U.S. patent application number 13/370342 was filed with the patent office on 2012-08-16 for device and method for depositing sheet-shaped substrates so as to form a stack.
Invention is credited to Soenke Christian Bluethgen, Dieter Gritzuhn, Frank Nagel.
Application Number | 20120205862 13/370342 |
Document ID | / |
Family ID | 46636287 |
Filed Date | 2012-08-16 |
United States Patent
Application |
20120205862 |
Kind Code |
A1 |
Bluethgen; Soenke Christian ;
et al. |
August 16, 2012 |
DEVICE AND METHOD FOR DEPOSITING SHEET-SHAPED SUBSTRATES SO AS TO
FORM A STACK
Abstract
The present invention relates to a device and a method for
depositing sheet-shaped substrates (6), in particular printing
materials, in a printing machine so as to form a stack. The device
comprises a tray (10) for receiving the substrates, said tray
having a tray surface (8) that is tilted about a first axis and
about a second axis, relative to a horizontal. Also provided are a
lifting device for lifting and lowering the tray, as well as a
first abutment having a first abutment surface and a second
abutment (26) having a second abutment surface, with the first and
the second abutment surfaces being arranged so as to be
perpendicular to each other, and with substrates deposited on the
tray coming to abut against the first and the second abutment
surfaces due to the tilting of the tray surface.
Inventors: |
Bluethgen; Soenke Christian;
(Ploen, DE) ; Nagel; Frank; (Kiel, DE) ;
Gritzuhn; Dieter; (Kiel, DE) |
Family ID: |
46636287 |
Appl. No.: |
13/370342 |
Filed: |
February 10, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13377836 |
Apr 24, 2012 |
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PCT/EP2010/058614 |
Jun 18, 2010 |
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13370342 |
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Current U.S.
Class: |
271/220 |
Current CPC
Class: |
B65H 2405/1136 20130101;
B65H 2301/4461 20130101; B65H 2406/112 20130101; B65H 2405/1111
20130101; B65H 2405/1412 20130101; B65H 2405/1142 20130101; B65H
31/26 20130101; B65H 2801/12 20130101; G03G 15/6552 20130101; B65H
2405/1115 20130101; B65H 2801/21 20130101; B65H 31/10 20130101;
B65H 2301/4212 20130101; B65H 29/246 20130101; B65H 31/36
20130101 |
Class at
Publication: |
271/220 |
International
Class: |
B65H 31/02 20060101
B65H031/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 30, 2009 |
DE |
DE 102009031117.3 |
Claims
1. Device for depositing sheet-shaped substrates in a printing
machine so as to form a stack, the device comprising: a tray for
receiving the substrates, the tray having a tray surface that is
tilted about a first axis and about a second axis, relative to a
horizontal; a lifting device for lifting and lowering the tray; a
first abutment having a first abutment surface; and a second
abutment having a second abutment surface, with the first and the
second abutment surfaces being arranged so as to be perpendicular
to each other, and with substrates deposited on the tray coming to
abut against the first and the second abutment surfaces due to the
tilting of the tray surface, wherein the lifting device is arranged
in such a manner that the lifting device lifts and lowers the tray
parallel to the second abutment surface.
2. The device according to claim 1, wherein the first axis is
parallel to a printing material transport axis, and the second axis
extends perpendicularly to the first axis and is in a plane
parallel to the tray surface.
3. The device according to claim 1, wherein the second abutment is
arranged so as to be perpendicular to the tray surface.
4. The device according to claim 1, wherein the second abutment is
vertically arranged.
5. The device according to claim 1, wherein the second abutment is
fastened to the tray.
6. The device according to claim 1, wherein the second abutment is
adjustable.
7. The device according to claim 6, wherein the tray includes a
linear guide for the second abutment.
8. The device according to claim 6, wherein a setting wheel is
provided, by means of which the second abutment can be
adjusted.
9. The device according to claim 1, wherein the second abutment is
configured as a wire bracket.
10. The device according to claim 1, wherein the first abutment is
part of a depositing member by means of which the substrates are
deposited on the tray.
11. The device according to claim 1, wherein the first abutment is
inclined in such a manner that it forms a right angle with an
adjacent region of the tray surface.
12. The device according to claim 11, wherein the lifting device
lifts and lowers the tray parallel to the first abutment
surface.
13. The device according to claim 1, wherein the tray surface
comprises a first and a second depositing region, the regions being
each tilted differently from the horizontal about the second axis.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of prior U.S. patent
application Ser. No. 13/377,836, filed Dec. 13, 2011, which is a
U.S. patent application Under 35 U.S.C. 371 of International Patent
Application No. PCT/EP2010/58614, filed Jun. 18, 2010, (published
as WO 2011/000717 on Jul. 7, 2011) each of which are hereby
incorporated herein by reference in their entirety.
[0002] The present invention relates to a device for depositing
substrates and to a method for depositing sheet-shaped substrates,
in particular printing materials, in a printing machine so as to
form a stack.
[0003] In printing technology, it has been known to print
sheet-shaped substrates and to subsequently deposit them so as to
form a stack on a height-adjustable tray. To do so, the substrates
are usually transported so as to be at a certain distance above the
tray or the uppermost sheet of a stack on the tray and are then
released, as a result of which the sheet falls down. It is known to
provide the tray with a slope that is inclined counter to a
transport direction of the substrate in order to enable the
substrates so slide against an abutment in order to form a defined
stack edge in transport direction of the substrates. Furthermore,
it is known to provide lateral abutments on the tray, said
abutments being intended to also provide an alignment of the stack
in lateral direction. For example, systems comprising lateral
guides are known, where said lateral guides can be moved toward
each other and away from each other in order to compress a
substrate stack between them and, in turn, to release said stack,
thus creating a defined lateral stack edge. However, such systems
are only suitable for smaller stacks that allow the needed
compression. In addition, such systems are associated with high
costs and are susceptible to trouble.
[0004] Also known are systems working with lateral guides, along
which the substrates slide when they are being ejected and which
are intended to, thus, convey the substrate into a predefined
position. However, systems of this type have the disadvantage that
their guiding accuracy is limited by the necessity of having to
always adjust the inside width between the lateral guides so as to
be greater than the nominal format width. Reasons for this are
cutting tolerances of the substrate as well as the conveying
deviations of individual sheets in the direction transverse to the
transport direction which are caused by the printing machine.
[0005] Consequently, when substrates are output in known systems,
stacking inaccuracies in the direction transverse to the substrate
transport direction occur frequently. Different disturbances such
as, e.g., a skewed alignment, also referred to as skew,
electrostatic charges, bending of the substrates, also referred to
as curl, as well as friction between the substrates, additionally
affect accurate stacking in a disadvantageous manner, with
light-weight sheets being affected more than heavier-weight sheets.
Consequently, the object of the present invention is to create a
device and a method for depositing sheet-shaped substrates, said
substrates covering a wide range of substrates, with increased
stacking accuracy, in particular in a direction transverse to the
substrate transport direction, so as to form a stack on a tray.
[0006] In accordance with the invention, this object is achieved by
a device in accordance with claim 1 and by a method in accordance
with claim 21. Additional embodiments of the invention result from
the respective subclaims.
[0007] In particular, a device is provided for depositing
sheet-shaped substrates, preferably printing materials, in a
printing machine so as to form a stack, said device comprising a
tray for receiving the substrates and comprising a lifting device
for lifting and lowering said tray. The tray has a tray surface
that is tilted about a first axis and about a second axis, relative
to a horizontal. Furthermore, the device has as a first abutment
with a first abutment surface and a second abutment with a second
abutment surface, the first and the second abutment surfaces being
arranged so as to be perpendicular to each other, and substrates
deposited on the tray coming to abut against the first and the
second abutment surfaces due to the tilting of the tray
surface.
[0008] Using a simple design, such a device allows a high stacking
accuracy because the alignment takes place on two abutments that
are arranged perpendicularly with respect to each other. One
advantage of such substrate stacks is that they can be processed
further without any intermediate steps. Further processing of the
substrate stack may comprise binding of said stack, for example.
Due to the appropriate double inclination of the tray, the
substrates automatically move against the abutments, without
requiring the use of expensive and complex mechanical systems. By
lifting and lowering the tray, it is possible to maintain an
essentially constant dropping height of the ejected substrates on
the stacks. The trays may be lifted and lowered in different ways.
For example, it is possible to lower the tray by a certain distance
after each ejection of a substrate sheets. Further, it is possible
to lower the tray by a corresponding greater path distance, after
each ejection of a prespecified number of substrate sheets.
[0009] In one embodiment of the invention, the first axis is
parallel to a printing material transport axis, and the second axis
extends perpendicularly to the first axis and is in a plane
parallel to the tray surface.
[0010] Preferably, the device comprises a gas supply arrangement
having a gas outlet opening that is directed at the lowest point of
the support surface. The support surface may be the tray surface
itself, on the one hand, or the substrates already on the tray
surface, on the other hand. The gas supply arrangement is disposed
to guide a gas stream at the tray plane or the substrate surface in
order to ensure a friction-reducing sliding of the sheet-shaped
substrates against the abutments. In addition, the substrates are
also carried along by the gas stream.
[0011] Preferably, the gas outlet opening is arranged at the height
of a depositing plane for the substrates. Consequently, it can also
be ensured that the gas supply unit generates an air cushion at the
appropriate height, where subsequent substrates can slide on said
air cushion in a friction-reduced manner against the abutments.
[0012] In particular, the gas outlet opening may be directed at a
region between the first and the second abutment surfaces. This
region is located in a corner of the tray, for example. Preferably,
the first and/or the second abutment should be configured in such a
manner that the gas stream may flow unimpaired past said abutments.
This can be achieved, for example, in that the second abutment is
at a sufficient distance from the first abutment such that the gas
can flow through. Also, the second abutment could have holes, for
example, or be configured as a wire bracket.
[0013] The gas supply unit may comprise a gas nozzle in order to
increase the discharge speed of the gas stream, this potentially
intensifying the friction-reducing effect on the substrates.
Furthermore, the use of a gas nozzle makes it easier to achieve a
desired direction of the gas stream.
[0014] In accordance with another exemplary embodiment, the gas
supply unit comprises a blower. However, it is also possible to
provide other devices that are capable of generating a gas
stream.
[0015] In one exemplary embodiment, the second abutment is arranged
so as to be perpendicular to the tray surface. Due to the resultant
90.degree. angle between the second abutment and the tray surface
there is no distortion perpendicular to the substrate transport
direction in the substrate stack located on the tray. In this
context, distortion is intended to mean an angle of the stack in
the direction toward the second abutment of less than
90.degree..
[0016] In an alternative embodiment of the invention, the second
abutment is vertically arranged. Such an arrangement of the second
abutment has the advantage that the tray may be lowered vertically
without increasing a distance to be traveled by the substrate up to
the second abutment by lowering the tray.
[0017] For a simple design of the device, the second abutment may
be fastened directly to the tray. In particular, the second
abutment may be adjustably arranged on the tray. As a result of
this, it is possible to adjust the abutment along a direction
transverse to the sheet transport direction. Such an adjustment
should be performed before the output of the substrates is started,
said adjustment being a function of the format of the substrate
that is used. The abutment may, in particular, be adjusted in such
a manner that the path, which the substrate must slide transversely
to the transport direction in the direction of the abutment, is
minimized. As a result of a thusly minimized sliding path distance
which the substrates must slide in the direction of the abutment, a
considerable improvement of the stack accuracy transverse to the
sheet transport direction can be achieved. In particular with
narrow substrates that would have to slide correspondingly larger
path distances when the abutments are non-adjustable, such an
arrangement can have a positive effect.
[0018] The adjustment of the abutment may be automatically
performed by motors or other electrical, or pneumatic actuators.
Inasmuch as, usually, most system controls of modern printing
machines contain information regarding the format width of the
substrate to be printed, this enables the determination of path
information for the abutment and can, subsequently, be
automatically translated into an abutment position, without the
intervention of an operator.
[0019] In order to ensure an efficient adjustment of the second
abutment, the tray may comprise a linear guide for said
abutment.
[0020] If, as mentioned above, the abutment is mechanically
adjusted, it is possible to provide--in another exemplary
embodiment--a setting wheel by means of which the position of the
second abutment can be adjusted. The setting wheel may act on an
axis that, in turn, acts--via a deflection--on the second abutment
and thus adjusts said second abutment transversely with respect to
the substrate transport direction.
[0021] In one embodiment of the invention, the lifting device lifts
and lowers the tray parallel to the second abutment surface. This
ensures that the distance to be traveled by the substrate up to the
second abutment remains the same, even with increasing stack
height. In the case of the second abutment arranged perpendicularly
to the tray surface, such lifting or lowering results in a
deviation of the lifting and lowering direction from the
vertical.
[0022] In one embodiment of the invention, the first abutment may
be part of a depositing member by means of which sheets are
deposited on the tray. This may be, for example, a rear wall of a
printing machine, said wall being below a substrate output where
the substrate will come to abut.
[0023] In particular, the first abutment may be inclined in such a
manner that it forms a right angle with an adjacent region of the
tray surface. If the tray is subsequently lifted or lowered
parallel to the first abutment surface, it is possible--in
combination with a second abutment provided vertically on the
tray--to produce a substrate stack which neither displays a
distortion in substrate transport direction nor transversely with
respect thereto; i.e., a 90.degree. angle is formed in both
directions.
[0024] In a further embodiment of the invention, the tray surface
may comprise a first and a second depositing region, said regions
each being tilted differently from the horizontal about the second
axis. As a result of this, it can be avoided that, during output to
the tray, the substrates must be transported at a too severely
inclined tray surface. In contrast therewith, a larger incline of
the tray surface is desirable in the first region of the tray
surface because this facilitates the sliding of the substrates on
the tray.
[0025] Furthermore, this can prevent a shifting of the substrates
already present on the tray.
[0026] The object that is the basis of the invention is also
achieved by a method for depositing sheet-shaped substrates, in
particular printing materials, in a printing machine, wherein the
sheet-shaped substrates are conveyed to a substrate support
comprising a tray, and a first and a second abutment so as to form
a stack. The tray is rotated about a first axis that is parallel to
a substrate transport axis and about a second axis that is
perpendicular to the first axis and parallel to a tray plane. The
method comprises the lowering of the tray and the generating of a
gas stream under a respective substrate that is being conveyed onto
the tray, said gas stream being directed at a region between the
first and the second abutments. In this method, the sheet-shaped
substrates are transported against the abutments due to the tilt
and the gas stream, an air cushion generated by the gas stream
reducing the friction between the sheet-shaped substrate and the
tray surface or between a sheet-shaped substrate and a substrate
that is already located on the tray. By lowering the tray, a
constant dropping height of the substrate to the tray surface or a
substrate located there is being maintained.
[0027] Preferably, the tray is lowered parallel to the abutment
surface of the second abutment. As a result of this, it is ensured
that the distance of the path for the substrate up to the second
abutment remains constant, despite lowering the tray. In one
embodiment, the second abutment extends perpendicularly to the tray
surface, which ensures a 90.degree. angle of the substrate stack
transverse to the substrate transport direction.
[0028] In an alternative embodiment of the invention, the second
abutment is arranged vertically relative to a horizontal.
[0029] The first abutment may form a right angle with an adjacent
region of the tray surface. Inasmuch as the tray surface is
inclined relative to the horizontal, this causes the first abutment
to also be inclined relative to the horizontal. Preferably, in this
embodiment, the tray is lowered parallel to the first abutment
surface, thus ensuring that the substrate stack displays an angle
of 90.degree. relative to the first abutment surface.
[0030] Hereinafter, the invention will be explained in greater
detail with reference to the drawings. They show in
[0031] FIG. 1 a schematic side view of a stacker region of a
printing machine comprising the inventive device for depositing a
substrate;
[0032] FIG. 2 a schematic plan view of the device for depositing a
substrate in accordance with FIG. 1;
[0033] FIG. 3 a schematic front view of the device for depositing a
substrate in accordance with FIG. 1;
[0034] FIG. 4 a schematic perspective representation of the device
for depositing a substrate in accordance with FIG. 1;
[0035] FIG. 5 a schematic plan view of an alternative device for
depositing a substrate;
[0036] FIG. 6 a schematic perspective representation of the
alternative device for depositing a substrate;
[0037] FIG. 7 a front view of the alternative device for depositing
a substrate;
[0038] FIG. 8 a schematic, perspective representation of the
alternative device for depositing a substrate; and
[0039] FIG. 9 a schematic side view of a printing machine
comprising another alternative device for depositing a
substrate.
[0040] Information regarding location or direction used in the
description hereinafter primarily relates to the depictions in the
drawings and should thus not be viewed as being restrictive.
However, they may also relate to a preferred final arrangement.
[0041] FIG. 1 shows a schematic side view of a stacker region of a
printing machine comprising a substrate output unit 1, a substrate
depositing device 2, as well as a gas supply unit 3.
[0042] The substrate output unit 1 comprises a plurality of
transport rollers 4 that are suitable to convey substrates 6 from a
printing region of the printing machine in a substrate transport
direction (from right to left in FIG. 1) as indicated by arrow A
toward the substrate depositing device 2.
[0043] In accordance with a first embodiment shown by FIGS. 1
through 4, the substrate depositing device 2 comprises a tray 10
with a tray surface 8. The tray surface 8 comprises a first
depositing region 12 located adjacent to the substrate output unit
1, and a second depositing region 14 located further away from the
substrate output unit 1. As is obvious from FIG. 1, the first and
the second depositing regions 12, 14 are inclined against the
substrate transport direction A, relative to the horizontal, the
first depositing region 12 being inclined more than the second
depositing region 14. FIG. 3 shows that the tray surface 8 is also
tilted about a first axis parallel to the substrate transport
direction A, relative to the horizontal. This tilting of the tray
10 about the first axis is combined with the inclination of the
first and second depositing regions, this corresponding to a
tilting of the tray 10 about a second axis perpendicular to the
first axis. As a result of this, the tray surface overall drops
downward toward an edge 18, said edge forming the lowest point of
the tray surface 8.
[0044] As is obvious from FIGS. 2 through 4, the tray surface 8 has
an elongated recess 20 with a center strip 22, these extending
along the substrate transport direction A. The recess 20, as well
as the center strip 22, extend from an outer end of the tray 10,
said end being remote from the substrate output unit, via the
second region 14 into the first region 12 of the tray surface 8. On
the one hand, the recess 20 facilitates the removal of a substrate
stack and, on the other hand, said recess facilitates the transport
of the substrate 6 over the tray surface 8.
[0045] As is also readily obvious from FIG. 2, an edge 24 is formed
between the depositing regions 12 and 14, said edge extending
transversely with respect to the substrate transport direction over
the tray surface 8. Although the edge is shown in the figures as a
cutting edge of two straight depositing surfaces 12, 14, said
depositing surfaces may also be connected via a rounded part.
[0046] A first abutment 25 essentially extending in vertical
direction--viewed in substrate transport direction A--is provided
adjacent to the first depositing region 12 of the tray 10, which
abutment 25 may be part of the substrate output unit 1 or the
substrate depositing device 2. In the shown embodiment, the
abutment 25 is a straight plate connected with the substrate output
unit 1. Furthermore, a second abutment 26 is provided on the tray
10, said second abutment extending at a right angle relative to the
first abutment 25 and to the tray surface 8. The second abutment 26
is configured as a wire bracket and fastened transversely with
respect to substrate transport direction A in the region 12 of the
tray surface 8. An adjustment may be performed, for example, by
means of a not illustrated setting wheel that moves the second
abutment along a not illustrated linear guide in the tray 10. The
adjustment may be performed manually or also automatically by means
of an appropriate drive and control unit. Alternatively, the second
abutment 26 may be stationarily fastened to the tray 10. The second
abutment 26 may also be configured as a stop baffle instead of as a
wire bracket, said stop baffle being provided, for example, with
gas passage openings.
[0047] In such an arrangement of the tray surface 8, a substrate
stack consisting of a plurality of substrates 6 will form a right
angle with the first and second abutments 25, 26 on the second
abutment 26; however, said substrate stack will be distorted at the
first abutment 25, i.e., the stack does not form a 90.degree. angle
in this direction. The reason for this is that the first abutment
25 and the depositing region 12 of the tray surface 8 form an angle
that is smaller than 90.degree..
[0048] The tray 10 can be moved up and down by means of a not
specifically illustrated lifting unit, with the movement occurring
parallel to a plane of the second abutment 26, as is shown by
double arrow B in FIG. 3.
[0049] Each of FIGS. 1 through 3 shows the gas supply arrangement 3
that is represented as a gas line element 30 (for reasons of
simplification, it was left out of the drawing of FIG. 4). This gas
line element is arranged laterally adjacent to the higher edge of
the tray 10 and is permanently mounted to the substrate output unit
1. Alternatively, said gas line element could also be mounted to
the substrate depositing device 2. The gas supply arrangement 3
comprises a gas supply that is not shown in the figures, said gas
supply arrangement being able to supply gas to the gas line element
30. For example, a ventilator or a pressurized air connection of an
external pressurized air source can be used.
[0050] On a free end, the gas line element 30 has a gas outlet
opening in the form of a gas nozzle 34 that is arranged at the
height of a depositing plane. In this case, the depositing plane is
formed by the tray surface 8 for a first substrate 6 ejected by the
substrate output unit 1. For all the subsequent substrates 6, the
depositing plane is formed by the previously ejected substrate 6,
respectively.
[0051] The gas nozzle 34 is essentially directed at a region
between the first abutment 25 and the second abutment 26. In
particular, the nozzle is inclined slightly downward, and the gas
stream exiting from the nozzle 34 flows over the depositing plane
in the direction of the lowest point of said plane in the region of
the corner 18 of the tray 10. As a result of the fact that the
second abutment 26 is arranged at a distance from the first
abutment 25 and, furthermore, is configured as a wire bracket, the
gas stream essentially flows off the opposite end of the tray
without being obstructed.
[0052] FIGS. 5 through 8 show an alternative embodiment of a
substrate depositing device 2. FIGS. 5 through 8 use the same
reference signs as the first embodiment in accordance with FIGS. 1
through 4. The substrate output unit 1 and the gas supply unit 3,
these also being provided in this embodiment, may have the same
design as those that have been previously described, so that it is
not necessary to describe them in detail. The gas supply unit 3 was
left out in order to simplify the illustration in FIGS. 6 and
8.
[0053] Again, the substrate depositing device 2 comprises a tray 10
that is designed as previously described. In particular, the tray
10 has a tray surface 8 with first and second depositing regions
12, 14, each being inclined relative to the horizontal. FIG. 7
shows that the tray surface 8 is also tilted about a first axis
parallel to substrate transport direction A, relative to the
horizontal. As a result of this, the tray surface 8, overall, again
slopes toward an edge 18, said edge forming the deepest point of
the tray surface 8.
[0054] Again, a first abutment 25 is provided adjacent to the first
depositing region 12 of the tray 10. Likewise, a second abutment 26
is provided on the tray 10. However, this abutment extends
vertically and not perpendicularly with respect to the tray surface
8, as was the case in the first embodiment, this being particularly
clear in FIGS. 5 and 7. As is readily obvious from FIG. 6, the
second abutment 26 is located laterally on the tray 10. However, in
this embodiment, too, the second abutment 26 may be arranged so as
to be movable in the depositing region 12 or 14 of the tray surface
8. In particular, the second abutment 26 is arranged adjacent to a
lower lying lateral edge of the tray 10. Said second abutment is
shown as a solid metal sheet, however, it may also be configured as
a wire bracket or as a perforated metal sheet.
[0055] Again, the tray 10 can be moved up and down by means of a
not specifically illustrated lifting unit, the movement taking
place parallel to a plane of the second abutment 26, i.e.,
vertically, as indicated by double arrow C in FIG. 7.
[0056] FIG. 9 shows another alternative embodiment of a substrate
depositing device 2. In FIG. 9, the same reference signs are used
as in the first embodiment in accordance with FIGS. 1 through 4.
The substrate output unit 1 and the gas supply unit 3, which are
also provided in this embodiment, may have the same design as those
previously described, so that a further description thereof is not
provided. In order to simplify the illustration in FIG. 9, the gas
supply unit 3 was left off.
[0057] Again, the substrate depositing device 2 comprises a tray 10
that is designed as the one above and inclined toward a lowest
point. Likewise, first and second abutments 25, 26 are provided,
the second abutment 26 being designed in accordance with the first
embodiment. However, said abutment could also have the design in
accordance with the second embodiment.
[0058] The essential difference with respect to the first two
embodiments is in the arrangement of the first abutment 25. The
first abutment 25 is inclined in such a manner that it forms a
right angle with the depositing region 12 of the tray 10. As a
result of this, a stack of substrates on the tray 10 forms a right
angle on its edge facing the first abutment 25, as well as on its
edge facing the second abutment 26.
[0059] Again, the tray 10 can be moved up and down by means of a
not specifically shown lifting unit, the movement following the
inclination of the first abutment 25, as is shown by double arrow D
in FIG. 9. At the same time, the up and down movement takes place
parallel to a first plane of the second abutment 26.
[0060] Hereinafter, a method for depositing sheet-shaped
substrates, in particular of printing materials, in a printing
machine, so as to form a stack will now be explained in greater
detail with reference to the figures and, in particular, to FIGS.
1, 3 and 9.
[0061] A substrate 6 is transported via transport rollers 4 of the
substrate output unit 1 in substrate transport direction A into the
region of the substrate depositing device 2. In particular, the
substrate is conveyed so as to be above the tray 10 that is in a
corresponding receiving position. After the transport rollers 4
have released the substrate 6, the substrate drops down onto the
tray 10. The gas supply arrangement 3 generates a gas stream under
the falling substrate, said stream being directed transversely and
slightly counter to the substrate transport direction. This gas
stream generates an air cushion between a depositing plane formed
by the tray surface 8, or by a substrate 6 located on the tray, and
the falling substrate 6.
[0062] Due to the double inclination of the tray 10 (counter and
transverse to substrate transport direction A), the substrate 6
slides easily over the depositing plane in the direction of the
first and second abutments 25, 26 and comes to abut against said
abutments. The movement in the direction of the first abutment 25
and the second abutment 26 is also aided in the direction of the
gas flow, with the air cushion preventing, or at least reducing, a
friction between the depositing planes and the substrate. The gas
stream may be used intermittently or also continuously.
[0063] In this manner, the substrates 6 may be deposited one after
the other to form a stack on the tray. After each substrate 6, or
after a specific number of substrates 6, the tray 10 is lowered by
the lifting device along the first abutment 25 and parallel to an
abutment surface of the second abutment 26. Depending on the
arrangement of the first and second abutments 25, 26, the tray 10
is lowered in vertical direction or in an inclined manner.
[0064] The inclined lowering of the tray 10 in conjunction with the
second abutment 26 positioned perpendicularly to the tray surface 8
ensures, in so doing, that a sliding path of the substrate 6 out of
a position it is in immediately upon the release by the substrate
output unit 1, toward the abutments 25 and 26 remains essentially
constant, even after lowering the tray 10.
[0065] Due to the ejection of the plurality of substrates 6 onto
the tray 10, a substrate stack is formed on the tray surface 8,
said substrate stack forming an angle with said tray depending on
the arrangement of the second abutment 26, said angle being either
90.degree. (first embodiment) or smaller than 90.degree. (second
embodiment).
[0066] The lowering of the tray 10 along the first abutment 25
takes place depending on the arrangement of the first abutment 25,
likewise vertically or inclined. If, as is shown by FIG. 1, the
first abutment 25 and the tray 10 form an angle that is smaller
than 90.degree., the tray 10 is lowered in vertical direction;
whereas, if the first abutment 25 is arranged at a right angle
relative to the tray 10, as shown by FIG. 9, the tray 10 is lowered
at an inclination along the first abutment 25.
[0067] A substrate stack that was produced on the substrate
depositing region 2 in accordance with FIG. 9 thus does not display
any distortions. This means that the substrate stack forms a
90.degree. angle relative to the first abutment 25, as well as
relative to the second abutment 26.
[0068] Hereinabove the invention was described with reference to
specific embodiments without being restricted to a specifically
represented form. In particular, it is possible to combine features
of an embodiment with features of another embodiment, or to
interchange certain features, in so far as compatibility has been
provided.
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