EP3585616B1 - Method and device for operating a rotary screen-printing machine - Google Patents

Description

The invention relates to a method and a device for operating a screen printing machine according to claims 1 and 15, respectively.

WO 2016/102187 A1 discloses a rotary screen printing machine with a first and a second screen cylinder which forms two printing points with an impression cylinder. Between the first and the second printing point, a radiation dryer directed towards the outer surface of the impression cylinder is provided. A squeegee arranged in the screen printing cylinder can be turned on and off from the inside against the screen printing form by a drive, mechanically independent of the rotation of the screen and impression cylinder.

Through the DE 10 2015 208 919 A1 a screen printing unit is known with a screen cylinder that can be attached and detached to an opposing cylinder and a squeegee that can be attached and detached to the screen in the screen cylinder.

The EP 1 582 349 A1 discloses a method and a device for printing on sheets conveyed by a chain conveyor using the screen printing process, the gripper pulling the sheet being picked up by a channel on the circumference of an impression cylinder as it enters the printing position and then positioned at the trailing channel end by the relative speed between the chain conveyor and the impression cylinder becomes. Meanwhile, the squeegee and the screen cylinder preferably remain shut off from the impression cylinder. During this phase, the squeegee and screen cylinder begin to move into the position required for printing. For printing, the screen cylinder is brought into contact with the impression cylinder and the doctor blade is brought into contact with the screen.

The EP 3 210 777 A1 wants to reduce waste by printing on the first sheet of a production. In the conventional procedure, on the other hand, the squeegee should only be adjusted after a full revolution of the adjusted screen cylinder.

When the screen printing cylinder is switched off, there may be an undesirable build-up of color on the outside of the screen due to a lack of ink removal and possibly existing rotation, which in the end can lead to undesirable contamination on the impression cylinder in the case of thick layers through contact with the impression cylinder surface or when printing the first sheets. This is particularly harmful in the event that intermediate drying takes place by means of a dryer aimed at the cylinder jacket surface. This quickly leads to color build-up. The dried ink becomes hard, especially if it is dried in between, forms peaks and can damage the screen printing form. The printing ink hardened in this way is very difficult to remove again from the cylinder surface.

The invention is based on the object of creating an improved method and an improved device for operating a screen printing machine.

The object is achieved according to the invention by the features of claims 1 and 15, respectively.

The advantages that can be achieved with the invention are in particular that the effort involved in cleaning the impression cylinder and / or the risk of damage to the screen printing form can be reduced considerably. As a result of the adjustment sequence, printing ink that collects on the outside of the screen printing when the screen printing cylinder is switched off is removed before the built-up ink would be distributed to undesired places on the sheet and / or impression cylinder by adjusting the squeegee. It is also advantageous if the pressing through of the printing ink is reduced by lower operating speeds during printing.

Embodiments of the invention are shown in the drawings and are described in more detail below.

Fig. 1

ein Ausführungsbeispiel für eine ein Druckaggregat umfassende Druckmaschine;

Fig. 2

eine detailliertere vergrößerte Darstellung des Ausführungsbeispiels für ein Druckaggregat aus Fig. 1 in a) bogenverarbeitender und b) in bahnverarbeitender Ausführung;

Fig. 3

eine schematische Querschnittsdarstellung durch ein Gegendruck- und/oder Transportzylindersegment;

Fig. 4

eine schematisch dargestellte Abwicklung eines Mantelflächensegmentes des Gegendruck- und/oder Transportzylinders;

Fig. 5

eine Prinzipskizze für a) die Abfolge von Phasen innerhalb einer An- und Abstellsequenz sowie b) der zugehörigen, den Antrieb betreffenden Betriebszustände;

Fig. 6

eine Prinzipskizze für die Abfolge von Phasen innerhalb einer An- und Abstellsequenz für a) ein größeres und b) ein kleineres Bedruckstoffformat;

Fig. 7

eine Prinzipskizze für die Abfolge von Phasen innerhalb einer An- und Abstellsequenz in Abhängigkeit von Lage und Länge der vorliegenden Druckbildlänge (L_B);

Fig. 8

eine Prinzipskizze für die Abfolge von Phasen innerhalb einer An- und Abstellsequenz in Abhängigkeit von Lage, Länge und Anzahl der in einer Druckbildlänge vorliegenden Druckstreifen;

Fig. 9

eine schematischen Darstellung einer eine Antriebseinrichtung und eine Steuereinrichtung umfassenden Rakeleinrichtung;

Fig. 10

eine schematische Darstellung für den Betrieb eines Siebdruckwerkes nach einer Produktionsunterbrechung;

Fig. 11

eine schematische Darstellung für das Herunterfahren eines Siebdruckwerkes bei fehlerbedingter Produktionsunterbrechung.

Show it:

Fig. 1

an embodiment of a printing machine comprising a printing unit;

Fig. 2

a detailed enlarged representation of the embodiment for a printing unit Fig. 1 in a) sheet processing and b) web processing design;

Fig. 3

a schematic cross-sectional view through a counter pressure and / or transport cylinder segment;

Fig. 4

a schematically illustrated development of a lateral surface segment of the counter-pressure and / or transport cylinder;

Fig. 5

a schematic diagram for a) the sequence of phases within an on and off sequence and b) the associated operating states relating to the drive;

Fig. 6

a schematic diagram for the sequence of phases within an on and off sequence for a) a larger and b) a smaller printing material format;

Fig. 7

a schematic diagram for the sequence of phases within a turn-on and turn-off sequence as a function of the position and length of the present print image length (L _B );

Fig. 8

a schematic diagram for the sequence of phases within an on and off sequence depending on the position, length and number of print strips present in a print image length;

Fig. 9

a schematic illustration of a doctor device comprising a drive device and a control device;

Fig. 10

a schematic representation of the operation of a screen printing unit after a production interruption;

Fig. 11

a schematic representation for the shutdown of a screen printing unit in the event of an error-related production interruption.

A printing machine, e.g. B. a sheet-fed printing press, comprises a feed device 01 on the input side, through which the printing machine is supplied with a sheet-like printing material 02, at least one printing unit 03, by which the printing material 02 is printed one or more times on one or both sides, and a product display 04 on which printed products or intermediate products are stacked or be designed continuously (see e.g. Fig. 1 ).

In a preferred embodiment shown in the figures and not claimed, the printing machine is used as a printing machine for printing securities, for example for printing web-like printing material 02, e.g. B. a printing substrate, or according to the invention for printing on sheet-like printing substrate 02, z. B. sheet of printing material 02 executed. The feed device 01 for the latter embodiment is z. B. designed as a sheet feeder 01, in which a stack of the printing material sheets 02 to be fed and printed can be arranged.

The printing unit 03 of the z. B. designed as a security printing machine printing machine is the printing material 02 in the area of at least one printing point 06; 07 designed to be printed on at least one printing material side in rotary screen printing. The printing material 02 to be printed in the screen printing process is available as printing material sheet 02 and / or as printing material 02 already printed by another printing process and / or as e.g. B. textile, linen, hemp and / or synthetic fibers comprehensive security paper and / or executed as a plastic substrate (polymer substrate) or as a hybrid substrate.

The printing machine is preferably designed as a sheet-fed printing machine for printing securities and z. B. designed to make from unprinted or preprinted sheet 02 printed sheets, in particular sheets of securities, such. B. to produce sheets of banknotes as products or intermediate products to be processed.

The printing material sheet 02 are z. B. held as layers of a stack of printing material in the feed device 01 designed as a sheet feeder 01, from which it is through a not shown in detail, z. B. suction cups comprehensive gripping device 08 individually recorded and isolated over a conveyor line 09, z. B. can be conveyed via a conveyor system 09, preferably designed as a belt system 09, and possibly a system drum up to an entry area in the printing unit 03. At the entrance to the printing unit 03, for example on a transfer drum 11, the printing material sheet 02 is transferred to a conveyor line assigned to the printing unit 03, e.g. B. is transferred to a conveyor system assigned to the printing assembly 03, through which the printing substrate sheet 02 has one or more printing points 06; 07 happens before it - for example via a transfer drum 12 - enters a third conveyor line 13 from the conveyor line assigned to the printing unit 03 or to a third conveyor line 13, e.g. B. a belt system 13, passed and through this up to the product display 04, z. B. a product display 04 comprising one or more sheet trays for stacking is transported.

In the case of a non-stressed web-processing version of the printing machine, the web-shaped printing material 02 in the area of the printing assembly 03 passes a conveying path which comprises one or more rollers and / or cylinders wrapped by the web.

In the preferred embodiment, the conveyor line assigned to the printing unit 03 of the sheet-fed printing press is preferably designed as a gripper system in which the printing substrate sheet 02 is conveyed through the printing unit 03 by successive transfer between a plurality of drums and / or cylinders following one another in the transport direction along the transport path. At the end of the z. B. a conveyor line designed as a gripper system, the printing substrate sheet 02 is delivered to the third conveyor line 13.

In the printing material path downstream of the printing assembly 03, one or more conditioning devices 14; 16; 17, for example one or more drying devices 14; 16 may be provided, for. B. a first drying device 14 and a further drying device 16, and / or a device 17 for applying the printing substrate 02 with directed magnetic field lines.

The printing unit 03 comprises at least one printing point 06 on at least one side of the conveying path, through which the printing substrate 02 can be or is printed on one of its printing substrate sides. The pressure point 06 is formed by a nipple point 06 of two rotating bodies 18; 21 or a nip point 06 between a cylinder 18 of a first printing unit 19 and a counter-pressure and / or transport cylinder 21 serving as an abutment for this cylinder 18.

Downstream of this at least one printing point 06, in the printing material path of the printing material 02, in particular in the conveying path through the printing unit 03 that adjoins the printing point 06 downstream, a first contact with the side of the printing material printed by the at least one printing point 06 can be arranged downstream of the printing point 06 in the printing material path Rotary body 22 may be arranged. This rotating body 22 cooperating with the freshly printed printing material side can, for. B. as a guide and / or transport roller of the conveyor system, as a conditioning roller for cooling or heating the printing substrate 02 or in particular for forming a further printing point 07 as a cylinder 22 of a printing unit 23 following the first-mentioned printing unit 19.

Such a second printing point 07 can be formed here by a nipple point 07 between the cylinder 22 of the second printing unit 23 and a cylinder acting as an abutment, which z. B. is formed by the first printing unit 19 serving as a counterpressure and / or transport cylinder 21 or a different further cylinder acting as a counterpressure and / or transport cylinder. in the Printing material path of the printing machine and / or printing assembly 03 can be provided upstream or downstream with one or more other such printing units acting on the same printing material side and / or one or more further printing units acting on the other printing material side.

In the preferred embodiment of the sheet-fed printing machine, the at least one counter-pressure and / or transport cylinder 21 comprises at least one, preferably several, e.g. B. three, holding devices 24, e.g. B. a one or a group of several grippers comprising gripper device 24, by which the leading end of a printing substrate sheet 02 can be picked up on the input side and released again on the output side to the downstream conveyor line. The gripper device 24 is here, for. B. in a provided in the otherwise cylindrical surface 27 of the cylinder 21 pit 26, the radially outwardly directed opening 28, z. B. pit opening 28, the cylinder jacket-shaped outer surface 27 interrupts and disturbs (see e.g. Fig. 2a )).

In the event that the web-processing version of the printing machine is not used, such holding devices 24 can be omitted (see e.g. Figure 2b )). Colloquially, the n-fold cylinder 21 comprises n panels, that is to say n circumferential sections U _D that can be used for printing in each case without interruption.

Irrespective of the type and number n of the holding devices 24 provided in the circumferential direction in the case of sheet printing, the respective pit opening 28 on the circumference of the counterpressure and / or transport cylinder 21 causes an interruption of the otherwise undisturbed cylindrical outer surface 27.

In an n-fold, ie single or multiple-size design, the counter-pressure and / or transport cylinder 21, viewed in the circumferential direction, comprises n, ie one or more circumferential sections U _D , in particular, which can be used as abutments during printing Cylinder circumferential sections U _D and n, that is, one or more circumferential sections U _N that encompass the holding devices 24 and cannot be used as an abutment during printing, in particular cylinder circumferential section U _N with a disturbed outer surface 27. The circumferential sections U _D that can be used as abutments during printing are also known colloquially as " Saddle "

The circumferential section U _N , which encompasses the opening 28 and is not suitable and / or intended for printing, has, along the continued circular line, a length L _N which is effective during unwinding and which corresponds to the length of the arc of a circle extending over the opening. The circumferential section U _{N which can be used} for printing accordingly has a length L _N which at the same time limits the possible print image length L _B upwards.

The circumferential section U _{N, which} cannot be used as a pressure abutment, can in principle only pass through the opening 28 of the pit 26 receiving the holding device 24 or, if applicable, through this opening 28 and - if provided - a functional section adjoining the leading and / or trailing side, for example an overlapping area of a possibly Inking aid 29 (see below) provided on the upstream side and / or a distance to be maintained from the trailing edge of the following pit opening to be maintained by definition. Conversely, the circumferential section U _{D that} can be used for printing can basically be given by the cylinder jacket section between a leading end of the interruption, for example the leading end of opening 28, and the trailing end of the same or next following opening 28 in the circumferential direction. In the event that the contour delimiting the disturbance on the lateral surface 27 is irregular, the length L _{N of} the circumferential section U _N that cannot be used for printing is, for example, the arc length considered in the circumferential direction between the first digit on the leading side and the last digit on the trailing side To understand the interruption in the undisturbed lateral surface 27 caused by the same holding device 24.

The at least one printing unit 19 and, in particular, also the at least one further printing unit 23, which interacts with the same printing material side, is a printing unit 19 operating according to screen printing; 23, briefly as screen printing unit19; 23, and the printing unit 19; 23 associated cylinders 18; 22 as a forme cylinder 18; 22 or as a so-called screen cylinder 18; 22, in particular as a screen printing cylinder 18; 22 formed.

The screen cylinder 18; 22 rolls on the lateral surface of the counter-pressure and / or transport cylinder 21 and forms in the area of its above-mentioned. Nipple point 06; 07 with the counterpressure and / or transport cylinder 21, the printing point 06; 07 off. The screen cylinder 18; 22 comprises in the area of its lateral surface as a printing forme 31; 32 a screen printing form 31 arranged concentrically to the real or imaginary cylinder axis; 32, in particular screen printing stencil 31; 32 ,. In the assembled state, this is releasably fastened, for example, on the end face on ring flanges not shown in detail. The screen printing stencil 31; 32 can basically be used as an endless cylinder jacket or sleeve-shaped screen printing stencil or as a finite, but in the assembled state, to form a screen printing stencil 31; 32 be executed.

Inside the screen cylinder 18; 22 is a doctor blade 34 of a - e.g. B. in Fig. 9 schematically shown - doctor device 33 is provided, which in a contact position "AN" in a circumferential area of the screen cylinder 18; 22 is made from the inside against the screen printing stencil 18, in which this the printing point 06; 07 forms with the counter-pressure and / or transport cylinder 21. This point can for example - based on the operating direction of rotation - a maximum of 5 ° in front of or behind the nip point 06; 07 can be provided with the counterpressure and / or transport cylinder 21. The squeegee 34 positioned in this way accumulates a bead of printing ink, which it rolls in front of it and through the permeable areas of the screen printing stencil 31; 32 pushes through to the outside.

In order to pass through the above-mentioned opening 28 on the counter-pressure and / or transport cylinder 21 through the nipple point 06; 07 to enable printing to be resumed as soon as possible in the following circumferential section U _D, an above-mentioned inking aid 29, for example an inking aid 29, can be used to temporarily and at least partially cover the opening 28. B. a cover element 29 designed as a flap 29, through which the opening 28 can be temporarily covered at least in the leading region of the opening 28. This enables premature adjustment of the squeegee 34, which is lifted off, for example when the nip passes through the open area of the opening 28. The cover element 29 can, for example, slightly overlap the undisturbed cylinder jacket circumferential section and, in this case, reduce the length L _D of the maximum circumferential section U _{D that can be used} for printing. This geometric shortening is due to the premature hiring z. B. more than balanced. As a result of the premature positioning, a pressure area start on the lead side - with regard to the unwinding during operation - can ideally adjoin the cover element 29 directly, but possibly additionally via a slight safety distance. An extension of the circumferential section U _N , which cannot be used for printing, beyond the leading opening edge and / or the distance between the earliest possible print area start and the trailing-side opening edge, for example between 10 mm and 50 mm, preferably at most 30 mm.

The maximum length L _{D that} can be used for printing is limited by the machine and / or security-related earliest possible start of the printing range and a machine and / or security-related trailing end of the latest possible printing range. The latest possible end of the pressure range can in principle start with the leading end of the following opening 28, e.g. B. the leading opening edge of the following opening 28, coincide or else - z. B. for reasons of safety and / or risk of contamination and / or the length of a phase P _from below for the Parking - to be kept at a distance a _S to be maintained from the trailing edge of the following pit opening (see e.g. schematically in FIGS. 3 and 4 ). The maximum usable for printing length L _D can, for example, by the length of the undisturbed circumference on the abutment, z. B. the counter-pressure and / or transport cylinder 21, or by other machine elements involved in the printing and / or transport or by the maximum usable length for the printing unit 19, viewed in the transport and / or circumferential direction; 23 provided printing forms 31; 32, hereinafter also referred to as print length for short, be limited. These sizes are regularly coordinated and essentially correspond to one another.

In a single embodiment of the counterpressure and / or transport cylinder 21, the following pit opening 28 is to be understood here as the same single pit opening 28.

Between the at least one printing point 06 and the downstream point in the printing material path, at which the printing material 02 comes into contact with the following rotary body 22 on its side printed by the printing point 06, a further drying device 36, e.g. B. a dryer 36, in particular an intermediate dryer 36 is provided, which is preferably designed as a radiation dryer 36. In order to create an active zone for the dryer 36 that is spatially narrowly delimited along the printing material path, a shadowing 37 that delimits the radiation effect upstream and / or especially downstream can be provided, for example through a wall 37 of a dryer 36 receiving the dryer 36 and towards the side of the printing material 02 open enclosure is given. In the embodiment designed as a radiation dryer 36, this comprises a one-part or multi-part radiation source 38 for electromagnetic radiation, e.g. B. for light, in particular for UV light, that is to say of light with at least a portion of emitted radiation power predominantly in the UV spectral range. The dryer 36 can in particular be designed as a UV-LED dryer.

The doctor device 33 (see, for example, schematically Fig. 2 and Fig. 9 ) comprises a bearing device of the squeegee 34 that enables a turning on and off movement and a drive device 39, 41, 48 through which the squeegee 34 with its squeegee edge - at least what the length and / or position of a on and / or position related to the cycle length L _Z. Parking sequence with at least one phase P _AN relating to a parking position "AN" and at least one phase P _AN relating to a parking position "AB"; P _AB , sequence for short, relates to - cyclically correlated during operation, in particular synchronized or clocked, to the rotational position of the counterpressure and / or transport cylinder 21 and / or cyclically correlated, in particular clocked, to the position of the substrate 02 to be printed in the direction of transport the screen printing stencil 31; 32 of the screen printing cylinder 18; 22 can be switched on and off or switched on and off. The correlation of the doctor blade movement generally relates to a direct or indirect correlation to the machine and / or printing material phase position, ie for example to the position and / or movement of a machine phase, in particular to a printing point 06; 07 relevant phase position, and / or to a position and / or a progress of the printing material 02 in the printing press. This machine phase can be determined by the indirectly or directly derived angular position of one of the affected pressure point 06; 07 forming cylinder 18; 21; 22 be. The variable relating to the progress of the printing material 02 can be an angular position signal of a machine element transporting the printing material 02 in correct register or a passage signal from a sensor system provided on the transport path.

The cycle length L _Z is preferably given by the repetition length between two successive printing sections, ie the shortest possible distance between the leading ends of two successive print image lengths. Depending on the physical variable to be considered, this can be spatially related to a path length between two locations or an angle or else temporally to the duration between two points in time. Taking into account the geometry and the transport speed profile, these variables can be converted into one another for example to refer to a relative position to the machine phase. The cycle length L _Z corresponds to the sum of the length of a circumferential section U _{D that is} maximally usable for printing when viewed along the transport path and a length L _{N of} a circumferential section U _N lying between two such circumferential sections U _D and not usable for printing. In the case of sheet-fed printing, the latter can be caused, among other things, by the means for sheet transport and for roller printing, among other things by interruptions caused by bumps or even gaps between the ends of the tensioned printing plates. For the presence of a counterpressure and / or transport cylinder 21, the cycle length L _Z corresponds, for example, to the total of the length of a circumferential section U _{D that can be used} for printing and the length L _{N of} a circumferential section U _N and / or n that cannot be used for printing -th part of the circumference of the counter-pressure and / or transport cylinder 21, which is n times the size or comprises n saddles.

Such a cycle length L _Z or the on-off sequence assigned to it comprises e.g. B. at least one phase P _AB with the squeegee 34 turned off and at least one phase P _AN with the squeegee 34 turned on. The term phase P _AN ; P _AN relate to a spatial or temporal variable. Such a cycle can have a sequence with only a single phase P _AB with the squeegee 34 turned off and one phase P _AN with the squeegee 34 turned on or, in a further development, also a sequence with several phases P _AN interrupted by a phase P _AB each with the squeegee 34 turned off employed doctor blade 34 include. As a result of the limited speed of movement when turning on and off the squeegee 34, between the phase P _AN with squeegee 34 employed in the actual working position, in which this, for example, not only directly up to, but with a slight deflection of z. B. at least 0.5 mm, ie a negative distance a _AN of a _AN = -0.5 mm, determined by the amount of the adjusting movement beyond the first touch contact, against the screen printing stencil 31; 32 is employed, and the phase P _AB with effectively turned off squeegee 34, in which the squeegee edge a slight distance a _AB from z. B. a _AB ≥ 0.2 mm, in particular 1.2 mm ≥ a _AB ≥ 0.4 mm, for the screen printing stencil 31; 32 assumes, a phase P _at the start or a phase P _from the shutdown.

To the fuzzy area between the actual parking and parking position "ON"; To keep "AB" and / or the area that cannot be used for printing as small as possible, but to enable high operating speeds without excessively strong impulses caused by the movement of the squeegee, is a - z. B. on the circumferential direction in the inner circumference of the screen printing stencil 31; 32 related - length of phase P _at the setting and / or phase P _{starting at} the setting z. B. between 80 mm and 200 mm, in particular between 110 mm and 150. However, the sum of the length of a phase P _from the stop and the length of a phase P _from the start corresponds at most to the length L _N of the circumferential section that cannot be used for printing U _N , which is given here for example at least by the width of the opening 28 seen in the circumferential direction and the distance a _S upstream of the trailing pit edge and possibly by the length of the above-mentioned overlap of an optionally provided cover element 29.

The doctor device 33 comprises (see e.g. Fig. 9 ) a control device 39, by means of which the doctor blade 34 can be switched on and off or switched on and off in the above-mentioned correlation to the machine phase of the printing press and / or to the progress of the printing substrate 02. By means of the control device 39, a drive means 41 causing the on and off movement of the squeegee 34 can be controlled in the above-mentioned correlation to the machine phase of the printing press and / or to the progress of the printing substrate 02 in such a way that the squeegee 34 alternately moves for one of the length of phase P. _AN with engaged squeegee 34 corresponding duration in the inclined position "AN" and - in particular after a transition phase caused by the duration of the phase change - for a duration corresponding to the length of phase P _AB with disconnected squeegee 34 in the parked position "AB". For this purpose, the drive means 41 is controlled by the control device 39 in such a way that the drive device is in during the phase P _AN with the doctor blade 34 engaged or for the corresponding duration T _AN an operating state BZ _AN causing the contact position "AN" and during phase P _AB with the squeegee 34 turned off or for the corresponding duration in an operating state BZ _AB causing the contact position "AB" (see, for example, schematically in Fig. 5 ).

The control device 39 can be formed by a coherent or distributed control circuit 39 or by a coherent or distributed data processing means 39 connected to one another in terms of signaling technology, it comprising switching and / or data processing means for performing the above-mentioned correlation. The control device 39 can be wholly or partially integrated into a machine control system connected to other actuating and / or drive means of the printing machine, or entirely or partially provided specifically for controlling the doctor blade 34.

The above-mentioned correlation of the sequence related to a cycle length L _Z to the machine phase and / or to the printing substrate progress occurs, for example, in FIG. B. by transmitting the machine phase and / or the printing substrate progress representing signals S _K via a signal connection 35 between the control device 39 and the machine phase of the printing press and / or the progress of the printing substrate 02 and the doctor blade control z. B. serving as master 42. This can be given, for example, by a sensor system 42 that detects the relevant machine phase of the printing press and / or the progress of the printing material 02 and / or by a drive control 42 controlling the direct or indirect drive of the cylinder 21. In an embodiment particularly suitable for retrofitting, this can be a component that is already provided in the machine and to be driven in register, e.g. B. the system drum, associated sensors 42 be. For machines for which several components or component groups relating to transport and / or printing are rotationally driven by mechanically independent drive motors via a common electronic master axis, the master axis encoder 42 serving as master 42 for the squeegee control can be equipped with such electronic master shaft 42 be or will be formed, which serves as a master for several further drive motors of the printing press. This master axis 42 can follow the rotary movement of a real angle signal as a real electronic master axis 42 or it can be generated as a virtual master axis by data processing means 39 and be specified for all coupled slave drives. The signal connection 35 is then formed by the coupling to the electronic master axis 42 and is implemented, for example, as a bus or network system.

The squeegee device 33 - or the said control device 39 that switches the squeegee 34 on and off in a correlation to the machine phase of the printing machine and / or to the progress of the printing material 02 - comprises control means 43 by which a length and / or position of at least one of the contact positions Phase P _AN relating to "ON" can be varied and / or is varied within a repeating cycle for switching on and off as a function of information relating to or representing the printing material format and / or the print image. In particular, the information relating to or representing the printing substrate format, in particular its length, and / or the print image can be information on the printing substrate length L02 viewed in the transport direction or on the printing image length L _B relating to the printing substrate sheet 02 or on the printing unit 19; 23 print patterns to be printed. As a result, the length and position of the phase P _AN can be used both for the circumferential direction on the inside of the screen printing form 31; 32 measured length as well as their temporal correspondence as duration or temporal classification related to the peripheral speed.

In a first variant, for the format-dependent or image-dependent control of the phase length and / or position, two or more discrete values or value ranges for the information in question, a corresponding number of discrete phase lengths and / or positions for the phase P _AN with the squeegee 34 on and / or a corresponding number of - z. B. at least partially each other spaced phase positions for the end of the phase P _AN with the doctor blade 34 engaged - for example in or by the control means 43 - be kept or provided.

In an alternative, however, it can be provided that a value for the phase length and / or position of the phase P _AN with the doctor blade 34 or for the phase position of the end can be provided by the control means 43 as a function of a value originating from a continuous value range of the relevant information the phase P _AN with employed doctor blade 34 from a continuous - and z. B. limited upwards and downwards - value range is provided or provided. "Continuous" should also be understood to mean a sequence of equidistant discrete steps, which is conditioned, for example, by restriction or rounding to the smallest steps to be considered and / or handled in the size to be considered.

The control device 39 processes signals S _K relating to the above-mentioned correlation into signals S _{R which} control the up and down movement of the doctor blade 34, taking into account a specific phase length and / or position for the phase P _AN or relating to the “AN” position Phases P _AN within a cycle or a cycle length L _Z. The specific phase length and / or position is obtained and provided by the control means 43 as a function of the printing material format, in particular its length, and / or the information that characterizes and / or relates to the print image, here for example also under the superordinate designation of the information relating to the printing Information I summarized (see e.g. Fig. 9 ).

The z. B. from the control device 39 for the correlated, in particular synchronized drive included control means 43 for providing the format and / or print image-dependent phase length and / or position can in turn by one or more connected or distributed circuit and / or Data processing means may be formed, wherein it comprises circuit and / or data processing means for determining a phase length and / or the phase position relating to the contact position "AN" as a function of the above-mentioned information on format and / or print image.

The control means 43 comprised by the control device 39 can - corresponding to the control device 39 itself - be completely or partially integrated into a control system connected to other actuating and / or drive means of the printing press, e.g. B. a planning and / or control level 47 to be assigned machine control integrated or provided decentralized and spatially close to the drive means 41 to be controlled.

The length and / or position of the at least one phase P _AN with the squeegee 34 engaged or the corresponding or temporal arrangement or a movement profile that takes this length or duration into account is determined on the basis of an assignment rule comprised by the control means 43 as a function of the information to be used and / or provided. The assignment rule can be stored in a table or as a functional context in a computing and / or storage means 52 comprised by the control means 43. This is also to be understood as a complex rule by means of which a movement profile taking into account the specific length and / or position is determined and / or created as a function of the information to be used.

The information determining the phase length and / or the phase end or the phase position can be sent to the control means 43, for example. B. be made available from the planning and / or control level 47 via a signal connection 45. This can be done, for example - in particular in the case of information relating to or representing the printing material format F and / or the print image - from a control station assigned to the planning and / or control level 47. The corresponding ones are on this one Information itself or information to be processed for this information can be manually selected or entered, for example via an operator interface. In a more automated form, the information or the information to be processed for this information can be obtained from data for product and / or production planning already electronically in the planning and / or control level 47 or a prepress stage. In a variant, which is to be preferred particularly when using information relating to the print length or the print pattern, the relevant information can be obtained from data already available in the prepress for the relevant print image extract.

The term "phase length" or "phase position" can be used here, if there is no recognizable distinction, as a short form for the above-mentioned "length" or "position", both the size and the position of the relevant phase in spatial terms (position, Angle) as well as - via the speed profile - their temporal correspondence as a duration or relative position within the synchronized cycle length L _Z. The times for the respective phase change and thus the phase length and the phase position are z. B. determined relative to the machine phase position and / or to the printing material phase position.

In a first embodiment for the configuration of the control means 43 or for controlling the squeegee movement, e.g. B. in Fig. 6 schematically indicated on the basis of a side view of a cylinder jacket development comprising a usable circumferential section U _D , printing substrate sections of a first format F.1, ie with a first printing substrate layer L02,1, and in a second operating situation printing substrate sections 02 of a second format F.2 are indicated, for example , ie can be or will be printed with a second substrate layer L02,1. Depending on the respective substrate position L02,1; L02,2 or information representing this length is the phase length of the phase P _AN with the doctor blade 34 or - for this case is preferred - one end of the phase P _AN with the squeegee 34 engaged is determined by the control device 39 and / or it takes place as a function of the respective printing material position L02,1; L02,2 or an item of information representing this length, switching the doctor blade 34 on and off in a respective cycle Z1; Z2 (see e.g. Fig. 5 ), in which the differing printing material layers L02,1; L02,2 phase lengths differing from one another for the respective phase P _AN with the doctor blade 34 attached or - for this case preferred - phase positions differing from one another for the end of the respective phase P _AN with the doctor blade 34 attached are or will be assigned. The phase position for the beginning of the respective phase P _AN with the doctor blade 34 employed can be the same and z. B. fixed, but possibly changeable. This can, for example, already lie before the beginning of the circumferential section U _N that can be used for printing in the manner set out above.

In a second, if necessary instead of or optionally for the first execution feasible or foreseeable execution, z. B. in Fig. 7 indicated schematically on the basis of a side view of a cylinder jacket development comprising a usable circumferential section U _D , the phase length of phase P _AN with squeegee 34 attached or at least one end of phase P _AN with squeegee 34 attached is determined by the control device 39 as a function of the respective printed image length L _B or . an item of information representing this length is determined. Under the print image length L _B z. B. in this case, the length should be understood, which on the forward side through the first and on the return side through the last through the pressure point 06; 07 the application of paint to be provided is limited. The pressure area 44 lying in between can have continuous or discontinuous pressure areas 44. For operating situations with different print image length L _B depending on the respective print image length L _B or information representing this length, the doctor blade 34 is switched on and off in a respective cycle Z1; Z2, in which the mutually different print image lengths L _B different phase lengths for the respective phase P _AN with the doctor blade 34 or different from each other Phase positions for the end of the respective phase P _AN with the squeegee 34 engaged are or will be assigned. The phase position for the beginning of the respective phase P _AN with the squeegee 34 employed can be the same and z. B. fixed, but possibly changeable. This can, for example, already lie before the beginning of the circumferential section U _N that can be used for printing in the manner set out above. The phase position for the beginning of the respective phase P _AN with the squeegee 34 engaged can, as above, be the same or a phase position dependent on the start of the print image.

In a third, if necessary instead of or alternatively to the first and / or second execution feasible or foreseeable execution, z. B. in Fig. 8 indicated schematically on the basis of a side view of a cylinder jacket development comprising a usable circumferential section U _D , several phases P _AN with a squeegee 34 and several phases P _AB with a squeegee 34 can be provided for each cycle length L _Z. A start and an end of the respective phases P _AN with the squeegee 34 on are determined by the control device 39 as a function of information representing the phase position of the print strips 46 of a print area 44, viewed in the transport direction, which are interrupted by strips that are not to be printed. For operating situations with a different pattern of strips to be printed and not to be printed, an individual, depending on the respective distribution of the print strips 46 or on information representing this distribution, a multiple turning on and off of the doctor blade 34 in a respective cycle, in which the print areas 44 deviating from one another in the distribution of the print strips 46 are assigned different patterns for the phase positions and / or lengths, ie the position of the respective beginnings and ends, of the respective phase P _AN with the squeegee 34 engaged. The information on the number and / or position of the print strips 46 is based, for example, on data obtained by evaluating the information provided by the print point 06; 07 to be printed image, in particular by evaluating the z. B. in the prepress in data form present target print image are or are obtained. It can be printed strips, which by z. B. narrower not to be printed strips are interrupted despite their discontinuity to be or will be combined into larger print strips 46.

In particular in connection with the first and the second embodiment, the control means 43 provide within the preferably fixed cycle length L _Z a ratio between the phase length of the phase P _AN relating to the contact position "AN" and that of the position position, based on the length of the covered inner circumference on the screen printing stencil "AB" relevant phase P _AB variierba.

The bearing and drive device of the squeegee 34 that enables the on and off movement in the above embodiments can in principle be designed as desired, provided that it preferably has at least one squeegee 34 that can be suitably switched on and off and one from the rotary drive of the screen printing cylinder 18; 22 and / or the counter-pressure and / or transport cylinder 21 includes a mechanically independently operable and / or operated drive 41, 48. This is for example - in particular without mechanical coupling to the drive of the screen printing cylinder 18; 22 or of the counter-pressure and / or transport cylinder 21 - can optionally be brought into an operating state BZ _AN causing the adjustment position "AN" of the doctor blade 34 and into an operating state BZ _AB causing the parking position "AB" of the doctor blade 34 (see e.g. Figure 5b )) with 5a)).

The from the rotary drive of the screen printing cylinder 18; 22 and / or the impression and / or transport cylinder 21 mechanically independently operated and / or operable and / or without a mechanical drive coupling for the rotary drive of the screen printing cylinder 18; 22 and / or the counterpressure and / or transport cylinder 21 designed drive 41, 48 can in principle be designed as desired in order to enable the squeegee 34 to be switched on and off in the aforementioned manner. The type of movement of the doctor blade 34 and / or the design of the drive can in principle be arbitrary be executed. The following examples reflect particularly advantageous designs, but should not necessarily restrict the solution on which the function is based.

Such a drive 41, 48 comprises at least one controllable drive means 41. This can be used, for example, as a drive means 41 that can be actuated by the application of a pressure fluid, such as a drive means 41. B. a pressurized cylinder-piston system, for example a hydraulic or pneumatic cylinder drive, or - as preferred here - as a - preferably angular position controllable - motor 41, such as. B. an electric motor 41, for example as a linear motor or as a rotary electric motor 41 can be formed.

On the output side, the drive means 41 is in operative connection indirectly or directly via a corresponding coupling with the doctor blade 34 to be moved. The operative connection can act on the doctor blade 34 directly without any gearing or via a gearing 48.

Such a transmission can in a first embodiment, for. B. by a linear movement of a linearly acting drive means 41, z. B. a drive means 41 which can be actuated with a pressure fluid, a transmission 48 which transmits an on / off movement of the doctor blade 34, for example comprising a plunger and / or a one or two-armed lever. In another advantageous embodiment of the drive, the coupling can be via a rotational movement of a rotationally acting drive means 41, e.g. B. an electric motor 41, in an on / off movement of the doctor blade 34 converting gear 48 take place or be implemented. In a third, advantageous embodiment, the drive can be designed as a linear drive, and the gear 48 as a rotary rotor movement of an electric motor 41, preferably configured with angular position control, into a linear movement of a carrier carrying the doctor blade 34, e.g. B. a spindle gear, executed.

With screen printing, a print "DN" can be added in the nipple point 06; 07 basically also take place in that when the doctor blade 34 is brought into its contact position "AN", the cylinder screen, which is elastic and / or deformable within certain limits, is used as a screen printing form 31; 32 is brought into physical contact with the impression cylinder 21 from a position spaced apart from the jacket surface 27. The screen printing form 31; 32 and the squeegee 34 can be adjusted independently of one another and is for moving between print-on "DN" and print-off "DB" of the screen cylinder 18; 22 a further drive means 49 different from the above-mentioned drive means 41, e.g. B. a motor 49, in particular an electric motor 49, or a pressure medium-operated drive means 40 such as a pneumatic cylinder 49 is provided. This can be used, for example, as a drive means 41 which can be actuated by pressurized fluid, e.g. B. a hydraulic or pneumatic cylinder, as an electric motor or in some other way.

In addition to the control device 39, through which the doctor blade 34 in the above. Correlation to the machine phase of the printing machine and / or to the progress of the printing material 02 can be switched on and off or switched on and off, and for example a master 42 providing the printing material feed and / or the machine phase position, control means 51 are provided by which the Turning the screen cylinder 18 on and off; 22 is brought about by appropriate control of the drive means 41, in that a corresponding signal is fed to the drive means 49 from the control means 51. An embodiment can be advantageous in which the entire adjusting mechanism for the squeegee 34 when the screen cylinder 18; 22 is moved with this. It can thus be avoided, for example, that the screen printing form 31; 32 when the screen cylinder 18; 22 is pressed into the squeegee 34 which may otherwise remain stationary.

From the control means 51, a signal switching the squeegee operation can also be fed to the control device 39. This is for example a permanent or the cyclical turning on described above can be activated and deactivated.

Due to the embodiment in which the squeegee 34 is switched on and off and the screen printing cylinder 18; 22 are effected independently of one another, is a particularly preferred mode of operation of the printing unit 19; 23 when starting up or restarting the machine or the printing unit 19; 23 feasible. Here, contamination of the surface of the impression cylinder 21 by from the screen cylinder 31; 32 originating printing ink can be largely prevented, or at least significantly reduced. Particularly in situations in which there is still or already printing ink in the interior of the screen cylinder, but no ink has yet been removed by the printing material 02 to be printed, printing ink that seeps through can collect on the outside of the screen, which subsequently lead to ink deposits on the lateral surface 27 of the impression cylinder 21 and feed there Can lead to damage or at least to great cleaning effort.

For example, the screen cylinder 18; 22 ink introduced or remaining in the event of production interruption seep through the pores. This is especially true when the screen cylinder 18; 22 with the doctor blade 34 already or still rotating. Due to the centrifugal forces, the printing ink can be pushed through the pores even more strongly.

The undesirable way on the outside accumulating printing ink can, for. B. by building up accordingly over several revolutions, for example with more than three revolutions, a greater layer thickness than the gap formed in Druck-Ab DB, so that it can at least partially reach the lateral surface 27 of the impression cylinder 21. At the start of printing, ie after the screen cylinder 18; 22 in print-on and the adjustment of the squeegee 34, on the outer surface of the screen, a paint roller is formed, which in the worst case does not come from Printing substrate 02 can be taken up and transported to the end of the sheet. There the remaining ink is distributed on the surface of the impression cylinder 21. Such ink contamination on the impression cylinder 21 is particularly disadvantageous in the above-mentioned case that a drying device 36, in particular an intermediate dryer 36, is directed at the lateral surface 27 and cannot be deactivated for the start-up process, for example.

In order to avoid such contamination, according to the invention the start-up or restart or the further start-up takes place after the screen printing cylinder 18 has been brought up due to a fault; 22 according to the following steps:
Starting from an operating situation, referred to here as the first phase, in which the screen cylinder 18; 22 is turned off by the impression cylinder 21 when the squeegee 34 is turned off, in a subsequent, second phase according to the invention, a plurality of printing material sheets 02 with the squeegee 34 still turned off with - for each printing material sheet 02 - screen cylinder 18; 22 through the printing point 06; 07 funded. The screen cylinder 18; 22, for example, when the above-described openings 28 are present in the lateral surface 27 of the impression cylinder 21 in the region of the openings 28, and then re-engaged. In a subsequent, third phase, subsequent printing material sheets 02 are operated with permanently or cyclically per printing material sheet 02 at least one squeegee 34. In the latter, in contrast to operation without a squeegee 34, as with the permanently activated squeegee 34, it should be an operational one Act squeegee operation. As a rule, there is still or already printing ink in the screen cylinder 18 during or at least towards the end of the first phase; 22, through which the risk of the above-mentioned contamination arises.

The adjustment sequence of screen cylinder 18; 22 and squeegee 34 is therefore carried out in such a way that first one or more turns only the sieve is turned on. During this time, the printing ink is on the outside of the screen printing form 31; 32 transferred to the printing substrate 02. When the doctor blade 34 is placed, there is only so much printing ink on the outside of the screen printing form 31; 32 that the printing material 02 can also absorb the amount of ink and there is no longer any ink roller in the nipple point 06; 07 can build up. Although this procedure can lead to a higher number of waste sheets at the start of printing, it helps to reduce or avoid costly cleaning processes of the impression cylinder 21.

In the second phase, preference is given to a plurality of printing material sheets 02, each with the screen cylinder 18; 22 through the printing point 06; 07 promoted, while the doctor blade 34 remains switched off for the duration required for this. In particular, in the second phase, two to nine, preferably two to six, sheets of printing material 02 are printed in this way with the screen cylinder 18; 22 through the printing point 06; 07 promoted, while the squeegee 34 remains switched off for the duration required for this, ie is not or is not switched on permanently or cyclically in squeegee operation.

The squeegee 34, which remained in the second phase when it was switched off, through the printing point 06; 07 conveyed printing material sheets 02 are downstream of the screen printing unit 19; 23 as waste sheets are preferably separated from the good sheets, in particular discharged and / or collected separately.

In an advantageous embodiment, a fixed but preferably predeterminable number of at least one, in particular a number from one to three, first in the third phase with the doctor blade 34 engaged with the screen cylinder 18; 22 through the printing point 06; 07 conveyed sheet of printing material 02, regardless of their quality, separated from the good sheets as waste sheets, in particular discharged and / or collected separately.

In a first variant for the starting position in the first phase, the screen cylinder 18 is located; 22 and / or the impression cylinder 21 at a standstill, and is accelerated to an operating speed in a start-up phase lying between the first and second phase and operated at this operating speed at least until further notice. This starting position is present, for example, if, in a planned manner or as a result of an error, production is interrupted, for example by shutting down the machine to a standstill.

In a possible second variant for the starting position, the screen printing cylinder 18; 21, for example only for a shorter period of time, without the machine and / or the screen cylinder 18; 22 is actually brought to a standstill. In the event of a possibly after the screen cylinder 18; 22 initially higher than a desired low operating speed, this is lowered to the lower operating speed in a braking phase between the first and second phase and then operated at the lower operating speed that may already exist or have been achieved after the lowering, at least until further notice.

The mentioned lower operating speed present or achieved in the second phase is significant compared to the target production speed, i. H. by at least a third of the target production speed, lower. For example, it corresponds at most to a sheet conveying rate through the printing point 06; 07 up to 4,000 sheets / hour, in particular from 2,000 to 4,000 sheets / hour.

The screen cylinder 18; 22 and / or the impression cylinder 21 in the course of the second and / or the third phase to a lower operating speed than the previously assumed operating speed by at least half greater and / or at least one sheet conveying rate through the printing point 06; 07 of at least 6,000 sheets / hour corresponding production target speed.

For the application in which the operation including the first, second and third phases takes place within the scope of a start or resumption of production, a sheet feed into the printing press is preferably synchronized by the sheet feeder 01 to the rotational angle position and / or speed of the sheet feeder 01 between the first and second phase Counter-pressure cylinder 21 added, the second phase with the adjustment of the screen cylinder 18; 22 to one, e.g. B. the first from the sheet feeder 01 as part of a recording or resumption in the printing point 06; 07 conveyed sheet of printing material 02 begins.

When the machine is started, the number of machine revolutions, in particular at least the screen cylinder revolutions before the first sheet of printing material 02 is printed, is preferably reduced to a minimum for starting or restarting. In addition, the machine speed is preferably only after the start of printing, that is, after the screen cylinder 18; 22 and the doctor blade 34, increased to production speed. As a result, less printing ink is pressed from the inside through the screen printing form 31, 32 to the outside in a shorter time with the lowest possible centrifugal force.

The resumption of production, for example, was preceded by an error-related interruption of production and a machine stop with a controlled shutdown. As a result of a detected error, e.g. B. a system error in the sheet feeder 01, z. B. lowering the machine speed, in particular the speed of the screen and / or impression cylinder 18; 21; 22 from production speed to a significantly reduced rate, ie by at least a third of the target production speed, and / or at most one sheet conveying rate through the printing point 06; 07 up to 4,000 sheets / hour corresponding operating speed. A further supply of printing material sheets 02 through the sheet feeder 01 is stopped, for example. Printing material sheets 02 already located in the transport path of the printing machine, e.g. B. a number from two to fifteen, are still indicated by the pressure point 06; 07 conveyed and at the reduced operating speed to the product delivery 04. After the last sheet of printing material 02 has been deposited in the product delivery 04, the machine can stop completely.

Preferably, the squeegee 34 is set down before the screen printing cylinder 18 is set down; 22. Although only a few seconds or even tenths of a second can lie in between, it can be advantageous in a further development if the screen printing cylinder 18; 22 only takes place after he has at least a large part, z. B. more two-thirds of its circumference on one by the pressure point 06; 07 conveyed sheet of printing material 02 is unrolled.

In the event of a planned or regulated machine stop (for example at the end of production or in the event of a production interruption, which may be due to errors, e.g. system errors, or also due to the production plan), the machine speed - especially during the last sheet of printing material 02 - with the doctor blade 34 preferably reduced as far as possible. The sheet transport from the printing nip to the delivery takes place at a reduced operating speed. As a result, with a lower centrifugal force, there is also less printing ink from the inside through the screen printing form 31; 32 pushed outwards.

Although a permanent adjustment or a cyclical activation and deactivation coupled mechanically with the angular position of the impression cylinder can be provided for the squeegee operation, the above for switching the squeegee 34 on and off by a drive means 41 for the squeegee drive that is mechanically independent of the rotary drive is preferred apply.

The procedure can also be applied to a drive of the printing machine and / or of the screen printing unit with cylinders 18; 21; 22, as well as a version with individually or in groups driven cylinders 18; 21; 22 apply. For example, in an advantageous embodiment, the screen printing cylinder 18; 22 can be driven independently of the impression cylinder 21, whereby when the machine is shut down with the screen printing cylinder 18; 22 its after-running and / or when the machine is started up with the screen printing cylinder 18 still switched off; 22 can shorten its advance. This also allows the contamination to be reduced.

The device for operating a screen printing unit 19; 23 in the above-mentioned manner comprises the above-mentioned control means 51 which control the screen cylinder 18; 22 after a first phase, in which it is parked by the impression cylinder 21 with the squeegee 34 switched off, in a second phase with the squeegee 34 permanently switched off during the passage of several printing material sheets 02 through the printing point 06; 07 at least two times per sheet of printing material 02, and in a subsequent third phase, in particular the production phase, for a number, in particular a multiplicity of z. B. more than 20, of printing material sheet 02 the doctor blade 34 permanently or at least once per printing material sheet 02 from the inside against the screen printing forme 31; 32 hires. The device and / or the control means 51 is set up accordingly for this, ie comprises a control routine which is implemented, for example, as a software program in the data processing means comprised by the control means 51.

List of reference symbols

01

Feed device, sheet feeder

02

Printing material, printing material sheet

03

Printing unit

04

Product display

05

-

06

Pressure point, nipple point

07

Pressure point, nipple point

08

Gripping device

09

Conveyor line, belt system, conveyor system

10

-

11

Transfer drum

12

Takeover drum

13

Conveyor line, belt system

14th

Conditioning device, drying device

15th

-

16

Conditioning device, drying device

17th

Conditioning device, device for applying magnetic field lines

18th

Rotary body, cylinder, form cylinder, screen cylinder, screen printing cylinder

19th

Printing unit, screen printing unit

20th

-

21st

Rotary bodies, cylinders, counter-pressure and / or transport cylinders

22nd

Rotary body, cylinder, form cylinder, screen cylinder, screen printing cylinder

23

Printing unit, screen printing unit

24

Holding device, gripper device

25th

-

26th

pit

27

Outer surface

28

Opening, pit opening

29

Coloring aid, cover element, flap

30th

-

31

Printing form, screen printing form, screen printing stencil

32

Printing form, screen printing form, screen printing stencil

33

Squeegee device

34

Squeegee

35

Signal connection

36

Drying device, dryer, intermediate dryer, radiation dryer

37

Shadowing, wall

38

Radiation source

39

Control device, control circuit, data processing means

40

-

41

Drive means, motor, electric motor

42

Master axis encoder, master, master axis, sensors, drive control

43

Control means

44

Pressure area

45

Signal connection

46

Print strips

47

Planning and / or management level

48

Transmission,

49

Drive means, motor, electric motor, pneumatic cylinder

50

51

-

52

Control means

53

Computing and / or storage means

a _AN

distance

a _AB

distance

a _S

distance

FROM

Storage shelf

AT

Line

BZ _AB

Operating condition

BZ _ON

Operating condition

DB

Print-off

DN

Print to

F.1

format

F.2

format

I.

information

L02.1

Substrate length

L02.2

Substrate length

L _B

Print image length

L _D

length

L _Z

Cycle length

L _N

length

P _from

phase

P _at

phase

P _AB

phase

P _AN

phase

S _K

signal

S _R

signal

U _D

Circumferential section, cylinder circumferential section (can be used for printing)

U _N

Circumferential section, cylinder circumferential section (cannot be used for printing)

Z1

cycle

Z2

cycle

Claims (15)

1. A method for operating a screen printing unit (19; 23) in a printing press comprising a screen cylinder (18; 22), which carries a screen printing form (31; 32), in which a squeegee (34) can be engaged from the inside against the screen printing form (31; 32) and disengaged therefrom, and which screen cylinder can be thrown onto an impression cylinder (21) such that a print position (06; 07) is formed and can be thrown off of said impression cylinder such that a gap is formed, wherein

   - in a first phase, the screen cylinder (18; 22) is thrown off of the impression cylinder (21) while the squeegee (34) is in a disengaged position, characterized in that

   - in a second phase, multiple printing substrate sheets (02) are conveyed through the print position (06; 07) while the squeegee (34) remains in a disengaged position and the screen cylinder (18; 22) is at least temporarily thrown on for each substrate sheet (02),

   - and finally, in a third phase, for subsequent printing substrate sheets (02) an operation is carried out in which the squeegee (34) is in an engaged position, perpetually or cyclically at least once for each printing substrate sheet (02).
2. The method according to claim 1, characterized in that in the second phase, multiple printing substrate sheets (02) are conveyed through the print position (06; 07) with the screen cylinder (18; 22) thrown on at least temporarily for each sheet, while the squeegee (34) remains in a disengaged position for the period of time required for this.
3. The method according to claim 2, characterized in that in the second phase, two to nine, preferably two to six printing substrate sheets (02) are conveyed through the print position (06; 07) with the screen cylinder (18; 22) thrown on at least temporarily for each sheet, while the squeegee (34) remains in a disengaged position for the period of time required for this.
4. The method according to claim 1, 2 or 3, characterized in that during or at least toward the end of the first phase, printing ink is located inside the screen cylinder (18; 22), and/or in that the screen cylinder (18; 22) and/or the impression cylinder (21) is/are in an idle state in the first phase, are accelerated to an operating speed in a startup phase between the first and the second phases, and are operated at this operating speed, at least for a time.
5. The method according to claim 1, 2, 3 or 4, characterized in that the printing substrate sheets (02) conveyed through the print position (06; 07) in the second phase while the squeegee (34) remains in a disengaged position are separated from the good sheets as waste sheets, in particular are ejected and/or collected separately, downstream of the screen printing unit (19; 23).
6. The method according to claim 1, 2, 3, 4 or 5, characterized in that a fixed but preferably pre-definable number of at least one, in particular a number of one to three first printing substrate sheets (02) conveyed through the print position (06; 07) in the third phase, with the squeegee (34) in an engaged position and the screen cylinder (18; 22) thrown on, is or are separated from the good sheets as waste sheets, in particular are ejected and/or collected separately, regardless of their quality.
7. The method according to claim 6, characterized in that the operating speed existing or reached in the second phase is significantly lower than the target production speed, i.e., at least one-third lower than the target production speed, and/or is equal at most to a sheet feed rate through the print position (06; 07) of up to 4,000 sheets/hour.
8. The method according to claim 1, 2, 3, 4, 5, 6 or 7, characterized in that, during the second and/or the third phase, the screen cylinder (18; 22) and/or the impression cylinder (21) is/are accelerated to a target production speed that is at least 1.5 times greater than the lower operating speed previously assumed and/or that is equal to a sheet feed rate through the print position (06; 07) of at least 6,000 sheets/hour.
9. The method according to claim 1, 2, 3, 4, 5, 6, 7 or 8, characterized in that the operation comprising the first, second, and third phases is carried out as part of a commencement or a resumption of a production run.
10. The method according to claim 9, characterized in that between the first and second phases, a sheet feeder (01) begins feeding sheets into the printing press in synchronization with the angular position and/or angular speed of the impression cylinder (21), and the second phase begins when the screen cylinder (18; 22) is thrown onto the first printing substrate sheet (02) that is conveyed from the sheet feeder (01) into the print position (06; 07) as part of a commencement or resumption.
11. The method according to claim 9 or 10, characterized in that the resumption of production is preceded by an error-induced interruption in production and a machine stop in which shutdown is controlled.
12. The method according to claim 11, characterized in that the squeegee (34) is moved to a disengaged position before the screen cylinder (18; 22) is thrown off.
13. The method according to claim 12, characterized in that the screen cylinder (18; 22) is thrown off after it has rolled with at least a majority of its circumferential surface along a printing substrate sheet (02) that is conveyed through the print position (06; 07) while the squeegee (34) is in a disengaged position.
14. The method according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 or 13, characterized in that during operation in which the squeegee (34) is engaged cyclically at least once per printing substrate sheet (02), an engagement and disengagement of a squeegee (34) against a screen printing form (31; 32) is carried out in a repeating cycle comprising a sequence of one or more phases (P_AN) relating to an engaged position ("AN") and one or more phases (P_AB) relating to a disengaged position ("AB"), and/or in that the squeegee (34) is engaged and disengaged by a drive means (41) that is mechanically independent of the rotary drive of the screen cylinder (18; 22) and/or the impression cylinder (21).
15. A device for operating a screen printing unit (19; 23) in a printing press, in particular for use in a method according to any of claims 1 to 14, comprising a screen cylinder (18; 22), which carries a screen printing form (31; 32), in which a squeegee (34) can be engaged from the inside against the screen printing form (31; 32) and disengaged from said printing form by a first drive means (41), and which screen cylinder (18; 21) can be thrown by a second drive means (49), which is different from the first drive means (41), onto an impression cylinder (21) such that a print position (06; 07) is formed and can be thrown off of said impression cylinder such that a gap is formed, wherein a control means (51) is provided, which is connected in terms of signals to the drive means (41; 49), characterized in that the control means (51) actuates the second drive means (49) to throw the screen cylinder (18; 22) at least temporarily, after a first phase, in which the screen cylinder (18; 22) is thrown off of the impression cylinder (21) and the squeegee (34) is in a disengaged position, in a second phase, in which the squeegee (34) is perpetually in a disengaged position during the passage of multiple printing substrate sheets (02) through the print position (06; 07) for each printing substrate sheet (02), and in a subsequent third phase, for a number of printing substrate sheets (02), said control means actuates the first drive means (41) to engage the squeegee (34) from the inside against the screen printing form (31; 32), perpetually or at least once for each printing substrate sheet (02).

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