Combined sheet-fed rotary printing machine for securities, especially banknotes

The printing machine is composed of an indirectly printing printing unit (A), and a sheet transport device (B), composed solely of drums (18, 19, 20, 22, 23, 24), and of a following intaglio printing unit (C). The indirectly printing printing unit (A) has two interacting blanket cylinders (3, 5), each of which is inked with several colors by several plate cylinders (12, 15; 7, 10). The sheets are passed onto one of the blanket cylinders (3) from a carry-over drum (2) and, after passing through the nip between two blanket cylinders (3, 5), thereby being printed on both sides, are taken over by a transfer drum (18) of the sheet transport device. The circumferential region which is located between the carry-over drum (2) and transfer drum (8) and over which the sheet passes extends over at most 180.degree., preferably less than 150.degree., so that that free circumferential region of this blanket cylinder not covered by the sheet is available for accommodating several plate cylinders.

FIELD OF THE INVENTION 
The invention relates to a combined sheet-fed rotary printing machine for 
securities, especially banknotes, according to the preamble of patent 
claim 1. 
PRIOR ART 
A printing machine of this type is described in EP-B-0,136,972. The 
indirectly printing printing unit of this known printing machine is 
composed of a blanket cylinder inked by several offset plate cylinders and 
of an impression cylinder interacting with this and therefore makes it 
possible for only one of the sheet sides to be printed. A carry-over drum 
and transfer drum interact with the impression cylinder, the sheet 
grippers of which take over a sheet from the carry-over drum and take it 
along, with it resting against the circumference of the impression 
cylinder, until it is grasped by the grippers of the transfer drum. In 
this arrangement the circumferential region which is located between the 
carry-over drum and transfer drum and in which the sheet is taken up on 
the impression cylinder is substantially larger than half the 
circumference of the impression cylinder. Furthermore, the transfer drum 
functions at the same time as a sheet-turning drum of a sheet-turning 
device and for this reason has a size corresponding to the length of two 
sheets, so that its diameter is twice as large as the diameter of the 
plate cylinders and of the carry-over drum which conventionally have a 
size corresponding to a single sheet, whilst the blanket cylinder and the 
impression cylinder are matched to the format of three sheets and 
consequently have three times as large a diameter as the plate cylinders 
and the carry-over drum. 
In the known combined printing machine, the sheet transport device is 
composed, as mentioned, of a sheet-turning drum interacting with the 
impression cylinder of the indirectly printing printing unit and 
functioning as a transfer drum, of a small drum belonging to the 
sheet-turning device and matched to the size of a sheet, of a drying drum 
of double the size, in the circumferential vicinity of which is arranged a 
drying device, of a register drum correcting the register and of a 
transport drum which transfers the sheets onto the impression cylinder of 
the intaglio printing unit and of which the size, like the size of the 
register drum, corresponds to the size of a sheet. Since this transport 
device, abandoning chain-gripper systems, works only with interacting 
drums in which the sheet passes directly from one drum onto the following 
drum, a perfect register is maintained with a high degree of reliability 
during the entire sheet transport between the indirectly printing printing 
unit and the intaglio printing unit, so that, in general, a possible 
register correction becomes necessary, at most, after a sheet turn and 
then is carried out automatically by the register drum. 
With the known printing machine mentioned, without the sheets being turned 
either one and the same sheet size can be printed with a multicolor offset 
print and with a multicolor steel intaglio print or, with the sheet being 
turned, one sheet side acquires a multicolor offset print and the other 
sheet side a multicolor steel intaglio print. 
SUMMARY OF THE INVENTION 
The object on which the present invention is based is to design a combined 
sheet-fed rotary printing machine of the type described in the preamble of 
claim 1, whilst preserving a sheet transport device composed only of 
drums, in such a way that the indirectly printing printing unit can work 
by recto-verso printing and a multicolor image can be produced on each of 
the two sheet sides. 
This object is achieved by means of the features indicated in the defining 
clause of claim 1. 
As a result of the design and arrangement of the carry-over drum and of the 
transfer drum in the indirectly printing printing unit, that free 
circumferential region of the second cylinder designed as a blanket 
cylinder which is not covered by a sheet is enlarged to such an extent 
that several, especially three or four offset plate cylinders and their 
inking units can be installed along this circumferential region, so that a 
sheet passing through the indirectly printing printing unit receives in 
each case a multicolor print in a simple way not only on its side 
confronting the first blanket cylinder, but also on the side resting 
against the second blanket cylinder. Where banknotes are concerned, these 
multicolor prints are preferably each a multicolor safety background which 
is completed in the intaglio printing unit, on one sheet side, by a 
multicolor steel intaglio print representing the main design. Thus, with 
this printing machine it is possible, in one operation, to produce 
complete banknote prints, in which the front side has a multicolor main 
design and a multicolor safety background and the rear side has a 
multicolor safety background, as is often customary especially on 
banknotes of low values. Furthermore, however, a main design can also be 
produced on the rear side if at least one of the plate cylinders of the 
indirectly printing printing unit is equipped with a wet-offset printing 
plate, preferably in the form of a dampened intaglio printing plate, which 
has a main design. 
Expedient embodiments of the printing machine according to the invention 
emerge from the dependent claims. An especially expedient embodiment, 
according to which the indirectly printing printing unit is convertible 
and, depending on the setting, makes it possible to produce a multicolor 
offset print or a multicolor collect print on one sheet side, is described 
in claim 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
According to FIG. 1, the combined sheet-fed rotary printing machine is 
composed of an indirectly printing printing unit A which the sheets run 
through first, of a following sheet transport device B, composed solely of 
drums, and of an intaglio printing unit C, into which the sheets pass at 
the end of the transport device B. 
The indirectly printing printing unit A, which is a printing unit working 
by recto-verso printing, has two interacting blanket cylinders 3 and 5 
arranged vertically above one another, which are each in touch with 
several plate cylinders 12, 15 and 7, 10 carrying offset printing plates 
and between which the sheets are printed simulataneously on both sides. 
Via several transport drums 1 and a carry-over drum 2 interacting with the 
blanket cylinder 3, the sheets pass onto the blanket cylinder 3, by the 
sheet grippers of which they are taken up. The direction of rotation of 
the two blanket cylinders 3 and 5 is indicated by arrows. After a sheet 
taken up by the blanket cylinder 3 has passed the printing point between 
the two blanket cylinders, it is grasped by a transfer drum 18 which 
interacts with the blanket cylinder 3 and which forms the first transport 
drum of the sheet transport device B. The circumferential region which is 
located between the carry-over drum 2 and the transfer drum 18 and in 
which a sheet is taken up by the blanket cylinder 3 is at most as large as 
half the circumference of the latter and, in the example under 
consideration, extends over approximately 135.degree.. In general, it is 
advantageous if this circumferential region extends over an angle of less 
than approximately 150.degree.. 
The transfer drum 18 has the same diameter as the carry-over drum 2 and the 
plate cylinders 7, 10 and 12, 15 which, as is conventional, are small 
cylinders which carry only one printing plate and the circumferential 
length of which is matched to the size of a sheet. The blanket cylinders 3 
and 5 are each intended for receiving three sheets and are therefore three 
times as large. 
With the arrangement and design of the carry-over drum 2 and of the 
transfer drum 18, that free upper circumferential region of the blanket 
cylinder 3 not covered by a sheet is at least as large as half the 
cylinder circumference; in the example under consideration, it extends 
over approximately 225.degree. and provides sufficient space for 
accommodating several plate cylinders, in the example under consideration 
four plate cylinders, of which, according to FIG. 1, the two plate 
cylinders 12 are arranged on the right of the vertical center line and the 
two plate cylinders 15 on the left of the vertical center line of the 
blanket cylinder 3. 
It is assumed in the example under consideration that the plate cylinders 
12 and 15 carry wet-offset plates. These are each inked by an inking unit 
13 and 16 and each dampened by a dampening unit 13' and 16'. The inking 
units 13 and the dampening units 13' are accommodated in an inking-unit 
stand 14, and the inking units 16 and dampening units 16' are accommodated 
in an inking-unit stand 17. 
The other blanket cylinder 5 interacts with plate cylinders which carry 
four offset printing plates and of which, according to FIG. 1, three plate 
cylinders 7 are installed on the right of the vertical center line and one 
plate cylinder 10 is installed on the left of the vertical center line of 
the blanket cylinder 5. It is assumed, once again, that these plate 
cylinders carry wet-offset plates. The three plate cylinders 7 interact 
with inking units 8 and dampening units 8' in a removable inking-unit 
stand 9, whilst the plate cylinder 10 interacts with an inking unit 11 and 
a dampening unit 11'. 
Furthermore, according to FIG. 1, in the circumferential vicinity of the 
carry-over drum 2 and of the preceding transport drum 1 there are fluff 
suck-off devices 32; these suck-off devices acting on one sheet side and 
the other can also be arranged in circumferential proximity to at least 
two successive transport drums 1. Moreover, in the lower circumferential 
region of the blanket cylinder 3 and of the blanket cylinder 5 there are 
automatically working blanket-washing devices 4 and 6 which, of course, 
during the printing operation of the printing unit assume an inoperative 
position moved away from the blanket cylinders. 
In the example under consideration, the transport device B has nine 
transport drums, specifically the transfer drum 18, a drum 19, four drums 
20, in circumferential proximity to which drying devices 21 are arranged 
for the drying of the two printed sheet sides, a sheet-turning drum 22 
belonging to a sheet-turning device, a drum 23 functioning as a register 
drum and at the same time as part of the sheet-turning device, and a 
further drum 24 which introduces the sheets into the intaglio printing 
unit C. The drums 18, 19, 20, 23 and 24 all have the same size matched to 
one sheet, whilst the sheet-turning drum 22 is matched to the size of two 
sheets and therefore has twice as large a diameter. 
This sheet-turning device is known and its functioning is explained, for 
example, in EP-B-0,136,972. If a sheet located on the drum 22 rotating in 
the direction of the arrow is not to be turned, it is taken over directly 
by the drum 23 in the usual way, the grippers of the latter grasping the 
front edge of the sheet arriving on the drum 22. If a sheet turn is to 
take place, the sheet, after passing completely through the nip between 
the drums 22 and 23, is grasped at its rear edge by the grippers mounted 
pivotably on the drum 23 and controlled correspondingly and is drawn onto 
the drum 23 in the direction of the straight arrow F, the previous rear 
edge of the sheet becoming the front edge of the sheet which is released 
simultaneously by the grippers of the drum 22. 
The drum 23, in its function as a register drum, ensures that possible 
deviations of the sheet positions from the exact register are corrected. 
Such a system for register correction and its functioning are described in 
the said EP-B-0,136,972. 
In the example according to FIG. 1, all the drums of the transport device 
B, the carry-over drum 2 and the transport drums 1 arranged in front of it 
are located at least approximately horizontally next to one another or in 
a horizontal plane. 
The intaglio printing unit C is composed of an impression cylinder 25, onto 
which the sheets pass from the transport drum 24, of a plate cylinder 26 
interacting with the impression cylinder 25 and carrying intaglio printing 
plates, of four stencil rollers 27 which are inked with different colors 
by inking units 28 and which ink the intaglio printing plates on the plate 
cylinder 26, and of a wiping device 30. All the inking units 28 are 
installed in a removable inking-unit stand 29. The sheets printed in the 
intaglio printing unit C are subsequently received by a transport system 
31, especially a chain-gripper system. 
With the printing machine described, banknotes can be provided on each of 
the two sides with a four-color offset print representing a safety 
background and, moreover, depending on the setting of the sheet-turning 
device, on one side with a four-color steel intaglio print as a main 
design. If appropriate, the other sheet side can also be provided with a 
main design in the printing unit A, this purpose then being served by one 
of the plate cylinders which, in this case, is preferably equipped with an 
intaglio printing plate which has a main design and of which the surface 
outside the depressions is dampened by the corresponding dampening unit, 
so that it does not receive any color during the inking of the printing 
plate. 
The printing machine according to FIG. 2 differs from that according to 
FIG. 1 in that the transport drums 1 according to FIG. 1 are replaced by 
another known sheet-feed system 33, for example by sheet transport bands. 
At the end of this sheet transport system 33, the sheets pass via a stop 
drum 33a and a carry-over drum 2 onto the blanket cylinder 3. A further 
difference from the printing machine according to FIG. 1 is that only one 
plate cylinder 12 with its inking unit is installed in the upper 
inking-unit stand 14 of the indirectly printing printing unit A, but 
instead three plate cylinders 15 with their inking units are installed in 
the other inking-unit stand 17. In this printing machine, that 
circumferential region of the blanket cylinder 3 over which a sheet passes 
extends over an angle of approximately 145.degree.. All the remaining 
components of the indirectly printing printing unit A, of the sheet 
transport device B and of the intaglio printing unit C are the same as in 
the exemplary embodiment according to FIG. 1. 
In the printing machine according to the exemplary embodiment shown in FIG. 
3, the lower half of the indirectly printing printing unit A prints by the 
collect printing process, also called the Orlof process, whereas the upper 
half prints by the offset printing process, as in the example according to 
FIGS. 1 and 2. The sheet-feed system 33 with the stop drum 33a, from which 
the sheets pass onto the carry-over drum 2, corresponds to that of the 
printing machine according to FIG. 2. In the sheet transport device B, in 
front of the sheet-turning drum 22 there are only four small transport 
drums, namely the transfer drum 18 and the following three drums 20, 
drying devices 21 being arranged in circumferential proximity to all four 
small drums. 
The remaining parts of the sheet transport device B and the intaglio 
printing unit C correspond to the exemplary embodiments according to FIGS. 
1 and 2. 
To execute a color collect print on one sheet side, the lower half of the 
indirectly printing printing unit A according to FIG. 3 is designed as 
follows: 
The two blanket cylinders 3 and 5 are moved away from one another. The 
plate cylinder 10 resting against the blanket cylinder 5 carries a collect 
printing plate having a complete printing design. Between this plate 
cylinder 10 and the blanket cylinder 3 there is an additional small 
cylinder in the form of an image transfer cylinder 34 which rests both 
against the plate cylinder 10 and against the blanket cylinder 3. Arranged 
on the right of the vertical center line of the blanket cylinder 5, 
according to FIG. 3, are four plate cylinders 7 carrying color selector 
plates which are inked with different colors by inking units 8. 
Furthermore, once again, in each inking unit 8 there is a dampening unit 
8' which, when a wet-offset printing plate is used, dampens this. 
The color selector plates have cut out reliefs which are respectively inked 
and correspond to those regions of the collect printing plate to be 
printed in a specific color and which transfer a multicolor image, with 
colors lying next to one another, onto the blanket cylinder 5 functioning 
as a color collect cylinder and itself inking the collect printing plate 
on the plate cylinder 10. The multicolor image of this inked collect 
printing plate is transferred, by means of the image transfer cylinder 34, 
onto the sheet which runs through between the blanket cylinder 3 and image 
transfer cylinder 34. The collect printing plate is preferably composed of 
a typographic printing plate, but can also be composed of a wet-offset 
printing plate, in which case this printing plate is dampened by a 
dampening unit which, as seen in the direction of rotation of the plate 
cylinder 10, is located behind the point of touch contact with the image 
transfer cylinder 34 and in front of the point of touch contact with the 
blanket cylinder 5. 
So that the image transfer cylinder 34 can be accommodated easily on the 
circumference of the blanket cylinder 3, the blanket cylinder 5 is 
arranged somewhat offset outwards, that is to say somewhat to the right 
according to FIG. 3, in relation to the blanket cylinder 3 located above 
it. As a result of this, on the circumference of the blanket cylinder 5, 
to the right of its vertical center line, there is space for the 
installation of four plate cylinders 7 carrying color selector plates, so 
that in this exemplary embodiment the blanket cylinder 5 interacts with 
five plate cylinders altogether. 
Because of this configuration, the sheet feed to the blanket cylinder 3 is 
offset somewhat upwards in relation to the printing machines according to 
FIGS. 1 and 2, and therefore that circumferential region of the blanket 
cylinder 3 over which a sheet runs and which is located between the 
carry-over drum 2 and transfer drum 18 is somewhat larger; in the example 
under consideration, it is equal to half the cylinder circumference, but 
if appropriate could also be made somewhat smaller directly. In the upper 
free circumferential region of the blanket cylinder 3 there are three 
plate cylinders, namely, on the right of the vertical center line, a plate 
cylinder 12 with its inking unit 13 in the inking-unit stand 14 and, on 
the left of the vertical center line, two plate cylinders 15 with their 
inking units 16 in the inking-unit stand 17. 
Thus, the sheets, when they run through the nip between the blanket 
cylinder 3 and image transfer cylinder 34, acquire a three-color offset 
print on one side and a four-color collect print on the other side. Safety 
backgrounds can consequently be produced in this way on both banknote 
sides by different printing processes, the offset printing process 
providing images with superposed colors and the collect printing process 
images with colors lying next to one another. 
FIGS. 4 to 6 illustrate a further exemplary embodiment of a printing 
machine, in which the indirectly printing printing unit A is convertible 
and can assume three different printing positions. The printing machine 
according to FIGS. 4 to 6 has the same sheet transport device B, the same 
intaglio printing unit C and an essentially identically constructed 
printing unit A as the printing machine already described according to 
FIG. 3. Like parts are designated by the same reference symbols. 
The differences are that the blanket cylinder 5 is adjustable between an 
offset printing position (FIGS. 5 and 6) and a collect printing position 
(FIG. 4), that the image transfer cylinder 34 is adjustable between a 
working position, in which it rests both against the blanket cylinder 3 
and against the plate cylinder 10, and an inoperative position moved away 
from these two cylinders, that the plate cylinder 10 is likewise 
adjustable, has an associated inking unit 11 and carries either an offset 
printing plate (FIGS. 5 and 6) or a collect printing plate (FIG. 4), and 
finally that the plate cylinders 7 touching the blanket cylinder 5 carry 
either offset printing plates (FIGS. 5 and 6) or color selector plates 
(FIG. 4). 
The sheet-feed system 33 with the stop drum 33a is the same as in the 
printing machine according to FIG. 3. The blanket cylinder 5 is assigned, 
in addition to the plate cylinder 10 with its inking unit 11, once again 
four plate cylinders 7 with their inking units 8 which are located on the 
right of the vertical center line of the blanket cylinder 5. Once more, as 
in the printing machine according to FIG. 3, the blanket cylinder 3 is 
inked by three plate cylinders 12 and 15 carrying offset plates. 
In the collect printing position according to FIG. 4, the blanket cylinder 
5 is moved away from the blanket cylinder 3; the plate cylinder 10 carries 
the collect printing plate having a complete printing design, rests 
against the blanket cylinder 5 and is separated from the inking unit 11 
assigned to it, this being obtainable in the simple way, for example, by 
setting back the adjacent inking rollers or transfer rollers. The image 
transfer cylinder 34 assumes its working position. The four plate 
cylinders 7 carry color selector plates. The collect printing position 
according to FIG. 4 and the collect printing image produced correspond 
exactly to the configuration of the printing machine described according 
to FIG. 3 and the collect printing image obtained there. 
In the offset printing position according to FIG. 5, the blanket cylinder 5 
is pressed against the blanket cylinder 3, as in the printing machine 
according to FIG. 1; the plate cylinder 10 carries an offset printing 
plate inked by the applied inking unit 11, rests against the blanket 
cylinder 5 and inks this. The plate cylinders 7 are likewise equipped with 
offset printing plates. The image transfer cylinder 34 assumes its 
inoperative position, in which it is moved away both from the plate 
cylinder 10 and from the blanket cylinder 3. In this case, the sheet 
passing through the nip between the impression cylinders 3 and 5 is given 
a three-color offset print on its upper side and a five-color offset print 
on its lower side. 
FIG. 6 shows a further offset printing position of the printing unit A, in 
which the blanket cylinders 3 and 5 are once again pressed against one 
another, but the plate cylinder 10 is moved away from the blanket cylinder 
5 and interacts with the image transfer cylinder 34 which assumes its 
working position and which is pressed against the blanket cylinder 3. The 
plate cylinder 10 carries an offset printing plate which is inked by the 
applied inking unit 11 and the image of which is transferred onto the 
sheet by means of the image transfer cylinder 34. The four plate cylinders 
7 carry offset printing plates which ink the blanket cylinder 5. A sheet 
thus, in the nip between the blanket cylinders 3 and 5, first receives a 
three-color offset print on its upper side and a four-color offset print 
on its lower side and thereafter receives a further single-color offset 
print on its lower side by means of the image transfer cylinder 34. 
The invention is not restricted to the exemplary embodiments described, but 
offers the possibility of many alternative versions, especially as regards 
the number and exact arrangement of the plate cylinders interacting with 
the blanket cylinders 3 and 5, the design of the sheet transport device 
composed of drums and the design of the intaglio printing unit.