Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to an apparatus for controlling
the ink supply on rotary printing presses with a test bench, with
adjusting members in individual ink zones and with a device for
adjusting the total ink quantity.
The object of the invention is, within the context of
progressive automation of the printing process, to simplify the
control of the ink supply of a printing unit and to make it
easier to supervise and more reliable in operation.
German Offenlegungsschrift 2 115 653 describes a
method and an apparatus for the telecontrol of adjusting and
driving members in printing presses, which make it possible to
telecontrol the entire ink supply by modifying the sectional
rotary movement of an ink doctor and the zonal ink supply by
modifying the individual adjusting members of an ink knife either
manually or from a central control point through the intermediary
of electric stepping motors. The position of the adjusting
members can be indicated visually by means of an impulse counter
or of a coding wheel. The inclusion of such a control system of
the adjusting members or stepping motors in closed control cir-
cuits e.g., by automatic measurement of the actual in~ layer
thickness on a printed image carrier and its comparison with a
desired layer thickness for the purpose of an automatic initiation
of the corresponding control lmpulses~ which is proposed in this
specification, is extremely onerous by its construction and is
uneconomic, e.g., for sheet-fed rotary printing presses, more
particularly for those of small format, when considered from the
standpoints of technical outlay and of production costs.
In the ink dosing method on a printing press disclosed
in German Offenlegungsschrift 24 34 680, the individual ink zone
adjusting members can be remotely adjusted during the printing
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process on the basis of the visual assessment of an edition sheet
on an observation table by the operator, by means of manually
operable switches. In this case the positions of the individual
adjusting members on the ink knife can be read off on a picture
screen.
With both apparatuses, the adjustment of the indivi-
dual adjusting member, e.g., those of the ink knife, is left
exclusively to the sense and experience of the operator, both as
regards the required direction of adjustment and of the magnitude
of the adjustment value, because no concrete guide values as to
magnitude and direction of adjustment are prescribed for him.
The adjustment of the adjusting members themselves which influence
the ink supply can thus only be performed on the basis of rough
visual estimation values. As a result of erroneous and mistaken
assessment of the printed product by the operator, corresponding
repeated recorrections of the adjusting elements influencing the
ink supply to an ink ]ayer thickness profile which corresponds
to an optimum ink density of a printed product, are unavoidable.
Starting from this prior art, it is the underlying aim
of the invention to produce a low cost monitoring apparatus for
controlling the ink supply on rotary printing presses, which in
order to facilitate the operation, indicates to the operator at
a central control point of the operating station the steps
according to direction and position which are required for a
rapid optimation of the ink supply during the printing process.
This aim isachieved according to the invention in that
tendency displays for ink density deviations from desired values
of a printed product, which indicate the direction of correction
for the adjustment of the adjusting members and/or of the devices
3~ for adjusting the total ink quantity, are associated with the ink
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zones associated(laccording to scale with the sheet. sy such a
display of the direction of adjustment of the ink quantity from
ink density variations during the printing process,the operator
is relieved of a possibly incorrect evaluation of the printed
product and consequent uncorrected adjustment of the ink supply,
and his work is thus considerably simplified Furthermore, the
required make-ready times are considerably reduced by this
arrangement.
In order to achieve an optimation of the ink supply
in the shortest time in order to achieve a better quality of
print, and thereby reduce wastage to a minimum, as an advanta-
geous further development of the invention intensity displays
of the ink density deviations are superimposed within the
context of selective tolerances upon the tendency displays
serving for the direction of correction, from which the operator
can infer the value of the magnitude of the required modification.
An example of a method for telecontrolling the ink
supply to inking units of rotary printing presses with an appara-
tus according to the invention, is that the difference values
between prescribed stored desired values of the ink density and
the actual values of the ink density of a printed product detec-
ted by means of an ink density measurement, which are obtained on
the basis of an arithmetical comparative value formation, are
rendered visible in a common display, taking selective tolerances
into consideration, as a tendency display for the modification of
the ink distribution of the zonal ink quantity and/or of the total
ink quantity and are used as a value for the modification quan-
tity. Such a method enables the operator to rely upon the fact
that his intervention in the ink supply will be effective only
in the correct ink zone, or superordinately in the required
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modification quantity across the total width of the ink supply.
The invention is described more fully hereinbelow with
reference to a basic construction illustrated in the drawings, ar.d
also of an extended exemplary embodiment.
In the drawing:
Fig. 1 shows a schematic plan of a basic construction
of the control apparatus with test bench according to the inven-
tion, and
Fig. 2 shows a schematic plan of a preferred exemplary
embodiment of the invention.
It should be explained initially that the illustration
and description of the invention are limited solely to its most
essential constituents, and means such as ink supply device,
control, drive and adjustment means and their associations are
assumed as known.
As shown in figure 1, a basic construction of the
apparatus according to the invention substantially comprises
three sections,
a test bench 1 with an ink density measuring device 2,
a display device 3 located at the top end of the test
bench 1 or above the same,
and an electronic evaluator device 4 arranged at the
left-hand side of the test bench 1.
The test bench l can be mounted directly on a rotary
printing press, and may also be arranged as a self-contained unit
independently of the same. The test bench l is connected through
the intermediary of control wires, in a manner not shown nor
described in detail, to driving and adjusting members of the
elements of an ink supply apparatus which determine both the
zonal ink supply and also the total ink quantity. As ink supply
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apparatus, an ink duct with doctor roller and continuous and
also subdivided ink knife, an ink spray device or a centrifugal
inking unit etc., may be provided. As adjusting members inter
alia the stepping motors known from telecontrol devices may be
adopted
The test bench 1 is provided for the precisely fixed
reception and for the measuring of a printed product 5 by means
of the ink density meter 2. The ink density meter 2 is consti-
tuted in this basic construction by an individual densitometer 6
which, considered transversely to the direction of travel of the
printed product 5, is arranged slidably across the total width
of the latter in a test beam 7. The test beam 7 itself is
mounted directly above the test bench 1 slidably in the longitu-
dinal direction of the printed product 5 on two lateral slide-
ways 8, so that any desired part of the printed product 5 can bemeasured with the individual densitometer 6.
The electronic evaluator device 4 is connected by means
of wires, not shown, to the densitometer 6 and to the display
instrument 3 located at the top end of the test bench 1. It is
also equipped with an operating keyboard 9 and with a numerical
display 10.
The display instrument 3 located at the top end of the
test bench 1 is equipped with any desired number of luminous dis-
plays 11 across its total width in conformity with the selected
division of its displayO The individual luminous displays 11
consist in each case of three light-emitting diodes (LED's) 12,
13, and 14 arranged mutually superposed. In the display instru-
ment 3 illustrated in the basic construction of figure 1, a lumi-
nous display 11 is associated with each of the ink adjustment
3~ zones 22 of the inking unit, not shown, so that in this case the
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number of the ink adjustment zones 22 corresponds to the number
of the zonal luminous displays 11.
The principle of operation with the invention is
described more fully hereinbelow.
During the printing run, a printed product 5 is
removed from the printing press and placed aligned on the test
bench 1. Now, by means of the densitometer 6, and utilizing a
print monitor strip 15 printed on the printed product 5, its ink
density values are detected metrologically, compared in the elec-
tronic evaluator device 4 with desired values previously fed into
the latter, and the existing colour density deviations of the
printed product 5 with reference to said prescribed desired
values beyond the scope of permitted and preselected tolerances
are made visible in the display instrument 3.
The zonal luminous display 11 of the display instrument
3 which is associated with each ink adjusting zone permits, by
its three LED's 12 to 14 arranged mutually superposed, both a
tendency display of the ink density deviations to be modified
with reference to the direction of the ink supply of the zonal
ink quantity and/or of the total ink quantity, and also super-
ordinately thereto, in a number of multiple possible combinations,
sorted into different preselective tolerance classes, an inten-
sity display as a quantitative value for the necessary modifi-
cation.
The tendency, whether more or less is to be supplied,
is indicated by the lighting up of the top or bottom LED 12 or
14 of a zonal luminous display 11.
various possible combinations of tendency and intensity
displays are now possible:
3u In a first combination stage~ only the central LED 12
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of a zonal luminous display 11 lights up. This signifies that
the measured actual value of the full tone ink density of the
printed products 3 coincides with the prescribed desired value
of the full tone ink density within the scope of a permitted and
preselected tolerance. Since no ink density deviation exists,
no tendency and also no intensity is displayed. In this case
no intervention with the ink supply is required,
In a second possible combination the central and the
bottom LED's 13 and 14 of a zonal luminous display 11 light up
simultaneously In this case the lighting up of the bottom LED
14 indicates the minus tendency of the deviation of the measured
actual value of the full tone ink density with reference to the
prescribed desired value of the full tone ink density. The
simultaneous lighting up of the central LED additionally pro-
vides an information as to the intensity of the existing inkdensity deviation. In such a case i.e., in the case of the
simultaneous lighting up of the central and bottom LED's 13 and
14, a slight minus deviation of the measured actual value of the
full tone ink density exists, but which exceeds a prescribed
tolerance classe and ranges in the minus range up to a deviation
of e.g., three tolerance classes with reference to the prescribed
desired value of the full tone ink density.
In a third display possibility, the lighting up exclu-
sively of the bottom LED 14 of a zonal luminous display 11 indi-
cates a minus tendency, i.e., a minus deviation of the measuredactual value of the full tone ink density from a prescribed
desired value of the full tone ink density, but which already
exceeds the scope of e.gO, three prescribed tolerance classes.
In a fourth combination stage, the two upper LED's 12
and 13 of a zonal luminous display 11 light up simultaneouslyO
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The lighting up of the top LED 12 indicates a positive tendency,
i.e., a plus deviation of the measured actual value of the full
tone ink density with reference to the prescribed desired value
of the full tone ink density. The simultaneous lighting up of
the central LED 13 also indicates the intensity of the existing
ink density deviation. This is greater than one prescribed
tolerance class and lies e.g., in the range between one and
three plus tolerance classes.
In a fifth stage of the possible combinations, in the
case of a plus deviation of the measured actual value of the full
tone ink density of e.g., more than three prescribed plus toler-
ances, the top LED 12 of a zonal luminous display 11 lights up.
From this it is therefore possible to infer a positive tendency
and great intensity of the ink density deviation.
A sixth luminous combination of a zonal luminous dis-
play 11, in which all three LED's 12 to 14 light up simulta-
neously, indicates a faulty measurement of the full tone ink
density. The measured actual value of the full tone ink density
of the printed product 5 is irregular and unsatisfactory e.g.,
due to a dirty measurement field, misprint, blotches, etc., i.e.,
the measurement must be checked.
When none of the three LED's 12 to 14 of a zonal
luminous display 11 light up, no desired value is present.
On the basis of the tendency and intensity displays of
the zonal luminous display 11, when unacceptable ink density
deviations are present the zonal ink supply can be corrected by -;`
adjusting the ink zone adjusting members, not shown, whilst the
tendency display serves as a guide for more or less ink supply
and the intensity display superimposed thereon indicates the
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quantitative value of the required variation.
If all the zonal luminous displays ll distributed
across the entire width of the display instrument 3 simultaneously
indicate too great or too low ink density, whilst the LED's lit
up lie roughly on a level, then this can be effectively remedied
in a particularly simple manner by a single modification of the
total ink quantity superimposed upon the zonal ink supply.
The tendency display for the ink supply may also, within
the ambit of the invention, occur in a different manner from that
above described. It is thus entirely possible to indicate the
tendency by correspondlng blinking of LED's or by brightness
variations in the latter. Instead of this, an analog scale
display or a digital display, e.g., in the form of a pulse counter
to count adjustment steps or gear steps of the ink zone adjusting
members, may of course likewise be provided.
Each of the prescribed and stored desired values of the
full tone ink density, e.g., of a matching sheet, each of the
measured actual values of the full tone ink density of the
printed product 5, and each of the ink density deviations both
in direction and also in magnitude detected by a desired actual
value comparison in the electronic evaluator device 4, can addi-
tionally be summoned by means of the operating keyboard 9 of the
ëlectronic evaluator device 4 and rendered visible in its numeri-
cal display lO.
A preferred embodiment of the invention extended with
reference to the basic construction of figure l, is equipped, in
addition to the three principal elements, the test bench l with
the ink density measuring device 2, the display device 3 for
displaying the ink density deviation tendency and the deviation
3J intensity and the electronic evaluator device 4, with an LED
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display 19 at the bottom end of the test bench to display the ink
layer thickness profile and with corresponding operating elements
20 located therebeneath for modifying the same, and also with a
doctor telecontrol21 on the right-hand side of the test bench 1.
An ink density measuring device 2 substantially modified compared
with that of the basic construction, is also adopted in this
embodiment.
The LED display 19 with the display of the ink layer
thickness profile extends across the total width of the test
bench 1 and is subdivided into thirty-two ink adjustment zones
22 To display the positions of the individual zonal adjusting
menbers, likewise thirty-two rows, each of sixteen LED's 23
arranged mutually superposed is provided, so that one vertical
row of LED's is associated with each ink adjustment zone 22 to
indicate the position of the adjustment member.
Beneath the LED display 19, in accordance with the
ink adjustment zones 22, operating elements 20 to control the
zonal ink quantity are provided. The operating elements 20
comprise thirty-two plus keys 24 to increase the zonal ink
quantity, and thirty-two minus keys 25 to reduce the same.
Adjustment members for adjusting the zonal ink quantity
are actuated by means of the operating elements 20 through the
intermediary of control wires not shown or described in detail.
With each ink zone adjusting member there is associated, in
manner known per se and therefore not illustrated, a potentio-
meter for reverting back the position or for reverting back the
position of the adjustment member to the display of the ink layer
thickness profile of the LED display 19.
The doctor telecontrol 21 for modifying the total ink
3~ quantity is provided with a feed-in keyboard 26 and with a digital
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display 27. As already mentioned previously in connection with
the ink zone teleadjustment, the ink stripe width on the ink
doctor, not shown, can be increased or reduced by modi~ying
its angle of rotation by means of a plus or minus key of the
feed-in keyboard 26. The relative angle of rotation of the ink
doctor, referred to its maximum stroke, can then be read off as
a percentage in the digital display 27.
The test beam 7 of the ink density measuring device 2
is subdivided into thirty-one individual measurement zonesO Of
these, sixteen measurement zones, arranged at respective mutual
intervals, are provided as full tone measurement zones for the
measurement of the full tone ink densities of the printed product
5, and the fifteen remaining spaces respectively located between
said full tone measurement zones are reserved as screen tone
measurement zones for the measurement of the screen tone ink
densities of the printed product 5.
Accordingly, the test beam 7 of the preferred embodi-
ment of figure 2 is equipped with sixteen full tone measurement
heads 28 arranged stationary at mutual intervals for measuring
the ink density values in the full tone of the printed product 5.
In order to measure the ink density values in screen tone, four
so-called jumper measurement heads 29 are provided which can be
inserted at will into the screen tone measurement zones located
between the full tone measurement heads 28.
The measurement beam 7 is limitedly adjustable and
correctable in the lateral direction, i.e., considered trans-
versely to the direction of travel of the printed product 5, from
a basic position 30 into three further test positions 31 to 33
for measuring the three basic colours cyanogen, magenta and
yellow and also for the colour black, of a four-colour printing
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system. For this purpose it is provided with a rack 34 which is
engaged by an adjusting pinion 35 which is fixed to a projection
36 arranged stationary on the slideway 8 of the test beam 7 and
can be rotated through the intermediary of a handwheel 37.
Also present on the movable test beam 7 is a four-part
colour index display 38 which co-operates with a colour marking
39 which is arranged on the projection 36. The colour index
display 38 serves to adjust and monitor the basic position 30
and the various test positions 31 to 33 of the test beam 7
Also in this extended embodiment, the division of the
display instrument 3 is modified so that a tendency and intensity
display in the form of a zonal luminous display 11 is associated
with each two ink adjustment zones 22. Said zonal tendency dis-
play 11 is then located in coincidence with the full tone test
heads 28 of the full tone test zones of the test beam 7.
The mode of operation with this embodiment o the
invention is explained more fully hereinbelow.
By means of the test beam 7 with the full tone test
heads 28 arranged at intervals and with the four jumper test
heads 29 located between them, four measurements are performed
consecutively, one for each colour of the four-colour printing
process, whilst after each measurement a lateral transverse dis-
placement of the test beam 7 is effected by rotating the hand-
wheel 22. Which colour is being tested instantaneously can
meanwhile be read off on the colour index display 38 arranged on
the test beam in conjunction with the colour marking 39 of the
projection 36.
At each measurement, therefore, sixteen test values fox
the full tone ink densities of a printing ink are obtained from
the sixteen full tone test heads 28, whilst there is one full tone
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ink density measured value for each two of the thirty-two ink
adjustment zones 26. Thus, after the test beam 7 has been dis-
placed laterally (transversely) three times, sixteen full tone
ink density measurement values of all the four printing inks are
available.
With the four so-called jumper test heads 29, the
values of the screen tone ink densities of the four printing
colours are determined by measuring screen test fields of the
printing monitoring strip 15, whereby additional information is
obtained as to the increase in the print by sliding and/or
doubling due to negative influences affecting the process, such
as reeling errors.
The full tone measured values are stored in ink densi-
ties in the evaluator device 4 and are automatically compared
with the desired values of the ink density in the full tone of a
printed sheet fed in at the start of the printing process, within
the context of preselected tolerances The ink density devia-
tions thereby detected are then,~as already explained in connec-
tion with the mode of operation of the basic construction of the
invention, rendered visible automatically and as a routine by
means of the sixteen zonal luminous displays 11 of the display
instrument 3 in the form of tendency and intensity displays.
Corresponding to the ink density deviations found, corrective
interventions into the zonal ink supply may be performed by means
of the operating elements 20, or in case of need the overall ink
quantity can be correspondingly modified by means of the feed-in
keyboard 26 of the doctor telecontrol 21.
It is self-evidant that the invention is naturally in
no way restricted to the basic construction and special embodi-
ments illustrated in figures 1 and 2 and explained in the
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description, both of which are to be regarded solely as examplesand are not intended to limit the inventionO It is self-evident
that other embodiments with numerous variations aseregards struc-
tural details are conceivable, which lie within the ambit mapped
out for the invention.
It is thus e,g., entirely possible to effect the display
of the ink layer thickness profile of the LED display 19, and also
the tendency and intensity display, by means of valves, liquid
crystals, through scale displays with corresponding needles and
through digital displays, to choose a different division of the
display instrument 3 or of the LED display 19, and also of the
test beam 7, or to provide different ink density measuring
devices. The arrangement of a display instrument 3 with tendency
and intensity displays of the ink density deviations for a plura- -~
lity of presses simultaneously also lies within the ambit set
out for the invention.
.
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