Method and apparatus for corrugating a flat material

The present invention relates to a method and apparatus for transporting a flat printed material being conveyed, such as a printed web of material, a ribbon, a signature, or the like. An exemplary apparatus includes a pair of seizing elements for transporting a web of material, and corrugation inducing elements arranged along a linear path adjacent to each other. The corrugation inducing elements are provided in a non-contacting manner on both sides of a transition area within which the flat printed material is conveyed, the corrugation inducing elements substantially extending along the transition area which is located between an output of the pair of seizing elements and the input to further processing elements to corrugate the flat printed material.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention is related to a method and apparatus for corrugating 
a flat material, such as a printed web in a folding apparatus assigned to 
a rotary printing press. 
2. State of the Art 
U.S. Pat. No. 5,029,842 relates to signature handling apparatus having a 
first conveyor which sequentially moves signatures to a discharge station. 
At the discharge station, the signatures are sequentially transferred to a 
receiving conveyor. A corrugator assembly is located at the discharge 
station to stiffen the signatures by forming corrugations which extend 
between leading and trailing end portions of the signatures. Although the 
corrugations are only temporarily maintained in the signature, the 
corrugator assembly is close enough to the receiving conveyor that a 
corrugation is maintained as a leading end portion of the signature moves 
to the receiving conveyor. Thus, the corrugator assembly is spaced from 
the receiving conveyor by a distance which is less than the distance 
between the leading and trailing end portion of the signatures. 
U.S. Pat. No. 5,107,733 relates to an apparatus for cutting and 
transporting a paper web in a folding apparatus of a printing press. The 
apparatus includes a pair of cutting cylinders for cutting web sections 
from the web, and a transporting device for transporting the web sections 
away from the cutting cylinders. The first cutting cylinder has at least 
one cutting anvil, and the second cutting cylinder has at least one 
cutting knife which meets the cutting anvil at a nip between the cutting 
cylinders to cut the web moving through the nip. A plurality of strips are 
supported on the first cutting cylinder and a plurality of strips are 
supported on the second cutting cylinder. The strips have positions on the 
cutting cylinders at which they impress a temporary reinforcing profile 
onto each newly formed leading portion of the web, when the strips move 
through the nip. At least one smoothing surface is also supported on the 
first cutting cylinder and at least one smoothing surface is also 
supported on the second cutting cylinder. The smoothing surfaces have 
positions on the cutting cylinders, wherein the smoothing surfaces remove 
the temporary reinforcing profile from the leading portion of the web when 
the smoothing surfaces move through the nip. 
The above-mentioned approaches impose a corrugated profile in order to 
stiffen the leading edge of a ribbon, web or signature by corrugating the 
ribbon, web, or signature with rollers having opposing large and small 
diameter sections. The roller surfaces can be steel brushes, Velcro-tape, 
or urethane, and must contact the ribbon, web or signature. This causes 
the roller surfaces to wear and can cause marking of the ribbon, or web 
signature. Different materials have consequently been used to prolong the 
life of the various roller components, although wear of these components 
still occurs. 
Known corrugating methods also have a large sensitivity to position 
adjustments, and different designs have been developed in an effort to 
reduce the sensitivity of the position adjustments. Furthermore, known 
methods of corrugating induce corrugation locally, such that the 
corrugation effect must be projected to the location where it is required. 
Accordingly, it would be desirable to improve the corrugation of a flat 
material, such as a ribbon, web or signature. 
SUMMARY OF THE INVENTION 
Given the state of the art and the technical problems arising in the field, 
the present invention is directed to improving corrugation of a flat 
material, such as a web of material, a ribbon or a signature, by inducing 
a corrugation effect at a location where it is required. 
A further object of the present invention is to produce a corrugation 
without contacting the flat material. 
Another object of the present invention is to provide a corrugating method 
which is less sensitive to position adjustment. 
According to the present invention, a method and apparatus are disclosed 
for transporting a flat printed material such as a printed web of 
material, a ribbon, a signature, or the like. An exemplary embodiment 
comprises: 
a pair of seizing elements for conveying the flat printed material; and 
corrugation inducing elements arranged adjacent to each other along a 
linear path, said corrugation inducing elements being provided in a 
non-contacting manner on both sides of a transition area within which said 
flat printed material is to be conveyed, said corrugation inducing 
elements substantially extending along said transition area, which is 
located between an output of said pair of seizing elements and an input to 
further processing elements, to corrugate said flat printed material. 
The present invention provides significant advantages. For example, the 
corrugation required for stiffening or stabilizing a flat material such as 
a web of material or ribbon is induced at the location where such 
stiffening is actually required. Furthermore, the stiffening can be 
achieved in a non-contacting manner so that the material is not damaged by 
marking, and so that components used to provide the stiffening are not 
subject to premature wear. 
The corrugation inducing elements can, for example, be hollow members 
charged with a gaseous medium such as compressed air, or can be 
electrically charged bars (e.g., bars electrically charged positively or 
negatively). Thus, a non-contact corrugation of material to be conveyed 
can be achieved without having any corrugation inducing elements 
physically touch a surface of the material. Consequently, neither surface 
of the web is exposed to the risk of marking. 
By arranging corrugation inducing elements in groups on either side of the 
material, a corrugating profile can be induced along an entire width of 
the material. For example, an evenly distributed reinforcing profile 
having peaks and valleys (i.e., a wave-shaped profile) can be used to 
significantly stiffen the leading edge of a web, ribbon or signature 
throughout the transition area. 
The reinforcing profile can also be strengthened by having members of the 
groups of corrugation inducing elements arranged spaced apart from each 
other to extend the magnitude of corrugation. The spacing of the members 
of the groups of corrugation inducing elements can be used to arrange the 
peaks and valleys in a sinusoidal shape.

DESCRIPTION OF PREFERRED EMBODIMENT 
FIG. 1 is a perspective view of a flat material, such as a web, ribbon or 
signature, to be conveyed along a conveying path extending substantially 
in a first (e.g., vertical) direction. 
As shown in FIG. 1, a web of material 1 which is to be cut into signatures 
is pulled by seizing elements, such as a pair of nip rollers 4, 5, in a 
downward direction. The nip rollers 4, 5 rotate, as indicated by the 
arrows, about axes of rotation 6. A transition area 7 extends from a 
location of a nip defined by nip rollers 4, 5 to a location of further 
processing (e.g., conveying) elements, such as a pair of cutting cylinders 
8. The pair of cutting cylinders 8 includes a knife cylinder 8.1 and an 
anvil cylinder 8.2. Both cylinders rotate about a respective axis of 
rotation 9, 10. On the circumference of the knife cylinder 8.1 are mounted 
two knives 11 which are arranged opposite each other. As can be derived 
from the FIG. 1 arrangement of knives 11 on knife cylinder 8.1, recesses 
12 are established along the circumference of knife cylinder 8.1 between 
the knives 11. The arrangement of anvil bars 13 on the anvil cylinder 8.2 
corresponds to the arrangement of the knives 11 on knife cylinder 8.1. 
Consequently, on the circumference of the anvil cylinder 8.2, recesses 14 
are established. 
Through cooperation of the anvil bars 13 with the knives 11, signatures are 
severed from the web of material 1 after the web has been conveyed through 
transition area 7. According to exemplary embodiments of the present 
invention, the transition area 7 is bridged by two groups of corrugation 
inducing elements 16, 17 respectively, the corrugation inducing elements 
17 being visible in the FIG. 2 illustration wherein the web 1 is not 
shown. In the partial view of FIG. 1, the first group 16 of corrugation 
inducing elements is shown to include four members 16.1 to 16.4, each 
being spaced from one other across a width of the web of material 1. 
Extended tube portions 23 (see FIG. 3) of the corrugation inducing 
elements 16.1 to 16.4 extend over a length of the transition area 7. In 
the FIG. 1 illustration, lower ends of the corrugation inducing elements 
reach into the nip between the pair of cutting cylinders 8. By having two 
groups 16, 17 of corrugation inducing elements arranged on either side of 
the web 1, a linear path 15 of the web extends substantially in vertical 
direction. The groups of corrugation inducing elements 16, 17 
respectively, corrugate the web of material 1 conveyed within the 
transition area 7 where a stabilizing and a stiffening of the forward edge 
of web is needed; that is, prior to the transversal cut performed by the 
pair of cutting cylinders 8. 
As mentioned previously, FIG. 2 shows the FIG. 1 arrangement with the web 1 
removed to reveal the second group of corrugation inducing elements 17. In 
FIG. 2, the groups of corrugation inducing elements are arranged opposite 
each other. A plurality of apertures 19 are assigned to the corrugation 
inducing elements, the apertures being arranged in rows 18 over a length 
(e.g., the entire length) of lower tube portions 23 of corrugation 
inducing elements 16.1 to 16.4 and 17.1 to 17.4. As those skilled in the 
art will appreciate, at each desired location along a length of the lower 
tube portion 23, a row of one or more such apertures can be provided about 
a circumferential portion of the lower tube portion which faces an area 
where the web 1 is to be conveyed. The apertures themselves can, of 
course, be of any desired shape and size (e.g., round, slit-shaped, and so 
forth). As with the first group of corrugation inducing elements 16, the 
second group of corrugation inducing elements 17 includes four members 
17.1 to 17.4. 
The corrugation inducing elements 16.1 to 16.4 are arranged in a staggered 
fashion relative to corrugation inducing elements 17.1 to 17.4 to provide 
a corrugated profile of the web of material 1 over an entire width of the 
web of material. Because the corrugation inducing elements are arranged 
evenly spaced apart from each other, the material to be corrugated can 
adopt a wave-like (e.g., sinusoidal) shape. The corrugation inducing 
elements 16.1 to 16.4 and 17.1 to 17.4 are connected to an air supply 
which provides compressed air to the corrugation inducing elements 16.1 to 
16.4 and 17.1. to 17.4. A continuously applied stream of air can thus be 
forced through the rows of apertures 18. Since the members 16.1 to 16.4 
located on a first side of the transition area 7 and the members 17.1 to 
17.4 located on a second side of the transition area 7 opposite the first 
side are, for example, in a staggered arrangement with respect to each 
other, the stream of air will provide air cushions in a wave shaped 
pattern for corrugation of the web of material 1 without requiring the 
corrugation inducing elements to physically contact the web. 
FIG. 3 is an enlarged view of both groups of corrugation inducing elements, 
shown in conjunction with a web of material. The first group of 
corrugation inducing elements 16 includes the members 16.1 to 16.4. 
Opposite the first group of corrugation inducing elements 16, the second 
group 17 is laterally staggered with respect to the first group 16 of 
corrugation inducing elements. Between the first and second groups of 
corrugation inducing elements 16, 17, the web of material 1 is shown to 
have adopted a corrugated state 20. The corrugated state 20 is 
characterized by respective peaks 29 and valleys 30. Given the corrugated 
state 20 in FIG. 3, as viewed from the side of the web on which 
corrugation inducing elements 16 are provided, the first member 17.1 of 
the second group of corrugation inducing elements 17 produces for a peak 
29. Opposite the first member 17.1 is space to allow the web of material 1 
to adopt the peak 29. In contrast, a valley 30 is formed with respect to 
the first element 16.1 of the first group of corrugation inducing elements 
16, when viewed from the side of the transition area where the first group 
of corrugation inducing elements 16 are arranged. 
As mentioned previously, the members 16.1 to 16.4 and 17.1 to 17.4 of the 
groups 16, 17 of corrugation inducing elements include an extended tube 
portion 23. The rows 18 of apertures 19 (FIG. 2) are arranged on a 
respective side of each extended tube portion 23 which faces the 
transition area where the web of material 1 is to be conveyed. As further 
shown in FIG. 3, the extended tube portions 23 are connected to upper tube 
portions 24 by curved portions 32. Via upper tube portions 24, an air 
supply is connected to the extended tube portions 23 bridging the 
transition area 7. The upper tube portions 24 of the second group 17 of 
corrugation inducing elements 17.1 to 17.4 are likewise connected to an 
air supply to generate air cushions along the rows 18 of apertures 19. 
FIG. 4 shows an exemplary larger scale corrugated state of a web or ribbon 
of material to be conveyed. In the transverse sectional view of FIG. 4, 
the web 1 is shown to have adopted a corrugated state. In the exemplary 
FIG. 4 embodiment, the members 16.1 to 16.4 of the first group of 
corrugation inducing elements 16 are evenly spaced apart from one another 
in a direction represented by arrows 22. Air cushions 33 generated by each 
of the members 16.1 to 16.4 produce valleys 30 in the web of material 1. 
These "valleys", which protrude in a direction toward the second group of 
corrugation inducing elements can, of course, alternately be considered 
"peaks" when viewed from the side of web 1 on which corrugation inducing 
elements 17 are located. On the other hand, the corrugation inducing 
elements 17.1 to 17.4 located on the other side of web 1 generate air 
cushions 34 for producing peaks 29 with respect to the side of the web on 
which the first group 16 of corrugation inducing elements 16.1 to 16.4 is 
located. Thus, along an entire width of the web of material (or any 
desired portion thereof), a wave shaped pattern can be established to 
create a corrugated shape. 
By means of sensors 25, 26 arranged on either side of the web of material 
1, a magnitude of corrugation can be detected. The sensors 25, 26 
respectively measure a distance 31 from a head of a given sensor to the 
surface of the web 1. As the distance 31 from sensor 26 to the corrugated 
web of material 1 becomes larger, the air pressure applied to members 16.1 
to 16.4 of the first group 16 of corrugation inducing elements from an air 
pressure supply 39 (e.g., compressor) can be increased via an air pressure 
controller 38 to maintain a desired corrugation shape. The air pressure 
controller 38 can be configured in any manner readily apparent to those 
skilled in the art to compare feedback from the sensors 25, 26 with one or 
more setpoints 37 (e.g., a setpoint associated with each sensor) to 
provide conventional closed-loop feedback. Via a feedback system, the 
corrugation can be adjusted to a desired magnitude. 
In the same way, the sensor 25 mounted on the web's other side will measure 
the magnitude of the distance 31 between the sensor's head and the surface 
of the web to be corrugated. The sensor 25 will adjust, via a feedback 
system, the air pressure within members 17.1 to 17.4 of the second group 
17 of corrugation inducing elements. As those skilled in the art will 
appreciate, the sensors 25, 26 respectively can also be used not only to 
control an increase of air pressure on an opposite side of the web 
conveying plane--but also to control a decrease in air pressure on the 
side of the web on which each respective sensor 25, 26 is mounted. 
Alternately, the sensors can be used to control both an increase in air 
pressure on one side and a decrease on the other side in any manner 
desired by the user to achieve any desired corrugation shape. 
Another exemplary embodiment of the present invention is shown in FIG. 5, 
wherein negatively and positively charged bars are used to induce a 
corrugation profile. In the FIG. 5 embodiment, the members 16.1 to 16.4 of 
the first group 16 of corrugation inducing elements are not connected to 
an air supply. Rather, the respective extended tube or bar portions 23 of 
FIG. 3 are negatively or positively charged. As already described in 
detail above, the members 16.1 to 16.4 can be evenly spaced from one 
another. In the FIG. 5 embodiment, one side of the web of material 1 can 
be negatively charged, while the other side thereof can be positively 
charged (or vice versa). 
In the FIG. 5 embodiment, the second group 17 of corrugation inducing 
elements including members 17.1 to 17.4 can be charged positively and 
arranged spaced apart from each other. The first group 16 of corrugation 
inducing elements can also be spaced apart in the manner described with 
respect to the FIG. 4 embodiment, but can be charged negatively. Upon 
passage of the web of material 1, a repulsive force is created on either 
side of the web to produce a wave (e.g., sinusoidal) shape of the web, and 
to prevent physical contact between the web surfaces and the bars of the 
groups 16, 17 of corrugation inducing elements. As described with respect 
to FIG. 4, sensors 25, 26 can be arranged on either side of the web 1 to 
provide feedback for regulating the corrugation profile via use of a 
closed-loop feedback control that includes a charge controller 41, and a 
power supply 42, in conjunction with one or more setpoints 40. As with the 
FIG. 4 embodiment, each sensor can be used to control the distance between 
the sensor and a corrugated surface of the web or the ribbon. 
The sensors 25, 26 can be used to control and adjust the respective charge 
load on each corrugation inducing element to maintain a desired preset 
distance 31 (i.e., corrugation magnitude) between each of the first and 
second groups 16, 17 of corrugation inducing elements relative to a 
respective side or sides of the web. As with the FIG. 4 embodiment, sensor 
25 can be used to control the charge on either or both sides of the web. 
Similarly, the sensor 26 can be used to control the charge on either or 
both sides of the web. 
As those skilled in the art will appreciate, the embodiments described 
above are by way of example only, and numerous variations exist. For 
example, rather than using the two sensors 25 and 26, a single sensor can 
be used to control the profile by allowing the single sensor to adjust the 
compressed air or charge on both sides of the web. As those skilled in the 
art will further appreciate, a plurality of the sensors 25, 26 can be 
included on both sides of the web to enhance the accuracy with which a 
desired corrugation profile is shaped. 
It will also be apparent to those skilled in the art that although 
exemplary embodiments have been described for producing a 
sinusoidally-shaped profile, any desired profile can be produced using a 
method and apparatus in accordance with the present invention. For 
example, corrugation inducing elements can be randomly placed on either 
side of the web 1. Further, the extended tube portions 23 need not be 
shaped as cylindrical tubes, but rather can be shaped as desired. For 
example, if the shape of these portions 23 is non-cylindrical (e.g., for 
example), box-shaped, then apertures can be located on a periphery thereof 
to create a more square-shaped profile of the web. Numerous variations 
will, of course, exist and be apparent to those skilled in the art. 
As those skilled in the art will also appreciate, the amount of corrugation 
introduced to the flat printed material can be randomly changed by the 
user in real time, during processing of the material. Such changes in the 
corrugation can, of course, be effected remotely by changing the 
setpoint(s). The use of such closed-loop feedback control, as described in 
accordance with exemplary embodiments of the present invention, reduces 
and/or eliminates the setting sensitivity that conventional systems 
experience, and permits compensation for changes in material conveyance, 
speed, tension changes and other time varying parameters. 
As those skilled in the art will appreciate, rather than using a plurality 
of rows apertures formed in a column along a length of the tube portion 
23, a single slit shaped aperture can be provided along a length of the 
tube. Alternately, multiple longitudinal slits can be included on each 
tube portion 23. 
It will be appreciated by those skilled in the art that the present 
invention can be embodied in other specific forms without departing from 
the spirit or essential characteristics thereof. The presently disclosed 
embodiments are therefore considered in all respects to be illustrative 
and not restricted. The scope of the invention is indicated by the 
appended claims rather than the foregoing description and all changes that 
come within the meaning and range and equivalents thereof are intended to 
be embraced therein.