Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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SDeCi fication
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The invention relates to a printing press, in particular
offset printing press, with a plurality of printing
units, said printing units, with the excep~ion of one,
being provided with circumferential- and side-register-
adjusting devices for register adjust~ent.
Known for multi-colour printing are offset printing
presses with a plurality of printing units, said
printing units being provided with circumferential- and
side-register-adjusting devices for register adjustment.
This makes it possible to correct the respective
positions of the individual printing plates for the
different colour separations, which is of great
importance with regard to the quali~y of the printed
product. The circumferential- and side-register-
adjusting devices necessitate elaborate and7 therefore1
cost-intensive design measures. It is usual, therefore,
to forego register-correction means in the delivery-end
printing unit of an offset printing press if said
printing unit is in the form of a varnishing unit. A
correction of the v rnishing-unit register is,
therefore, possible only by means of elaborate measu-res,
such as the changing of the position of the rubber
blanket on the rubber-blanket cylinder., This calls,
however, for extensive operations (in particular:
releasing, aligning, clamping etc.). Moreover,:
adjustment is difficult and success is also
considerably dependent on the skill and experience of
the printer.
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The object of the invention, therefore, is to indicate a
Drintin~ Press of the init1ally mentioned kind in which
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it is possible in simple and l~w-cost manner to achieve
correct positions of the subjects or the printing units.
The object of the invention is achieved in that, for the
erfect of a register adjustment of the non-adjustable
printing unit, said printing unit is assigned a
control-command input device such that a relative
change in position of the subject of the non-
adjustable printing unit is accomplished by logically
consistent register adjustments of the adjustable
printing units. Consequently, there is, as it were, a
fictitious 'setting of the non-adjustable printing
unit in that the position or its subject is changed in
relation to the positians of the subjects of the other
printing units, with this being accomplished no-t by a
change in position of the subject of the non-adjustable
printing unit (which, owing to its lack of
adjustability, would not be possible in the first
place), but by logically consistent, relative register
adjustments of the other, adjustable printing units.
For the correct alignment of the individual printing
plates, the adjustable printing units are set to align
precisely with the position of the subject of the non-
adjustable printing unit. This is made possible, for
example, in simple ~anner from the control console of
the printing press thanks to the control-command input
device according to the invention. The control commands
can be inputted manually or also automatically. It is
possible to dispense with the previously described
elaborate, known measures, such as the positional
correction of the rubber blanket. The invention is not
restricted to the non-adjustable printing unit being in
the form of a varnishing unit, but can be employed, for
example in multi-colour printin~, also in the printing
unit of a specific colour separation. Since, in this
printing unit, it is possible according to the invention
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to forego register adjustmentt there is a simplification
in construction. A corresponding saving in cos~s is the
result.
In a further development of the invention, so-called
register marks are used to detec~ the positions of the
subjects of the printins plates of the individual
printing units. These register marks are provided on
the printing forme t particularly printing plate, and are
visible in the form of a corresponding impression on
the printed product. The register marks are preferably
in the form of register crosses. These register crosses
are usually in the non-image area of the stockt for
example in the region of the corners of a printed sheet.
These register crosses permit simple and accurate ~
positional regulation of the subjects or printing plates
of the individual printing units in that the relative
positions of the individual register crosses are
detected and are brought into precise alignment with one
another by means of register adjustment. This means
thatt alsot the subjects of the printing plates assigned
to ~he printing units are in preoise alignment with
respect to one another. Such register marks are
provided, however, only on the adjustable printing
units, i.e. those provided with circumferential- and
side-register-adjusting devices. If - as in the case of
a varnishing unit - there is a non-adju,st~ble printing
unit, it is not possible to employ positional detection
by means of register marks. In this case, it is then
necessary, in order to assess the position of the
subject, to have recourse, for example, to the
determination of the position of the border of the
subject.
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In order to set the registers, the control-command input
The inputting of a desired positional correction causes
the control apparatus to i~itiate the req~ired register
adjustment. In this connection, the control apparatus
may execute the setting of the registers consecutivelY
or also simultaneously. Simultaneous settings make it
possible to achieve very short set-up times.
In all cases, the register adjustment according t~ the
invention is executed wi~h logical consistency both in
terms OT magnitude and also in terms of direction.
Since this is possible in bo~h the circumferential and
side direc~ions, there is a comprehensive correction
facility provided.
According to a preferred embodiment of the inven~ion,
it is provided th~t the adjustment data obtained from
the set~ing of the register of a printing unit
selecta~le in accordance with specific criteria as the
lead printing uni~ are automatically used by the control
apparatus in setting the other printing units, with
account being taken of the position-deviation data,
pertaining pri or to setting, of said other printing
units with respect to the lead printing unit. The lead
printing unit pri nts the so-called base col our, wi th it
being possible in multi-colour printing to nominate as
the base colour one of the colours, for example C, M, Y
(C = Cyan, M = Magenta, Y = Yellow) or B (B = Black).
Once the relative positions of the subjects of the
other, adjustable printing units in relation to the
base-colour-print.ing, adjustable printing unit are
known, then, for the precise alignment of the individual
adjustable printing units with respect to one another,
it is merely necessary to determine the adjustment data
with regard to the lead printing unit in relation to the
position of the subject of the non-aPjustable printing
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control-command input device, there is not only a
register adjustment of the base-colour printing unit,
but also at the same time a register setting of all
other adjustable printing units, since the register
positions to be assumed by said adjustable printing
units can be determined automatically on the basis of
the existing data. This results in a considerabl0
facilitation of work and also in a very high setting
accuracy. The high setting accuracy results from the
fact that the positions of the subjects of the
individual adjustable printing units can be determined
~ith great accuracy on the basis of the already
described register crosses. Overall, therefore, it is
possible to make a precise register setting of all
printing units, with the result tha~ it is possible more
or less to operate without printing any waste.
Since the position-deviation data are established by
determination of the positions of the machine-readable
register marks, it is possible for there to be automatic
measuring by means of a register-mark reader, in
particular a register-cross reader. The register-cross
reader is an optical instrument that detects the
register crosses with a lens arrangement and evaluates
them with respect to their positions. The necessary
corrections of the register settings on the printing
units are computed by the instrument and/or by the
control apparatus and are, if required, indicated
directly on a display. According to a pre~erred
embodiment of the invention, however, the computing data
can also be supplied direc~ly to the control desk of the
printing press and can be used to control the actuators
~or the circumferential and side registers. Such a
register-cross reader is ~nown ~rom DE-OS 37 19 766, to
the contents of which reference is hereby made.
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Since the measures indicated may result in deviations
between the position of the subject of the printed
product and the edge of the stock, it is provided in a
further development of the invention that side and front
lays, serving to align the stock, are co-adjusted by the
control apparatus in such a manner that the subject of
the printed product is at the desir~d distances from the
edges of the stock. If the printing press is in the
form of a sheet-fed printing press, the individua1
sheets, supplied, for example, from a suction-head
apparatus, are positioned in accordance with the
positioning of the side and front lays. This again
compensates for the displacement of the subjec~ with
respect to the edge of the stock, such displacement
resulting from the circumferential and side-register
adjustments. If the register adjustments lead to a
displacement (magnitude and direction) of the printed
image, the side and front lays are adjusted by the same
magnitude and in the same direction, with the result
that, overall, the deviations are again compensated for.
Such ccmpensatory adjustment may, of course, alsa be
performed automatically by the control of the printing
press.
Preferably, the setting of the registers and the
adjusting of the side and front lays is performed
uniformly at low speed. This measure prevents the
production of waste when adjustment is performed while
the press is in operation, since, given a uniform speed
of setting and adjusting, the individual ~olour
separations remain in alignment with one another, also
during the adjusting process. The low speed guarantees
that, during setting and adjusting, ~here is no
essential increase in size of the halftone do~s of the
printed jmages, s;nce the ink dots that build up and
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press as a resul~ of the displacement deviate only to an
insignificant extent in their form, i.e the deviation
is not visible under normal viewing. In particular, it
is provided that the speed of setting and adjusting is
dependent on the positioning travel and/or on the speed
of the press. In the case of a small deviation, i.e. in
the case of only a short positioning travel, it is
possible - without considerably deteriorating the print
quality - to operate at a relatively high speed of
setting and adjusting. This appli~s also to high press
speeds.
The invention relates further to a process for the
correction of the register setting on printing units of
a printing press, in particular of an offset printing
press, preferably for use on a printing press of the
previously described kind, the printing units of which,
with the exception of one, are provided with
circumferential- and side-register adjustment, wherein,
for the effect of a register adjustment of the non-
adjustable printing unit, the relative position of the
subject of said printing unit is changed by logically
consistent register adjustments of the adjustable
printing units.
It is provided in particular that selected as the lead
printing unit is that adjustable printing unit whose
subject has the desired position with respect to the
edges of the stock or most closely approximates said
position. The lead printing unit prints the so-called
base colour. Furthermore, the relative position-
deviations of the subjects of the adjustable printing
units with respect to the position of the subject of the
lead printing unit are determined and stored in a
storaae device Drovided for this Purpose. Such
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manner with a register-mark reader, in particular a
register-cross reader. The optical apparatus of the
register-cross reader is directed at the register
crosses of a proof/specimen print or similar, so that
the instrument is ahle to determine the existing
deviation data and to supply them to the storage device.
Determination and evaluation are preferably automatic.
Since the printed image of the non-adjustable printing
unit, which is, in particular, in the form of a
varnishing unit, do~s not comprise any register crosses
or similar, the positional deviation of the subject of
the lead printing unit with respect to the position of
the subject of the non-adjustable printing unit must be
determined by the printer and be inputted at the control
console of the printing press. Preferably, the printer
uses the borders of the subject to determine the
positional deviation. On the basis of the stored
position-deYiation data between the position of the
subject of the lead printing unit and the positions of
the subjects o~ the other adjustable printing units, a
register adjustment of the lead printing unit causes an
;automatic, logically consistent correction to the
register set~ings of the other adjustable prin~ing
units. This makes it possible, with great accuracy and
relatively little effort, to correct the register
settings at the printing units of the printing press.
In particular, the printer need merely det~rmine "by
hand the positional deviation between~the subject of
the lead printing unit and the position of the sùbject
of the non-adjustable printing unit; the other positions
or positional deviations are automatically detected by
the register-cross reader and are relayed to the control
apparatus of the printing press.
The invention is illustrated on the basis of a specimen
embodiment with reference to the drawings, in which:
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Fig. 1 shows a schematic view of an of~set printing
press for multi colour printing ~ith varnishing unit;
Fig. 2 shows a partial view of a printed sheet provided
with register-cross mark;
Fig. 3 shows a top view of ~ printed sheet, the position
of which is settable by side and front lays; and
Fig. 4a to c show the positions of the subJects of
various colour separations of the offset printing press.
Fig. 1 shows in a schematic representation an offset
printing press 1, which comprises four printing units 2,
3, 4 and 5. The offset printing press l is in the form
of a sheet-fed press, i.e. it is supplied by means of a
she~t-supply apparatus 6 with sheets 8 forming the stock
7, with said sheets 8 then passing through the
individual printing units 2 to 5 and being removed at
the end of the press in the form of a finished printed
product and preferably being deposited there on a pile
(pile of sheets 9).
The printing units 2 to 4 are provided with
circumferential- and side-register-adjusting devices 10
for register adjustment. The respective actuator for
the circumferential register is identif,ied by "U" and
the corresponding actuator for ths side register is
identifi,ed by "S" tFig. 1). The actuators 'U" and "S"
are connected via lines 11 to a control console 12 of
the offset printing press 1. The control console 1~ is
further connected via lines 13 to actuators VM and SM of
side and front lays 14, 147, which determine the sheet
position.
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Whereas the printing units 2 to 4 produce di~,~erent
colour separations in multi-colour printins, the
printing unit S represents a varnishing unit 15. The
varnishing unit 1~ does not comprise any
circumferential- or side-register-adjusting devices,
with the result that i~s resister- or subject position
is dependent on the position of the rubber blanket cn
the corresponding rubber-blanket cylinder. A simple
register correction - as in the case of the printin~
units 2 to 4 - canno~ be executed in the case of the
varnishing unit 15, since a change in the position of
the rubber blanket is possible only by elaborate
measures (releasing, positioning, clamping). To this
extent, for the purposes of the present application, the
printing unit 5 is assumed to be a non-adjustable
printing unit.
According to the invention, however, the effect of a
register adjustment of the non-adjustable printing unit
5 by means of a control-command input device 16, which
is accommodated in the control console-12 and interacts
with a control apparatus 25, can be achieved in that a
relative change in position of the subject of the non-
adjustable printing unit 5 is accomplished by logically
consistent register adjustments of the adjustable
printing units 2 to 4. Thus, according to the desired
register adjustment of the printing unit 5, which,
hawever, is not feasible owing to the lack of
adjustability, the effect of an adjustment is brought
about in that the other, a~justable printing units Z to
4 are adjusted in their respective subject positions by
means of the actuators "U and/or "S in relation ~o the
subject of the printing unit 5. The logical consistency /,
of such adjustment means in the final analysis that all
printing units 2 to 5 assume in relation to one another
those positions that were in ~act to be achieved by the
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register adjustment (not possible, however) of the
printing unit 5.
To facilitate the measuring of the posi~ions of the
individual printing plates of the various colour
separations, register marks 17, in the form of register
crosses 18, are provided in the non-image areas of the
sheets 8, particularly in the region of the corners of
the sheets (Fig. 2). Insofar as the register crosses 18
assigned to the printing units 2 to 4 are in alignment
one on top of the other, the printing plates are in the
correct positions necessary for satisfactory printing
results. No register crosses are assigned to the
printing unit 5, which is in the form of ~he varnishing
unit 15; the necessary1 correct alignment of the
corresponding subject in relation to the positions of
the subjects of the other printing units 2 to 4 must,
therefore, be performed by the operator (printer) by
means of visual examination, particularly on the basis
of a comparison of the positions of the borders of the
subjects. If there are deviations, the effect of a
register adjustment of the, in fact, non-adiustable
printins unit 5 can be achieved on the basis of the
measures acc~rding to the invention.
The principle on which the invention is based is now
explained in greater detail with reference to Fig. 3,
which shows a sheet 8, on which is disposed a colour
separation 19. Said colour separation 19 has been
produced by one of the printing units 2 to 4 (for the
sake of simplicity, discussion is to be confined
initially to the colour separation of just one printing
unit). The subject 20 of the varnishing unit 15 is "
shown by shading in Fig. 3. Colour separation 19 and
subject 20 exhibit relative positional deviations with
resDeCt to one another. with the result that theY are
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not in alisnment. Deviation x applies to the
circumterential register of the adjustable printing unit
(e.g. printing unit 4) and deviation y applies to the
co~rssponding side register. Consequently, a register
mark t7 assigned to the colour separation 1g and
situated in the,corner of the subject has the position
P1, which deviates frorn a position P2, which is assumed
by ~he upper, right-hand corner Ot the subject 2~ or the
varnishing unit 15. Since a register adjustment of the
varnishing unit 15 is not possible, tha logically
consistent register adjustmen~ of the adjustable
printing unit is performed according to the inventien in
such a manner that the colour separation 19 is brought
into alignment with the subject 20. During the
adjustmen~ process, position P1 moves towards positicn
P2 until both positions are in alignment one on top o
the other. In the course o~ register adjustment~
therefore, the colour separa~ion 20 is displaced by
deviation x and by deviation y. This displace~ent means
that there is now a change in the distances between the
colour separation 19 and the edges 21 and 22 of the
stock. In order to re-establish the original
situation, the front lays 14' and the side lays 14 are
moved, by means of actuators VM and SM, respectively, by
deviations x and y, likewise in the same dtrection and
by the same amount, with the result that the sheet
assumes a corresponding, new position.
The correction to the register settings of the printing
press 1 according to a pre~erred procedure is now to be
explained in the following. Fig. ~ a-c show a colour
separation 23 of ~he printing unit 2, a colour
separation 24 of the printing unit 3 as well as the
colour separation 19 of the prin~ing unit 4. The
subject 20 of the varnishing unit 15 is likewi~e shown,
with this being indicated by the continuous solid line.
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In Fig. 4a, all colour separations 19, 23 and 24 as well
as the subject 20 have different positions. For the
sake of clarity~ the deviations shown are exaggerated.
Let it be as~umed that the colour separation 23 is at
- distance a from the upper edge 21 of the stock and at
distance b from the side edge 22 of the stock. Let it
further be hypo~hesized that distances a and b are the
desired distances, with the result that the colour
separation 23 is correc~ly positioned on the sheet 8.
Consequently, the printing unit 2 assigned to the colour
separation 23 represents a lead printing unit, with the
corresponding colour of said lead printing unit being
termed the base colour.
A specimen sheet is now taken from a proof and is
visually evaluated by the printer with regard to the
positional correction required between the subject Z0
and the colour separation 23. According to Fig. 4b, a
correction by dimension c is necessary to the
circumferential register and a displacement by dimension
d is necessary to the side register; since the colour
separation 23 is already in its correct position with
respect to the edges 21, 22 of the stock, it is in fact
necessary to perform a corresponding register
adjustment to the varnishing unit 15. This, however,
is not possible, since - as previously explained - the
printing unit 5 is not provided with circumferential- or
~ide-resister-adjusting devices. To this extent,
accor~ing to the invention, the effect of the register
adjustment of the non-adjustable printing unit ~ by the
inputting of dimensions 5 and d as determined by the
printer into the control-command input device 16 on the
control console 12 is achieved in that a relative change
~n position is performed with log;cal consistency by the
register of the adjustable printlng unit 2.
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So that the printer does no~ need 1ikewise visually to
determine the positional deviations of the subject 20
with respect to the colour separations 24 and 19 of the
printing units 3 and 4 and to input said deviations at
the control console, there is provided the automatic
measurement of position-deviation data e, f, g and h,
which resu1ts from the relative positions of the colour
separations 24 and 19 with respec~ to the colour
separation 23 of the lead printing unit. These
position-devia~ion data e, f, 9, h are established by
determination of the ~ositions of register crosses 18
assigned to each of the colour separations 19, 23 and 24
~Fig. 2). Use is made for this purpose of a so-called
register-cross reader, which scans the register crosses
1 a wi th its optical system, and, therefrom, indicates on
a display the necessary adjustment data corresponding to
the position-deviation data or, alternatively, according
to a further development of the invention, supplies such
adjustment data to the control console 12 for automatic
correction of the register settings.
Since, to this extent, the relative positions of khe
colour separations 19 and 24 with respect to the colour
separation 23 of the lead colour are known to the
control of the printing press 1 and, further, the
positional deviation between the subject 20 and the
~olour separation 23 has been inputted by the printer, a
correspondingly logically consistent register
~djustment of the printing units 2, 3 and 4 can:be
effected in such a manner that all printed images are in
alisnment with the subject of the varnishing unit 15.
The printed image of the finished prin~ed product would
then~ however, assume an incorrect position ~ith respect
to the edges 21 and 22 of the stock, To eliminate this
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14' are - as already explained previous1y with reference
to Fig. 3 - adjusted in magnitude and direction
according to dimensions c and d (Fig. 4b), with the
result that the desired distances a and b are re-
established.
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