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A-3562
Arrangement and corresponding method for fast image data
transfer in printing pr=esses
Description
The present invention relates to an arrangement and a
corresponding method f<.~r fast image data transfer according to
the preamble of patent claim 1.
An arrangement of this typEe and a corresponding method are
disclosed by US 6,029,576. In t=his case, flexible finishing of
a printed product is made iaossible, and t_he ability to
allocate the printing ~:~res:;es used in a print shop is
achieved. For_ this purpose, in the prepress area there are,
inter alia, a computer and two storage units. Image-specific
data are stored in the fir:>t storage un~_t= of a computer, and
printing control-specific ~,.rnage c(ata are storied in the second
storage unit. After a cc~nc~_ete job has koE:en allocated to a
:specific printing press in the print shop, a selection is made
from print control--spe~~:ifi~: i.magE: dat=a with which the job can
be controlled in an opti_murn way on tine <~Llocated printing
press . The associated imag=~-spE:c_: f ir_ and print control-
specific image data is then t:ran:;mitted jointly, via a local
network or a bus system, ofu which a plurality of imagesetting
systems comprising RIf (raster image processor), press
computer and printing press erected in the machinE; room
depend, to the RIP of the c=orresponding printing press for the
purpose of imagesetting and c~ontr_ol.
Furthermore, EP 755 786 discloses a device for controlling a
printing press, in particular a sheet:-fed offset printing
press, which device has a p.lural.:Lty of computers with
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memories. The individual computer: are ~~onnected to one
another via a bus system (e.g. CAN Bus) constructed as a
network. Via the bus and an inters=ace provided as a special
connection, a programming unit: c:oupl.ed thereto can implement
the changeover of the compu::er <connected to the bus from a
state corresponding to the !normal caress operation into a
programming state.
Furthermore, it is gener~~lly ~inown that, _~_n digital printing
presses, during the imagesettinc~ c->peration the separation data
previously generated by i~he RIP are transmitted to the laser
imagesetting units. In order to be able to prevent the
imagesetting being terrr~inated, a ~aata transfer with a
continuous data rate matched to tile respective imagesetting
speed and system configuration is required. Consequently, in
the case of digital printing presses, the requirement on the
overall data rate incrE-ases with t-.he number of printing units,
since there is an imagesetting unit ir_ each printing unit.
Since the RIf accor_dinc~ to th~= prior art is generally not
capable of making the required over-al_1_ data rate available
during the irnagesettinc~, ir.termedi<~te storage of the
separation data is reqr.rirea. This means that the data is
firstly copied from the RIF' to one or more intermediate
memories and then read fr_orr~, the intermediate memories at the
required data rate dur:_ng the imagesett:ing. A significant
feature of a universal imaqesetting system in this case
consists in being easy to ~,cale; this means that the system
must be suitable t.o meet ttve requirement.; relating to smaller
and larger press configurations to the s~~me extent.
In imagesetting systems wh~_ch are current=ly available, hard
disks are used as storage rneds.a for buffering the separation
data. Since hard disks are sensitive to ;hocks, these are
integrated in a separate ~>l.orage unit in a switch cabinet and
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not within the printing ~>re:~s. ThE.~refore, no direct access
from the imagesetting un,~t t o t: he r.ard disks is possible. The
provision of a special st~or~ge unit, which is capable of
supplying up to six imageser:tyng i.znits with image data, is
known. On the input side, this unit has an SCI interface, via
which the separation data is tr<~nsmitted to the storage unit.
On the output side, there are six proprietary optical bus
systems for transmitting the data to the imagesetting units.
The internal electronics are processor-based and ar_e able to
drive up to six hard disks, which can be fitted as desired.
The disadvantage with this arrangement. is that it is difficult
to scale with regard tc~ co~t.s and perfcsrmance. This is because
this solution is optim<ul or:l.y in the ease of presses having
exactly six or twelve printing units; i.n the case of a
configuration deviating frc.m this, there are components in the
system which are not required in terms c:,f performance and
cause unnecessary cost=~. S_rrce the imagesetting units have no
direct access to the hard <tisks, a further computer system is
additionally always re<~uircvd, which performs the management of
the hard disks and the datat transfer t=o t:.he imagesetting
units.
A further approach to <~ bet:ter sealed printing system consists
e~n providing a computer sy;->tem with a hard disk for each
printing unit. The conuect;:or between the RIf and the computer
systems is implemented via ar_ E;thernet interface, and each
imagesetting unit is conne~::ted indiv:iduaLly t:o the associated
computer system via a seri.;l bus line. irr this case, the
computer system or the PC ~end:~ t:he imagesetting data to the
respecti..ve printing unit.. %-~lthouc;h this covariant meets the
requirements wits regar_r.~ t~ scaleability, this advantage is
supposed by relativf=_ly h_~gh r_osts for the requisite computer
systems.
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Ir_ is an object of she present: invention to provide an
arrangement and a method for fast s.mage transfer in printing
presses, it being possible for t=hc_~ intermediate storage of the
image data to be scaled easily with regard to costs and
performance.
According to the invention, this is achieved in an arrangement
having the features of patent claim 1 and a method as claimed
in patent claim 10. A :;ystE-rn arch:itect:ure which can be scaled
easily with regard to c::ost~ and performance is provided,
having intermediate bwtfering of the image or separation data
for an imagesetting sy~~tem for digital printing presses and
CtP systems. The ir_vent:ion is based on storage media which use
the same bus interface as the imagesett=ing units and to which
all the bus subscriber: cari make access via this bus system.
That is t:o say, both the cc~mputex de:>:ignated the data manager
and the respective imageset:.ting units have access to these
storage media v.ia one ,~r.d i-.he same bus s~.rstem. Before the
netting of an image, the d<:ita. manager cc:>yies the separation
data received from the F;IP to t:he respective storage medium.
!:>2~ring the imagesetting, t;ze data is read from the storage
medium again by the irnage.~;:tt:ing units. ,=~s a result, the
imagesetting units have direct access to the storage media
without the circuitous r_our~e via a further computer system.
Within the imagesetting system, !:.hera is only one bus system,
vi.a which the separation c~;_~t:a is k>oth written and read.
Provision is advantageously made for, if possible, all the
imagesetting units to be cc~nnect;~d to the storage units merely
via a single individual data 1_ine of the bus system. This
solution is particulamly cost-effective and, in addition, has
t=he advantage that th~:ere ~s no fixed as~oci.ation between the
printing units and thc:e stc>rage units. Thus, even shortly
before t:he imagesetting o~~eration, a change in the data
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assignment i_s possible with:>ut: recopying the image or printing
data. The system and, in particular, the individual. data line
in this case must be suitable for the correspondingly high
data rates which occur.
According to a preferred embodiment, at least two storage
units are assigned to c>n~s irnagesett:ing unit. In this case, the
higher data throughput of the c>ve.rall arrangement as compared
with a configuration havinc only one hero disk per
imagesett.ing unit is ac:~vantageous. In addition, subsequent
expansion of the storage o pacity of the system is made easier
in this embodiment. Furthermore, the fail. safety o.f the system
is increased by stc~ragae un.~ t;s which from time to time are
redundant..
In order to be able to adayt the arrangement optimally to the
respective requirements in respect of performance and costs,
provision can be made fo.r ~:he c:omponents to be connected to
<one another via a common bls system but to make use of
c~i_fferent transmission media or standard: of a bus system
e.g. copper cable, gl.a~>s fiber).. Provision can also be made
for access to be made to t~'oe st:oo-age unit. on the data manager
side and on the imageset=t:ing side via different bus systems.
Three exemplary embodiments of the arrangement according to
the invention fo.r .fast :Lmage data transfer, as wel..l as the
method according t:c tY.a invent:io:n, are described below; in the
drawing:
Fig. 1 shows, in very sim~:lified form in a basic illustration,
the first exemplary embodiment o the printing arrangement,
Fig. 2 shows the second e~:emplary embodiment of the
arrangement, and
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Fig. 3 shows a detail of th~_: arrangement according to the
third exemplary embodirr~ent.
According to the first exemplary enubodiment according to Fig.
l, a raster image proces:~or (RIP) 1. is connected to a data
manager 3. The RIP 1 receives image/separation data from
computers (not illustrated) from t;he prepress area. Since the
RIP is not. involved in the actual imagesetting operation, as a
result of the interrrlediate buffering of the image data
explained below, the architecture places no special
requirements on the RIf 1. This data manager 3 is connected in
parallel to numerous st.oraaP units 7 via a bus system 5. The
image data is not stored in the data manager 3 but outside the
data manager, in the st:orac~e units 7. The data manager 3 has a
number of bus streams whicr: is sufficient for the respective
press configuration wh_~ch, in particular, is determined by the
number of printing unit=s. The bus streams are suitable for the
data rate required for the imagesetting. In addition, the data
manager 3 has a suitable ir;terface to the RIP 1. The
performance of the dat<~ manager ? influences the overall
performance of the printinct arrar_gement too the extent that all
t;he image data is transferred to the storage units 7
;download) via the data manager ~~efore tkle imagesetting.
Therefore, a PC or an irvdu:~trial PC is u:~ed as the data
manager 3. Each storage un_t 7 ins in each case connected via a
line of the bus system 5 t:~~ precisely one printing unit or one
imagesetting unit ~~. Can th~~ pri.nt:ing unit side, a system is
therefore required whi~~ku p~ovide:~ a corresponding bus
connection with thE:e require:~d data rate. In this case, data
rates of up to 2.0 MBytei s ire required i.n order tc carry out
the print jobs. In addition, the imagesetting unit 9 must be
:apable of communicating with t:he corresponding storage unit 7
aria a protocol. Tr_e data m,~nager 3 is therefore not
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incorporated in the printin:~ data transmission during the
imagesetting; during the im.~gesett.ing operation, the
imagesetting units 9 make d:irecl~ access to the storage media 7
connected to them. The max iwum achievable imagesett.:ing rate,
as distinct from the dcwnload operation, therefore does not
depend on the performance of the data manager 3. The system
can in principle be scalfJd as desired by adding further
storage media 7 and imag~°set:t.ing units 9 to the bus system 5.
Substantially independent c:f t.heir number, only one data
manager ~ is required for the management <~nd distr_ibution of
the printing data to tt~e storage units 7.
The printing arrangement according to Fig. 1 is based on a
serial bus system, which i:defined i.n the IEEE1394 standard
and is a,~so known under thE:desicnati.on I,irewire. For this bus
system 5, suitable hard di.:;ks are available as the storage
unit 7, and can be con:zect_F.d directly to the bus system. These
disks are standard IDE c~r ;-.'CSI: hard disks, which have an
appropriate convert=er. fur~~hermor:e, any desired hard disks can
be used, provided that there i:~ ~~ suitable converter available
on the bus system used. Al:emat_~vely, i-~r principle use could
be made of a USB2.0 syst:ern, f_or which there are likewise
arorage media with direct dus connection, but whose restricted
cable length makes use :Ln panting presses much me>re
c:~ifficult. In addition, the fiber channel. known from the
professional PC sector could bf~ .zsed, which likewise offers
hard disks with direct: bus connect: ion. The storage medium must
be able to store ,urge amounts of stored data (at least
several GByte) , in order to ;~e ah>1_e to keep a plurality of
print jobs zn reserve in ~-arallel.. In addition, the printing
data must be capable c~f being read at: the required data rate
during the imagesetting o~=eration. The hard disks are located
outside the printing press, in a separate switch cabinet (not
illustrated) . The -imac~ese! ting L.nits ~~ c>f the printing press
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can access the hard drives :directly v.ia the bus system 5. The
computer required to control the sprinting unit is not
i_l.lustrated in Fig. i.
In an enlarged system haling a pl.zrality of printing presses
(not shown), a plurality of RIPs 1 or else a plura7_ity of data
managers 3 could be provided in order to improve the
performance, all being connected to one another via one
network or via, forexample, two part networks. The advantage
of a plurality of RIPS is that, in thE: event: of a plurality of
printing presses being present, a plurality of print jobs can
be scanned in parallel, anti therefore a higher throughput of
jobs is possible. for exam~~l e, in the <:a;~e of a 10-color
printing press, one print rianager col.nLd be provided for every
five printing units.
According to the second exEemplary embodiment, shown in Fig. 2,
increased performance .~f tt~e bus system '~ or lower
equirements on the imacfes~~tt.ing units a.re assumed. This makes
it possible to connect a nzmbei: c:f storage units 7 to a number
of imagesetting un-its 9 via an individual, data line 11 of the
bus system 5. The assignment of t_.he storage units '7 to the
printing units or imac~e;~ett:inq units 9 is not defined rigidly,
instead the data manager 3 defin<-es this assignment. flexibly,
j ob by j ob, in a ~saitab:Le way c~e~' ending on the print j ob/print
jobs that are outstanc:ing. 'The m_zmber of imagesetting units 9
.,an therefore differ from the number of storage units 7. If
the storage units 7 provice an adequate data rate, a plurality
of imagesett.ing units 9 can make access to one of the member
units 7 during the images~tting operation.
In the third exemplar~,r emu>odiment, which may be designed in
principle like the arrangement according to the first or the
second exemplary emboc.~ime~r~t or a suit~at~ie mixed form, a
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CtP (Computer to Plate) syst= ~m i:~ :>hown as a detail. In this
case, it is typical in particular that images are set
continually without relat=i~a~ly :Long pauses. The download time,
that is to say the time to a,opy the image data to the storage
unit 7, is particularly c~.ritica:L. Therefore, according to Fig.
3, two storage units 7 a:re K~roV.ided for each image.>etting unit
While images are being set from one storage unit., new
separation data can be written to t=he other storage unit
simultaneously as reqW red by the data manager 3. In addition,
the fail safety of this printing arrangement can be increased
owing to the storage units which may possibly be redundant
during specific print .jobs.
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List. of Designations
1 Raster image processor (RI1?)
3 Data manager
Bus system
Storage unit
Imageset.ting unit
11 Individual dai~a Line
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