Note: Descriptions are shown in the official language in which they were submitted.
1326868
PROCESSING PAPER AND OTHER WEBS
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to web processing
systems, which may perform operations such as forming an
image on a web (e.g. of paper) by printing, copying or
other marking process, (hereinafter generally referred to
as "printing") and/or handling arrangements such as folding
or format adjustment. The present invention is particu-
larly, but not exclusively, concerned with processing
systems in which the paper or other material orginates as a
continuous web on a roll.
SUMMARY OF THE PRIOR ART .
It is very well known to pass paper from a roll
through a printing machine to form a series of images on it
and then rewind, sheet or fold it into various formats.
However, there are fundamental problems which provide a
serious limitation to the efficiency of such machines.
There is the problem of "down-time". Once the printing
machine has been set up, and the paper put in motion,
printing can occur very rapidly. However, with the known
machines long delays can occur when any change is made to
the method of delivery or to what is being printed. For
example, if a different image is to be printed, or if the
repeat length of the image is to be changed, or if a
different colour is to be used, or the folded format is to
be changed, then the print run has to be stopped. The
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design of the known printing machines is such that it is
extremely difficult to make such changes, and hence it is
common for the time such machines are not working (the
down-time) to be much longer than the effective working
time.
A further problem of existing arrangements is that
printing machines are designed for a specific printing
application, the machine being available as a single
entity. What this means, in practice, is that if the owner
of the machine wants to carry out more complex operations
than are currently possible on his machine, he must under-
take quite major engineering or buy a whole new machine.
SUMMARY OF THE INVENTION
The present invention is therefore concerned with
overcoming, or at least ameliorating, these problems to
design a web processing system in which many changes can be
made whilst the system is in operation (can be made "on the
fly") and which may also have the advantage of being
modular so that the system may be expanded in capability if
required.
The web processing system with which the present
invention is concerned may be divided into three parts.
Firstly, there is the part of the system which takes the
web from a roll or reel and feeds it to the rest of the
system. Secondly, there is the part which forms an image
on the web, and thirdly there i5 a handling arrangement for
the printed web. The present invention has several
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aspects, each concerned with various parts of such a
system.
The first aspect is concerned with the handling of
rolls and the input of a web to a printing machine or other
imaging apparatus. When webs are input into a printing
machine, problems occur at the end of the web. If the
machine is not to be stopped, then some splicing arrange-
ment is necessary to attach the end of one web to the -
beginning of the next. There are two known systems for
achieving this. Firstly, there is a system known as a
"flying splice" in which joining is carried out with the
surface of the new roll moving at the same speed as the
running web. The second system is known as a "zero-speed
splice" in which the join is effected while both the new
roll and the running web are stationary but the press is
kept running by means of a reservoir of web such as a
festoon.
The first aspect of the present invention seeks to
improve the efficiency of the roll handling and the
splicing system. In its most general form, this aspect
moves rolls of web material on suitable supports, e.g.
mobile unwind stands relative to a splicer of a web
processing apparatus. With one roll of web material being
drawn into the web processing apparatus, another web may be
brought up to the splicer, the two webs spliced together,
and the web from the second roll drawn into the machine.
Splicing may be achieved by flying or zero-speed splicing.
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Thus according to this aspect, there may be provided
a method of feeding web material to a web processing
apparatus, the method comprising, moving, relative to a
splicing position, a first reel of the web material from an
initial position of that reel towards a final position for
that reel; withdrawing web material from the first reel
into the web processing apparatus; moving, relative to the
splicing position, a second reel of the web material from
an initial position of that second reel to a final position
for that reel; splicing the web material of the first reel
to the web material of the second reel at the splicing
position, separating the splice from the web material
remaining on the first reel, and then withdrawing web
material from the second reel into the web processing
apparatus; and completing the movement of the first reel to
its final position.
Also there may be provided a mobile unwind stand for a
reel of web material, having a movable base, means for
supporting the reel such that it is rotatable about its
longitudinal axis, and means for controlling the rate of
that rotation, and a system for feeding web material to a
web processing apparatus, having a plurality of such mobile
reel stands, and a splicer adjacent an entrance to the web
processing apparatus, the splicer being adapted to splice
web material of a reel on one of the mobile unwind stands
which is being fed to the entrance to the web processing
apparatus to web material of a reel on another of the
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mobile unwind stands.
The mobile unwind stands provide: the transport
systems between the paper store and the machine; the roll
stand from which the web is unwound; and the means for
returning part-used or reject rolls to the store. In use,
successive reel stands may be positioned sequentially
adjacent the splicing unit, and moved so that as the
required amount of material has been unwound from one roll,
the next can be in position. Thus, a replacement roll can
be positioned, and the original roll removed, with the
printing machine continuing its operation throughout. This
reduces the amount of roll handling, facilitates the
organisation of work at this part of the machine so as to
fit in more flexibly with other machine operating tasks;
and permits a machine layout with a better material flow,
particularly in situations where part-used or reject rolls
are to be removed from the machine.
The next three aspects of the invention are concerned
with the imaging arrangement. These aspects are particu-
larly, but not exclusively, concerned with a web fed offset
press. Such presses typically comprise, for each colour to
be printed, and each repeat length: a pair of blanket
cylinders between which the web passes (blanket-to-blanket
formation); a pair of plate cylinders in contact with a
corresponding blanket cylinder, and on which the image to
be printed is mounted; and an inking and dampening system
for each plate cylinder. Such a system is known as a
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"perfecting" press, as it prints on both sides of the web.
It is also known to provide an impression cylinder, and a
single blanket cylinder, plate cylinder, and inking and
dampening system, if only one side of the web is to be
printed.
The second aspect of the present invention proposes an
imaging apparatus such as a web-fed offset perfecting
press, comprising a plurality of cartridges in an array or
stack, or even a plurality of stacks. A common unit for
printing medium is then provided in common for several
cartridges. Thus, this aspect may provide a web-fed
printing apparatus comprising a plurality of cartridges in
an array, for printing a web feedable through the array,
and at least one unit containing printing medium, each
cartridge hav~ng means for transferring the printing medium
from the unit to the web; wherein the at least one unit is
mounted relative to the array so that the at least one unit
and the cartridges of the array are capable of relative
movement, thereby to permit successive interaction of the
at least one unit with at least two of the cartridges.
The cartridges may form a web-fed offset printing press, in
which case each cartridge may have a pair of blanket
cylinders, and a corresponding pair of plate cylinders.
The common unit may then be an inking and dampening unit
displaceable relative to the cartridges to supply
selectively the plate cylinders of at least some of those
cartridges, or alternatively the cartridges themselves may
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be movable. Thus, it becomes possible to have a printing
sequence that can be varied in detail in which the
following features can be carried out: the inking and
dampening unit is placed in an operative position for a
first cartridge and a print run is carried out for that
cartridge; then the blanket cylinders of the first
cartridge are moved away from the web; the blanket
cylinders of a second cartridge (which has different
characteristics such as the nature of the image, the image
pitch or colour) are moved into contact with the web when
the inking and dampen-ing unit has moved to that cartridge.
A new printing run can thus be started at the second
cartridge with very little time delay. It then becomes
possible to change, e.g., the image on a plate cylinder of
the first cartridge, whilst the printing machine is
running.
The apparatus may include a plurality of inking and
dampening units for supplying respective different colours
simultaneously to a plurality of selected cartridges (with,
in general, at least an equal plurality of cartridges not
then being supplied). There may be a plurality of arrays
or stacks with driers interposed as required, or a system
in which the cartridges can be exchanged for others stored
elsewhere.
It is also pQssible to achieve the feature of inter-
changability between one printed image and another, by
providing a web-fed printing apparatus comprising a
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plurality of cartridges in an array for printing a web
feedable through the array, each cartridge having means for
transferring printing medium from a unit for containing
such printing medium to the web, the means including at
least one printing cylinder which is adapted to contact the
web, wherein the at least one printing cylinder of one of
the cartridges has a different circumference from that of
the at least one blanket cylinder of at least one other of
the cartridges.
The printing cylinder may be a blanket cylinder of an
offset press, there then being a plate cylinder between the
unit for containing the printing medium and the blanket
cylinder. For an offset perfecting press there will then
be a blanket cylinder, and a corresponding plate cylinder
on each side of the web. For other offset presses there is
one blanket cylinder, with an impression cylinder on the
other side of the web. For a gravure press, the printing
cylinder is etched, and the printing medium is transferred
from the unit directly to the printing cylinder. Similarly
in a flexographic or letter press, printing medium is
transferred directly to the cylinder, which in this case
has a raised surface carrying the printing medium. For
gravure, flexographic, and letter presses there is again an
impression cylinder on the other side of the web to the
printing cylinder.
The third aspect of the present invention concerns
movement of the blanket cylinders of a printing apparatus
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into and out of contact with the web and their corres-
ponding plate cylinders. In the known systems, the
cylinders are constrained so that the blanket cylinders
must be precisely mounted in order to achieve their
required setting with respect to one another and their
corresponding plate cylinders when printing commences.
This aspect of the present invention, however, envisages
means for moving one of the blanket cylinders towards and
away from the plate cylinder and the other blanket
cylinder, and hence away from the web, and biasing means
for preventing that other blanket cylinder following
completely the movement of the first blanket cylinder.
This aspect may therefore provide a web-fed printing
apparatus having at least one cartridge, the or each cart-
ridge having a pair of plate cylinders and a pair of
blanket cylinders; wherein: the or each cartridge has means
for controlling movement of a flrst one of the blanket
cylinders between a first position and a second position;
the first position corresponding to a printing position, in
which the first blanket cylinder is in contact with a
corresponding one of the plate cylinders, and also applies
a force to the other blanket cylinder, which force holds
the other blanket cylinder in a first position in contact
with the other plate cylinder; the second position corres-
ponding to a withdrawn position, in which the first blanket
cylinder is withdrawn from contact with the corresponding
plate cylinder, and also from the other blanket cylinder,
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the withdrawal of the first blanket cylinder from the other
blanket cylinder permittin~ that other blanket cylinder to
move from its first position to a second position in which
it is withdrawn from contact with its corresponding plate
cylinder.
Thus, the blanket cylinders move between inoperative
positions, in which no printing occurs, and an operative
position in which the web is held between the two blanket
cylinders, and the two blanket cylinders bear against the
plate cylinders so that an image can be transferred.
The fourth aspect of the invention concerns the
relationship between the printing arrangement and the sub-
sequent web handling. The printing industry has developed
in two directions. One of them is concerned with the
handling of elongate webs, such as described above, whilst
the other is concerned with handling material in sheet
form. In general, each type has its associated problems,
and workers in the art tend to concentrate on their own
field. It has been realised, however, that the problems of
folding occurring ln the field of elongate web handling can
be effectively solved using techniques from the sheet
handling field, which techniques have been evolved to
handle the products of a sheet-fed printing machine. There-
fore, the fourth aspect of the present invention proposes
that the output of a web printing machine is cut into
sheets and is fed to a sheet folding system.
Thus this aspect may provide a method of processing at
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least one web of material comprising printing on the at
least one web, cutting in a time relationship with the
printing the or each printed web into a plurality of
separate sheets, and folding each sheet by a folder whose
action is timed in dependence on the arrival of a sheet at
the folder, wherein there is continuous movement of the
material from prior to the printing to the commencement of
the folding of the sheets.
This aspect may also provide a ~ethod of processing at
least one web of material, comprising printing on the at
least one web, forming a longitudinal fold in the or each
printed web, cutting in a timed relationship with the
printing the or each web into a plurality of separate
sheets, and folding each sheet by a folder whose action is
timed in dependence on the arrival of a sheet at the
folder.
Furthermore, this aspect may provide a method of
processing at least one web of material, comprising
printing the at least one web, forming transverse per-
forations in the printed web, cutting in a timed relation-
ship with the printing of the or each web into a plurality
of separate sheets, and folding each sheet by a folder .-
whose action is timed in dependence on the arrival of a
sheet at the folder.
In a similar way, the present invention may provide a
web processing system comprising an apparatus for printing
continuously at least one web of material, means for trans-
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12ferring the printed web continuously to a means for cutting
the web into a plurality of separate sheets, which means
has an action having a timed relationship with the printing
means, and means for transferring the sheets continuously
to a means for folding the sheets, which folding means has
an action which is timed in dependence on the arrival of a
sheet at the folding means:
a web processing system comprising an apparatus for
printing at least one web of material, means for forming a
longitudinal fold in the or each web, means for cutting the
web into a plurality of separate sheets, and means for
folding the sheets;
a web processing system comprising an apparatus for
printing at least one web of material, means for forming
a transverse perforation in the or each web, mjeans for
cutting the web into a plurality of separate sheets, and
means for folding the sheets.
Once the web has been cut, it can be fed to a buckle,
knife, or combination folder which may perform various
known folding operations on each sheet. This is particu-
larly advantageous when handling lightweight stock, in that
the known sheet systems cannot easily handle such stock, at
least not unless they run at very reduced speeds.
However, it is easy to make an initial fold in the web from
the web printing machine, thereby stiffening the material.
It also becomes possible to provide a perforation for the
first fold made by the folding machine.
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BRIEF DESCRIPION OF THE DRAWINGS
Embodiment~ of the invention will now be described in
detail, by way of example, with reference to the accompany-
ing drawings, in which:
Fig. 1 shows a general view of a paper handling system
with which the present invention is concerned;
Fig. 2 shows a schematic view of a paper web input
system;
Figs. 3a and 3b show the alignment arrangement for the
system of Fig. 2 in plan and side view respectively;
Fig. 4 shows a first embodiment of a web-fed offset
perfecting press embodying the second aspect of t~e
invention;
Fig. 5 shows a plan view of the drive system for the
press of Fig. 4;
Fig. 6 shows a side view of the drive system for the
press of Fig. 4;
Fig. 7 shows a second embodiment of a web-fed offset
perfecting press embodying the second aspect of the present
invention;
Figs. 8 and 9 show a third embodiment of a web-fed
offset perfecting press embodying the second aspect of the
present invention, Fig. 8 being a side view and Fig. 9
being a plan view;
Fig. 10 shows a detail of the cylinder movement system
of the press of Figs. 4 or 7, or 8 and 9, illustrating an
emhodiment of the third aspect of the present invention;
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14
Figs. 11 and 12 each show axial and radial views of a
cylinder with adjustable diameter;
Figs. 13 and 14 show alternative paper folding
systems;
Fig. 15 shows one form of processing and folding paper
from a web printing machine, embodying the fourth aspect of
the present invention; and
Fig. 16 shows an alternative paper processing
arrangement.
DETAILED DESCRIPTION
Referring first to Fig. 1, a web (in this example,
paper) handling system with which the present invention is
concerned involves three parts. A first part, generally
indicated at 1, takes paper from one or more paper rolls in
the form of a web 2 and transports it to a printing unit 3
and an optional drying unit 4. As illustrated in Fig. 1, a
right-angled turn in the paper web 2 is achieved by passing
the paper round an angled bar 5. After passing through the
printing unit 3, and the drying unit 4, the paper web 2 is
again turned for convenience through 90 via bar 6, and
passed to a cutting and folding arrangement generally
indicated at 7. Sheets of paper printed, cut and folded as
appropriate then pass for e.g. stacking in the direction
indicated by the arrow 8. Of course, any arrangement of
paper web input unit 1, printing station 3, drying station
4, and cutting and folding arrangement 7 may be provided,
the actual configuration depending on space and similar
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constraints.
As discussed above, the present invention is concerned
with various developments of the components of this system.
Fig. 2 shows one embodiment of a transport and feeding
arrangement 1 for material (e.g. paper) on rolls. It
consists of a splicing unit generally indicated at 10 and a
series of mobile reel stands in the form of roll trans-
portation trolleys 11, 12 (although only two are shown,
more may be provided). Each trolley consists of a base 13
with wheels or castors 14 which supports roll-lifting and
carrying arms 15. The arms 15 of each trolley 11, 12 carry
a roll 16 of paper with its axis generally horizontal so
that the web of paper may be drawn from the roll and
supplied to the splicing unit 10. Each trolley has means
for controlling the unwinding of a roll in e.g. the arms 15
of the trolley 11,12. The leading end of each trolley
11,12 may be provided with means for interconnecting with
the trailing edge of another trolley, or they may be queued
without being connected. In this way, it becomes possible
to push the trolleys 11,12 sequentially under the splicing
unit 10, so that as one roll is used up, another may be
started. This idea of queued trolleys carrying paper rolls
may be used with flying splicing arrangements, but zero-
speed arrangements are preferred and the arrangement illus-
trated in Fig. 2 corresponds to the latter.
The trolleys serve for transport from the paper store
to the machine and back, and as roll stands from which the
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paper is unwound. They can be queued so that they may be
positioned sequentially adjacent the splicing unit, and
moved so that as one roll finishes (on trolley 12) the next
(on trolley 11) can be in position. The running web on the
trolley 12 is therefore positioned to pass over a roller 17
at the splicing unit 10 at substantially the same angle, so
that each subsequent splice is of a predetermined cut off
length and is on the same side of the web. This reduces
the amount of roll handling, enables the work at this part
of the machine to be fitted in more flexibility with other
machine operating tasks; and permits a machine layout with
a better material flow, particularly in situations where
part used or re~ect rolls are to be removed from the
machine.
As shown in Fig. 2, a paper web 18 from the leading
trolley 12 passes via the roller 17 and a pressure plate 19
to a festoon system 20. The festoon system 20 has a roller
21 which is movable between the position shown in solid
lines and the position shown in dotted lines. ~he roll 16
carrying the next web 22 of paper to be used is mounted on
the second trolley 11, and its leading end mounted on a
pivotable unit 23. The privotable unit 23 has a pressure
system 24 into which the leading ends of the paper web 22
is fitted, preferably when the unit 23 is in its withdrawn
position shown in dotted lines.
As the first web 18 is run, the roller 21 is moved to
the position shown in solid lines so that there is a
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significant amount of paper running within the festoon unit
20. When the end of the web 18 being withdrawn from the
trolley 12 approaches, or it is desired to replace one web
with another, the input of the web 18 to the festoon unit
20 is stopped, but the output (in the direction of arrow
25) continues as the roller 21 moves towards its dotted
position. With the part of the web 18 adjacent the
pressure plate 19 stationary, the unit 23 is swung through
the position shown in solid lines until the attachment unit
24 comes in contact with the pressure plate, thereby
pressing the end of the web 22 (on which adhesive is
provided) onto the web 18, causing a splice. The web 18 is
then cut below the pressure plate 19 by a knife 26, unit 23
is then withdrawn, and the web 22 may then be drawn into
the festoon unit 20 and the roller 21 moved back to its
original position shown by a full line.
The accuracy of the feed of a web 18,22 into the
splicing unit 10 and hence through the festoon unit 20 to a
printing machine depends on precise alignment of the axis
of the rolls 16. If the axis of rolls 16 is not precisely
positioned perpendicular to the direction of arrows 25 of
the output from the festoon unit 20, there is the risk that
the web 18,22 may be creased or "track" (i.e. move side-
ways) in the printing machine. To prevent this, it is
desirable that there is an arrangement for aligning the
trolleys 11,12, and hence the rolls 16, below the splicing
unit. One such arrangement which may be used is shown in
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Figs. 3a and 3b.
There are two different alignments needed: to ensure
that the axis of the rolls is precisely transverse to the
direction of movement of the web, and to ensure that the
axis of the roll is at the correct distance from the
splicer 10. Fig. 3a shows the first of these. As
illustrated, one of the arms 15 of a trolley 11 has two
guide balls 30 rotatably mounted on its outer surface, and
the other arm 15 has a single guide ball 31, which is
rotatably mounted, but also spring loaded, on its outer
surface. When the trolley 11 is passed below the splicer
10 (in Fig. 2) the balls 30,31 contact a pair of guide
rails 32, one on each side of the trolley. The two balls
30 ensure that the corresponding arm 15, and hence the rest
of the trolley 11, is precisely aligned with the guide rail
32, and the spring loaded ball 31 ensures adjustment due to
slight variations in the width of the trolley. The three-
point contact of the balls 30,31 gives accurate alignment
with the guide rails 32, which themselves may be accurately
aligned with the direction of movement of the web.
As was mentioned with reference to Fig. 2, the
trolleys are mounted on wheels or castors 14 and in theory,
if the floor 33 was prefectly flat, and the wheels were
precisely made, this would ensure accurate vertical
positioning of the axis of a roll 16. In practice,
however, such accurate positioning is not possible, and
therefore the Fig. 3b shows one way of achieving vertical
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positioning. Each trolley ll has a pair of support rollers
35 on each side thereof, and a ramp 36 is positioned on the
floor 33 generally below the splicer 10. As the leading
wheel 14 of the trolley ll moves onto the ramp 36, the
support rollers 35 engage a pair of guide rails 37, one on
each side of the trolley 21. The guide rails 37 slope
upwardly in the direction of trolley movement, so as the
trolley ll moves, the action of the support roller 35 and
the rail 37 is to lift the rear wheel or castor 14 of the
trolley 11 clear of the floor 33. Hence the vertical
position of the trolley, and hence the roll 16, is
determined primarily by the guide rail 37.
As the trolley moves forwards, the support roller 35
moves through positions A to J shown in Fig. 3b.
The system described above requires the arms 15 of the
trolley 11 to be locked in position during the movement of
the trolley 11 below the splicer 10. It is also thought
possible to achieve accurate vertical positioning by moving
the arms 15 to a position determined by a suitable stop,
although such an arrangement is not preferred.
Thus, Figs. 3a and 3b illustrate one embodiment of the
first aspect of the present invention, embodied as ~ueuing
trolleys for paper rolls.
As explained with reference to Fig~ l, the paper web
then passes to a printing unit 3. Fig. 4 illustrates an
embodiment of such a unit 3, being a web-fed offset
perfecting press according to the second aspect of the
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present invention. As illustrated, the press has three
cartridges 40,41,42, with each cartrid~e having a pair of
blanket cylinders 43,44 in blanket-to-blanket con-
figuration, and a pair of plate cylinders 45,46 the outer
surface of each of which is formed by a printing plate in
contact with a corresponding one of the blanket cylinders
43,44: i.e. each cartridge contains a "printing couple". --
Normally the plate and blanket cylinders have the same
diameter, but it is also known to have plate cylinders of
half the circumference of the corresponding blanket
cylinder. As illustrated, the cartridges 40,41,42 are
immediately ad~oining each other, as this gives the array
of cartridges 40,41,42 a small size. It would be possible,
however, for the cartridges 40,41,42 to be in a spaced-
apart array. The web 2 passes round a roller 47 and
between the pair of blanket cylinders 43,44 of each
cartridge 40,41,42. It is preferable if the cartridges
40,41, and 42 are stacked substantially vertically but
substantially horizontal arrangements are also possible
including arrangements in which the cartridges are movable
transverse to the web. The image to be printed on the web
2 is carried on the plate cylinders 45 and 46, and
transferred via the blanket cylinders (hence "offset"
printing) to the web. This, in itself, is known.
As shown in Fig. 4, a unit containing printing medium,
e.g. an inking and dampening train 48,49 is provided on
each side of the web. The inking and dampening train 48,49
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are capable of moving vertically separately or together and
each may contain throw-off mechanisms to facilitate that
vertical movement (compare trains 48 and 49).
When printing is to occur, the inking and dampening
trains 48,49 are moved in the vertical direction to
register with one of the cartridges 40,41,42. The inking
and dampening rollers 50 are brought into contact with the
plate cylinders 45,46 by means of mechanisms which ensure
correct operating geometries and pressures. As illus-
trated, the inking and dampening trains 48,49 are provided
on each side of the web 11, but are common to all three
cartridges 40,41,42. If the cartridge 41 is to print, the
trains 48,49 are operated so that the inking and dampening
rollers 50, move into contact with the two plate cylinders
45,46 of that cartridge 41. A printing run then occurs.
At the end of that printing run, the inking and dampening
trains 48,49 are moved to their thrown-off configurations
(as shown for 48) and the trains 48,49 are moved vertically
until they are adjacent one of the other two cartridges
40,42. By moving the inking and dampening rollers S0 into
contact with the plate cylinders 45,46 of another cartridge
40 or 42, a new print sequence can operate.
It is also possible for the cartridges to move
vertically, with the trains remaining stationary, but this
is mechanically more difficult to achieve. Note also that
this arrangement permits "in machine" storage of the
cartridges, which is more efficient than the known arrange-
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13~6868
22ments.
A suitable drive system for the press of Fig. 4 will
now be described with reference to Figs. 5 and 6. As shown
in the plan view of Fig. 5, the inking and dampening trains
48,49 are mounted on a support frame 51 movable relative to
the main frame 52 of the press which supports the cylinders
43,44,45,46 via end supports 52a. The mechanism for
horizontal movement of the inking and dampening trains
48,49 is not shown, but Fig. 4 shows that a stop 53 may be
provided on the support frame 51 to limit this horizontal
movement.
The vertical movement of the support frame 51, and
hence of the inking and dampening trains 48,49 is con-
trolled by a hoist motor 54 mounted on the support frame
51. That motor 54 drlves a shaft 55 extending across the
support frame 51 and connected via bevel gears 56,57 to two
shafts 58,59. Shaft 58 drlves a pinlon 60 engaging a
toothed rack 61 on the main frame 52. Simllarly, shaft 59
drives two pinions 62,63 also attached to the main frame 52
which engage corresponding toothed racks 64,65 on the
opposite side of the main frame 52. Thus rotation of the
motor 54 drives shafts 55,58,59 causing the pinions
60,62,63 to move either up or down on their corresponding
racks 61,64,65, hence moving the support frame 51 relative
to the main frame 52. In this arrangement, a three-point
mounting is used, but it would also be possible to provide
a four or more point mounting by providing pinions
132~868
- ~ 23
additional on the shafts 58,59 with corresponding racks on
the main frame 52. Accurate vertical positioning of the
support frame may be achieved either by accurate control of
the motor 54 or by providing a stop 66 (see Fig. 4) on the
main frame 52. The stop 66 may be spring-loaded so that it
moves out from the main frame 52 when the support frame 51
moves past it, and the support frame 51 then lowered onto
the stop 66. Clearly the stop 66 has to be depressed to
permit downward movement of the support frame 51, e.g. to
operate cartridge 40 in Fig. 4.
The drive for the cylinders 43,44,45,46 will now be
described. In fact, the drive train for cylinders 43,45
and the train for cylinders 44,46 are the same and the
following refers only to the cylinders 43,45.
A shaft 67 extends up the main frame 52 and movably
on it, but engaged for rotation with it is a gear 68 which
meshes with a corresponding gear 69 connected to a shaft 70
which extends to a worm 71 which mates to a worm wheel 72.
A shaft 73 is secured to the worm wheel 72 and is supported
on the support frame 51 by a support 74. At the end of
shaft 73 remote from the cylinders 43,45 is an air cylinder
75 which is capable of moving the shaft 73 axially. At the
other end of the shaft 73 is a clutch plate 76 which
engages a corresponding clutch plate 77 on a stub shaft 78
extending from the plate cylinder 45. The clutch plates
76,77 and their attached shafts 73,78 pass through an
aperture 79 in the main frame 52. At the end of the plate
.
~326868
24
cylinder 45 are gears 80 which mesh with corresponding
gears 81 on the blanket cylinder 43.
Thus, when the air cylinder 75 moves the shaft 73 so
that the clutch plates 76,77 are in engagement, drive from
the shaft 67 is transmitted via gears 68,69, shaft 70, worm
71, worm gear 72, shaft 73, clutch plates 76,77, and the
stub shaft 78 to the plate cylinder, and hence via gears
80,81 to the blanket cylinder.
When the air cylinder 75 moves the shaft 73 to
disengage the clutch plates 76,77 no drive is transmitted.
Furthermore, this movement of the shaft 73 is sufficient to
move the clutch plate 76 clear of the aperture 79,
permittlng the whole assembly on the support frame to be
moved relative to the main frame 52 to another cartridge.
This arrangement has the advantage that cylinders of
cartridges not in use cannot have any drive thereto, and
therefore can be handled safely, e.g. for replacement of
the printing plates of those cylinders. Since the cylinder
drive mechanism moves with the inking and dampening trains,
it is impossible accidentally to drive cylinders which are
not to print at any particular time.
The clutch formed by clutch plates 76,77 has another
function. The clutch plates 76,77 form a "single position"
clutch preset to synchronise the position of the corres-
ponding plate cylinder 45 to the drive. Thus, irrespective
of the initial position of the plate cylinder 45, its
rotation will be synchronised with the rotation of the
- ' ' ,: " ' , .
3 ~ ~ 8 6 ~
shaft 67.
Sometimes, however, it is desired to vary the
synchronisation of the shaft 67 and the plate cylinder 45,
to advance or retard the printing image relative to the
main drive. To do this, the worm 71 is moved along shaft
70 by a linear actuator 82, which normally holds the worm
71 fixed on the shaft 70. This rotates the worm wheel 72
which, via shaft 73, and clutch plates 76,77 rotates the
plate cylinder 45 relative to the position of the drive
shaft 67. The movement of the worm 71 may also be achieved
using a motor or a hydraulic ram. Movement of the other
plate cylinder 46 relative to the shaft 67 may be achieved
in the same way either simultaneously with or separately
from movement of the plate cylinder 45.
The drive to the inking and dampening cylinders 50 of
the inking and dampening tralns 48,49 will now be described
with reference to Fig. 6. Although Fig. 6 is an equivalent
view to that of Fig. 4, the cartridges 40,41,42 have been
omitted for the sake of clarity, as has the drive from
hoist motor 54 to move the support frame 51 relative to the
main frame 52.
As can be seen from Fig. 6, gears 83 extend from the
shaft 70 from gear 69 to the worm 71. These gears 83
engage on an epicyclic gearing 84 on a further shaft 85.
Each end of the shaft 85 carries gears 86 which engage
gears 87 which connect to the drive system within the
inking and dampening units in a conventional way. Thus the
.
~ ~ - , - -
.
.
: ~ ~
`" 1326868
26
shaft 70 is connected to shaft 8S and the drive from shaft
69 which drives the cylinders 43,44,45,46 as discussed with
reference to Fig. 5 also drives the inking and dampening
rollers 50.
However, this synchronisation depends on the diameter
of the plate cylinders 45,46, and if the press has two
different sizes of cylindes, the drive system discussed
above can only be in synchronisation for one size, and
printing would be out of synchronisation when the inking
and dampening units 48,49 were moved to a cartridge having
cylinders of a different size. The arrangement of Fig. 6
overcomes this by providing an auxiliary drive motor 88
connected via the epicyclic gearing 84 to the shaft 85.
The speed of rotation of that auxiliary motor 88 is sensed,
and the result fed to a comparator 89 which compares that
speed wlth the speed of rotation of rollers 90 between
which the paper web passes. These rollers 90 may also be
associated with epicyclic gearing. If it is found that the
drive is not synchronised, then the motor 88 is speeded up
or slowed down until synchronisation is achieved. Thus the
drive to the motor 88 modifies the drive transmitted by the
gearing 83 to the shaft 85.
Fig. 6 illustrates a further feature of the system,
namely that the shaft 67 which drives the plate and blanket
cylinder is driven from a shaft 91 which extends beyond the
printing station. Thus, additional printing stations may
be connected to the shaft or, as illustrated in Fig. 6, may
3268S8
27
be connected to the perforating tool of a pre-folder 92, or
the perforator and cutter of a cutting station. These will
be described in detail later, but as can be seen the main
shaft 91 has gears 93 driving a shaft 94 of the pre-folder
92 which rotates a perforating tool 95. Again, epicyclic
gearing 96 may be provided, linked to the comparator 89.
As illustrated in Fig. 4, one pair of inking and
dampening trains 48,49 is provided in common for three
cartridges. In general, therefore, the three cartridges
may have different images on their plate cylinders, or even
different sizes of cylinders, so that by changing from one
cartridge to another, the print length may be varied.
Other arrangements are also possible, however. Fig. 7
illustrates an example of this having four cartridges 100,
101,102,103, each of which is similar to the cartridges
40,41,42 of the arrangement shown in Fig. 4. The web 2 of
paper passes up the middle of the cartridges 100,101,
102,103. Four inking and dampening trains are provided, an
upper pair 104,105 serving the upper two cartridges 100,101
and a lower pair 106,107 serving the lower two cartridges
102,103. In this way, for example, it is possible to print
two different colours in like size print cylinders, and yet
still maintain the possibility of change of image and/or
repeat length. Also, as shown in Fig. 7, the cylinders of
the cartridges may be different sizes, e.g. with the
cylinders of cartridges 100,102 being smaller than the
cylinders of cartridges 101,103. The press shown in Fig.
. ."
.: . , .
28 1326868
7, apart from having four cartridges, as discussed above,
may be generally similar to the press of Fig. 4, and have a
drive similar to that described with reference to Figs. S
and 6. Therefore, further detailed description of the
arrangement of Fig. 7 will be omitted.
One feature of this system is that by adding
additional cartridges, and possibly additional inking and
dampening trains 48,49, the number of different printing
operations can be lncreased.
The embodiment described above with reference to
Figs. 4 to 7 have the inking and dampening units moving
vertically relative to a vertically stacked array of
cartridges. It is also possible to have a horizontal
arrangement in which cartridges are in a fixed horizontal
array and the inking and dampen~ng units are movable
relative to the cartrldges on which printing is to
commence. One or two inking and dampening units may be
used. The drive to the plate cylinders and the inking and
dampening units is as described in the vertical unit shown
in Fig. 5. The difference lies in the fact that a
horizontal power shaft running parallel to the main power
shaft may be used to drive the plate cylinders. The drive
from the main power shaft may be provided by a vertical
shaft connectlng the power shaft to the horizontal shaft
through two pairs of bevel gears.
As described above, the array of cartridges is fixed
and the inking and dampening units are movable. Since the
29 132~86~
present invention depends on relative movement, it is also
possible to have the inking dampening units fixed and move
the cartridges of the array. The cartridges may be moved
by many ways, such as rollers, guide rails, or pneumatic
jacks, and the drive to the plate cylinders of the
cartridges may be achieved by single toothed clutches as
described with reference to Fig. 6. The advantage of an
arrangement using movable cartridges is that the inking and
dampening units are fixed and hence the drive to the system
may be fixed. However, it is currently considered to be
more difficult to move the cartridges than to move the
inking and dampening units.
A further embodiment involving fixed inking and
dampening units and movable cartridges is shown in Figs. 8
and 9. This embodiment has four cartridges 111,112,113,114
such as to form a carousel 115. As illustrated in Fig. 8,
each cartrldge has a pair of plate cylinders 116 and a pair
of blanket cylinders 117 in a manner generally similar to
the plate and blanket cylinders of the cartridges 40,41,42
of the embodiment of Fig. 4. However, it can be seen from
Fig. 8 that the plate and blanket cylinders 116,117 of the
cartridges 111,113 are smaller than the blanket cylinders
116,117 of the cartridges 112,114. This enables the
cartridges 111,113, and the cartridges 112,114 to give
different point repeat lengths.
A web 2 of paper enters the printing machine via
rollers 118,119 to move along a horizontal path through two
. .
114,112 of the four cartridges 111,112,113,114 of the
carousel 115. The carousel is rotatably supported on a
frame 120 and a second frame 121 supports one or two inking
and dampening units 122 (one inking and dampening unit is
shown more clearly in Fig. 9). Where one inking and
dampening unit is provided it is preferably on the side of
the carousel llS into which the web is fed. Where two
inking and dampening units are provided they are normally
on opposite sides of the carousel 115 to permit the
cartridges 111,113 or the cartridges 112,114 to be driven.
The print~ng machine shown in Figs. 8 and 9 may
operate in one of several ways. For example, it is
posslble to carry out a print run using only cartridge 114,
and during that print run, cartridge 112 may be prepared
for a different print run. When the print run through
cartridge 114 is completed, the blanket cylinders 117 of
cartridge 114, may be withdrawn from the web 2, and the
drive to that cartridge removed and then the blanket
cyllnders 117 of cartridge 112 moved into contact with the
web and a drive applied to cartridge 112. A print run may
then be carried out using cartridge 112 and cartridge 114
prepared. If cartridges 112 and 114 have the same printing
repeat length or printing diameter, it is possible to carry
out two colour operation with cartridges 112 and 114
working in tandem.
To change printing to cartridges 111,113, a motor 123
drives the carousel 115 and turns it on its frame 120,
--- 132~ 58
31
through goo so that the cartridges 111,113 are aligned with
the web 2. Accurate positioning of the carousel may be
achieved by steps (not shown). This rotation of the
carousel 115 means that the web 2 must be broken in order
to change from one pair of cartridges to the other, and
hence this embodiment is less advantageous than the
embodiment of Fig. 4. As shown by arrow 124, the carousel
115 may be rotated clockwise or anticlockwise, as desired.
The drive arrangement for the embodiment of Figs. 8
and 9 will now be described. Referring particularly to
Fig. 9, a shaft 125 (which may be connected to a drive
system for an entire printing system as discussed with
refernce to Fig. 6) drives via gears 126 a shaft 127, and
hence via gears 128 to a drive arrangement 129 for the
inking and dampening unit 122. The drive arrangement 129
may be similar to that described with reference to Fig. 6,
i.e. the drive may pass via epicyclic gearing 130 which may
be acted on by an auxiliary motor 131 enabling the synchro-
nisation of the drive.
The shaft 127 also has a further gear 132 which
connects to a worm 133 acting on a worm wheel 134. The
worm wheel turns a shaft 135, at one end of which is a
linear actuator 136 and at the other end of which is a
clutch 137. The clutch 137 connects to a shaft 138 which
drives a plate cylinder 116 of one of the cartridges
111,112,113,114. Thus the drive to the cartridge of this
embodiment is generally similar to that described with
,
1~268~8
32
reference to Fig. 5, and its operation will theref~re be
immediately apparent.
As shown schematically on the right hand side of Fig.
9, the shaft 127 may also extend to the opposite edge of
the carousel 115, to drive another inking and dampening
unit (not shown).
A further development of the arrangement shown in Fig.
4 (or Figs. 7 or 8 and 9) is concerned with the mounting of
the cylinders within the cartridges 40,41,42 (100,101,
102,103 or 111,112,113,114). Clearly, if the cylinders
were mounted in a conventional manner each time a cartridge
is required to be changed, the printing positions would
require precise and lengthy re-setting. Therefore, the
third aspect of the present invention concerns an
arrangement for moving the blanket cylinders easily into
and out of their precise contact positions. When they are
in contact, printing can occur. When they are moved out of
contact they can then not hamper continuous printing, e.g.
by a different cartridge. Furthermore, a cartridge may be
removed from a press and replaced e.g. by a cartridge
having cylinders of different size, and brought into
precise running setting quickly and easily. In this way,
many changes may be made to the machine with minimum
downtime.
One embodiment of the system for moving the blanket
cylinders 43,44 into and out of contact with the web and
their adjacent cylinders is shown in Fig. 10. The solid
-
- ~
~ 1326868
33
lines represent the position of the cylinders when they are
printing, the dotted lines when they are not. One blanket
cylinder 44 is pressed into contact with its associated
plate cylinder 46, with the gears 79,80 in Fig. 5 engaged,
and also bears against the other blanket cylinder 43 ~the
web being then nipped between the blanket cylinders 43 and
44 to ensure good contact for printing). The blanket
cylinder 43 then bears against its plate cylinder 45.
Normally, a slight freedom is provided in the mounting of
the blanket cylinders 43,44, so that when blanket cylinder
44 is pressed into contact with its ad~acent cylinders,
both cylinders will automatically position themselves into
their precise printing positions by the reactions of the
contact pressures to their associated plate cylinders and
their co-acting blanket cylinder.
To engage the blanket cylinders 43,44 one of them
(cylinder 44 in Fig. 10) is movable so that lts axis moves
between positions B and A. This may be achieved, e.g. by
mounting the end so the support on which the cylinder rests
in a slot, with one end of the slot corresponding to
cylinder axis in position B and the other formed in such a
way as to allow the cylinder axis to have freedom from the
slot sides when in position A. The cylinder axis is
pressed into position B by a loaded plunger 140 when
printing is not taking place, so that blanket cylinder 44
is in the position shown in dotted lines, and is also out
of contact with its corresponding plate cylinder 46 and the
: . . . .. .
-~ 34 1326868
other blanket cylinder 43.
The other blanket cylinder 43 is carried on a
pivoted support 141 which allows the cylinder axis to
move along a restricted arc within an oversize hole (not
shown). The boundary of this hole does not influence the
axis position when the blanket cylinder 43 is in contact
with plate cylinder 45 but does restrict the amount of
movement away from that plate cylinder. This permits a
gap to open between blanket cylinder 43 and plate
cylinder 45 as blanket cylinder 44 moves to position B
and also a gap between blanket cylinder 43 and 44 by
cylinder 43 being able to follow cylinder 44 but not far
enough to maintain contact with it. A similar effect can
also be achieved by mounting the support of the blanket
cylinder 43 in a slot arranged to allow contact with
plate cylinder 45 but restrict movement away from it. If
nothing holds the cylinder 43 in contact with plate
cylinder 45 it moves away on its pivoted support 141
under a separating force which may be provided by
gravity. It is required that the separating force should
not exceed a threshold value. If the gravitational (or
other) force on the roll 43 exceeds this value, the
separating force is reduced by means of a spring 142 or
other biasing means such as an air cylinder acting on the
pivoted support 141.
As shown in Fig. 10, the blanket cylinder 44 is also
mounted on a bracket 143 which is connected to a lever
144 pivoting at point 145. When lever 144 is moved, e.g.
, : .. :
. . . .
13268~8
by a pneumatic system 146, to the position shown in solid
lines, a force is applied to blanket cylinder 44 which
moves its axis against the pressure of plunger 140 away
from position B towards position A (i.e. the printing
position). The blanket cylinder 44 abuts its plate
cylinder 46, and also contacts the other blanket cylinder
43, moving it to contact the other plate cylinder 4S.
The precise positioning and pressure achieved is finally
determined by the reactions of the blanket cylinders to
their adjacent cylinders and the controlled forces moving
them into position (and no longer by the influence of
their mounting slots or holes).
Thus, by providing means for moving one of the
cylinders into and out of a printing position, and means
for the other cylinder to follow over a restricted
distance controlled by force reactions, at the "on"
position and slot or hole limits at the "off" position,
printing may be disengaged and re-engaged quickly and
simply, even after a different cartridge has been
installed in the press. That i5 to say, the system
provides force loading and self-setting. Ideally the
cylinder should run on a continuous surface, and this is
best achieved by cylinder bearers (to be discussed
later).
The printing machines discussed with reference to
Figs. 4 to 10 thus generally permit printing to occur
continuously, but also permit changes of cartridges to be
made with quick and easy establishment of the precise
., , : , . ~ . . . :
.
.
. .
_~ 36 1~32~8~
settings required. This is very important in minimising
down-time. The arrangement shown in Fig. 4 is
particularly applicable to single colour (including
black) printing. It is also applicable to colour
printing although then difficulties may occur in having
common inking and dampening trains, and a large number of
cartridges and inking and dampening trains may become
necessary.
Figs. ll and 12 illustrate a design of cylinder -
which is particularly useful in the present invention.
Each cylinder has a core 150 of a given size to which rim
units of differing thicknesses may be fitted, as desired.
Fig. 11 shows a cylinder with a relatively thick rim unit
151 and Fig. 12 shows a cylinder with a relatively thin
rim unit 152. By interchanging the rim units the
effective diameter of the cylinder can be changed,
without removing the core 150 from the press. The rim
units 151, 152 are anti-corrosive (acid gum in the
damping fluid may otherwise cause corrosion) and removal
of the rim units also allows easy maintenance.
As shown in Figs. 11 and 12, the rim unit 151, 152
supports a printing plate 153, connected to it by clips
154, 155 which enable the printing plate 153 to be
stretched around the cylinder. Figs. 11 and 12 also show
the end rings 156 and clamps 157 at the end of the
cylinder for holding the rim unit 151, 152 onto the core
150. The rings 156 act as bearers to ensure smooth
rotation of the cylinders, as has been mentioned
,
132~6%
37
previously. Note that the rings 156 are slightly thicker
than the rim units lSl, 152 so that their radially outer
surface corresponds exactly with the outer surface of the
printing plate 153.
Once the paper web has been printed, then another
aspect of the invention comes into play. In most cases,
the possibilities for folding of paper whilst in web form
are limited (although one or more longitudinal folds may
be made as will be described later), but few complicated
folding combinations are practicable with the output from
web printing machines. On the other hand, there are
various techniques for folding paper sheets in e.g. gate
folds, multiple transverse folds and longitudinal folds;
two are illustrated in Figs. 13 and 14.
Fig. 13 shows an arrangement known as a knife folder
in which the paper sheet 160 passes over a pair of
contra-rotating rollers 161, 162. With the sheet 160
stationary in that position, a knife 163 i6 lowered,
forcing the sheet 160 into the "nip" 164, thereby
providing a firm fold. The sheet 160 is then drawn down
between the rollers 161, 162 for subsequent use. The
knife 163 will normally be connected to a photocell or
similar detector which detects the presence of sheet 160
below the knife. In this way the folding operation can
be synchronised with the arrival of the paper sheet 160
at the folder, rather than synchronised with e.g. an
earlier stage of the printing operation.
Fig. 14 shows an arrangement known as a buckle folder
., .. . ~ , . . . .
" 1326868
38
in which a sheet of paper 170 passes between a first pair
of contra-rotating rollers 171,172 and its leading edge
strikes a ramp 173. The action of the rollers 171,172
forces the paper sheet 170 up the ramp 173, until its
leading edge strikes a stop 174, the position of which is
determined by the desired position of the fold. When paper
strikes the stop 174, it can no longer move up the ramp,
and so the action of rollers 171,172 is force the paper
sheet 170 into the nip defined between roller 172 and
another roller 175. This forms a sharp fold in the paper,
which then pa~ses downwardly due to the action of rollers
172 and 175. It may then strike another ramp 176 and move
downwardly to another stop 177. In this position the sheet
170 is then acted on by rollers 175 and 178, between which
is another nip causing further folding. It is also possible
to perforate the folded paper longitudinally by passing it
through a perforating nip formed by rollers 179. Thus, the
system in Fig. 14 permits successive transverse folding and
perforating of the sheet, and by providing several such
units with one or two ramps, any number of transverse folds
may be provided. If the direction of movement of the sheet
is changed between one buckle folder and the next, both
longitudinal and transverse folds may be provided.
However, the first fold is generally a transverse one, or
extra equipment would be needed. Again the folding of the
sheet 170 ls in timed dependence on its arrival at the
folder, not in dependence of the timing of the printing
, . ~ . -, . . .
' . .
.. . . .
~` 1326868
39
operation.
It is also possible to provide folders which are a
combination of knife and buckle folders.
Referring now to Figs. 15 and 16, a paper web 2 from a
web printing machine (e.g. as in Fig. 4) is cut into sheets
by a knife arrangement 180. Fig. 15 shows a perspective
view of the arrangement, and the web 2 from the printing
machine is first turned through 90 by a bar 6 as has
already been described with reference to Fig. 1. Of
course, this is not essential and the web path to the knife
arrangement 180 may be straight as shown by dotted lines in
Fig. 15. This knife unit 180 may be powered from a drive
shaft common with the printing station, as described with
reference to Fig. 6, i.e. the knife unit 180 shown in Figs.
15 and 16 corresponding to the element 91 in Fig. 6. A
drier unlt may also be provided as discussed with reference
to Fig. 1. Once the knife arrangement 180 has cut the web
2 into sheets, they may be passed to a folder 181 which may
be e.g. a buckle folder such as shown in Fig. 14, although
a knife folder as shown in Fig. 13 may also be used. One
factor to bear in mind is that the speed of the web from
the printing machine may be faster than can be handled by
the known sheet folding systems, and it may be necessary to
divide the sheet flow so that sub-streams follow two or
more routes. In this example a divider 183 is provided so
that some sheets pass straight on to the folder 181, and
others are diverted to another folder 182. Further changes
, ~
. - . ,...................... ~ , '
: ~ :
13;~
, ~ .
in direction may occur at units 184 and 185. Such two-
route handling of paper sheets is known, and therefore it
is unnecessary to discuss it in greater detail here.
Clearly, it is possible to provide for any number of folds,
depending on the use to which the paper is to be put.
Whereas, as explained above, the first fold is
generally a transverse fold in sheet fed systems~ Fig. 16
shows a simple way of providing a first, longitudinal, fold
in the paper. This is particularly important with thin
paper which cannot easily be handled by buckle folders such
as shown in Fig. 14. The paper web 2 from the printer -
machine and (possibly) the drier passes to a former 190
which is triangularly shaped so that a longitudinal fold is
placed in the paper as it moves downwardly from a roller
191 to a pair of guide rollers 192, between which a throat
is formed. Thus, the paper fed to a buckle folder
generally indicated at 193 has already been folded once, in
the longitudinal direction, and is therefore less subject
to malfunctioning in the folder. Again, however, a knife
or similar cuttes 194 has to be provided before the web
enters the buckle folder 193.
As described above, the folds are made directly to the
paper. However, to ease the transverse folding, a
transverse perforating unit 195 may be provided upstream of
the knife or other cutter 194. Furthermore, the use of a
web printer permits longitudinal perforation to facilitate
the longitudinal folding shown in Fig. 16, by means of the
:. , , ~ ., ~. .. . .
---" 13268~8
41
continuous perforating wheel 196 producing perforations
197. Furthermore, this wheel 196 may be powered from the
main drive shaft to the printing station, as was described
with reference to Fig. 6. Likewise, any other longitudinal
fold can be produced on a continuous basis. Perforation
also assists quality by permitting air to escape from
within the fold.
!. . ~ ~ -
'' `
',~ . ' ` . :'
