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(11) | EP 0 142 995 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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Registration control method and device for rotary press Verfahren und Vorrichtung zum Steuern des Registers einer Rotationsdruckmaschine Procédé et dispositif de repérage pour presse rotative |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] The present invention relates to a multicolour rotary press such as a gravure rotary press and more particularly to a register control method and device therefor.
[0002] From the standpoint of control theory, registration control in a multicolor rotary press is extremely complicated so that it is difficult to provide a control device providing both fast response and also stability. That is, to reduce spoilage to a minimum, a fast response is needed. However, hunting then results so that stability is adversely affected.
[0003] In US-A-4,264,957 there is disclosed a method of register control wherein the web strain between two successive units of a rotagravure control printing press is controlled by an adjustably movable compensation roll, and wherein the compensator roll in automatically moved to a new calculated position in response to detection of a register error between the successive units, the resulting change in web strain being sufficient to eliminate the error.
[0004] The displacement of the shaft of the compensation roll is controlled in response to the error signal by the so-called PD control so that the drive time and direction of rotation of the motor controlling the compensation roll is calculated in response to proportional, integral and differential commands. Because the calculation involves system constants in the form of proportional, differential and integral feedback gains, it is necessary to adjust these values each time a machine is commissioned or printing conditions are changed.
[0005] In view of the above, the present invention has for its object to provide a registration control method and device for automatically calculating optimum correction values depending upon the construction of a printing press and in response to printing conditions when registration errors are detected, and correcting registration errors quickly in response to the calculated correction values, thereby reducing spoilage to a minimum.
[0006] To the above and other ends, according to the present invention, the optimized gains Kp and Dα in PD control are obtained in response to the pass length (11) between the adjacent plate cylinder units, the pass length (12) between the plate cylinder and the position at which a register mark is to be detected, the radius (r) of the plate cylinder, the compensator roller displacement velocity (v) and/or the printing speed (V) on the assumption that the correct registration control can be effected by using some of various factors affecting the registration control which can be correctly analyzed and in response to the optimized gains, the position of the shaft of a compensator roller is displaced, thereby accomplishing registration.
[0007] The above and other objects, effects, features and advnatages of the present invention will become more apparent from the following description of preferred embodiments thereof taken in conjunction with the accompanying drawings
Brief Description of the Drawings
[0008]
Fig. 1 is a view used to explain the construction of a multicolor rotary press to which the present is applied;
Figs. 2-7(a) and 7(b) show experimental results which confirm validity of the registration control method in accordance with the present invention;
Fig. 2 shows a standard case;
Fig. 3 shows a case in which only the printing speed is varied with other factors or parameters remained unchanged;
Figs. 4(a) and 4(b) show the characteristic curves prior to and after the adjustment in accordance with the present invention when the phase length between the adjacent units is varied;
Figs. 5(a) and 5(b) show characteristic curves when the pass length between a plate cylinder and a position at which a register mark is to be detected is varied;
Figs. 6(a) and 6(b) show characteristic curves when the compensator roller velocity is varied;
Figs. 7(a) and 7(b) show characteristic curves when the radius of a plate cylinder is varied;
Fig. 8 shows characteristic curves when the tension exerted to printing paper is varied; and
Fig. 9 shows charactersitic curves when the elongation coefficient of printing paper is varied.
Description of the Preferred Embodiments
[0009] Prior to the description of preferred embodiments of the present invention, a prior art registration control device will be briefly described so that the problems or defects thereof become more apparent.
[0010] Fig. 1 shows a prior art registration control device. In Fig. 1, only plate cylinder units 11 and 12 with impression cylinders 21 and 22 of a multicolor rotary press are shown. A printing paper or the like is transported from the plate cylinder unit 11 to the plate cylinder unit 12. Guide rollers 23 and a compensator roller 20 are interposed between the plate cylinder units 11 and 12. The deviation between a register mark printed by the preceding plate cylinder and a register mark printed by the succeeding plate cylinder can be made zero by shifting the shaft of the compensator roller 20.
[0011] In order to control the shift of the shaft of the compensator roller 20, the output pulses from a pulse generator PG of the preceding plate cylinder 11 and the output from a scanning head SH disposed adjacent to the succeeding plate cylinder 12 are applied to a mis-registration detection circuit 21. The output of the detection circuit 31 is applied through a PD control circuit 32 to a register motor drive circuit 33 so as to drive a register motor M for shifting the shaft of the compensator roller 20.
[0012] In this case, the control of the displacement of the shaft of the compensator roller 20 is effected by the so-called PD control. That is, a registration error E derived from the detection circuit 31 and its derivative dE/dt are substituted in the following equation (1) so that the drive time At and direction of rotation of the register motor M are obtained. In response to thus obtained drive time and the direction of rotation, the compensator roller is shifted by Δt.
where
Kp: proportional gain (constant)
KD: differential gain (constant)
[0013] In general, the proportional gain Kp and the differential gain KD are constant and depending upon the construction of a printing press and printing conditions such as pass length between units, the position of a scanning head, the velocity of a compensator roll, a printing speed, circumferential lengths of cylinders and so on, hunting results and response is considerably degraded.
[0014] Therefore according to the prior art, frequency corrections such as one correction per rotation of a plate cylinder have not been employed, but a method is employed in which one correction is effected for from two to ten rotations of plate cylinder or in which feedback gains (that is, both Kp and KD are adjusted simultaneously) are changed in order to avoid hunting.
[0015] However, according to the above-described methods, an operator must adjust the number of correction times and gains so that the printing operation becomes very complicated. Furthermore, the adjustment is made in such a way that gains are set at considerably lower levels so as to avoid hunting under any conditions. Therefore, the above-described method is not excellent in view of controllability of response, stability and so on. In other words, that one correction is made for two or more rotations of a plate cylinder merely attains a result inferior to the case in which one correction is made per rotation. As a result, many spoilages occur.
[0016] In order to overcome the above-described problems, control response must be improved, but in the case of registration control, the improvement of response results in unstability. The reason is that the analyses of various factors affecting the registration control have not yet been sufficiently made so that it has been difficult to find out an optimum point at which response and stability requirements are satisfactorily attained. There are many factors which cannot be correctly analyzed. For instance, they are rotary speeds and sizes of various rollers of a printing press in addition to the timing deviation between the operation of a device and its detection when the position at which a register mark is detected is located behind a plate cylinder and the elongation of printing paper or the like.
[0017] In view of the above, so far the registration control has been improved only in a trial-and-error manner so that no satisfactory result has not been obtained.
[0018] Referring again to Fig. 1, the construction of a multicolor rotary press will be described in more detail.
[0019] A printing paper is guided by a guide roller 23 and passes between the preceding unit comprising the plate cylinder 11 and the impression cylinder 21 so that a first color image is printed on the printing paper. Thereafter the printing paper is transported through the guide rollers 23 and the compensator roller 20 to the succeeding unit comprising the plate cylinder 12 and the impression cylinder 22 so that a second color image is printed. Thereafter the printing paper is transported to the succeeding unit through guide rollers or to a discharge unit.
[0020] In the preceding unit, a first register mark is printed and in the succeeding unit, a second register mark in printed. These register marks are detected by the scanning head SH disposed behind the position at which the plate cylinder 12 is made into contact with the impression cylinder 22 and the output of the scanning head SH is applied to the mis-registration detection circuit 31. The output signal from the scanning head SH represents a time deviation ΔTe between the first and second register marks.
[0021] Meanwhile, pulse signals representative of the rotational speed of the plate cylinder 11; that is, the pulse signals representative of the transport speed v of printing paper is applied from the pulse generator PG of the plate cylinder 11 to the mis-registration detection circuit 31. (The pulse generator PG generates gate signals for detecting the register marks). Then, in response to the pulse signals and the output signal from the scanning head SH, the detection circuit 31 calculates a mis-registration or registration error E. That is,
where n: the rotational speed of the plate cylinder 11 and
r: the radius of the plate cylinder.
[0022] The registration error E is applied to a PD control circuit 32 so that the register motor drive signal is generated by PD calculation. The register motor M which is rotated at a constant speed is driven by a register motor drive circuit 33 so that the position of the shaft of the compensator roller 20 is controlled. Thus, the registration operation is carried out.
[0023] When the register motor M which displaces the position of the shaft of the compensator roller 20 is of a constant speed type, the displacement of the position of the shaft of the compensator roller 20 is in proportion to the drive time of the register motor M. Therefore the PD control circuit 32 calculates a drive time in accordance with the general PD control equation. That is, a drive time At is given by the following equation:
where
Kp: proportional gain,
KD: differential gain,
Ek: registration error detected this time, and
Kk-1: registration error detected in the preceding detection.
In this case, the drive time Δt is so selected that it will not exceed the rotational
period of a plate cylinder so that one correction can be made per rotation of the
plate cylinder.
[0024] Extensive studies and experiments were made by the inventor and it was found that Kp and KD in Eq. (3) can be obtained by the following equations:
where
I1: the pass length between the adjacent plate cylinder units,
12: the pass length between the plate cylinder and the position at which the register mark is detected,
v: the velocity of the compensator roller, and
r: the radius of the plate cylinder.
f1 and f2 are functions of I2 and f3 is a function of r. All the function fl, f2 and f3 are monotonously reducing function and have positive values. That is,
Validity of Eqs. (4) and (5) can be confirmed from experimental results as shown in
Figs. 2-7(a) and 7(b).
[0025] Fig. 2 shows that various factors used in registration control of a multicolor rotary press are all optimized. Experimental results shown in Figs 3-7(a) and 7(b) are compared with those shown in Fig. 2 and evaluated. The optimized conditions as shown in Fig. 2 can be obtained as follows:
Parameters
[0026] Unless otherwise stated, the parameters of a multicolor rotary press are as follows:
(1) Tension:
The tension T1 of printing paper which is fed to the preceding unit is constant and is 15 kg while tension of printing paper fed into the succeeding unit is 15 + ΔT2 kg.
(2) Velocity of printing paper V:
100 m/min = constant
(3) The radius of plate cylinders r:
0.14 m
(4) The pass length I1 between the adjacent units:
7.8m
(5) The length 12 between a plate cylinder and the position at which a register mark is detected: 0.48 m
(6) The velocity V of the displacement of the shaft of the compensator roller: 0.5 mm/sec.
(7) Other parameters:
The variation in tension Δt2; the change in position of the compensator roller Δc; and the registration error E represents only deviations from the above-described parameters and initial values.
Explanation of Characteristic Curves
[0027] If the deviation of the register mark is detected 0.5 mm in Fig. 2, then the compensator roller is shifted for At calculated on the base of 0.5 mm/sec. As a result, the compensator roller is displaced by +0.67 mm at the most from the initial position and remains at the position ±0.25 mm.
[0028] In response to the change 6c in the position of the compensator roller, the tension applied to printing paper between the adjacent units is 15 + 0.66 kg at the maximum, 15 - 0.02 kg at the minimum and becomes 15.00 kg finally.
[0029] Because of the operations carried out in the manner described above, the registration error E is reduced in time and becomes 0.00 mm finally. Thus, registration is accomplished.
Fig. 3 shows the characteristic curves when the printing velocity V is varied. In this case, registration control can be carried out relatively rapidly and smoothly as compared with the standard case as shown in Fig. 2. That is, it has been confirmed that the above equations (4) and (5) do not include the printing speed V and that even when the printing speed varies, registration control is not affected.
Figs. 4(a) and 4(b) - 7(a) and 7(b) show experimental results of factors contained in the above equations (4) and (5).
Fig. 4(a) shows the characteritistic curves when the gains Kp and KD remain unchanged while the pass length I, between the adjacent units is increased from 7.8 m to 14 m. In this case, the control of the position of the compensator roller is carried out for At obtained by calculation. The gain Kp and KD, however, are different from those in Eqs. (4) and (5) so that hunting results.
[0030] On the other hand, in Fig. 4(b), the gains Kp and KD are optimized by Eqs. (4) and (5) so that hunting can be substantially suppressed.
[0031] Fig. 5(a) shows the characteristic curves when the gain Kp and KD are maintained at the standard values while the pass length 12 between the plate cylinder and the position at which the register mark is detected is increased from 0.48 m to 0.88 m. in this case, hunting results.
[0032] On the other hand, in Fig. 5(b), the gains Kp and KD are optimized according to Eqs. (4) and (5) so that hunting is suppressed.
[0033] Figs. 6(a) and 6(b) show characteristic curves when the compensator roller displacement velocity V is varied from 0.5 mm/sec to 1 mm/sec while the gains are maintained at the standard values (Fig. 6(a)) and gains are calculated from Eqs. (4) and (5). It is seen that hunting can be suppressed by adjusting the gains Kp and Kp.
[0034] Figs. 7(a) and 7(b) show characteristic curves when only the gain KD is adjusted; that is, when the radius r of the plate cylinder is changed from 0.14 m to 0.08 m. As is clear from Eqs. (4) and (5), the radius r of the plate cylinder is only contained in Eq. (5) and is not included in Eq. (4). Therefore, when the radius r of the plate cylinder is changed, only the gain KD is changed but the gain Kp remains unchanged. In this respect, the radius r of the plate cylinder is fundamentally different from the pass length I1 between the adjacent units, the pass length 12 between the plate cylinder and the position at which the register mark is detected and the compensator roller displacement velocity v explained above with reference to Figs. 4(a) and 4(b) - Figs. 6(a) and 6(b).
[0035] Validity of Eqs. (4) and (5) are confirmed from the above-described explanation in conjunction with the characteristic curves as shown in Figs. 2-7(a) and 7(b). Furthermore, it should be noted that Eqs. (4) and (5) constitute only the essential factors which can be correctly analysed in registration control. The gains Kp and KD obtained from Eqs. (4) and (5) can better cope with various conditions which are expected to occur in registration control so that it can be said that the registration control system can be remarkably consolidated.
[0036] So far with reference to Figs. 2-7, it has been described how the factors which can be correctly analysed in registration control can be processed.
[0037] Figs. 8 and 9 show characteristic curves obtained when the influence on registration control of other factors such as variations in tension of printing paper, an elongation coefficient of printing paper (which is dependent upon the qualtiy of paper) and so on. Fig. 8 shows the characteristic curves when the tension T of printing is changed from 15 kg to 30 kg. The characteristic curves as shown in Fig. 8 are substantially similar to those shown in Fig. 2. Fig. 9 shows the characteristic curves when the elongation coefficient of printing paper is changed from 0.00022 I/kg to 0.00005 I/kg. The characteristic curves as shown in Fig. 9 are also substantially similar to those as shown in Fig. 2.
[0038] That is, it can be said that in response to variations in tension and quality of printing paper, it is not needed to adjust the gain in registration control.
[0039] It follows therefore that in registration control it suffices to adjust the gains Kp and Ko of the PD control in response to the pass length (I1) between the adjacent plate cylinder units, the plass length (12) between the plate cylider and the position at which the register mark is deteted, the compensator roller displacement velocity (v) and the radius (r) of the plate cylinder.
[0040] In the above-described embodiment, it has been assumed that the compensator roller velocity v be constant. However, depending upon types of printing presses, there are compensator rollers whose displacement time is constant (the rotatinal period T of the plate cylinder) and whose displacement velocity is variable. In this case, instead of the equations (3), (4) and (5), the following equations (3)', (4)' and (5)' are used:
where:
Kp': proportional gain,
KD': differential gain,
Ek: registration error at present,
Ek-1: registration error prior to one rotation of the plate cylinder,
11: pass length between adjacent units,
12: pass length beteen the plate cylinder and the position at which the register mark is detected,
V: printing speed, and
r: the radius of the plate cylinder.
f1', f2', f3': monotonously reducing function.
[0041] As described above, in the case of registration in a multicolor rotary press by PD control, in response to the pass length (I1) between the adjacent units, the pass length (I2) between the plate cylinder and the position at which the register mark is detected, the compensator roller displacement velocity (v), the radius (r) of the plate cylinder and the printing speed (V), the gains Kp and KD are optimized so that registration control can be carried out with excellent response and stability. As a result, as compared with the conventional registration control system, spoilage can be much reduced.
where
Kp: proportional gain,
KD: differential gain
Ek: present registration error,
Ek-1: previous registration error,
and gains Kp, KD are adjusted, characterised in that: each time when the printing conditions (pass
length between units, position of the scanning head, velocity of a compensator roll,
printing speed of circumferential length of cylinders) are changed, new proportional
and differential gains Kp and KD are calculated according to the following equations:
where
I,: pass length between the adjacent units
I2: pass length between plate cylinder and position at which a register mark is detected v: displacement velocity of a compensator roller
r: the radius of a plate cylinder
f1, f2, f3: monotonously decreasing functions f1, f2, f3 >0
T: rotation period of a plate cylinder
and in that, in response to a calculated value, said compensating roller (20) is displaced
at the predetermined velocity v.
where
K'p: proportional gain,
K'D: differential gain,
Ek: present registration error,
Ek-1: previous registration error,
and the gains K'p and K'D are adjusted, characterised in that each time when the printing conditions (pass
length between units, position of the scanning head, velocity of a compensator roll,
printing speed, or circumferential length of cylinders) are changed, new porportional
and differential gains K'p and K'D are calculated according to the follwing equations:
where
K'p = proportional gain
K'D = differential gain
I1: pass length between the successive units
I2: pass length between a plate cylinder and a position at which a register mark is detected
V: printing speed
r: radius of a plate cylinder
f'1, f'2, f'3: monotonously decreasing functions, f'1, f'2, f'3 >0
and in that, in response to a calculated value, said compensating roller (20) is displaced for a predetermined period during the rotation speed T of a plate cylinder.
calculation means (32) responsive to a detected registration error for executing a
PD operation based on the following equation to determine a displacement time At for
said compensator roller (20),
where
Kp: proportional gain,
KD: differential gain,
Ek: present registration error,
Ek-1: previous registration error
and means for adjusting Kp and KD and characterised in that: each time when the printing conditions (pass length between
units (11, 12), position of the scanning head (SH), velocity of the compensator roll
(20), printing speed, or circumferential length of cylinders) are changed, the calculation
means (32) calculate new proportional and differential gains Kp and KD according to the following equations:
where
I1: pass length between the adjacent units (11, 12)
12: pass length between plate cylinders (12) and a position (SH) at which a register mark is detected
v: displacement velocity of a compensator roller (20)
r: the radius of a plate cylidner (11, 12)
fi, f2, f3: monotonously decreasing functions fi, f2, f3 >0
T: rotation period of a plate cylinder (11, 12) and in that means (M) responsive to a calculated value displace said compensation roller (20) at a predetermined velocity v.
calculation means (32) responsive to a detected registration error for executing a
PD operation based on the following equation to determine a displacement velocity
v for said compensator roller (20),
where
K'p: proportional gain,
K'D: differential gain,
Ek: present registration error,
Ek-1: previous registration error
and means for adjusting K'p and K'D characterised in that each time when the printing conditions (pass length between
units (11, 12), position of the scanning head (SH), velocity of the compensator roll
(20), printing speed, or circumferential length of cylinders) are changed, the calculation
means (32) calculate new proportional and differential gains K'p and K'D according to the following equations:
where
K'p = proportional gain
K'o = differntial gain
I1: pass length between the ajacent units
12: pass length between a plate cylinder (12) and a position (SH) at which a register mark is detected
V: printing speed
r: radius of a plate cylinder.
f'1, f'2, f'3: monotonously decreasing functions, f'1, f'2, f'3 >0
and in that means (M) responsive to a calculated value displace said compensating
roller (20) for a predetermined period during the rotation period T of a plate cylinder
(11, 12).
worin bedeuten:
Kp: Proportionalverstärkung
KD: Differentialverstärkung
Ek: Vorliegender Registerfehler
Ek-1: Vorhergehender Registerfehler;
un wobei die Verstärkungsfaktoren Kp, KD eingestellt werden, dadurch gekennzeichnet, daß jedesmal dann, wenn die Druckbedingungen
(Weglänge zwischen den Einheiten, Position des Abtastkopfes, Geschwindigkeit der Kompensationswalze,
Druckgeschwindigkeit oder Umfangslänge der Zylinder) geändert werden, neue Proportional-
und Differential-Verstärkungen Kp und KD nach der folgenden Gleichungen errechnet werden:
worin bedeuten:
I1: Weglänge zwischen den benachbarten Einheiten;
12: Weglänge zwischen dem Plattenzylinder und der Position, an der eine Registermakierung festgestellt wird;
v: Verschiebungsgeschwindigkeit einer Kompensationswalze;
r: Radius eines Plattenzylinders;
f1, f2, f3: monoton abnehmende Funktionen f1, f2, f3 > 0
T: Rotationsperiode eines Plattenzylinders,
und daß die Kompensationswalze (20) in Abhängigkeit von einem errechneten Wert mit
der vorbestimmten Geschwindigkeit v verschoben wird.
worin bedeuten:
K'p: Proportionalverstärkung
K'p: Differentialverstärkung
Ek: Vorliegender Registerfehler
Ek-1: Vorhergehender Registerfehler;
und die Verstärkungsfaktoren K'p und K'D eingestellt werden, dadurch gekennzeichnet, daß jedesmal dann, wenn die Druckbedingungen
(Weglänge zwischen den Einheiten, Position des Abtastkopfes, Geschwindigkeit einer
Kompensationswalze, Druckgeschwindigkeit oder Umfangslänge der Zylinder) geändert
werden, neue Proportional- und Differential-Verstärkungen K'p und K'D nach folgenden Gleichungen errechnet werden:
worin bedeuten:
K'p: Proportionalverstärkung;
K'D: Differentialverstärkung;
I1: Weglänge zwischen aufeinanderfolgenden Einheiten;
12: Weglänge zwischen einem Plattenzylinder und einer Position, an der eine Registermarkierung gemessen wird,
V: Druckgeschwindigkeit,
r: Radius eines Plattenzylinders,
f'1, f'2, f'3: monoton abnehmende Funktionen, f'1, f'2, f'3 > 0
und daß die Kompensationswalze (20) für eine vorbestimmte Periode während der Rotationsperiode T eines Plattenzylinders in Abhängigkeit von einem errechneten Wert verschoben wird.
worin bedeuten:
Kp: Proportionalverstärkung
KD: Differentialverstärkung
Ek: Vorliegender Registerfehler
Ek-1: vorheriger Registerfehler
und eine Vorrichtung zum Einstellen von Kp und KD, dadurch gekennzeichnet, daß jedesmal dann, wenn die Druckbedingungen (Weglänge zwischen
den Einheiten (11, 12), Position des Abtastkopfes (SH), Geschwindigkeit der Kompensationswalze
(20), Durchgeschwindigkeit oder Umfangslänge der Zylinder) geändert, werden, die Rechenvorrichtung
(32) neue Proportional- und Differential-Verstärkungen Kp und KD nach den folgenden Gleichungen errechnet:
worin bedeuten:
I1: Weglänge zwischen den benachbarten Einheiten;
12: Weglänge zwischen den Plattenzylinder und der Position, an der eine Registermarkierung festgestellt wird;
v: Verschiebungsgeschwindigkeit einer Kompensationswalze (20)
r: Radius eines Plattenzylinders (11, 12);
fi, f2, f3: monoton abnehmende Funktionen f1, f2, f3 > 0
T: Rotationsperiode eine Plattenzylinders,
und daß eine auf einen errechneten Wert ansprechende Vorrichtung (M) die Kompensationswalze (20) mit der vorbestimmten Geschwindigkeit v verschiebt.
eine Rechenvorrichtung (32), die auf einen gemessenen Registerfehler anspricht und
eine auf fer folgenden Gleichung basierende PD Operation ausführt, um eine Verschiebungsgeschwindigkeit
v für die Kompensationswalze (20) zu bestimmen
worin bedeuten:
Kp: Proportionalverstärkung
KD: Differentialverstärkung
Ek: Vorliegender Registerfehler
Ek-1: vorheriger Registerfehler
und eine Vorrichtung zum Einstellen von K'p und K'o, dadurch gekennzeichnet, daß jedesmal dann, wenn die Druckbedingungen (Weglänge zwischen
den Einheiten (11, 12), Position des Abtastkopfes (SH), Geschwindigkeit der Kompensationswalze
(20), Druckgeschwindigkeit oder Umfangslänge der Zylinder) geändert werden, die Rechenvorrichtung
(32) neueu Proportional- und Differential-Verstärkungen K'p und K'D nach den folgenden Gleichungen errechnet:
worin bedeuten:
K'p: Proportionalverstärkung
K'D: Differentialverstärkung
I1: Weglänge zwischen den benachbarten Einheiten;
12: Weglänge zwischen dem Plattenzylinder und der Position, an der eine Registermarkierung festgestellt wird;
V: Druckgeschwindigkeit;
r: Radius eines Plattenzylinders;
t'1, f'2, f'3: monoton abnehmende Funktionen f'1, f'2, f'3 > 0
un daß eine auf den errechneten Wert ansprechende Vorrichtung (M) die Kompensationswalze
(20) für eine vorbestimmte Periode während der Rotationsperiode T eines Plattenzylinders
(11, 12) verschiebt.
Kp étant le gain proportionnel,
KD étant le gain differentiel,
Ek étant l'erreur actuelle de repérage,
Ek-1 étant l'erreur antérieure de repérage,
et les gains Kp, KD sont réglés, caractérisé en ce que, chaque fois que les conditions d'impression sont
changées (longeur du passage entre les ensembles, position de la tête de balayage,
vitesse d'un cylindre compensateur, vitesse d'impression ou longueur circonférentielle
de cylindres), de nouveaux gains proportionnel et différentiel Kp et KD sont calculés d'après les équations suivantes:
avec
Δ≤T
I1 étant la longueur du passage entre ensembles adjacents,
I2 étant la longueur du passage entre un cylindre porte-cliché et la position de détection d'un repère,
v étant la vitesse de déplacement d'un cylindre compensateur,
r étant le rayon d'un cylindre porte-cliché,
fi, f2, f3 étant des fonctions décroissant de façon monotone,
fi, f2, f3 > 0
T étant la période de rotation d'un cylindre portecliché,
et en ce que, en fonction d'une valeur calculée, le cylindre de compensation (20)
est déplacé à la vitesse prédéterminée v.
K'p étant le gain proportionnel,
K'D étant le gain différentiel,
Ek étant l'erreur actuelle de repérage,
Ek-1 étant l'erreur antérieure de repérage,
et les gains K'p et K'D sont réglés, caractérisé en ce que, chaque fois que les conditions d'impression sont
changées (longueur du passage entre les ensembles, position de la tête de balayage,
vitesse d'un cylindre compensateur, vitesse d'impression ou longueur circonférentielle
des cylindres), de nouveaux gains proportionnel et différentiel K'p et K'D sont calculés d'après les équations suivantes:
K'p étant le gain proportionnel,
K'D étant le gain differentiel,
I1 étant la longueur du passage entre les ensembles successifs,
12 étant la longueur du passage entre le cylindre porte-cliché et un emplacement auquel un repère est détecté
V étant la vitesse d'impression,
r étant le rayon d'un cylindre porte-cliché,
f'1, f'2, f'3 étant des fonctions décroissant de façon monotone,
f'1, f'2, f'3 > 0
et en ce que, en fonction d'une valeur calculée, le cylindre de compensation (20)
est déplacé pendant une période prédéterminée au cours de la période de rotation T
du cylindre porte-cliché.
un dispositif de calcul (32) commandé par une erreur détectée de repérage et destiné
à exécuter une opération de réglage PD en fonction de l'équation suivante destinée
à déterminer un moment de déplacement Δt du cylindre compensateur (20)
Kp étant le gain proportionnel,
KD étant le gain différentiel,
Ek étant l'erreur actuelle de repérage,
Ek-1 étant l'erreur antérieure de repérage,
et un dispositif de réglage de Kp et Kp, l'appareil étant caractérisé en ce que, chaque
fois que les conditions d'impression sont modifiées (longueur du passage entre les
ensembles (11, 12), position de la tête de balayage (SH), vitesse du cylindre compensateur
(20), vitesse d'impression ou longueur circonférentielle des cylindres), le dispositif
de calcul (32) calcule de nouveaux gains proportionnel et différentiel Kp et KD d'après les équations:
Δ≤T
1, étant la longueur du passage entre ensembles adjacents (11, 12),
I2 étant la longueur du passage entre les cylindres porte-cliché (12) et une position (SH) à laquelle un repère est détecté,
v étant la vitesse de déplacement d'un cylindre compensateur (20),
r étant le rayon d'un cylindre porte-cliché (11, 12),
fi, f2, f3 étant des fonctions décroissant de façon monotone,
f1, f2, f3 > 0
T étant la période de rotation du cylindre porte-cliché (11, 12),
et en ce qu'un dispositif (M) commadé par une valeur calculée déplace le cylindre
de compensation (20) à une vitesse prédéterminée v.
un dispositif de calcul (32) commandé par une erreur détectée de repérage est destiné
à exécuter une opération de réglage PD en fonction de l'équation suivante, destinée
à la détermination d'une vitesse de déplacement v du cylindre compensateur (20)
K'p étant le gain proportionnel,
K'D étant le gain différentiel,
Ek étant l'erreur actuelle de repérage,
Ek-, étant l'erreur antérieure de repérage, et un dispositif de réglage de K'p et K'D,
caractérisé en ce que, chaque fois que les conditions d'impression sont modifiées
(longueur du passage entre les ensembles (11, 12), position de la tête de balayage
(SH), vitesse du cylindre compensateur (20), vitesse d'impression ou longueur circonférentielle
des cylindres), le dispositif de calcul (32) calcule de nouveaux gains proportionnel
et différentiel K'p et K'D d'après les équations suivantes:
K'p étant le gain proportionnel,
K'D étant le gain differentiel,
I1 étant la longueur du passage entre les ensembles adjacents,
12 étant la longueur du passage entre un cylindre porte-cliché (12) et une position (SH) à laquelle est détecté un repère,
V étant la vitesse d'impression,
r étant le rayon d'un cylindre porte-cliché,
f'1, f'2, f'3 étant des fonctions décroissant de façon monotone,
f'1, f'2, f'3 > 0
et en ce qu'un dispositif (M) commandé par une valeur calculée déplace le cylindre
de compensation (20) pendant une période prédéterminée au cours de la période de rotation
T d'un cylindre porte-cliché (11, 12).