HK1089728A - Method for driving a satellite offset press and satellite offset press - Google Patents

Description

Method for driving satellite offset printing press and satellite offset printing press

Technical Field

The invention relates to a method for driving a satellite offset printing press and a satellite offset printing press.

Background

From DE 10259496 a1, an offset printing press for multicolor printing on a printing material is known, in which the impression cylinder, the transfer cylinder and the forme cylinder each have at least three segments of identical length in the circumferential direction, wherein the number of segments on the transfer cylinder corresponds to the number of segments on the impression cylinder plus an integer multiple of one segment. All of the rollers may be conventionally driven by a gear transmission. And each roller or group of rollers may be provided with a separate drive. In each case, the drive of the drum is effected in such a way that the segments roll on one another in register (pa β genau). In four-color printing, therefore, a printing press structure with a bulky cylinder is obtained, which is expensive in terms of material and cost.

Disclosure of Invention

The aim of the invention is to develop a satellite offset printing press and a method for operating the same, which enable multicolor printing to be achieved in one process at low cost.

According to the invention, a method for driving a satellite offset printing press is proposed, in which method a forme cylinder is driven synchronously with the associated transfer cylinder, wherein sectors of the forme cylinder and of the transfer cylinder lying in the circumferential direction are rolled in register with one another, and sectors of the transfer cylinder and of an impression cylinder cooperating with these transfer cylinders and having a sheet gripped thereon lie in register with one another, wherein: after each complete revolution, the speed of the impression cylinders is reduced and increased again so that the transfer cylinders are advanced at least over the length of a sector in the circumferential direction.

According to the invention, a satellite offset printing press is also proposed, having: an impression cylinder which interacts with at least two satellite printing units for printing on the sheets, wherein each printing unit comprises at least one transfer cylinder and a plate cylinder having an inking unit, wherein the impression cylinder, the transfer cylinder and the plate cylinder have segments of the same length in the circumferential direction; a device for feeding the sheet to the impression cylinder and for discharging the sheet; and at least one drive for the rollers; wherein: the transfer cylinder and the plate cylinder can be driven synchronously and the drive of the impression cylinder can be controlled independently of the drive of the transfer cylinder and of the plate cylinder, wherein the speed of the impression cylinder can be varied during one revolution of the transfer cylinder.

The task of the invention is solved by the technical scheme. Advantageous configurations result from the following solution.

Advantageously, the speed of the impression cylinder is reduced and raised again when the passages between the sectors of the transfer cylinder are located opposite the impression cylinder.

Advantageously, the axes of the impression cylinder and of the associated transfer cylinder lie parallel in a horizontal plane.

Advantageously, the axes of the plate cylinder and of the transfer cylinder of the printing unit each lie parallel in a plane, wherein the planes are substantially perpendicular to the horizontal plane.

Advantageously, the plate cylinder and the transfer cylinder can be jointly driven by one motor.

Advantageously, the plate cylinder, the transfer cylinder and the impression cylinder each have two segments of the same length.

According to the invention, the central impression cylinder is provided with a separate drive and is braked and accelerated during a revolution in such a way that the transfer cylinder, which is driven synchronously with the plate cylinder, is advanced by a sector length in the circumferential direction.

In a special geometric configuration of a double-sized transfer cylinder relative to a double-sized forme cylinder, the width of each channel in the impression cylinder in the circumferential direction is configured such that the rotational speed of the impression cylinder is reduced by means of a servo drive when the channel passes by the transfer cylinder in such a way that the transfer cylinder and the forme cylinder can be rotated further over a pressure surface during the process time. The impression cylinder is accelerated to the peripheral speed of the transfer cylinder at the beginning of the printing of the next pressure side of the transfer cylinder.

Drawings

The invention will now be described in detail by way of examples, which show:

figure 1 is a schematic view of a satellite offset printing press,

FIGS. 2.1 to 2.15 are phase diagrams of the satellite offset printing press according to FIG. 1, shown in steps of 90 DEG, and

FIG. 3 is a graph of the velocity of the impression cylinder versus the machine angle.

Detailed Description

Fig. 1 shows a schematic representation of a satellite offset printing press with an impression cylinder 1, two transfer cylinders 2, 3 and two plate cylinders 4, 5. The cylinders 1-5 are rotatable in the direction of the arrow 6, wherein the axes of rotation of the impression cylinder 1 and the transfer cylinders 2, 3 lie parallel in a horizontal plane h and the axes of rotation of the plate cylinders 4, 5 and the transfer cylinders 2, 3 each lie in a vertical plane v. Each of the rollers 1-5 has two segments A-J each having a pressure surface of the same length in the circumferential direction. Between the segments A-J, the rollers 1-5 have channels 7. In the channel 7 of the impression cylinder 1, a gripper system 8 for gripping a sheet 9 is provided. In the channel 7 of the transfer cylinders 2, 3, there are holding and clamping devices 10 for elastic inserts 11 on the individual segments a to D. The printing films 12 are tensioned onto the segments G to J of the forme cylinders 4, 5, each printing film being stored on an unwinding roller 13 and tensioned by a winding reel 14. During printing, the wrappings 11 come into rolling contact with the sheets 9 gripped on the segments E, F. And contact is also made between the printed film 12 and the corresponding envelope 11. The plate cylinders 4, 5 are assigned inking unit rollers 15, in which inking rollers 16 can be pressed onto and off from the printing foil 12. Each plate cylinder 4, 5 is also assigned an imaging device 17 which comprises laser diode arrays by means of which image dots which receive printing ink can be produced on the printing foil 12.

The satellite offset printing press also comprises a feeder 18 for separating the sheet 9 from a stack 19 and feeding the sheet 9 into the gripper system 8. In detail, the feeder 18 includes a suction head 20, a feeder table 21 having a belt conveying system, an oscillating gripper 22, and a conveying cylinder 23.

The satellite offset printing press also comprises a delivery 24 with a chain gripper system 27 guided by guide wheels 25, 26 for feeding the sheet 9 from the gripper system 8 to a pile 28. A dryer 29 is arranged in the transport path of the sheet 9.

For driving the satellite offset printing press, two electric motors 30, 31 are provided, which are connected to a control device 32. The electric motor 30 is connected via a transmission 33 to a gear train which drives the transfer cylinders 2, 3, the forme cylinders 4, 5 and the inking unit rollers 15, 16. The electric motor 31 is connected via a transmission 34 to a gear train for driving the impression cylinder 1, the transport cylinder 23 and the guide wheel 25. The rotational positions of the transfer cylinders 2, 3 and the plate cylinders 4, 5 are detected by a single rotational amount sensor 35. The rotational position of the impression cylinder 1 is obtained by a rotation amount sensor 36. These rotation amount sensors 35 and 36 are connected to the control device 32.

The operation of the satellite offset printing press will now be explained in more detail with reference to fig. 2.1 to 2.15. Partial images of the primary colors cyan, yellow, magenta and black are produced on the printing film 12 by the image forming device 17. For this purpose, the impression cylinder is moved by the motor 31 and is fixed in the rotational position shown in fig. 1, in which the channel 7 is located opposite the transfer cylinders 2, 3. The plate cylinders 4, 5 are driven by means of a motor 30 for imaging. The imaging rotation speed depends on the characteristics of the printed film 12 and on the power and number of the laser diodes of the laser diode array in the imaging device 17. In image formation, the transfer cylinders 2, 3 and the ink form roller 16 are released from the plate cylinders 4, 5.

During printing, the transfer cylinders 2, 3 are pressed against the plate cylinders 4, 5. The printing film 12 is inked by the inking rollers 16, wherein one inking roller 16 always inks one printing film 12 in such a way that during the rotation of the plate cylinders 4, 5 it periodically presses on the relevant printing film 12 and lifts it again. During printing, the transfer cylinders 2, 3 rotate continuously at a nearly uniform circumferential speed in synchronism with the plate cylinders 4, 5, wherein the ink is transferred from the printing film 12 to the blanket 11.

Fig. 2.1 shows the satellite offset printing press at a machine angle of 0 degrees. The sheet 9 is transferred into the gripper system of the segment E of the impression cylinder 1. The impression cylinder 1 has the same peripheral speed as the adjacent transfer cylinders 2, 3. When the impression cylinder 1, the transfer cylinders 2, 3 and the plate cylinders 4, 5 continue to rotate synchronously, the sheet is printed with black ink. The sectors A, E of the transfer cylinder 2 and impression cylinder 1 are rolled against each other, which is represented at a machine angle of 90 degrees as shown in fig. 2.2. Fig. 2.3 shows that at a machine angle of 180 degrees, a second sheet 9 is transferred into the gripper system 8 of the segment F of the impression cylinder 1. As the impression cylinder 1 continues to rotate synchronously with the adjacent transfer cylinders 2, 3, a second partial image of cyan ink is printed on the sheet 9 on segment E and a first partial image of magenta ink is printed on the sheet on segment F at a machine angle of 270 degrees as shown in fig. 2.4. Once the partial images of cyan and magenta inks have been printed, the impression cylinder is braked and the adjacent transfer cylinder continues to rotate uniformly. The transfer cylinders 2, 3 are then advanced by a pressure surface, as shown in fig. 2.5 to 2.7, over a machine angle of 360 to 540 degrees. At the beginning of printing of the segment B, D of the transfer cylinders 2, 3, the impression cylinder 1 is also accelerated to the uniform rotational speed of the transfer cylinders 2, 3. As shown in fig. 2.8 at a machine angle of 630 degrees, the sheet 9 on segment F then receives a second partial image of cyan ink and the sheet 9 on segment E receives a third partial image of magenta ink. When the impression cylinder 1, the transfer cylinders 2, 3 and the forme cylinders 4, 5 continue to rotate synchronously, as shown in fig. 2.9 and 2.10 at machine angles of 720 degrees and 810 degrees, the page 9 on the segment E is printed with the fourth partial image of yellow ink and the page 9 on the segment F is printed with the third partial image of black ink. When the sheet 9 in the segment E is completely printed, the impression cylinder 1 is braked again after the printing has ended, while the transfer cylinders 2, 3 continue to rotate synchronously with the plate cylinders 4, 5. As shown in fig. 2.11 at a machine angle of 900 degrees, the sheet 9 is transferred to the chain gripper system 27 of the delivery 24. While a sheet 9 that has not yet been printed is fed to the gripper system 8 on the segment E. Thus, two revolutions of the impression cylinder 1 are required for completing one sheet 9. Fig. 2.12 and 2.13 show that the transfer cylinders 2, 3 are rotated over one pressure surface again at machine angles of 990 and 1080 degrees. At a machine angle of 1080 degrees, impression cylinder 1 is accelerated again to the rotational speed of the adjacent transfer cylinders 2, 3, so that a third revolution of impression cylinder 1 is started. Next, the second sheet 9 on the segment F is printed with a fourth image of yellow ink. The third sheet 9 in the segment E receives a first partial image of black ink. This stage is shown at 1170 degrees of machine angle in figure 2.14. When the impression cylinder 1, the transfer cylinders 2, 3 and the forme cylinders 4, 5 continue to rotate synchronously, the second sheet 9 on the segment F is completely printed. As shown in fig. 2.15 at a machine angle of 1260 degrees, the second sheet 9 is transferred to the chain gripper system 27 of the delivery 24, while the next sheet 9 not yet printed is fed to the gripper system 8 on the segment F.

The inking unit of such satellite offset printing presses can be constructed from conventional belt (zonal) ink metering units or as Anilox inking units.

Fig. 3 shows a variation of the rotational speed of the impression cylinder 1. The control device 32 regulates the electric motor 31 in such a way that, in addition to the phase 37 in which the impression cylinder rotates synchronously with the adjacent transfer cylinders 2, 3, there is a braking phase 38 and an acceleration phase 39 of the impression cylinder 1. In order to generate the control signal for the electric motor 31, the signals of the rotation quantity sensors 35, 36 are processed in the control device 32. The control device 32 and the electric motor 31 are designed in such a way that the braking phase 38 and the acceleration phase 39 are completed in a short time.

List of reference numerals

1 impression cylinders 2, 3 transfer cylinders

4. 5 plate cylinder 21 feeder table

6 arrow 22 swing type gripper

7 channel 23 transport cylinder

8 gripper system 24 delivery

Guide wheel for 9 sheets 25, 26

10 fixing and gripping device 27 chain gripper system

11 pile of lining 28

12 printing film 29 dryer

13 unwinding roller 30, 31 motor

14 winding roller 32 control device

15 roller 33, 34 transmission device

16 form rollers 35, 36 rotation amount sensor

17 stage of imaging device 37

18 feeder 38 braking phase

19 pile 39 acceleration phase

20 suction head

Claims (8)

1. Method for driving a satellite offset printing press, in which method a forme cylinder is driven synchronously with the associated transfer cylinder, wherein sectors of the forme cylinder and of the transfer cylinder lying in the circumferential direction are rolled against each other in register, and sectors of the transfer cylinder and of an impression cylinder cooperating with these transfer cylinders, which has a sheet gripped thereon, lying in register, are rolled against each other, characterized in that: after each full revolution, the speed of the impression cylinder (1) is reduced and increased again so that the transfer cylinders (2, 3) are advanced by the length of a sector at least in the circumferential direction (6).

2. A method according to claim 1, characterized in that: when the channels (7) between the segments (A, B, C, D) of the transfer cylinders (2, 3) are located opposite the impression cylinder (1), the speed of the impression cylinder (1) is reduced and raised again.

3. A satellite offset press having: an impression cylinder which interacts with at least two satellite printing units for printing on the sheets, wherein each printing unit comprises at least one transfer cylinder and a plate cylinder having an inking unit, wherein the impression cylinder, the transfer cylinder and the plate cylinder have segments of the same length in the circumferential direction; a device for feeding the sheet to the impression cylinder and for discharging the sheet; and at least one drive for the rollers;

the method is characterized in that:

the transfer cylinders (2, 3) and the plate cylinders (4, 5) can be driven synchronously; and

the drive of the impression cylinder (1) can be controlled independently of the drive of the transfer cylinders (2, 3) and of the plate cylinders (4, 5), wherein the speed of the impression cylinder (1) can be varied during one revolution of the transfer cylinders (2, 3).

4. Satellite offset printing press according to claim 3, characterized in that: the axes of the impression cylinder (1) and of the associated transfer cylinders (2, 3) lie parallel in a horizontal plane (h).

5. Satellite offset printing press according to claim 4, characterized in that: the axes of the forme cylinders (4, 5) and of the transfer cylinders (2, 3) of the printing unit are each situated parallel in a plane (v), wherein the plane (v) is essentially perpendicular to the horizontal plane (h).

6. Satellite offset printing press according to claim 3, characterized in that: the forme cylinders (4, 5) and the transfer cylinders (2, 3) can be jointly driven by a motor (30).

7. Satellite offset printing press according to claim 3, characterized in that: a separate drive (31, 34) is assigned to the impression cylinder (1).

8. Satellite offset printing press according to claim 3, characterized in that: the forme cylinders (4, 5), the transfer cylinders (2, 3) and the impression cylinder (1) each have two segments (A-J) of the same length.