Note: Descriptions are shown in the official language in which they were submitted.
HEIDELBERG ~ -341 ~ 1 - 24 . 05 . 1982
The invention relates to a feeder for sheet-fed rotary
printing presses with pull-type lays which are coupled
to the press drive and impart a pulling motion to each
incoming sheet, also with a device for checking the
correct lateral sheet position as well as for inter-
rupting the sheet feed in the case of incorrect sheet
position.
Known versions of the above-mentioned invention are
single-sheet feeders or stream feeders. The aligning
of a sheet, essential for accurate printing, takes place
in two directions during transport over the feed table,
firstly the front alignment, and secondly the lateral
alignment. Several front lays guarantee reliable
positioning of the sheet front edge. Lateral aligning
takes place usually through pull-type lays.
Pull-type lays on sheet fed printing presses have the
task of precisely aligning the incoming sheet by means
of lateral pulling. This alignment must take place
with extreme precision since errors in alignment may
result in differences in the inking between the copies.
Sheet-fed printing presses with pull-type lays are
known from publication DE-OS 30 11 626 ~1. The sheet
which is being aligned is pressed onto the suction open-
ings in the sheet plate with the aid of a dabber roller.
The vacuum which supports the acceleration process
can act for a defined period of time so that the great
static friction when the sheet is at rest is over-
come and the sheet is prevented from fouling on the
stop by switching off the suction air.
HEIDELBERG A-341 - 2 - 24.05.1982
Publication DE-OS 24 60 747 also discloses devices for
the in-registe~ positioning of the sheets which are to
be printed. A device is described which obtains the
desired positioning accuracy without the use of pull-
type lays. A measuring head with two photo~sensors is
attached at the side of the feed plate, and the
ascertained later~al difference is used as a guide for
the lateral displacement of the gripper drum. However,
the lateral displacement of the gripper drum is diffi-
cult from the mechanical and technical point of view
and does not always lead to in-register positioning.
Furthermore, the use of twophoto-sensors is very costly.
The object of the invention is, using the simplest
means, to monitor both the correct pulling end position
as well as the pulling operation, and to shorten the
set-up times and downtimes of the sheet-fed rotary
printing presses.
The object of the invention is achieved in that a sensor
is disposed at at least one lateral edge of the feeder
for checking the correct sheet infeed and the lateral
position of the sheet whereby said sensor supplies
signals which are processed by digital control electronics,
thus influencing the control of the press.
An advantage of this is that thanks to the display on
the light-emitting diode display panel the operato~
of the sheet-fed rotary printing press knows
immediately which kind of fault is present and, there-
fore, can immediately take appropriate action.
A further embodiment of the invention consists in that
the sensor is so disposed that before the pulling
r
H~IDEL~RG A-341 - 3 - 24.05.1982
motion the sheet is first of all outside, but at
the end of the pulling motion inside the response
range of the sensor whereby a corresponding
annunciation is made through the control electronics.
An embodiment of the invention is that the control
electronics annunciates a fault if a sheet is already
in the response range of the sensor before the pulling
operation.
In an advantageous embodiment of the invention from the
signal sequence supplied by the sensors in whose response
range the sheet assumes its two setpoint positions before
and after pulling the control electronics detects the
assignment of one of the sensors to the direction of
motion of the pull-type lays in the case of a change in
pulling direction and thereafter only annunciates a
fault on the basis of signal sequences from this sensor.
The sensors may consist either of reflex switches or
light barriers or reflex light barriers. They may also
be capacitive or pneumatic measuring pickups.
In an embodiment of the invention coupled to the control
electronics is a light-emitting diode display panel
with the respective relevant operating statuses and
the light-emitting diodes indicating faults. The
lighting up of the corresponding light-emitting diodes
makes it possible to detect the fault easily and
quickly, which has a positive effect on the undesired
downtimes of sheet-fed rotary printing presses.
f ~ d ;~
HEIDELBERG A-34 1 - 4 - 24 . 05 .1982
The digital control electronics is so designed that
the signals from the sensors on the setpoint position
of the sheet are, through the intermediary of a buffer
memory an`d a read-only memory, displayed on the light-
emitting diode display panel or, in the event of
incorrect position of the sheet, the control electronics
triggers an alarm, visual or audible, or influences the
control of the press.
A further advantage of the invention is that the sensors
are independent of the pulling direction, i.e. they are
functionally and structurally so designed that they are
equally suitable for both pulling directions.
The device according to the invention thus permits
improved monitoring and aligning of the sheet feedO
The automatic detection of the pulling direction makes
it possible, with the aid of the sensors, to change
the pulling direction without any additional effort.
Without this automatic change of pulling direction it
would be necessary to switch-over the control cr to
remove the unused sensor from the working area or to
convert the sensor to the other side.
An embodiment of the invention is described in the
following with reference to the drawings.
Fig. 1 shows a sheet-fed printing press with feed
and delivery table.
Fig. 2 shows an arrangement of the pull-type lay-
check on the feed table with sheet resting
in position before the pulling operation.
Fig. 3 shows a slot initiator in position a.
~2~
-
HEID~LBERG A-341 - 5 - 24.05.1982
Fig. 4 shows an arrangement of the pull-type lay check
on the feed table with sheet resting in position
after the pulling operation.
Fig. 5 shows a slot initiator in position b.
_ Fig. 6 shows a flowchart.
Fig. 7 shows a block diagram.
Fig. 8 shows a light emitting diode display panel.
In the in-line sheet-fed printing press 1 shown in Fig. 1
the sheets 8 being printed are fed from a sheet feeder 12
via the feed table 2 to the feed drum 13 of a first
printing unit 14. The printing unit 14 includes a plate
cylinder 21, rubber-covered cylinder 16 and an impression
cylinder 15. After each sheet 8 has been provided with
a first print, it is transferred via transport cylinders 17
and a transfer drum 18 lying between the latter to a
further printing unit 19. The printing unit 19, in turn,
includes a plate cylinder 21, rubber-covered cylinder 16
and a back-pressure cylinder 22. After the sheet 8 has
been provided with a further print in the printing unit 19,
the sheet is delivered onto a delivery pile 4 with the
aid of a delivery chain 20.
Sheet checking elements, e.g. in the form of reflex
switches 7, are attached to the feed table 2 in the
front side region. A slot initiator 23, consisting
of a scanning switch 10 and a scanning disc 11, is
coupled via control electronics to the sheet checking
elements in the form of reflex switches 7. The
scanning disc 11 of the slot initiator 23 is mounted
on a single-revol~tion shaft which is not shown in
any greater detail. The scanning disc 11 which is
controlled by the machine cycle can assume two scanning
points, namely a and b. The scanning disc 11 of the
HEIDELBERG A-341 - 6 - 24.05.1982
slot initiator 23 shown in Fig. 3 is in scanning p~int a.
This means that the sheet 8 is already up against the
front lays 6, as shown in Fig. 2, but the sheet 8 has
not yet been pulled against the side lay 24 by the
pull-type lay 9. Due to the sequence of the machine,
the sheet 8 is now pulled by the pull type lay 9, for
example, to the left to the side lay 24. At the same
time, the scanning disc 11 of the slot initiator 23
reaches scanning point b, as shown in Fig. 5. After
the pulling operation the sheet 8 is in the response
xange of the reflex switch 7 and on the side lay 24 of
the pull-type lay 9, as shown in Fig. 4.
The flowchart shown in Fig. 6 shows the schematic
sequence of pull-type lay checking.
With the power supply switched on and the sheet-fed
printing press 1 running, the control electronics
detects on the basis of the signal sequence of the
scanning switch 10 together with the two reflex switches 7
whether the pulling operation is ended. In accordance
with the signal sequence stored in the control
electronics, the control electronics decide auto-
maticaily the pulling direction, either "right" or
"left".
If no definitive signal sequence is delivered by the
sensors, there is a fault annunciation, and scanning
is repeated.
After the control electronics, on the basis of the
delivered signal sequence, has detected that, for
example, pull~nq has tak place to the le~t, this i~
HEIDELBERG A-34 1 - 7 - 24 . 05 .1982
indicated on the light-emitting diode display panel 33
which i5 fixed easily visible for the printer on a metal
wall between the sheet feeder 12 and printing unit 14
of the sheet-fed printing press.
Each pulling operation is monitored in this manner.
If, after the pulling operation is completed, there
is no signal sequence corresponding to the pulling
operation "left", the control electronics gives a fault
annunciation which is indicated on the light-emitting
diode display panel 33.
At the same time, the control electronics monitors
whether the pulling direction has changed on the basis
of the signal sequence at the reflex switches 7. If
there has been no change, there is clearly a pulling
fault which is likewise indicated on the light-emitting
diode display panel 33.
If, on the basis of the signal sequence, a change of
pulling direction has been detected, the control
electronics automatically monitors the pulling operation
"right", and once again there is an indication on the
light-emitting diode display panel 33. The scanning
points, the in~ormation on the respective operating
statuses and the automatic decision on the pulling
direction which goes to the right just as well as to
the left are repeated for each newly incoming sheet.
The block diagram of the pull-type lay check shown in
Fig. 7 shows a machine cycle 25 which controls the
period of time for measuring the actual values through
2~ 3G~
HEIDELBERG ~-3~1 8 - 24.05.1982
the comparator and the transmission of the signals to
the light-emitting diode display panel 33, also refle~
switches 26 and 27 which are connected via amplifier 28
to the inputs of the buffer memory 29 whose inputs and
outputs are symbolically grouped, and the outputs of
the buffer memory 29 lead to the inputs of a read-only
memory 30 whose outputs are connected partly to a
light-emitting diode display panel 33 and to an audible
fault annunciation device 32 (which is not shown in
greater detail) and partly to the inputs of the bufEer
memory 29.
The control electronics are designed such that, during
one machine cycle 25, they scan the status of the
reflex switches 26,27 twice. The first scanning point
is before the pulling operation. The status oE the
reflex switches 26,27 is transmitted via the amplifier 28
into the buffer memory 29 which conducts this information
into an EPROM, a programmable read-only memory 30. The
read-only memory 30 is programmed such that it waits
for the status report of the second scan which consists
in whether the sheet, after pulling, has reached the
characteristic setpoint position or not.
~hen the read-only memory 30 has stored all the informa-
tion necessary for a machine cycle 25, it transmits,
in accordance with its programming, digital values to
the light-emitting diode display panel 33 which re-
produces the signal sequence of the respective
operating status, or digital values are transmitted
to the fault annunciation device 32 which consists of
audible signal generators.
These scanning points and information on the respective
operating statuses are repeated for each incoming sheet.
HEIDEI,BERG A~341 ~ 9 - 24.05.1982
The light-emitting diode display panel 33 in Fig. 8
consists of the indication elements 34 to 45 which
light up accordingly for the respective operating
statuses. More specifically, the indication elements
34 to 45 are shown in three rows; in one row are ^
the three light-emitting diodes 34, 35, 36. The light-
emitting diodes 34, 35 are yellow illuminating indication
elements for the right-hand/left-hand reflex switches
respectively. The status of the slot initiator 23 is
shown by the yellow light-emitting diode 36. In the
next row the symbol illuminated fields 40, 41, 42, 43,
44, 45 indicate the respective pulling operations. The
yellow symbol illuminatedfields40, 43 correspond to
the side position. If the side position is correct,
the symbol illumina~ed fields 44 and 41 light up green
for the right-hand side and left-hand side respectively.
If the side position is incorrect the symbol illuminated
fields 42 and 45 indicate the fault in red. The green
light-emitting diodes 37, 39 indicate whether the sheet
is correctly positioned, and incorrect positioning is
indicated by light-emitting diode 38.
