U.S. patent application number 09/855479 was filed with the patent office on 2002-02-14 for method for alignment of sheet-like materials.
Invention is credited to Dobberstein, Dieter Karl-Heinz, Haupt, Joachim Heinrich, Peter, Karlheinz Walter, Pierel, Frank, Sahlmann, Jurgen, Sing, Gerhard Rudolf, Spilz, Rolf Johannes, Staack, Hans-Gunter Werner.
Application Number | 20020017755 09/855479 |
Document ID | / |
Family ID | 7642223 |
Filed Date | 2002-02-14 |
United States Patent
Application |
20020017755 |
Kind Code |
A1 |
Dobberstein, Dieter Karl-Heinz ;
et al. |
February 14, 2002 |
Method for alignment of sheet-like materials
Abstract
The invention relates to a method for the alignment of
sheet-like material (1). Its alignment occurs via rotation elements
(25), wherein the sheet-like material (1) is rotated around its
central axis in order to print on the front and backsides. During
the rotation of the sheet-like material (1) around its central
axis, the material's leading edge (23) remains in its aligned
position. Into the conveyor surface (9) is incorporated a sensor
pair (30), preferably in the form of CCD line sensors, with which
the sheet-like material (1) is aligned on the same lateral edge
(24) following the rotation, as is the case during the alignment
procedure of the sheet-like material (1) before it is rotated
around its center axis.
Inventors: |
Dobberstein, Dieter Karl-Heinz;
(Melsdorf, DE) ; Haupt, Joachim Heinrich;
(Eschborn, DE) ; Peter, Karlheinz Walter;
(Molfsee, DE) ; Pierel, Frank; (Kiel, DE) ;
Sahlmann, Jurgen; (Ellerdorf, DE) ; Sing, Gerhard
Rudolf; (Kiel, DE) ; Spilz, Rolf Johannes;
(Gettorf, DE) ; Staack, Hans-Gunter Werner; (Kiel,
DE) |
Correspondence
Address: |
Lawrence P. Kessler
Patent Department
NexPress Solutions LLC
1447 St. Paul Street
Rochester
NY
14653-7103
US
|
Family ID: |
7642223 |
Appl. No.: |
09/855479 |
Filed: |
May 15, 2001 |
Current U.S.
Class: |
271/227 |
Current CPC
Class: |
B65H 9/002 20130101;
B65H 2553/41 20130101; B65H 9/20 20130101 |
Class at
Publication: |
271/227 |
International
Class: |
B65H 007/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 17, 2000 |
DE |
100 23 919.6 |
Claims
1. Method for aligning sheet-like materials (1), wherein the
alignment is performed by means of rotation elements (25) and the
sheet-like material (1) is rotated around its middle axis, in order
to print the front and back sides, wherein the leading edge (23) of
the sheet-like material (1) remains in its aligned position,
characterized in that a conveyer surface (9) contains a sensor pair
(30), with which the sheet-like material (1) is aligned on the same
lateral edge after it has been rotated around its middle axis, just
as during the alignment process of the sheet-like material (1)
prior to its rotation around its middle axis.
2. Method according to claim 1, characterized in that the sensor
pair (30) is provided in the conveyer surface (9) within the areas
of the lateral edges (24) of the sheet-like material (1).
3. Method according to claim 1, characterized in that the same
measuring point is always used for aligning the sheet-like material
(1) on the lateral edge (24).
4. Method according to claim 1, characterized in that the
determination of the position of the lateral edge (24) of the
sheet-like material (1) occurs by means of a sensor array of the
sensor pair (30) that is oriented perpendicularly to the feed
direction (22) of the sheet-like material (1).
5. Method according to claim 1, characterized in that two CCD line
sensors (30) are included in the determination of the lateral
alignment of the sheet-like material (1).
6. Method according to claim 1, characterized in that the alignment
of the sheet-like material (1) occurs in the area of the lateral
edges (24) that borders on its leading edge.
7. Method according to claim 5, characterized in that during the
rotation of the sheet-like material (1) around its middle axis, an
exchange of position of the lateral edges (24) occurs, while the
position of the leading edge (23) of the sheet-like material is
retained.
8. Arrangement for the alignment of sheet-like material (1),
wherein the alignment of the sheet-like material (1) is undertaken
by means of rotation elements (25), and the sheet-like material (1)
is rotated around its center axis in order to print on the front
and back sides, wherein the leading edge (23) of the sheet-like
material (1) remains in its aligned position, characterized in that
a sensor pair (30) in the form of lines, which enables the
alignment of the sheet-like material (1) on the same lateral edge
(24) of the sheet-like material following its rotation around its
central axis, is incorporated into the upper conveyor surface
(9).
9. Printing press with a feeding arrangement for sheet-like
material (1), wherein the alignment of the sheet-like material (1)
occurs by means of rotation elements (25) and the sheet-like
material (1) is rotated around its central axis in order to print
on the front and back sides, wherein the leading edge (23) of the
sheet-like material (1) remains in its aligned position,
characterized in that a sensor pair (30), with which the sheet-like
material (1) is aligned on the same lateral edge (24) following the
rotation around its central axis, as is the case during the
alignment procedure of the sheet-like material before it is rotated
around its central axis, is incorporated into a conveyor surface
(9).
10. Digital printing press with a feeding arrangement for
sheet-like material (1), wherein the alignment of the sheet-like
material (1) occurs by means of rotation elements (25), and the
sheet-like material (1) is rotated around its central axis in order
to print on the front and back sides, wherein the leading edge (23)
of the sheet-like material (1) remains in its aligned position,
characterized in that a sensor pair (30), with which the sheet-like
material (1) is aligned on the same lateral edge (24) following the
rotation around its central axis, as is the case during the
alignment procedure of the sheet-like material (1) before it is
rotated around its center axis, is incorporated into a conveyor
surface (9).
11. Electro-(photo)graphic printer with a feeding arrangement for
sheet-like material (1), wherein the alignment of the sheet-like
material (1) occurs by means of rotation elements (25), and the
sheet-like material (1) is rotated around its central axis in order
to print on the front and back sides, wherein the leading edge (23)
of the sheet-like material (1) remains in its aligned position,
characterized in that a sensor pair (30), with which the sheet-like
material (1) is aligned on the same lateral edge (24) following the
rotation around its central axis, as is the case during the
alignment procedure of the sheet-like material (1) before it is
rotated around its center axis, is incorporated into a conveyor
surface (9).
Description
[0001] The invention relates to a method for improving the
alignment precision of a sheet-like material, which, prior to
further processing, is accurately aligned on a conveyor surface
with respect to its rotational position, i.e., its slanting
position viewed in the feed direction.
[0002] DE 44 16 564 A1 relates to a sheet alignment device. This
device for aligning a sheet moving along an essentially flat
conveyor belt enables the alignment of a moving sheet in a
multitude of orthogonal directions, for example, transversing the
conveyor belt, in the direction of the conveyor belt, and to
eliminate skewed positions of the sheet-like material in relation
to its conveyor belt. The device has a first roller arrangement,
having a first pressure roller, that is positioned in such a way
that it can revolve around an axis that lies on a surface running
parallel to the surface of the conveyor belt and progresses
essentially at a right angle to the direction of the sheet conveyor
along the conveyor belt. A second roller arrangement has a second
pressure roller that is positioned in such a way that it can
revolve around an axis that lies on a surface running parallel to
the surface of the conveyor belt and progresses essentially at a
right angle to the direction of the sheet conveyor along the
conveyor belt. Furthermore, a third roller arrangement is provided,
having a third pressure roller, that is positioned in such a way
that it can revolve around an axis that lies on a surface running
parallel to the surface of the conveyor belt and progresses
essentially at a right angle to the direction of the sheet conveyor
along the conveyor belt. The third roller arrangement, which can
revolve around an axis that lies on a surface running parallel to
the surface of the conveyor belt and progresses essentially at a
right angle to the direction of the sheet conveyor along the
conveyor belt, can be moved along its rotational axis in a
direction transversing the conveyor belt. Finally, a control device
is provided that is connected to the first, or respectively second,
or third roller arrangement and that alternatively controls the
rotation of the first and second roller arrangement, in order to
align the leading edge of a sheet rotating in the direction of the
sheet conveyor along the conveyor belt in a position that is at a
right angle to the direction of the sheet conveyor. The control
device furthermore controls the rotation and transverse movement of
the third roller arrangement, in order to align the moving sheet in
the direction transversing the direction of the sheet conveyor, as
well as in the direction in which the sheet moves along the
conveyor belt.
[0003] The sheet alignment device known from DE 44 16 564 A1 is
capable of fulfilling the required alignment precision only to a
limited degree. In order to achieve the required alignment
precision, an extensive modification of the sheet alignment device
from DE 44 16 564 A1 is necessary, which does not appear to be
economical.
[0004] In the case of rotary printing presses that process sheets
(of paper) and function according to the offset principle, the
sheets are conveyed on the feeder table in a ragged or uneven
arrangement before they are aligned on the side and pull guides
provided on the surface of the feeder table. After the effected
alignment of the sheet-like material, the materials is transferred
in an aligned condition to a pre-gripper, which accelerates the
sheet-like material up to machine speed and then delivers it to a
paper-guiding cylinder that is located behind the pre-gripper
device. Other alignment concepts generally use cylinder-shaped
rollers, on the core of which there is a rubber coating. If, with
such a configuration, an alignment of sheet-like material is
performed during its feeding, by changing the speed between rollers
that grip the sheet-like material on the left and right, then the
sheet-like material is rotated around a point of rotation that is
located on the stationary roller or, during the feeding, outside
the roller with the lower rotational speed or between the two
rollers.
[0005] If the printing of the front and backsides of the sheet-like
material is accomplished with the same printing mechanism in two
passes, then a double adjustment of the sheet-like material is
imperative. If the leading edge is to be retained during the
rotation, then the sheet is rotated around the center axis in the
feed direction, in the process of which the lateral edges of the
sheet are reversed. If the lateral alignment occurs with only one
sensor, then the reference edge is lost for the subsequent
operation, so that the quality of the registration stability of the
printing image on the front side in relation to the printing image
on the reverse side of the sheet-like material is limited by the
angle tolerances and the size fluctuations of the paper format.
[0006] In view of the solutions known from prior art, as well as
the demonstrated technical problems, the task of the invention is
the substantial improvement of the alignment precision of
sheet-like material during feeding in the direction of sheet
feed.
[0007] According to the invention, this task is accomplished by the
features of claim 1.
[0008] The advantages attainable according to the invention can be
seen above all in the fact that now the influences of the angle
tolerances and size fluctuations of the respective matter to be
printed in relation to the quality of the alignment are eliminated,
since the sheet-like material is aligned on one and the same
lateral edge during the first pass and after the rotation. The
lateral alignment with only one sensor would mean a loss of the
reference edge for the subsequent operation, whereas the pair of
line sensors within the alignment surface, which is provided
according to the invention, allows a referencing to one and the
same position during first form (printing), as well as during the
first form and reprinting.
[0009] According to the method recommended by the invention, a
sensor pair is provided in the conveyor surface for the sheet-like
material, within the area of the lateral edges of the sheet-like
material, wherein the line-shaped extension reaches over such an
area perpendicular to the feed direction of the sheet-like
material, in which the respective lateral edge of the sheet will
most likely be encountered. The larger the dimensions of the
extension of the pair of line-shaped sensors arranged perpendicular
to the feed direction of the sheet-like material, the greater the
flexibility of the printing matter format that can be
processed.
[0010] In another embodiment of the recommended method according to
the invention, the same measuring point is always used for aligning
the sheet-like material on the lateral edge. By this means, the
alignment of the sheet-like materials, following its rotation in a
rotating module, is independent from the printing matter tolerance,
such as, for example, lateral shrinking of the printing matter. The
determination of the position of the lateral edge of the sheet-like
material results preferably via a sensor array of the sensor pair
that is oriented perpendicular to the feed direction of the
sheet-like material. In an advantageous embodiment, a CCD line
sensor can be arranged as a sensor pair on the sheet-feeding plane
within a feeding arrangement of sheet-like material. According to
the recommended method of the invention, the alignment occurs in
the area whose leading edge borders on areas of the respective
lateral reference edge of the sheet-like material. By evaluating
the offset of the respective frontal area of the lateral edges in
relation to the leading edge of the sheet-like material, the
smallest offsets can be measured by the line sensors arranged on
the conveyor surface of the sheet-like material and corrected by
the succeeding segment rollers. A recording of the lateral offset
of the rear areas of the lateral edge of the sheet-like material
would delay the detection of the offset of the lateral edge to one
page; on the other hand, the offset being adjusted on the rear edge
of the sheet-like material would be measured so large that, in the
case of large formats, it would lie outside of the recognition and
recording range of the CCD line sensors.
[0011] The arrangement recommended according to the invention for
the detection of the side positions of a sheet-like material by
means of a sensor pair that is arranged in the conveyor surface,
can particularly be used on sheet-processing printing presses or
according to the principle of electrography or electro-photography,
or also on other digital printing presses. In this regard, it is
irrelevant whether an image is generated on the surface of
image-generating or image-display cylinders of the enumerated
printer or printing machine by the depositing of a toner, which is
ultimately fixed, or whether the image is generated according to
other methods on the surface of image-transmitting components.
Essential for the transmission of the printing image to the surface
of the sheet-like material is its correct alignment in relation to
its feed direction through the printing press or the printer.
[0012] With the aid of the drawing, the invention will now be
explained in more detail.
[0013] Shown are:
[0014] FIG. 1 a apparent positional deviation of a printed printing
image relative to the printing matter surfaces receiving this
image,
[0015] FIG. 2 an offset of the printing image on the sheet-like
material characterized by a rotational offset,
[0016] FIG. 3 an offset of the printing image imprinted on the
underside and top side of a sheet-like material in first form and
reprint,
[0017] FIG. 4 the lateral view of a sheet intake area of a
sheet-processing machine reproduced schematically,
[0018] FIG. 5 top view of the alignment components, the sensory
mechanism, and the drives for the sheet-like material relative to
the rotation elements aligning its feed direction,
[0019] FIG. 6 the rotation elements designed as segment rollers
above the sheet conveyor surface of the sheet-like material,
and
[0020] FIG. 7 the alignment of a sheet-like material with the
drives of the segment rollers effecting the alignment.
[0021] The representation according to FIG. 1 shows a sheet-like
material, for example, a printing sheet 1, which is aligned at a
right angle to its feed direction 22. Imprinted on the surface of
the printing sheet 1 is a printing image 2 that is surrounded by a
frame-like border 3. The marked deviations of .DELTA.x or .DELTA.y
within the printing surfaces 2 and the frame 3, which indicate a
positional error in the x and y directions, can be adjusted by
pressing on the printing image 2 on the surface of the printing
sheet 1. The deviations designated by reference numbers 4 and 5
respectively are positional deviations, whereas in the
representation according to FIG. 2, angle deviations .delta.
.theta. of printing image 2 are represented in relation to its
position on the printing sheet 1.
[0022] In the representation according to FIG. 2, the apparent
angle errors .DELTA..phi. are designated by reference number 6. The
printing image 2 can be imprinted at the indicated positions on the
surface of the printing material 1, during which this (material) is
conveyed forward, with its leading edge 23 in the sheet feed
direction.
[0023] The representation according to FIG. 3 shows in a schematic
view the so-called turn registration, wherein the offsets appearing
respectively between the printing images 2 on the front and reverse
sides of the sheet-like material 1 are marked by reference number
7. In the representation according to FIG. 3, these are designated
by reference number 7 or with "and". The turn registration
particularly plays a role in the case of translucent papers of
marginal weight and extremely light paperweight, as well as of
brochure printing.
[0024] The representation according to FIG. 4 shows in a
schematically reproduced lateral view the intersecting point of
sheet alignment and the ascent onto a conveyor belt. An aligning
unit 8 precedes a conveyor belt 10, which encircles a run-up roller
11 or, respectively, a control roller 12, on the surface of which
the sheet-like material 1 is transported up to the conveyor surface
9. After passing the alignment unit 8, which will be described in
more detail below, the aligned sheet-like material 1 reaches the
surface of the conveyor belt 10 at the conveyor surface 9. After
passing the run-up roller 11, the sheet-like material 1 is admitted
by means of an adjustment flap or adjustment lip, which is movable
in the direction of adjustment 13. The adjustment lip or adjustment
flap can be a plastic component that can be moved from an engaged
position 13.1 to a disengaged position 13.2. Here, this is
represented merely schematically in solid or dotted lines, wherein,
for the adjustment, a separate drive in the form of a pneumatically
actuating regulator, an electrical drive, can be provided, just as
an adjustment by manual means is also conceivable.
[0025] By means of an adjustment flap or an adjustment lip, a
pressing of the sheet-like material 1 onto the surface of the
conveyer belt 10 occurs, wherein at the moment of adjustment, the
sheet-like material 1 is located in its aligned state. After
passing the pressure element, the sheet picked up on the surface of
the conveyer belt 10 passes a loading unit 14. In this loading
device 14 an electrode 15, which effects a static loading of the
sheet-like material 1 and thereby provides for its adhesion to the
surface of the supporting conveyer belt 10, is contained within a
hood-shaped covering. A leading edge sensor 17, which is only
schematically reproduced in the representation according to FIG. 4,
is placed behind the loading device 14. This sensor is comprised of
a radiation source 18, which precedes a lens arrangement 19 and
which is arranged underneath the sheet conveyer surface 3. The
radiation field 20 emanating from the lens arrangement 19
penetrates the sheet conveyer surface 9 and encounters an aperture
arrangement that is provided above the conveyer surface 9 of the
sheet-like material 1. The aperture arrangement is followed by a
receiver 21, which senses and signals the presence of a leading
edge 23 of the sheet-like material 1 in correspondence with the
radiation penetrating the aperture arrangement.
[0026] From the representation according to FIG. 5, the top view
shows the alignment unit 8, the components of which are reproduced
here in schematic representation. The alignment unit 8 is reached
by a sheet-like material 1 that is transported in the feed
direction 22. The leading edge 23 of the sheet-like material 1 is
offset in relation to the feed direction 22 of the sheet-like
material 1, whereby a slanted progression of the lateral edge 24 of
the sheet-like material 1 becomes apparent. As soon as the sheet
leading edge 23, which lies in a slanted position in relation to
the feed direction 22, transverses a first light barrier 26, the
drivers 27, marked with M1 or M2, which drive rotational elements
25 via single axes 32, are accelerated to the rate of feed. Control
of the drives 27 (M1 or M2), which is triggered via the light
barrier 26, ensures that each sample of sheet-like material 1 comes
into contact with identical peripheral sections of the rotation
elements 25, which are arranged as segment rollers in the preferred
embodiment. Possibly occurring differences of the feed movements,
which could be traced back to the dimensional and shape tolerances
of the two rotation elements 25, thereby occur identically in each
sample of the sheet-like material 1 and can easily be calibrated
out.
[0027] After both of the rotation elements 25 are set into rotation
motion by passing the first light barrier 26, the sheet-like
material 1 is transported at the rate of feed over one of the
additional light barriers 30.1, which are located behind the first
light barrier 26. This light barrier 30.1 can, for example, be
positioned behind a CCD sensor cell, which extends essentially
perpendicular to the feed direction of the sheet-like material 1.
By means of the line-shaped formation of the sensor line 30, the
lateral areas of all common printing matter formats can be
recorded.
[0028] As soon as the first of the two sensors of the light barrier
30.1 has detected the sheet leading edge 23 of the sheet-like
material 1, a counter begins to count in motor steps. The counting
process is then ended and the determined difference is stored when
the second sensor trips the light barrier 30.1. The CCD line
sensors of the sensor pair 30 are embedded in the feed surface of
the sheet in such a way that they do not impede the transport of
the sheet-like material 1. From the counter reading that was
ascertained in this manner, a correction value is determined and
communicated, as an additional feed, to the segment roller drive
that was last activated, i.e., either drive 27, which is designated
by M1, or drive 27, which is designated by M2. In this way, the
rotation bodies 25, which are appropriately shaped as segment
rollers, are accelerated to the rate of feed until the preset path
difference is completely equalized and, thereby, the sheet leading
edge 23 of the sheet-like material 1 is aligned precisely
perpendicular to the feed direction 22 of the sheet-like material
1. At the end of this corrective process, the sheet leading edge 23
is oriented exactly perpendicular to the feed direction.
[0029] After the correction has occurred, the sheet-like material 1
is transported in the feed direction 22 and delivered from the
first pair of segment rollers 25 to the subsequently arranged pair
of rotation bodies 25, which can be contained on a common axis 31.
Now, the segment roller pair 25 that is driven by drive 27, or M1,
and drive 27 (M2) is switched off and moves into its resting
position, where it does not come into contact with the sheet-like
material 1 with its peripheral surfaces.
[0030] The sheet-like material 1 that is now correctly aligned in
relation to its relative position then ascends onto the sensor
field 30, e.g., onto the CCD line, where the position of the
lateral edges 24 of the sheet-like material is determined. A
positional change for drive 27, which is designated by M4, is
ascertained from the determined measurement value. The drive shaft
of drive M4 extends parallel to the feed direction 22 of the
sheet-like material 1. By means of this drive 27, which is recorded
in a second orientation 29, a correction of the position of the
sheet-like material 1 occurs parallel to its feed direction 22,
(cf. FIG. 7) (i.e., a lateral alignment of the sheet-like
material).
[0031] Following this, such a sheet-like material 1, which is
aligned in its relative position and in its lateral position
underneath an adjustment flap or adjustment lip element that is
placed in a position 13.1 or 13.2, ascends onto the conveyer belt
10, in order to enter the printing unit that follows in the
correctly aligned position. The representation according to FIG. 6
shows a possible embodiment variant of the rotation elements 25
that are contained in the alignment unit 8 located above the
conveyer surface 9. The rotation elements 25 are designed, in the
preferred embodiment, as segment rollers, which have a peripheral
surface that is characterized by an interruption. The segment
rollers 25 rotate in the rotational direction 34 characterized by
the depicted arrow and describe an approximate 3/4 circle in
relation to their respective rotational axis. Under the respective
segment rollers 25, a roller that supports a sheet-like material 1
is depicted. This can be designed in one piece, or it can receive a
coating on its periphery. The rotation bodies that serve as segment
rollers 25 are depicted in a resting position in the left part of
FIG. 6, while in the right part of FIG. 6, they seize, with the
peripheral surface, a sample that is transported in the feed
direction 22 of the sheet-like material 1. This is thereby
transported according to the rotational direction 34 in the feed
direction 22 of the sheet-like material 1. FIG. 7 shows the
correction of the relative position of the sheet-like material 1
when it passes the alignment unit 8. In the position of the
sheet-like material 1 shown in FIG. 7, the material's leading edge
23 has just reached the last sensor of the light barrier 30.1, so
that, at this point, drive 27 of the segment roller 25, which is
designated by M1, can be activated, in order to equalize the
relative position of the sheet-like material 1 in relation to the
feed direction 22. In contrast to drives M3 and M4, which can be
linked by means of a continuous drive shaft 31, the segment rollers
25 that are connected to the drives M1 and M2 are driven
respectively by single shafts 32. After the relative position of
the sheet-like material 1 is corrected by diverse feed rates on the
respective drives 27 (M1 or M2) of the respective segment rollers
25, the sheet-like material 1 receives a correction of its lateral
position. After the position of the lateral edges 24 of the
sheet-like material 1 is measured by line-shaped CCD sensors 30,
the sheet-like material 1 is now correctly aligned laterally to the
feed direction 22 by a displacement of the sheet-like material, via
drive M4, which occurs on its conveyer surface 9 before reaching
the adjustment element 13 and before ascending onto the conveyer
belt positioned behind it. With the drive 27 (M3) oriented in the
first orientation 28, the feed of the sheet-like material 1 with a
correctly aligned leading edge 23 is guaranteed by means of a
common shaft 31, whereas this material is aligned in lateral
position by means of drive 27 (designated by M4) contained in a
second orientation 29.
[0032] With the method according to the invention that recommends
the use of a CCD line sensor pair 30, a retention of that lateral
edge during the lateral alignment of the sheet-like material 1 can
be made possible, which already served to align the sheet-like
material 1 during the first printing. If the sheet-like material 1
that was already printed in the first printing is reprinted in the
same printers, then its lateral edge 24 comes to lie above the
other respective sensor of the line sensor pair 30 after being
rotated around the middle axis of the sheet-like material 1, so
that the alignment occurs on the same lateral edge 24. If the same
measuring point in the area of the leading edge of the lateral
edges 24 is used for this in both adjustment operations, then the
registration stability for the positioning of the top side to the
printing of the bottom side is directionally independent of the
paper tolerances.
[0033] During a re-printing of the sheet-like material 1, which has
already been printed on one side, alignment impairments from paper
tolerances can be avoided during alignment, if it is guaranteed
that the alignment of the sheet-like material 1, during its second
run-through, through identical printing mechanisms, occurs on the
same position of the lateral edge 24, i.e., in the front area of
the lateral edge 24, which extends from the leading edge 23 of the
sheet-like material 1. If CCD line sensors are used as sensor pair
30 on the conveyer surface 9 for the sheet-like material 1, then
these can extend perpendicular to the feed direction 22 of the
sheet-like material 1 to such an extent that all common printed
material formats can be accommodated, regardless of whether they
are for paper, for cardboard, or also for foils. This enables an
increase in the flexibility of a printing press used for diverse
printed materials, regardless of whether it is an electrographical,
an electro-photographic, or another digital printing machine. The
proposed method for aligning the sheet-like material 1 before the
ascension onto a conveyer belt 10 can naturally also be used on
conventionally operating rotary printing presses, which process
sheet-like material 1. For this purpose, the line sensor pair 30
should be arranged at the end of the feeder table directly in the
area of the side and pull guides, which precede a pre-gripping
device with which the aligned sheet-like material 1 is accelerated
to machine speed and delivered to paper-guiding cylinders.
[0034] List of Reference Numbers
[0035] 1 sheet-like material
[0036] 2 printing image or format
[0037] 3 frame
[0038] 4 positional error in y direction
[0039] 5 positional error in x direction
[0040] 6 rotational error
[0041] 7 offset printing ground (or base), front and back sides
(1)
[0042] 8 alignment unit
[0043] 9 conveyor surface
[0044] 10 conveyor belt
[0045] 11 run-up roller
[0046] 12 control roller
[0047] 13 adjustment direction
[0048] 13.1 first position
[0049] 13.2 second position
[0050] 14 loading unit
[0051] 15 electrode
[0052] 16 support
[0053] 17 leading edge sensor
[0054] 18 radiation source
[0055] 19 lens
[0056] 20 radiation field
[0057] 21 radiation receiver
[0058] 22 conveyor direction of sheet-like material
[0059] 23 leading edge
[0060] 24 lateral edge
[0061] 25 segment rollers
[0062] 26 light barriers (Ernst)
[0063] 27 drivers of segment roller
[0064] 28 first orientation drive
[0065] 29 second orientation drive
[0066] 30 line sensor pair
[0067] 30.1 light barrier
[0068] 31 continuous shaft
[0069] 32 single shaft
[0070] 33 segment roller periphery
[0071] 34 rotational direction
[0072] 35 segment roller, active position
[0073] 36 segment roller, inactive position
* * * * *