The present invention is directed to a flexographic printing press. The flexographic printing press has at least one forme cylinder, which is driven by its own electric motor. At least one flexographic printing plate is carried on the at least one forme cylinder.
An arrangement for inking a roller of a printing group is known from WO 03/047864 A2 and which is usable in connection with an inking system for a printing group of a double-width printing press. Either two doctor blades, which are arranged side-by-side in the axial direction of the roller, or one doctor blade of a length of at least four side-by-side arranged newspaper pages, can be independently placed against the roller or moved away from the roller.
EP 1 435 292 A1 discloses a printing unit with a satellite cylinder, with which satellite cylinder, four plate cylinders work together. Each one of the plate cylinders supports four flexographic printing plates in the axial direction. Each one of the plate cylinders is arranged in eccentric bearings.
DE 101 03 631 A1 describes a flexographic printing press, whose plate cylinders are seated in linear guides.
DE 10 2004 001 467 A1, EP 1 082 225 B1, DE 101 23 138 A1 and DE 102 51 977 A1 all describe electric motors with permanent magnets.
The object of the present invention is directed to providing a flexographic printing press.
In accordance with the invention, the object is attained by the provision of at least one forme cylinder that is driven by its own motor and which carries at least one flexographic printing plate. The motor for each such forme cylinder may be an angular position-regulated electric motor. Four such forme cylinders may directly work with a satellite cylinder. Journals of each forme cylinder are seated in linear bearings arranged in lateral frames of the printing press. Each forme cylinder can be moved, together with a stator of its associated drive motor.
The advantages to be gained with the present invention consist, in particular, in that a press is provided, which is easy to produce, or to operate, which is comparatively spatially compact, and which makes possible a high printing quality.
An ideal installation position of the cylinders or rollers, in respect to limiting or eliminating possible cylinder vibrations, is achieved by the employment of linear guides for the forme cylinders and screen rollers of the printing groups. In addition, short adjustment paths are accomplished by the cylinder seating, and therefore no synchronizing spindle is required. The expensive installation of three-ring bearings is unnecessary.
The use of a synchronous motor and/or of a drive mechanism, with excitation by a permanent magnet as the drive motor for the printing group cylinders or the screen roller, provides a particularly simple, and yet strong drive mechanism for these rotating bodies.
A dryer is arranged in such a way that the waste heat from the dryer again dries a paper web running over it. Accordingly, the time required for drying, or the path required for drying, is shortened.
An additional advantage is provided because of the coupling of the chamber doctor blade with the linear bearing of the screen roller. It is advantageous, in connection with a hydraulic engagement of the doctor blade system, in contrast to a pneumatic engagement, that the hydraulic pressure column is not compressible. However, it is disadvantageous with this embodiment, that a rapid disengagement of the doctor blade chamber from the screen roller is not possible in the case of a required position change of the screen roller, for example because of a paper rip. By use of the coupling with the linear carriage of the screen roller, which is provided in accordance with the present invention, this disadvantage is avoided.
In accordance with further embodiments of the present invention, it is possible to print at variable section lengths, from which a particularly efficient possibility for operating the flexographic printing press results.
In accordance with a further aspect of the present invention, it is contemplated to clear the surface of a screen roller, by suction, prior to the entry of the screen roller into the chamber doctor blade. Because of this, the print quality, in particular, of the press can be improved and dirt accumulation can be reduced.
In accordance with a further aspect of the present invention, the possibility is provided of making the imprinting of paper webs of different widths possible in a simple manner.
Preferred embodiments of the present invention are represented in the drawings and will be described in greater detail in what follows.
Shown are in:
Referring initially to
Each satellite printing unit 03 comprises a central cylinder 05, namely the satellite cylinder 05, which is used as a counter-pressure cylinder 05, as well as several, and preferably at least four, and in the case of the preferred embodiment, exactly four, printing groups 04, each of which printing groups 04 is arranged on the satellite cylinder 05. Each such printing group 04 is configured for letterpress printing, and in particular for flexographic printing. The general construction and the mode of functioning of flexographic printing groups 04 is generally known in the art, so that it is not necessary to address this construction and mode of operation here in detail. Therefore, for the sake of clarity, in the very schematic representation, in accordance with
The embodiment of the present invention, in accordance with
The flexographic printing press is, for example, configured for newspaper printing. Viewed in the axial direction of the cylinders 05, 06, 07, the width of the press is such that the forme cylinders 06 have at least two, and preferably have four, newspaper pages in the axial direction as the print image 29. Preferably, the diameter of the forme cylinders 06 has been selected in such a way that the forme cylinders 06 have four newspaper pages as the print image 29 in the circumferential direction. The barrel of the forme cylinder 06 can, in particular, have a circumference of 1,100 mm to 1,300 mm, and a length of 1,400 mm to 1,800 mm.
In the axial direction, the forme cylinders 06 each preferably support four flexographic printing plates, which are not specifically represented here side-by-side, and two flexographic printing plates one behind the other in the circumferential direction.
Preferably, the diameter of the satellite cylinder 05 is a whole number multiple, and in particular is three times, the diameter of the associated forme cylinders 06. However, it can also be advantageous to dimension the satellite cylinder 05 such that its diameter is, in particular 2.5, times the diameter of the associated forme cylinder 06. In accordance with a further aspect of the present invention, it is advantageous to dimension the circumference of the satellite cylinder 05 such, that it corresponds to a whole number multiple of the section length of a printed product which is printed or manufactured by the use of the flexographic printing press.
The forme cylinder 06, the screen roller 07 and the chamber doctor blade 08 of each one of the printing groups 04 are respectively arranged in such a way that they can be placed against the satellite cylinder 05 and can be moved away, and out of contact with the satellite cylinder 05. For this purpose, the forme cylinders 06, the screen rollers 07 and the chamber doctor blades 08 are seated in bearing units 14, as are depicted schematically in
All of the cylinders 05, 06, 07, or in other words, the satellite cylinder 05, the forme cylinders 06 and the screen rollers 07, in particular, are each driven by their own drive motors 121, which are not specifically represented in
In the discussion which follows, and making specific reference to
Viewed in the actuating direction S, as seen in
The connection of the cylinder 06, 07, or of the bearing block 74 on the drive side of the printing tower 01, to a drive mechanism, such as, for example, to a drive motor 121, takes place, as shown, by way of example in
As represented in
On a side of the printing press, which is opposite the drive side of the cylinder 06, 07, in particular opposite to the drive side of the cylinder 06, which is embodied as a forme cylinder 06, the journal 64 is preferably connected with an arrangement for accomplishing the axial movement of the cylinder 06, such as, for example, with a lateral register drive mechanism, which is not specifically represented. For this purpose, the shaft 78, which may be connected with the journal 63, 64 in the way shown in
The embodiment of the linear bearings 70 in such a way that the bearing elements 72, 73, which work together, are both provided at the component bearing unit 14, and not as one part at the lateral frame 11, 12 of the printing tower 01, or of the printing unit 03, makes possible a pre-assembly and a pre-adjustment or setting of the bearing tension. The advantageous arrangement of the two linear bearings 70 enclosing the bearing block 74 makes possible a setting free of play. This is because the two linear bearings 70 are placed opposite each other in such a way that the initial bearing tension and the bearing forces undergo, or absorb, a substantial component in a direction which is perpendicular to the axis of rotation of the cylinder 06, 07. Therefore, the linear bearings 70 can be adjusted in that direction, perpendicular to the axis of cylinder rotation, which adjustment is important for the setting, free of play, of the cylinders 06, 07.
Since the cylinder 06, 07, including the journals 63, 64 and the bearing unit 14, do not themselves penetrate the lateral frame 11, 12, they, already pre-assembled, as well as the pre-adjusted or correctly initially tensioned bearings, including the radial bearing 71, as well as the linear bearing 70 can be inserted, in the form of a module, as cylinder unit 80 into the printing unit 01. With respect to “non-penetration”, and to the above definition, in regard to the clearance, it should be advantageously understood in the wider sense that there is such a “non-penetration”, at least in the area of the intended final position of the cylinders 06, 07, and at least on a continuous path from a frame edge to the location of the final position. The cylinder unit 80, as depicted in
The bearing units 14 are arranged on the inner walls of the lateral frames 11, 12 in such a way that the cylinders 06, 07, and in particular their bearing units 14, are supported, on the side of the bearing units remote from the cylinders, by the lateral frame 11, 12, an arrangement which has static and assembly advantages.
The linear bearings 70, including the bearing units 72, 73 represented in
If, as can be seen in
The inclined effective or guide surfaces 72.1, 73.1, 72.2, 73.2 are arranged in such a way that they counteract a relative movement of the bearing elements of the linear bearing 70 in the axial direction of the cylinder 06, 07. In other words, the linear bearing 70 is “set” in the axial direction.
Advantageously, the linear bearings 70 of both of the bearing units 14, which are assigned to the front of a cylinder 06, 07, have two pairs of cooperating effective surfaces or guide surfaces 72.1, 73.1, 72.2, 73.2 which are arranged in this way with regard to each other. However, in this case, at least one of the two radial bearings 71 of the two bearing units 14 advantageously has a slight bearing play, Δ71, in the axial direction of the cylinders 06, 07.
In
Mounting aids 89, such as, for example, set pins 89, can be provided in the lateral frame 11, 12 and can be used to aid in the correct placement of the bearing units 14, or of the cylinder units 80, including the bearing unit 14, on which mounting aids 89 the bearing unit 14 of the completely assembled cylinder unit 80 is aligned prior to being connected with the lateral frame 11, 12 by releasable retaining elements means 91, such as, for example, screws 91, or even by material-to-material contact by welding. Appropriate elements 92, such as, for example clamping screws 92, can be provided, as may be seen in
The cylinder 06, 07 with journals 63, 64 and with a preassembled bearing unit 14 is schematically represented in
The structural unit, or bearing unit 14 which can be mounted as a whole, is advantageously located in the manner of a housing, possibly open in part, of, for example, the support 78 and/or for example, is provided as a frame, without a reference symbol in
The bearing elements 72, which are fixed to the frame, are arranged substantially parallel to each other and define the actuating direction S, as is depicted in
Placement of the cylinder 06 and/or of the roller 07 into the print-on position takes place by movement of the bearing block 74 in the direction of the print location by the application of a force F that is exerted by at least one actuator 82 on the bearing block 74. In particular the force F can be applied by the use of a force-controlled actuator 82 or of one defined by a force, by the use of which, a defined, or a definable, force F can be applied, in the print-on direction, on the bearing block 74, as depicted in
At a side of the bearing unit 14, which is facing the print location, the bearing unit 14 has an element 79, such as, for example, a detent 79, whose location can be changed and which acts to delimit the actuating path toward the print position. The position of the detent 79 can be changed in such a way that a detent face 83, which acts as the detent, can be varied along the actuating direction S at least in an area. Thus, in an advantageous embodiment of the present invention, an adjusting device or adjustable detent 79 is provided, by the use of which the location of an end position of the bearing block 74 close to the print position can be set. A key-type drive mechanism, which will be described below, is used for the path limitation/adjustment. In principle, setting of the detent 79 can take place manually or by the use of an adjusting assembly 84, which is embodied as an actuator 84, as discussed below) Moreover, in an advantageous embodiment, a holding or clamping assembly, which is not specifically represented in
In an ideal case, the exerted force F, the restoring force FR, and the position of the detent 79 are selected in such a way that, in the contact position, no substantial force ΔF is transmitted between the detent 79 and the detent face of the bearing block 74, so that for example the following applies: |ΔF|<0.1*(F−FR), in particular |ΔF|<0.05*(F−FR), ideally |ΔF≈0. In this case, the contact force between the cylinders 06, 07 is essentially determined by the force F which is exerted by the actuator 82. The line force in the nip locations which is, inter alia, decisive for ink transfer, and therefore for print quality, is therefore not defined primarily by an actuating path but, with a quasi-free detent 79, is defined by the force F and the resulting equilibrium. In principle, after finding the base setting, with the forces F suitable therefor, a removal of the detent 79, or of a corresponding fixation in place, which is only active during base setting, would be conceivable.
In principle, the actuator 82 can be embodied as any arbitrary actuator 82 which is capable of exerting a defined force F. The actuator 82 is advantageously configured as an actuating assembly 82 which can be operated by a pressure source, and in particular which is configured as a piston 82 that is movable by the use of a fluid. In view of possible twisting, the arrangement of several, and as depicted in
For placement of the cylinders 06, 07 into the print-on position, the bearing unit 14, which can be mounted in one piece, has two actuators 82, which can be simultaneously actuated, which act in the same direction and whose force attack points on the bearing block 74 are spaced apart from each other in a direction which is perpendicular to the cylinder axis.
A controllable valve 93 is provided for use in operating the actuators 82, which are here configured as hydraulic pistons 82, in the bearing unit 14. For example, valve 93 is configured to be electronically triggerable and, in one position, relieves the pressure from a hydraulic piston, or at least places that pressure on a lower pressure level, while in the other position of the valve 93, the pressure P, which causes the force F, is applied. In addition, a leak line, not specifically depicted here, is provided for safety.
To avoid too large contact/out-of-contact paths, but to still prevent tangled webs, it is possible to provide a path limitation on the side of the bearing block 74, remote from the print location, by the provision of a detent 88, whose location can be changed and whose force can be limited. Detent 88 can act as an overload safety device, and can be configured, for example, as a spring element 88 which detent 88, in the operational print-off position, in which print-off position the pistons 82 do not exert pressure and/or have been retracted, is used as a detent 88 for the bearing block 74 in the print-off position. In case of an entangled web or other excess forces exerted from the direction of the print position, detent 88 does yield and releases a larger path of travel of the bearing block 74. Therefore, a spring force of this overload safety device or detent 88 has been selected to be greater than the sum of the spring forces from the spring elements 81. Therefore, a very short actuating path, of, for example, only 1 to 3 mm, can be provided for making operational contact/out-of-contact.
In the represented embodiment, as shown in
The detent 79, here configured as a key 79, can be moved by the use of an actuator 84, such as, for example, by the use of an actuating assembly 84, which can be actuated by a pressure-medium, such as a piston 84 which can be actuated by means of a pressure-medium in a work cylinder with a double-acting piston, via a transmission member 85, configured as a piston rod 85, or by an electric motor via a transmission member 85 which could be embodied as a threaded spindle. This actuator 84 can either be active in both directions or, as represented in
In principle, the detent 79 can also be configured in another way, such as, for example, as a tappet, which can be adjusted and fixed in place with respect to the actuating direction S such that it forms a detent face 83, which can be varied in the actuating direction S and which can be fixed in place, at least during the adjusting process, for the movement of the bearing block 74 in the direction of the print location. In an embodiment of the present invention, which is not specifically represented, setting of the detent 79 takes place, for example, directly parallel with the actuating direction S by a drive element, such as, for example, by a cylinder which can be operated by a pressure medium and which has a double-acting piston, or by an electric motor.
In the discussion which follows, and by making reference to
The motor 121, which may be embodied either as a synchronous motor 121 or as an excited permanent motor 121, preferably has permanent magnet excitation. In other words it is configured to be excited by a permanent magnet. The rotor 266, or armature 266, of the synchronous motor 121 has poles which are constituted by permanent magnets 267. For example, motor 121 has a constant zero-speed moment in the range between 100 Nm and 200 Nm. The synchronous motor 121 advantageously has a maximal torque in the range between 600 and 800 Nm and, in particular has a maximum torque of approximately 700 Nm. The permanent magnets 267 preferably contain rare earth materials.
The motor 121, which may be embodied as a synchronous motor 121 or as a permanently excited motor 121, has, for example, a theoretical idling speed in the range between 500 U/min and 600 U/min.
To accomplish rpm regulation, for example, a frequency converter may be connected upstream of the motor 121, which may be embodied as a synchronous motor 121 or as a permanently excited motor 121.
An angle of rotation sensor 274 is preferably provided on the motor 121, which motor 121 is embodied as a synchronous motor 121 or as a permanently excited motor 121. Note
A cooling arrangement, and in particular a ventilator wheel or a liquid coolant circuit, is advantageously provided on the motor 121, which motor 121 is embodied as a synchronous motor 121 and/or as a permanently excited motor 121.
In addition, a braking device can be provided on the motor 121, which motor 121 is embodied as a synchronous motor 121 or as a permanently excited motor 121. However, during generator operation the motor 121 can also be employed as a braking device.
An axis of rotation of an angle of rotation sensor 274 can be arranged coaxially to the axis of rotation of the rotor 266 of the motor 121.
The stator 269 of the electric motor 121 has windings 268 for use in generating magnetic fields by the application of electrical energy.
In an advantageous variation of the present invention, the drive motor 121 is embodied for being rotatorily driven as an exterior rotor motor, particularly also one with permanent magnets 267 at the rotor 266, which is now located on the exterior, as seen in
Reference is now again made to
Each forme cylinder 06 can be placed, finely adjustable, by the use of its linear bearing 15, against the assigned satellite cylinder 05. Each screen roller 07 can be placed, finely adjustable, by the use of its linear bearing 15, against the assigned forme cylinder 06. Each chamber doctor blade 08 can be placed, finely adjustable, by the use of its linear bearing 15, against the assigned screen roller 07, all of which cylinder and roller placements preferably being pressure-regulated.
The arrangement of the forme cylinders 06 at the circumference of the respective satellite cylinder 05, as seen in
As in the case of the preferred embodiment depicted in accordance with
The screen rollers 07 are arranged, with respect to the respective forme cylinders 06, in such a way that the axis of rotation of a screen roller 07, the axis of rotation of the assigned forme cylinder 06 and the axis of rotation of the assigned satellite cylinder 05 are all located on a common straight line. Based on the selected positions of the cylinders 05, 06 in relation to each other, there is achieved by this orientation that, when the forme cylinder 06 is placed against the satellite cylinder 05, the screen roller 07 can be synchronously displaced with the same displacement value as the forme cylinder 06. A pressure pre-tension which may be set between the screen roller 07 and the forme cylinder 06 thus does not change.
Furthermore, the chamber doctor blade 08, which is seated on the linear bearing 15, that is, in turn, coordinated to the linear bearings of the screen roller 07 and which is placed, in a pressure-regulated manner, against the assigned screen roller 07, is coupled with the linear bearing 15 of the screen roller 07 in such a way that the chamber doctor blade 08 is forced to follow every positional change of the screen roller 07 without a change in the print-on position. In principle, such a function can also be resolved by the use of control technology. However, the mechanical solution, as will be explained by reference now to
An actuator 19 which, in particular, can be operated by a pressure medium and which actuator 19, in the case of the preferred embodiment, can comprise a force-controlled cylinder-piston arrangement 19, acts between the chamber doctor blade 08, or between the carriage 74 of the linear bearing 15 of the chamber doctor blade 08 and the carriage 74 of the linear bearing 15 of the screen roller 07. For this purpose, a cylinder 21, which can be supplied with a working fluid, is connected with the chamber doctor blade 08, or its carriage 74. A piston 22, which is displaceably guided in the cylinder 21, is connected, by its piston rod 23, with the carriage 74 of the linear bearing 15 of the screen roller 07. The chamber doctor blade 08 is pre-stressed into its disengaged position by the provision of a restoring spring 24 that is arranged in the cylinder 21, as may be seen in
In a representation of a preferred embodiment of the present invention and corresponding to that depicted in
It should be pointed out that the principle of operation of the above-explained solution for the coupling between the screen roller 07 and the chamber doctor blade 08, as well as the principle which is represented in connection with
The basic adjustment, or the zero adjustment, of the linear bearings 15 will be explained in the discussion which now follows. To adjust a linear bearing 15, the forme cylinder 06 is preferably used without printing plates 27, or is covered with printing plates 27, such as, for example, flexographic printing plates 27 of a defined thickness. The detent key 79 of the linear bearing 70 is retracted, and the linear bearing 70 is placed, for example hydraulically, against suitable detents, such as the shell face of the counter-pressure cylinder or the satellite cylinder 05, or is placed against measuring rings or detents which are fixed in place on the frame. In this zero position, the detent key 79 is retracted and an acknowledgement of the position of the detent key 79 and/or of its assigned drive mechanism, such as an electric motor 121 is preferably provided to a control device. The detent key 79 is retracted, again by a predefined distance, from this zero position of the detent key 79, and therefore from the zero position of the forme cylinder 06 and/or of the screen roller 07, by the use of which retraction, the contact pressure, for bringing the cylinder 06 or the screen roller 07 into contact, is fixed.
In particular, the zero adjustment of the linear bearings 15 can take place as will now be discussed in what follows. See also, in connection with this discussion, the depictions of
For placement of the forme cylinder 06 against the satellite cylinder 05, the detent key 79 of the linear bearing 15 of the forme cylinder 06 is initially extended until the potentiometer 32 at the actuating motor 33 has reached the maximum value. Thereafter, the forme cylinder 06 is shifted in the direction of the satellite cylinder 05 by use of the hydraulic pistons 82, as is depicted in
This state of positioning is shown in
In the next step, in accordance with the present invention, the hydraulic pistons 82, as may be seen in
Subsequently, the detent key 79 is displaced, by operation of the actuating motor 33, over a predetermined length “x” into the gap, in order to pull the forme cylinder 06 away from the satellite cylinder 05 sufficiently far so that the gap size, which is required for printing, has been achieved. As a rule, in that case, the print image 29 then rests, under a slight prestress, against the paper which is to be printed. The position of the detent key 79 is always indicated by the utilization of the potentiometer 32 that is positioned at the actuating motor 33. Process-related changes in the gap can be realized by adjustment of the detent key 79, in the course of which changes the pressure-charged hydraulic pistons 82 always dependably clamp the carriage 74 of the linear bearing 70 against the detent key 79, as depicted in
In the next step of the operation, in accordance with the present invention, and with the detent key 79 fully extended, the screen roller 07 is displaced toward the forme cylinder 06 until the measuring rings 31, which are arranged at the front or end faces of the forme cylinder 06, rest against the shell face of the screen roller 07. In this case, the forme cylinder groove 34 must point toward the screen roller center. In the next step, the hydraulic pistons 82 of the linear bearing 70 of the screen roller 07 are charged with a maximum pressure pmax, and subsequently the detent key 79 is moved into the gap by operation of the actuating motor 33. The end position of the detent key 79 is indicated by the maximum electric current consumption of the actuating motor 33. The actuating motor 33 is switched off and the pressure being exerted on the hydraulic pistons 82 is adjusted to a lower pressure p1. The detent key 79 is subsequently displaced into the gap by operation of the actuating motor 33 for a predetermined length “y” in order to move the forme cylinder 06 away from the screen roller 07 far enough that the gap size, which is required for printing, has been reached.
The upper detailed view depicted in
Reference is now again made to
In connection with the placement of the forme cylinder 06 against the satellite cylinder 05, it is also advantageous with such an arrangement, as depicted in
In connection with a placement of the forme cylinder 06 against the satellite cylinder 05, the screen roller 07 can now be displaced synchronously by the same placement amount as the forme cylinder 06 because of the selected position of the cylinders 05, 06, 07 in respect to each other. The result is that the pressure prestress, which exists between the screen roller 07 and the forme cylinder 06, does not change.
Differing from the preferred embodiment of the present invention, which is depicted in accordance with
In accordance with a further embodiment of the present invention, a flexographic printing unit 03, such as, for example, a satellite printing unit 03 with at least eight forme cylinders 06, is provided, as seen in
With a printing unit 03 of the configuration represented in
Accordingly, the placement of the screen roller 07 takes place selectively, or alternatively, between the one and the other detent 79. A center position of the screen roller 07, in which it is in contact with neither of the two forme cylinders 06, is achieved, for example, in that the one detent key 79 is completely moved into the gap assigned to it, while simultaneously the oppositely located hydraulic piston 82 as depicted in
In this case, the arrangement can in particular, be such that the hydraulic pistons 82 are mechanically connected, on both sides, with the carriage 74 of the linear bearing 70 of the screen roller 07. The rear of the hydraulic elements is configured as an inclined plane and, together with the associated detent key 79, forms an inclined plane.
In addition to the embodiment explained above, by reference to
As depicted in
Moreover, every forme cylinder 06 is seated in a linear bearing 15, again, not specifically represented here and can be precisely placed against the satellite cylinder 05. Each screen roller 07 is also seated in a linear bearing 15, also not specifically represented here, and can be precisely placed against the forme cylinder 06. Furthermore, each chamber doctor blade 08 is seated in a linear bearing 15 and can be placed, in a pressure-regulated manner, against its associated screen roller 07. Each chamber doctor blade 08 is mechanically coupled with the linear bearing 15 of the associated screen roller 07 in such a way that it is forced to follow every position change of the screen roller 05 without a change in the print-on position. Reference is made, with regard to the respective details, to the previous description in connection with other preferred embodiments.
The screen roller 07 of each printing group 04 is arranged in such a way that the axes of rotation of the screen roller 07, the forme cylinder 06 and the satellite cylinder 05 are located on a common straight line. Based on the selected position of the cylinders 05, 06, 07 in relation to each other, it is possible, in the course of an advancement of the forme cylinder 06 toward the satellite cylinder 05, to displace the screen roller 07 synchronously with the same advancement amount as is imparted to the forme cylinder 06. The result is that the pressure pre-tension between the screen roller 07 and the forme cylinder 06 does not change.
Each forme cylinder 06 has, distributed in its circumferential direction, at least one printing section 27a, 27b, or 27c, 27d, and at least one non-printing section 30, all as is depicted schematically in
Viewed in the circumferential direction of the forme cylinders 06, the printing sections 27a, 27b, or 27c, 27d, or the printing plates 27a, 27b, or 27c, 27d, preferably are each of the same length and are distributed, preferably equidistantly, over the circumference of the forme cylinder 06.
It is possible to produce printed products with variable printing cylinder circumference lengths by the use of a printing unit 03 with the above-described configuration. This is achieved in that the print image 29 to be imprinted is distributed in equal parts on two printing plates 27a, 27b, or 27c, 27d, which are assigned to different forme cylinders 06.1, or 06.2, wherein the greatest length of the print image 29 may maximally amount to the circumference of a forme cylinder 06, less twice the width of the white edges, less an area for slowing or accelerating the forme cylinder 06.
The printing plate 27a of the first forme cylinder 06.1 deposits the first partial print image 37A on the paper web 02 which is being conducted over the satellite cylinder 05. The printing plate 27c of the second forme cylinder 06.2 subsequently deposits the second partial print image 37C on the paper web 02, maintaining the correct registration and color congruence. In the same way, the printing plate 27b of the first forme cylinder 06.1 deposits the first partial print image 37B on the paper web 02, and thereafter the printing plate 27d deposits the partial image 37D on the paper web 02. The imprinted partial images 37A and 37C, as well as the imprinted partial images 37B and 37D each constitute a section length.
To compensate for the difference between the cylinder circumference of the forme cylinder 06 and the print length, the forme cylinder 06 is slowed, by the use of drive techniques, and is thereafter again accelerated to the production rpm, which is accomplished, in particular, with the aid of the drive motors 121, or the synchronous motors 121, as explained with reference to
It is advantageous in this context, in connection with letterpress printing, that the printing sections 27a, 27b, 27c, 27d are raised, and that the non-printing section 30 are located lower than the printing sections. The slow-down and acceleration process of the forme cylinders 06 takes place in the area in which the non-printing sections 30 rotate past the satellite cylinder 05 and the screen roller 07. In connection with the configuration, in which the screen roller 07, the forme cylinder 06 and the satellite cylinder 05 are located on a straight line, it is advantageous if, in its acceleration phase, the forme cylinder 06 is not in contact with either the paper web 02 or the screen roller 07, and in the course of the printing process, the one printing plate 27 is inked via the screen roller 07, while the other printing plate 27 is positioned to be printing. It also follows from this, that the circumferential speed of the screen roller 07 and of the satellite cylinder 05 are equal and are “constant”, and that only the forme cylinder 06 must be cyclically accelerated and slowed.
The production of three and more printed products of lesser section length can be realized in the same way. The printing plate 27a or the printing plate 27b now contains a whole partial image, as well as half of the second partial image. The printing plate 27c or the printing plate 27d now contains the second half of the second partial image, as well as an entire third of the whole third partial image.
By the use of a printing unit 03 which is configured as explained above, it is also possible to produce printed products having variable section length, provided that the longest product is shorter than half the cylinder circumference, less the white edge, as well as an area which is of such dimensions that the forme cylinder 06 can again be accelerated into its correct angular position in relation to the printed product.
As explained above, the embodiments of the present invention, in accordance with
The above described possibility of a variable section length also offers the user an economically attractive option of printing a second format without the cutting which is otherwise unavoidable in connection with the same format. The omission of the otherwise arising costs of cutting, including the costs of paper and cutting equipment, can result in an advantageous amortization of the described solution. A second printing press, for use in printing the second format, can possibly be completely omitted, and the printing press that is suitable for two formats can furthermore be operated at particularly high capacity. Because of this, the efficiency of the solution in accordance with the invention is optimized.
In order to be able to match the length of the print sections to a length of a fold section of a folding apparatus 123, which is typically arranged downstream of the printing unit 03, or downstream of the printing tower 01, it is advantageously possible to provide that the section length of the folding apparatus 123 can be changed, because of which a highly efficient production of printed products becomes possible. Examples of a suitable folding apparatus 123, with variable fold section length, such as a folding apparatus 123 which can be placed indirectly or directly downstream of the printing units 03 or of the printing towers 01, will be explained in what follows by means of
An embodiment of a variable folding apparatus 123 with a field system 7:7 is represented in
Electric motors 131, and in particular servo motors 131, which can be controlled independently of other drive arrangements, are provided for driving the various functional elements of the folding apparatus 123. The cylinder portion and the delivery portion of the folding apparatus 123 can be driven independently of each other. Preferably, the cylinder 128 has folding blade systems arranged on fitting supports and also has holding systems, such as, for example, gripper systems or spur needle systems.
Spacing between the holding system and the folding blades of the folding blade cylinder 128, as a function of the diameter of the forme cylinder 06, can be adjusted remotely and can be controlled by a control arrangement.
In accordance with a further advantageous aspect of the present invention, a suction arrangement is assigned to the screen roller 07 of a web-fed rotary printing press, such as, for example, a flexographic printing press.
In connection with the construction of chamber doctor blades, it is necessary, inter alia, to insure that air, which has been introduced into the chamber doctor blade via the emptied small cups of the screen roller, can escape again from the chamber doctor blade, or can be forcibly removed from it. The air, which may be introduced into the chamber doctor blade, forms air cushions under overpressure. These lead to the lift-off of the chamber doctor blade, which has been placed into contact with the screen roller, with a regulated force, from the screen roller. Because of this, a thin ink film is created on the screen roller surface, which, in turn, leads to increasing density values in the printed product.
For example, the ink is pumped into the chamber doctor blade, and the ink is subsequently suctioned off, together with any air which may have been introduced into the chamber doctor blade, via a second pump, which second pump, as a rule, is a compressed air-driven diaphragm pump. The amount of the suctioned-off ink and air mixture is typically twice as large as the pumped-in amount of ink. In order to prevent underpressure, the chamber doctor blade is connected by bores with the air which is introduced into it. It is disadvantageous, in connection with this embodiment, that paper dust particles, which may be torn off the paper web after contact with the printing plate, as well as other particles of dirt, are again conveyed into the chamber doctor blade by the screen roller. These are then mixed with the printing ink in the chamber doctor blade, and are not forcible removed by the suction system. Also, ink which, although it had been pulled out of the small cups of the screen roller during contact with the printing plate, had not been applied to the paper web but was instead conveyed back on the surface of the screen roller, is stripped off by the end doctor blade of the chamber doctor blade and drips off the end doctor blade. This leads to dirt accumulation in the doctor blade system.
It is now proposed, in accordance with the present invention, to suction off the surface of the screen roller 07 prior to the surface of the screen roller 07 entering an inking arrangement which is assigned to the screen roller 07, such as, for example, a chamber doctor blade 08.
By the provision of this screen roller suction, the disadvantages described in connection with the prior art are avoided. Moreover, because of the aspiration of the air out of the small cups of the screen roller, prior to the contact of the screen roller with fresh ink, the filling of the small cups with fresh ink is improved. Additionally, no air-enriched and soiled ink is passed on to the printing plates 27.
Suctioning of the surface of the screen roller 07 is preferably performed in such a way that the suction arrangement constitutes a closed system together with the chamber doctor blade 08. The small screen roller cups which have now been emptied by suction no longer come into contact with the ambient air.
A preferred embodiment of this aspect of the present invention will be explained in greater detail in what follows, making reference to
The printing unit 03 represented in
The suction arrangement 38 comprises a hood-like housing 39 which is extending over the entire axial length of the screen roller 07, as seen in
At least one aspirating opening 42 has been formed in the housing 39. In the case of the preferred embodiment, a single aspirating opening 42 is provided in one of the lateral walls 41, which single aspirating opening 42 is defined by a connecting sleeve 43. This connecting sleeve 43 preferably extends in the axial direction of the screen roller 07, and is usable for connecting a hose or a pipe, which is not specifically represented, for aspirating the mixture of air and ink in the housing 39. The suctioned-off mixture is supplied to an ink tank 44, which is provided with a downstream-connected filter circuit 45, such as, for example, a filter arrangement 45, and the cleaned ink is returned to the printing process. The aspirating opening is preferably oriented axis-parallel with the screen roller 07.
While preferred embodiments of a flexographic printing press, in accordance with the present invention, have been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that various changes in, for example, the supply of the paper webs, the arrangement of the superstructure, and the like could be made without departing from the true spirit and scope of the present invention which is accordingly to be limited only by the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
10 2005 028 424.8 | Jun 2005 | DE | national |
10 2005 032 120.8 | Jul 2005 | DE | national |
10 2005 039 074.9 | Aug 2005 | DE | national |
10 2006 003 013.3 | Jan 2006 | DE | national |
This application is the U.S. national phase, under 35 USC 371, of PCT/EP2006/063027, filed Jun. 8, 2006; published as WO 2006/134070 A2 and A3 on Dec. 21, 2006 and claiming priority to DE 10 2005 028 424.8, filed Jun. 17, 2005; to DE 10 2005 032 120.8, filed Jul. 7, 2005; to DE 10 2005 039 074.9, filed Aug. 18, 2005 and to DE 10 2006 003 013.3, filed Jan. 23, 2006, the disclosures of which are expressly incorporated herein by reference.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2006/063027 | 6/8/2006 | WO | 00 | 11/15/2007 |