, utilize the phenomenon of electrical discharge. U.S. Pat. No. 4,210,847
shows a fan element having an outer cylindrical nonconductive housing, at one end
of which a grounded grid is mounted, while a wire applied to a voltage is provided
at the other end. When a voltage of up to 20 kV is applied, discharge takes place
at the front uninsulated end of the wire, thus generating, in the vicinity of the
wire, ions which are accelerated toward the grounded grid due to the prevailing
electrical field. By pulse transmission, even noncharged air molecules are accelerated
in the direction of the grid aperture of the fan element, with the result that
an air stream of up to 500 ft./min (about 15 m/min) is obtained. Such a fan element
is distinguished by a high degree of reliability, along with a simple configuration
and a low weight, and by an air stream which can be controlled by the applied voltage.
U.S. Pat. No. 5,006,761 describes a similar device for generating an air stream,
which, in addition to preventing point discharges and reducing the production of
toxic gases due to the discharges, provides an essentially spherical body which
is attached to the tip of the discharge wire, with the result that a discharge
takes place uniformly on the outer surface of the discharge wire.
Moreover, a German company named ETR-GmbH in Dortmund, Germany has developed
a fan which likewise utilizes the acceleration of charged air molecules between
a discharge electrode and a target electrode for flow generation and which reaches
flow velocities of up to 3 m/s. It is also proposed to combine individual fans
into fan configurations, for example as a planar checkered configuration, in order
thereby to increase the flow cross section. In the case of a cross-sectional area
of 1 m
2, a volume flow of 11,000 m
3/h can be generated through
the use of the fans described.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a device for generating
an air stream in a duplicating machine which overcomes the above-mentioned disadvantages
of the heretofore-known devices of this general type and which has a simple and
maintenance-free construction and which makes it possible to control the strength
of the air stream accurately and simply.
It is accordingly another object of the invention to provide methods for guiding
and depositing flat products in duplicating machines, in which methods flow fields
are generated, the local strength of which can be controlled accurately and in
a simple manner.
An object of the present invention is, furthermore, to provide a method for the
zonal powdering of print carriers in duplicating machines, in which method a flow
field is generated, the local strength of which can be controlled accurately and simply.
With the objects of the invention in view there is provided, in combination
with a duplicating machine, a device for generating an air stream in the duplicating
machine, including:
at least one fan unit for generating the air stream; and
the at least one fan unit having at least one ionic fan.
In other words, the device according to the invention for generating an air stream
in a duplicating machine, in particular in a printing machine, which has at least
one fan unit, is distinguished in that the at least one fan unit includes at least
one ionic fan.
The device according to the invention allows the printer to control the air stream
accurately by the supply of voltage to the ionic fan. Furthermore, with the accuracy
of the control of the air stream being maintained, the dimensions of the ionic
fan can be reduced appreciably, as compared with conventional propeller fans, with
the result that, according to the invention, the printer achieves a saving of space
in the duplicating machine by the use of one or more ionic fans. It is possible,
moreover, to provide the electrodes of the at least one ionic fan on a carrier,
with the result that such a configuration, for example planar, of the electrodes
can be reduced in dimensions down to the microstructure range through the use of
known cost-effective production processes. The use of ionic fans also leads advantageously
to a reduction in the noise level and to wear-free operation, since moved parts,
such as, for example, the propellers, are dispensed with and there is consequently
also no need to keep these in stock. The latter aspect results, as compared with
known fans, in a markedly increased useful life.
In a further refinement of the device according to the invention, the at least
one fan unit may include a number of ionic fans provided essentially adjacent to
one another so as to follow a space curve, in particular so as to follow a straight
line. It is thereby possible, according to the invention, to set up and provide,
for example, rows of ionic fans transversely, parallel or in any desired orientation
to the direction of transport of flat products in the duplicating machine. Furthermore,
due to the compact form of construction, even curved configurations of ionic fans
can be produced, which, for example, can be adapted to the contour of a printing-unit
cylinder in a printing machine and be provided in the vicinity of the cylinder.
A further version according to the invention may include a suction strip or a blowing
strip at points of transfer of flat products, for example sheets, from one transport
system to a following transport system, for example from one transport cylinder
to the next, the strips assisting the transfer of products, for example in order
to prevent damage to the products.
It is also possible, moreover, for the at least one fan unit of the device according
to the invention to include a number of ionic fans provided essentially adjacently
to one another and distributed over a given area, in particular over a level or
planar area. For example, a matrix of ionic fans can thereby be set up in the simplest
possible way, in which the ionic fans are provided next to one another in a check-board
configuration or a honeycomb configuration, and such an ionic-fan matrix can be
provided preferably in the vicinity of the transport path of flat products in a
duplicating machine and act upon the flat products such print carriers through
the use of an air stream. It is also possible to provide such a matrix of ionic
fans with any desired curvature in space, in order, for example, to integrate it
into the meandering transport path of print carrier sheets in a sheet-fed rotary
printing machine.
According to another feature of the invention, the electrodes of individual
ionic fans may be provided on printed circuit boards and thus very many and very
small ionic fans may be provided in a confined space. A circular target electrode,
as an example, can have a diameter of 100 μm and be provided at a distance
of a few centimeters from adjacent target electrodes. Such fan assemblies can be
used preferably in copiers.
In a way according to the invention, the number of ionic fans can be controlled
individually in order to generate a desired flow field, that is to say each individual
ionic fan generates a desired flow, so that the superposition of the individual
flows produces a desired flow field. Such a flow field may, in this case, have
any desired contour, for example the flow strength may decrease toward the edge
regions transversely to the direction of transport of a flat product in a duplicating machine.
It is possible, moreover, during the transport of flat products, to support their
trailing free end through the use of a specifically set flow field during transport,
in such a way that flapping of the tailing end is reduced or is suppressed essentially
completely. Thus, for example, known detection devices may be used for determining
the position of the free end of a flat product in space and the local strength
of the flow field may be modified, for example via a regulating device, in such
a way that this position is approximated or brought closer to a desired position
of the free end of a flat product. It is also possible, by a presence detection
devices, to determine whether a flat product is located in the vicinity of one
or more ionic fans, and, in the absence of the flat product, at least to reduce
the output of the respective ionic fans. Furthermore, it is possible to switch
off individual ionic fans of the fan configuration, which, for example during the
processing of small-format flat products, generate an air stream outside the region
of the flat products. In this case, for example, optical or acoustic, in particular
ultrasonic single-point sensing methods and devices or else methods operating over
a large area, using stereoscopy or strip projection, may be employed for sheet
position detection.
According to the invention, the air streams of individual ionic fans may
also have different directions. This may take place, for example, as a result of
the mechanical orientation of the individual fans or else, preferably, in that
the target electrodes of the fans are set up in such a way that they can be activated
in a segmented manner. Thus, for example, the annular target electrode of a fan
may be subdivided into four segments which can be individually provided with a
voltage, with the result that the ionic current is deflected or guided from the
discharge electrode to the target electrode segment provided with voltage and therefore
leaves the ionic fan in a variably controllable direction.
A device according to the invention may be distinguished, furthermore, in that
the at least one fan unit is provided adjacent to a transport path of flat products,
in particular of print carriers, for example paper sheets or board sheets. By virtue
of the configuration according to the invention adjacent to the transport path,
it advantageously becomes possible favorably to influence or guidingly to support
or assist the transport of the flat products through the use of the air flow generated
by the fan unit. Thus, for example, a large-area configuration of ionic fans may
be used, instead of a conventional sheet guide plate, for guiding print carrier
sheets in a machine processing print carrier sheets, with the result that a stabilized
transport of the print carrier sheets is achieved and smudging of freshly printed-on
printing ink at the guide device can advantageously be prevented. At the same time,
according to the invention, in contrast to the use of conventional guide plates,
it is possible, when the large-area ionic fan configuration is used, to modify
the flow strength locally and thus act specifically on the flat products. In the
prior art, this can be carried out only by exchanging the guide plate. In this
respect, the device according to the invention may advantageously be configured
in such a way that it is suitable for acting upon at least part of the surroundings
of the flat products with overpressure or underpressure, as compared with the normal
atmospheric pressure or ambient pressure, for the purpose of guiding the flat products.
In general, it is possible to use the ionic fans in two different operative directions,
so that, for example, they can exert a sucking or blowing action on the print carrier
sheets in the direction of these print carriers. Thus, during the above-described
guidance of the print carrier sheets while being transported through a sheet-processing
machine, it may be advantageous, for example, to act upon the trailing end of the
guided print carrier sheet with overpressure, in order to prevent these ends of
the print carrier sheets from coming into contact with the blowing device or other
guide devices, but it may also be advantageous to act upon a trailing end of a
guided print carrier sheet with underpressure. Thus, for example, it is advantageous,
during the guidance of the print carrier sheet through the use of a transport cylinder,
the front end of the print carrier sheet being retained by transport grippers of
the transport cylinder, to suck up and retain the trailing end of the print carrier
sheet on the transport cylinder through the use of a generated underpressure and
thereby prevent the trailing end from coming into contact with other components
in the vicinity of the transport path of the print carrier sheets. In sheet turning
devices, too, a print carrier sheet can be guided and turned by adhesion on the
turning drum through the use of a generated underpressure. For this purpose, according
to the invention, fan units containing ionic fans may be provided within a cylinder
or may be integrated into the surface of the latter.
A further device according to the invention is distinguished in that a powder
container
with at least one feed unit is provided, the feed unit transporting the powder
from the powder container into the air stream of the at least one ionic fan. It
thus becomes possible also, for example, to apply powder to print carrier sheets
via the accurately controllable electrically charged air stream of the ionic fan,
uncontrollable powder turbulences advantageously being avoided and the specific
local application of powder to the print carrier sheet thereby being possible.
In this case, the charged air molecules may serve as carriers for the powder particles
which are bound via electrostatic forces to the charged air molecules or are entrained
by these likewise via electrostatic forces. Linear or areal, i.e. flat, configurations
of powder devices, which are operatively connected to ionic fans, may also be provided
according to the invention, with the result that, for example, a linear powder
application transversely to the direction of transport of the print carrier sheets
or else areal application of powder to these print carrier sheets becomes possible.
Due to the controllability of the ionic fans, it is also possible, in addition
to the normal continuous powder application, to produce a powder profile and transfer
it specifically to the print carrier sheets. What can be achieved thereby is that
respective printed zones on a print carrier are acted upon by different powder
quantities according to the quantity of their ink or lacquer application. This
advantageously leads to a saving of powder for the printer, since this can be adapted
exactly to the necessary powder requirement on the print carrier sheet. Moreover,
particularly in zones of the print carrier sheet in which no ink has been applied,
the powder quantity can be reduced to a minimum or even completely. It is also
possible, furthermore, to suck away any excess powder from the surroundings of
the print carriers through the use of at least one further fan unit. In this case,
the at least one further fan unit, which may likewise include at least one ionic
fan, may be provided adjacently to the powder application fan units, or, in the
case of a linear or areal configuration of the powder application fan unit, suctioning
or vacuuming individual fans or fan groups may also be provided between the applying
individual fans of the fan unit. The sucked-away powder may advantageously be introduced
again into the powder circuit of the machine processing print carriers, thus resulting
in a further cost saving for the printer.
Since a charge can also be transmitted to the flat products through the use
of the ionic fans, ionizing strips, which, if appropriate, are present in the duplicating
machine for charging the flat products, can advantageously be dispensed with.
According to an advantageous mode of the invention, the powder container,
the at least one feed unit and the at least one ionic fan are configured to apply
the powder to flat products, such as print carriers and in particular paper sheets
and cardboard sheets.
According to another mode of the invention, the at least one ionic fan
includes a plurality of individually controllable ionic fans configured to be controlled
for a zonal powdering of the flat products. The controllable ionic fans are advantageously
configured to be controlled in a direction transverse to the transport direction.
With the objects of the invention in view there is also provided, a duplicating
machine configuration, including a duplicating machine, such as a printing machine,
including an air stream generator for generating an air stream, and the air stream
generator for generating the air stream including at least one fan unit having
at least one ionic fan.
With the objects of the invention in view there is further provided, a delivery
configuration for a duplicating machine, including a delivery having an air stream
generator for generating an air stream, and the air stream generator including
at least one fan unit having at least one ionic fan.
With the objects of the invention in view there is also provided, in combination
with a duplicating machine, a cylinder configuration, including a cylinder disposed
in the duplicating machine, the cylinder having an interior region, and an air
stream generator for generating an air stream disposed in the interior region of
the cylinder, the air stream generator having at least one fan unit with at least
one ionic fan. The duplicating machine may be a rotary offset printing machine.
With the objects of the invention in view there is also provided, a method for
guiding flat products in a duplicating machine, the method includes the steps of:
generating a flow field of air streams with a plurality of controllable
ionic fans of a fan unit;
guiding flat products, at least in given sections of a duplicating machine,
with the flow field of air streams.
In other words, a method according to the invention for guiding flat products,
in particular print carriers, in duplicating machines, the flat products being
guided at least partially by an air stream, is distinguished in that a flow field
is generated, using a fan unit having a number of controllable, in particular individually
controllable ionic fans. By the flow field being generated with any desired predeterminable
contour, the flat products can advantageously be guided, stabilized, and damage,
particularly to their surface, can be prevented. It is also advantageously possible
to adapt the flow field in a continuous manner or in steps to the transport conditions
in the duplicating machine or to disturbing influences, for example caused by drying
devices, for example to the flat products guided past the fan units, in particular
to their position in space or even to their presence or absence. Due to the action
on the flat products through the use of the number of ionic fans, it is thus possible
to ensure that a maximum permissible flapping amplitude of the flexible flat products,
which depends inter alia on the weight of the flat products, is maintained.
With the objects of the invention in view there is also provided, a method of
depositing flat products in a duplicating machine, the method includes the steps of:
generating a flow field of air streams with a plurality of controllable
ionic fans of a fan unit; and
at least supporting a depositing of flat products with the flow field of air
streams
in a duplicating machine.
In other words, a further method according to the invention, which is used when
flat products are deposited in duplicating machines, in particular when print carriers
are deposited, the depositing of the flat products being at least assisted by an
air stream, is distinguished by the generation of a flow field, using a fan unit
having a number of controllable, in particular individually controllable ionic
fans. When the method according to the invention is used, an advantageously controllable
and therefore controlled depositing of flat products, in particular of print carriers,
is achieved. By the flow field being generated through the use of the individually
controllable ionic fans, the depositing of flat products can be carried out in
such a way that a compact deposited pile of sheets without displaced individual
sheets is obtained. In this case, it is advantageously possible, for example, by
the method according to the invention, to generate a flow field such that the print
carriers to be deposited are pressed centrally onto the depositing pile very firmly
by the individual flows in a direction transverse to the direction of transport
of the print carriers, while the strength of the individual flows is reduced outward
in the outer regions. The sheet newly to be deposited is thus pressed onto the
depositing pile from the center toward the outer regions, so that an air cushion
possibly present under the sheet newly to be deposited can escape, transversely
to the direction of transport, from under the print carrier sheet during the depositing
operation. Furthermore, the flow field can also be adapted to the material properties
of the print carriers or other flat products to be deposited, such as, for example,
to their bendability, with the result that, both in the case of very thin and flexible
products and in the case of thicker and less bendable flat products, such as for
example, board sheets, the depositing can be carried out in a desired way, in a
controlled manner and without damage being caused to the flat products.
With the objects of the invention in view there is also provided, a method of
powdering print carriers in a duplicating machine, the method includes the steps of:
generating a flow field of air streams with a plurality of controllable
ionic fans of a fan unit; and
feeding powder to print carriers in a duplicating machine by using the flow
field of air streams for performing a zonal powdering of the print carriers.
In other words, a method according to the invention for the zonal powdering of
print carriers in duplicating machines, in particular in printing machines, the
powder being fed to the print carriers by an air stream, is distinguished by the
generation of a flow field, using a fan unit having a number of controllable, in
particular individually controllable ionic fans. The method according to the invention
makes it possible to carry out the application of powder to the print carriers
in a turbulence-free manner and with a locally varying powder feed. As a result,
advantageously, even those print orders which have zonally highly fluctuating ink
applications can be provided with a zonally varied powder quantity.
Furthermore, it is advantageously possible to combine the methods for
guiding or for depositing flat products with the method for powdering print carriers,
that is to say to use at least some of the ionic fans, used for guiding and depositing,
at the same time for powdering.
In general, it is also possible, in the above-described devices and methods,
to
activate the individually controllable ionic fans in a configuration of a plurality
of ionic fans by computer assistance, in which case preset values for the varying
flow strengths of the individual ionic fans can be gathered, for example, from
preprepared flow profiles which, for example, are stored. Such flow profiles may
have been filed, that is to say stored, for example, for varying print orders,
print carriers, varying ink or dampening-medium application or else for varying
production-run speeds. However, it is also advantageously possible, furthermore,
to calculate the flow profiles from measured printing parameters of a printing
machine, such as, for example, a production-run speed of the latter, and to modify
the flow profiles during the operation of the duplicating machine. For example,
the flow profile of a sheet guide device in the case of an increasing production-run
speed can be reinforced as a whole.
With the objects of the invention in view there is also provided, a method of
transporting print carriers in a duplicating machine, the method includes the steps of:
generating blast air with at least one ionic fan; and
using the blast air for one of transporting and assisting a transport of print
carriers at least in one section of a duplicating machine.
Other features which are considered as characteristic for the invention are
set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in
a device and a method for generating an air stream in a duplicating machine, it
is nevertheless not intended to be limited to the details shown, since various
modifications and structural changes may be made therein without departing from
the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together
with additional objects and advantages thereof will be best understood from the
following description of specific embodiments when read in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic sectional view of an ionic fan according to the invention;
FIG. 2 is a diagrammatic sectional view of a linear configuration of a plurality
of ionic fans according to the invention for guiding a print carrier sheet;
FIG. 3 is a diagrammatic perspective view of a matrix configuration of ionic
fans according to the invention in the delivery of a printing machine;
FIG. 4 is a diagrammatic sectional view of a powder device with an ionic fan
according to the invention for powdering print carriers; and
FIG. 5 is a diagrammatic side view of a duplicating machine including ionic
fans according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawings in detail and first, particularly,
to FIG. 1 thereof, there is shown a sectional view, the diagrammatic configuration
of an ionic fan
2, the latter being limited outwardly by a nonconductive
housing
4 which may be formed, for example, of a glass or a ceramic. The
ionic fan
2 is delimited at its front end by a conductive grid
8,
while an electrically conductive wire
6 provided with an insulation
10
is positioned at its rear end through the use of fastening arms, which are not
illustrated. The insulation
10 likewise may be formed of a glass or a ceramic.
Instead of the grid
8, a conductive ring may also be provided at the front
end of the ionic fan
2. In the exemplary embodiment shown, a device for
generating a voltage
14 is provided, which is connected via a line
18
to the wire
6 and via a line
16 to the grid
8. A voltage or
a high voltage, for example of the order of magnitude of about 2 to 3 kV, can thereby
be generated between the wire
6 and the grid
8. It is also possible,
however, for the grid
8 to be grounded and for the voltage device
14
to be connected only via a line
18 to the wire
6, a voltage thereby
being generated at the wire
6 in relation to ground. The applied voltage
primarily brings about a discharge at the front end
12 of the wire
6,
with the result that, in the vicinity of this end
12, gas ions are generated
which undergo acceleration in the direction of the grid
8 in the electrostatic
field between the wire
6 and the grid
8. By pulse transmission from
the gas ions to nonionized gas atoms or gas molecules
20, these, too, are
accelerated in the direction of the grid
8, this giving rise to an air stream
through the housing
4 of the ionic fan
2, which leaves the ionic
fan
2 as a directed flow
22. An air stream with a range of about
20 cm can thus be generated. Air is thereby sucked into the interior of the ionic
fan
2 from outside at a rear end of the ionic fan
2, as indicated
by the arrow
24.
It is also conceivable to use only an annular diaphragm as an electrode instead
of the grid
8. When a plurality of individually activated annular diaphragms
or apertures with different diameters are used, the aperture diameter of the ionic
fan can be modified by the selected activation of a specific annular diaphragm
and therefore, with the air stream volume remaining the same, the flow velocity
can be modified.
FIG. 2 shows a sequence of ionic fans
2 which have a configuration as
described in FIG.
1 and are provided closely next to one another. Each individual
ionic fan
2 has, in turn, an insulating housing
4 and an insulation
10 and also an electrically conductive grid
8 and an electrically
conductive point
6 which are electrically connected to a voltage device
32 in each case via a line
16 and
18, a carrier
30
and further lines
34. Provided on the carrier
30, are conductive
connections from the respective lines
16 and
18 of each individual
ionic fan
2 to respective lines of the number of lines
34 of the
voltage device
32, so that the voltage device can apply a desired voltage
or high voltage to selected ionic fans
2 via a control device, which is
not illustrated. This voltage can be applied to the ionic fan for a relatively
long period of time, but there may also be provision for modifying the voltage
in time. Three selected ionic fans
2 generate the same air stream
38
in each case, which is illustrated by the same length and the same number of arrows
38. Three further selected ionic fans
2 generate a locally variable
air profile
39 which corresponds to a linear flow field and is illustrated
by the different length of the arrows
39. A print carrier sheet
50,
which is transported by a transport gripper
40, through the use of gripper
fingers
42 and gripper supports
44 attached to it, has, particularly
at its freely trailing end
52, a wavy profile which corresponds to the flow
profile
39. As may be gathered from FIG. 2, the print carrier sheet
50
can be spaced further away from the ionic fans
2 through the use of a stronger
air stream
39a and the print carrier sheet
50 can be brought
nearer to the ionic fans
2 through the use of a weaker air stream
39b.
A specific action of the ionic filters
2 on the position of the print carrier
sheet
50 is thereby possible. By a detection device, not illustrated, for
detecting the position of the print carrier sheet
50 in space, in particular
the position of the print carrier sheet in relation to the row of ionic fans
2,
position-related measurement values can be transmitted to an integrated control
device in the voltage device
32, so that the latter can modify the flow
profile
39 of selected ionic fans via a modified voltage in order to correct
the position of the print carrier sheet
50.
FIG. 3 shows a matrix configuration of ionic fans
2 which all have a
conductive outlet orifice, for example in the form of a grid
8 or merely
a conductive border of the nonconductive housing and a conductive discharge point
6. The two electrodes
6 and
8 are conductively connected to
a voltage device
16 via respective lines
18 and
16. In a similar
way to that described in FIG. 2, each individual ionic-fan segment
2 of
the matrix configuration can be individually activated by the voltage device
14
via lines and the air flow of each individual segment can be set as a result. It
thereby becomes possible to generate a flow profile or a flow field
62 which,
as shown in FIG. 3, may, for example, have a V-shape in cross section. A print
carrier sheet
59 which is to be deposited on a depositing pile
60
and is fed to the depositing pile
60 in the direction of the arrow
64
is pressed by the flow profile
62 onto the depositing pile
60 more
firmly in the center
66 of the flow profile
62 than in the edge regions
68 of the flow profile
62. The air located under the print carrier
sheet
59 to be deposited can thereby escape transversely to the direction
64.
The powder device shown in FIG. 4 includes an ionic fan
2 having discharge
electrodes
6 and
8 which are connected to a voltage device
14
via lines
16 and
18. Also shown are a powder storage container
70
with powder
72 contained therein and a metering device
74 with a
metering roller
76. The powder
72 in the storage container
70
is conveyed through a gap between the metering roller
76 and the outer wall
of the metering device
74 as a result of the rotation of the metering roller
76 and is fed to the air stream of the ionic fan, thus giving rise to an
air/powder mixture
78 which is blown onto a print carrier sheet
50.
At the same time, the rotational speed of the metering roller
76 and/or
the voltage applied to the ionic fan
2 can be adapted to the machine speed,
with the result that speed-compensated powdering becomes possible. The print carrier
sheet
50 is, in this case, transported by a transport gripper
40
through the operative region of the powder device and over and beyond a guide device
80. Powder devices of this type may be provided next to one another, transversely
to the transport path of the print carrier sheets
50, in a way not illustrated
and can thus apply the powder to the print carrier sheet
50 in a zonally
meterable manner. A further fan unit
90 configured to suck away excess powder
from the print carrier and its surroundings is schematically shown.
FIG. 5 shows, in diagrammatic form, a duplicating machine
101, such as
a printing machine, including ionic fans according to the invention. The duplicating
machine
101 includes a sheet feeder
102 with a pile of sheets
103
to be processed. A duplicating unit
108 includes a cylinder
142.
A fan unit
143 including ionic fans is disposed in an interior region of
the cylinder
142. A delivery
104 including a further fan unit
144
deposits the sheets in a delivery pile
105.
*
