EP2233291B1 - Printing group and method for operating the same - Google Patents

Description

The invention relates to a printing unit, in particular the printing unit of a rotary printing machine, in particular the printing unit of a newspaper printing press, in particular the printing unit of a wet offset printing press. The invention further relates to the method for operating the printing unit according to the invention.

It is known printing units via a central drive to drive the so-called king wave, or to provide each printing unit individually with a drive which drives all the rotational body of the printing unit via corresponding drive wheel trains, or individual cylinders, such as pressure and / or forme cylinder individually to drive ( DE 196 232 24 A1 ). In the latter case, the single drive of the cylinder comprises that via this drive, as a rule, the associated inking and / or dampening units are also driven by drive wheel trains by means of the individual drive of the cylinder. The individual drive of the printing unit is achieved with a position-controlled drive. For this purpose, an angle encoder is mounted on the forme cylinder or the printing cylinder, with which the current position can be determined.

From the DE 10 2005 041 184 A1 It is known to use a frictional connection of cylinders, for example of forme cylinder, dampening roller and driven dampening ductor in order to brake and fix the forme cylinder. The DE 10 2005 041 184 A1 Proposes to use the dampening duct drive for fixing the plate cylinder during adjustment and service work when the drive of the plate cylinder is turned off and therefore can not brake it.

The WO2007 / 099147 A2 describes a printing unit for long narrow cylinders of a printing press, with a printing cylinder, a forme cylinder and an inking unit. The inking unit has two positive cylinders close to the cylinder cylinder, which can be forcibly driven together or individually by a drive motor. The two distribution cylinders are not directly in contact with each other, but both cooperate with at least one transfer roller, which is arranged between the two Reibzylindern in the roller mill of the inking unit. From the DE 197 01 219 A1 a printing unit is known, with an inking unit in which the ink fountain roller is driven with a single drive to adjust the speed of the ink fountain roller to control the coloring. The DE 200 03 767 U1 relates to a printing unit with a driven film roller, the rotational speed and / or direction is independently controlled or regulated.

The ductor roller of an inking unit - hereinafter referred to as "ductor" - usually has its own drive. The speed of rotation of the ductor makes it possible to control the amount of ink which is fed into the inking unit. The ink is first transferred from the ductor to a so-called film roller. An inking unit includes a number of other rollers, such as applicator rollers, distributor rollers or Transfer rollers. These rollers form a so-called roller mill, which transfers the ink film from the film roll to the forme cylinder. At each transition of the color from one roller to the other there is a color separation or color trituration, thereby reducing the viscosity of the ink, or the ink is conditioned in terms of their rheological properties so that between the inking rollers and the forme cylinder can run the offset process, that is, the ink is transferred to the print material in accordance with the image on the printing cylinder via the printing cylinder. The rollers of the inking unit from the applicator rollers to the film roller are driven by a gear connected to the forme cylinder. The disadvantage here is that the transmission ratios of the transmission are fixed, the ratio of the surface speed of the rollers therefore can not be changed dynamically. Also, the construction of such gear is complex and therefore expensive.

The specified gear ratios do not provide a way to affect the energy requirements of the printing unit. In fact, in the contact zone between two rolls, for example, the rubber layers are flexed. In addition, shear forces occur at different surface speeds which lead to friction losses and increased wear of the roll surfaces.

The fact that the speed of the ductor is used as a manipulated variable for the ink supply, is also historically conditioned: If the printer wants to influence the ink supply over the entire printing width, he can achieve this without great effort by means of the ductor speed. The alternative to take the position of all color screws, is much more complex. The duct speed is usually preset as a function of the production speed automatically according to a so-called 1-run-up curve and can be adjusted proportionally to the preset value. A disadvantage of this procedure is that the image-dependent variation of the color decrease over the width of the inking unit is not optimally taken into account.

It is an object of the invention to provide a printing unit and a method available, with which the ink transfer from the ductor to the forme cylinder is improved over the prior art. Another object of the invention is to reduce the number of required transmission components of a printing unit and thereby reduce the costs of, for example, maintenance and energy.

The present invention overcomes the disadvantages mentioned with a printing unit according to claim 1 and a method for operating the printing unit according to claim 7.

Furthermore, the printing unit according to the invention offers the possibility of adjusting operating parameters during the printing process and thereby optimizing the energy consumption and the wear of the components. Further properties of the printing unit emerge from the subclaims.

In the printing unit is the printing unit of a printing press, in particular a rotary printing press for newspaper printing, in particular the printing unit of a wet offset printing machine, the printing unit has a printing cylinder, at least one forme cylinder with an engagable with the forme cylinder inking unit. The printing unit may additionally have a dampening unit.

The inking unit has a ductor which transfers color from an ink supply to a film roller. The inking unit furthermore has at least two further rollers, for example application rollers, transfer rollers or distributor rollers, which form a compactor which extends between the forme cylinder and the ductor. In this case, the ductor and the film roller are gear-coupled, that is, connected to each other by means of a transmission, so that the single roller of one of the two rollers, the other roller is driven along via the transmission. Furthermore, in the printing unit there is a frictional coupling on at least one contact line of a roller of the roller mill to another roller of the printing unit, for example to the film roller, or to the forme cylinder.

Rolls of a printing unit, specially driven rollers, can basically be classified according to the nature of their mechanical drive. A distinction is made between different groups, which are briefly explained below for clarity.

One group includes all of the rollers that are coupled to the form cylinder by mechanical transmissions and driven by a single-drive motor that drives one of the cylinders or one of the group's rollers. This group is called a cylinder-driven group.

One group contains all of the rollers which are coupled to the ductor via mechanical gears and driven by a single-drive motor which drives the ductor or one of the group's rollers. This group is called a duct-driven group. In a preferred embodiment of the invention, the film roll belongs to the group of duct-driven rolls.

It may be that single, multiple or all rolls of an inking unit are cylinders driven by a cylinder. But it can also be that individual, several or all rollers of an inking unit are duct-driven rollers. Finally, there is also the possibility that individual, several or all rollers of an inking unit are coupled to one or more own motors with single drive. The single-driven rollers are referred to in this case as a paint-driven.

There may be other rolls or groups of rolls coupled directly or via mechanical gears to other engines. These rollers are referred to as intermediate driven rollers.

To drive a group of driven rolls, a motor and a corresponding drive are required. It does not matter for the implementation of the invention, in which way the mechanical coupling of the engine is made to the roller group. For example, the motor may be coupled to the group via an axial connection or by means of toothed belts, gears, chains, shafts or other mechanical devices.

The motor may be a DC motor, an AC motor or, for example, a three-phase motor. It can be a synchronous motor or an asynchronous motor. In particular, it may be a hollow shaft motor. This can for example be installed in a roller of the group. The drive of the group of form cylinder driven rollers is position-controlled. The drive of the other driven rollers can be position-controlled, speed-controlled or torque-controlled. In particular, it is possible to automatically switch between the control types or to adapt the control parameters to different operating conditions.

An advantageous embodiment of the invention has corresponding devices for measuring the variables to be controlled of the respective groups of driven rollers. These include, for example, encoders for measuring the angular position or the speed. Such encoders may e.g. be mounted on the axis of one of the rollers of the group in question, or on another component of the transmission. In particular, such donors can also be integrated in the engine. It is also possible to evaluate operating parameters of the drive system in order to determine, for example, the torque of the motor.

In a preferred embodiment of the invention, a combination of the types of control takes place. This is to be understood as follows. In a control loop, manipulated variables are automatically adjusted to approximate measured values (actual value) to a desired value (setpoint). The deviations from the actual and setpoint represent errors that are minimized by the control system or kept below a certain threshold. The error may be in the form of a position error, for example, a position control attempts to minimize or eliminate this error.

In an advantageous embodiment of the method according to the invention, a combination of the different modes of operation is achieved by weighting the errors (e.g., position, rotational speed, torque) differently. It is possible, for example, to set a position-controlled operating mode at low speeds, and to select a predominantly speed-controlled or torque-controlled operating mode at higher speeds. The transition of one operating mode into another can take place, for example, by means of a stepwise change of the mechanical conditions. The mechanical conditions are determined, for example, by the following variables: delivery of the rolls (distances of the rolls), contact force of the rolls to each other, size of the contact strip between two contacting rolls (nip), rotation speed of a roll, relative surface speed of two or more rolls (Leading) and other variables that are changeable only by mechanical influence in the printing press.

Another way to switch between different operating modes is to select the current value of the new controlled variable immediately before changing the controlled variable. This setpoint can then, for example, gradually after changing the operating mode to be changed. Thus, a change of mode can be done without causing an abrupt change in the mechanical conditions.

It is also possible to adjust the operating mode based on the measured values of another group of driven rollers. For example, it is possible to increase the drive torque of the motor of one group of driven rollers to relieve the drive of another group of driven rollers of the same printing unit. It is also possible to set the rotation speed and thus the lead of one group of driven rolls different from that of another group, e.g. to achieve better color trimming or increased or decreased color transport.

A deviation of the surface speed of two superimposed rolling rolls is referred to as lead or lag. A lag can be considered as a negative lead. In the following, the term advance will be used to mean both positive and negative overshoot. Overfeed may be desirable, for example, to better rub the ink. Too large a lead between the rollers and the forme cylinder may be disadvantageous because it may be e.g. accelerates the wear of a roller or the wear of the printing form or can lead to printing defects.

There may be rollers that are not coupled to a motor by means of mechanical transmissions, such rollers are referred to herein as passive rollers. The passive rollers form a separate group. Rollers whose surfaces are in contact with each other may but need not belong to the same group of rollers.

If there are two rolls of different groups of surface contact, the two rolls are referred to as friction-coupled, or it is said that the two rolls have a pure friction coupling on their contact line.

A passive roller must be frictionally coupled to at least one driven roller in order to be rotated. Passive rollers have the characteristic that no mechanical gears are needed to drive them. They may also be friction-coupled to two or more rolls of the same group or different groups. In particular, can a passive roller coupled to a plurality of rollers having different surface speeds.

The frictional forces acting on the contact lines between the rollers are tangential to the surface of the rollers. The passive roller is rotated at a surface speed that is between the highest and lowest surface speeds of the rollers friction-coupled to it. This is done in such a way that the sum of the torques acting on the passive roller disappears, thus minimizing the stress on the rollers involved and thus reducing the wear.

The inking unit has at least one passive roller, which is frictionally coupled to at least two driven rollers. The at least one passive roller is friction coupled to at least two rollers which are not both members of the same group of driven rollers.

It is possible in principle that two or more passive rollers are frictionally coupled with each other. This requires that the friction force between these rollers be smaller than the force that occurs at the points of friction coupling with the driven rollers. Otherwise, there is a risk that the friction forces are insufficient to drive the passive rollers. To simplify the transmission, in particular to reduce the transmission components, it may still be advantageous to produce friction couplings between passive rollers.

The axial movement of the wheels can be controlled by means of gears or e.g. by separate drives (motor, magnet, pneumatics) or e.g. by "Scandrive gearbox" (during rotation, an axial movement is forced by means of a gearbox).

The speed of the ductor and film roller is set by the gearbox so that the film roller rotates at a higher speed than the single-driven ductor. In this case, any desired speed ratio between the ductor and film roller can be adjusted via the transmission by appropriate design measures, if appropriate, the ratio of the two roller rotational speeds can also be adjustable, regulated and / or adjustable via the transmission.

What has been described here with reference to the combination of ductor and film roller, applies equally to the interaction of two or more arbitrary rollers of the inking of which at least one has a single drive and wherein the or the individual drive / e at least one gear at least one other roller of the inking unit with drives.

The transmission can be a gear transmission, a toothed belt or chain transmission or any other transmission with which a rotation of a first rotation body can be transmitted to a second rotation body, changed and / or adjusted. The gear can permanently couple the ductor and the film roller, so that a rotational movement of the driven roller always causes a rotational movement of the coupled thereto via the gear roller / n, but the coupling can also be such that the not individually driven roller to the individually driven roller before the start of the single drive or single drive can be switched on and off of this or can, or the individually driven roller to the not individually driven roller according to and can be turned off.

The on / off, meant here is the time of the start of the on / off, can be specified in the program of the printing press or caused by the operator by hand. This point in time may depend on the running speed of the printing press, the running time of the machine or on other factors, which are predetermined for example in the machine control. In any case, in the case of a turn-on / turn-off solution, a display is to be provided which shows the operating personnel in which position the rollers are located relative to one another. In addition, it can be provided that, for example, no start of printing is possible if it is determined by means of suitable sensors that the driven roller and the drive-connected roller (s) are not coupled via the transmission, or it can be a warning signal, an optical or audible, are generated when an actual situation on the transmission does not coincide with a predetermined for example in the machine control target situation.

The gear coupling the ductor to the film roll, for example, may be configured such that a change in the peripheral speed of the single-driven roller changes the peripheral speed of the non-individually driven roller such that a Size ratio between the peripheral speeds of the two rolls constant, that is always the same. Less preferably, it is not excluded that the peripheral speed of the non-individually driven roller changes so that the size ratio between the peripheral speeds changes, for example, as the peripheral speed of the single driven roller increases, the size ratio between the peripheral speeds decreases means that the co-driven via the gear roller is accelerated in proportion less than the individually driven roller. The same applies to the case that the ratio of the peripheral speeds is increased, that is, the non-individually driven roller in proportion to experience more acceleration than the individually driven roller.

The film roll may have an overfeed with respect to the forme cylinder. At the same time, the peripheral speed of the forme cylinder is transferred to rollers lying in the direction of the film roller. In this case, the rotation of the rollers between the form cylinder and film roll can be done via gear or friction. In this case, a pure friction coupling must exist on at least one roller. At this at least one point lead different advances of the form cylinder side or film roll side driven rollers to a slip between the rollers.

According to the invention, the ductor and the film roll belong to the same group of driven rolls. Thus, it comes to a determination of the ratios of the peripheral speeds of the ductor and film roll. The printing unit thus has at this point a degree of freedom less than printing units of the prior art. However, the peripheral speed of the film roll driven rolls can be adjusted independently of the peripheral speed of the die cylinder driven rolls, whereby the printing system roll system gains an extra degree of freedom.

The printing unit may include a dampening unit. This may have its own drive, or at least one group of driven rollers. It may also contain passive rollers. The relationships described above with regard to wear optimization through the use of passive rollers in the inking unit apply in the same way to the rollers of a dampening unit. Also, a printing unit has more degrees of freedom in terms of its adjustment when at least one roller of the dampening unit belongs to a group of driven rollers.

The printing unit may, in addition to the inking unit and dampening unit, comprise further components, such as a cylinder washing apparatus, which are well known in the art and therefore are not separately mentioned and / or treated here.

In the method according to the invention, the peripheral speed of the film roller, which is determined either by the single drive or by the gear coupling, are transferred directly or via intermediate rollers by frictional forces on the distributor roller or the distributor rollers. As a result, the peripheral speed of the distributor roller is determined by the drive of the inking unit or the one inking roller, and no longer, as known in the prior art, predetermined solely by means of appropriate gear connections of the peripheral speed of the forme cylinder. Not equal circumferential speeds (positive or negative lead) can improve the color trimming in the roller mill.

Figur 1:

eine schematische Ansicht eines Druckwerks gemäß dem Stand der Technik.

Figur 2:

eine schematische Ansicht eines erfindungsgemäßen Druckwerks mit duktorgetriebener Filmwalze.

Figuren 3 bis 9:

Ausführungsformen eines erfindungsgemäßen Druckwerks mit unterschiedlichen Gruppen getriebener Walzen und passiver Walzen.

The invention will be explained in more detail below by means of embodiments with reference to the accompanying drawings. The figures show in detail:

FIG. 1:

a schematic view of a printing unit according to the prior art.

FIG. 2:

a schematic view of a printing unit according to the invention with duct-driven film roll.

FIGS. 3 to 9:

Embodiments of a printing unit according to the invention with different groups of driven rollers and passive rollers.

In the FIG. 1 is a printing unit according to the prior art shown. All rollers, with the exception of the ductor 9 are coupled via gearbox with the forme cylinder 2.

In the FIG. 2 an inventive printing unit 20 is shown schematically. In this case, only the transmission connections between the pressure cylinder 1 and the forme cylinder 2, as well as a transmission connection between the ductor 9 and the film roller 8 are indicated. The film roll 8 belongs to the group of duct-driven rolls. The ductor 9 has a Motor 11 on. With this motor 11, the ductor 9 is driven. In addition, the ductor 9 is coupled via a gear with the film roller 8 so that during a rotational movement of the directly driven ductor 9, the film roller 8 is rotated via the transmission. The coupling of the two rollers may be fixed, but it is preferably formed so that the film roller 8 on the rotating ductor 9 on and can be turned off, or the ductor 9 with the ink fountain 15 to the film roller 8 on or. can be turned off by this. As a result, the ductor 9 can be rotated independently of the printing operation, for example, to set a stable color setting before starting printing. The gear connects the two rollers 8, 9 so that the size ratio between the peripheral speed of the ductor 9 and the peripheral speed of the film roller 8 always remains the same. For example, the size ratio of the peripheral speeds between the ductor 9 and the film roller 8 may be 1: 5, 1:10 or 1:20, that is, the peripheral speed of the film roller 8 is always five times, ten times or twenty times as large as that of the ductor 9.

FIG. 3 shows an embodiment in which the dampening roller 12, the dampening driver 13 and the rider roller 14 belong to the group of form cylinder driven rollers. The inking rollers 3 and 4, the transfer roller 6, the film roller 8 and the ductor 9 belong to the group of duct-driven rollers. The riders 5 and 7 are passive rollers. The engine 10 of the cylinder-driven group acts on the impression cylinder. The motor 11 of the duct-driven rollers acts on the ductor 9. The rollers 5 and 7 may be, for example, traversing rollers, such as those from the DE 10 2008 012 385.4 are known.

FIG. 4a shows a detail in which the engine 11 of the group of duct-driven rollers is coupled to the ductor 9.

FIG. 4b shows a detail in which the engine 11 of the group of duct-driven rollers is coupled to the film roller 8.

FIG. 5 shows an embodiment in which the dampening driver 13, the inking roller 4, the transfer roller 6, the film roller 8 and the ductor 9 belong to the group of duct-driven rollers. The wheels 5 and 7, the inking roller 3, the dampening roller 12 and the dampening roller 14 are passive rollers. The engine 11 of the duct-driven rolls acts on the ductor 9. Between the passive rollers 3 and 5 is Friktionskopplung. This requires that the frictional force between the passive rollers must be smaller than the frictional force between the passive rollers and the driven rollers contacting them.

FIG. 6 shows an embodiment in which the film roll 8 belongs to the group of ductor-driven rolls which is coupled to the ductor 9 via a gearbox so that, for example, the ratio of the surface speed of the ductor to the film roll is 1: 5. Motor 11 of the duct driven rollers acts on the ductor 9. All other rollers, with the exception of the stirrer 5, which is a passive roller, belong to the group of cylinders driven by a cylinder. The slider 5 touches three of the cylinders driven by the cylinders 3, 4 and 6, of which it is jointly driven by friction. The roller 7 and the film roller 8 are frictionally coupled. Thereby, the lead between the rollers 7 and 8 can be adjusted freely, whereby the inking unit receives an additional degree of freedom.

FIG. 7 shows an embodiment in which the film roll belongs to the group of duct-driven rolls. Motor 11 of the duct-driven rollers acts on the ductor 9. The dampening roller 12, the dampening driver 13 and the rider roller 14 are driven by a cylinder. The motor 10 is coupled to the impression cylinder 1. The applicator rollers 3 and 4, as well as the transfer roller 6 form an interposed group whose motor 16 is coupled to the transfer roller 6. Reiber 5 and 7 are passively driven. The slider 5 is frictionally coupled to three rollers 3, 4, and 6 of the same group. The grater 7 is frictionally coupled to two rollers 6 and 8 of different groups.

FIG. 8 shows an embodiment in which the rollers 12, 13 and 14 of the dampening unit form a separate group of driven rollers, which are coupled to the motor 17. Likewise, the rollers 3, 4, 5, 6 and 7 form a separate group of driven rollers, which are coupled to the motor 16. Film roller 8 and ductor 9 are ducted.

FIG. 9 shows an embodiment in which the rollers 12 and 14 of the dampening unit form a separate group of driven rollers, which is coupled to the motor 17. The rollers 3, 4, 6, 8 and 9 are ducted. The drivers 5 and 7, as well as the dampening driver 13 are passive rollers.

LIST OF REFERENCE NUMBERS

1

pressure cylinder

2

form cylinder

3

Inking roller

4

Inking roller

5

distributor roller

6

Transfer roll

7

distributor roller

8th

film roller

9

ductor

10

engine

11

engine

12

Dampener roller

13

dampening distribution

14

riding roller

15

paintbox

16

engine

17

engine

Claims (10)

1. A printing unit of a printing machine, in particular a rotary printing machine, comprising at least:

   a) a printing cylinder (1);

   b) a form cylinder (2);

   c) an inking unit which can be applied to the form cylinder and which comprises at least

   c1) a ductor (9),

   c2) a film roller (8) and

   c3) a roller frame consisting of two or more rollers, wherein

   d) the ductor (9) and the film roller (8) are gear-coupled and comprise an individual drive (11), and

   e) a friction coupling exists on at least one line of contact between a roller of the roller frame and another roller of the printing unit or on the form cylinder (2), characterised in that

   f) the inking unit comprises at least one passive roller (7) which is friction-coupled to at least two driven rollers (6, 9), the two driven rollers (6, 9) do not belong to the same group of driven rollers, and the two driven rollers (6, 9) exhibit different surface speeds.
2. The printing unit according to Claim 1, characterised in that at least one roller (3, 4, 5, 6) of the inking unit is coupled to a drive which is not connected to the form cylinder (2) via a gear.
3. The printing unit according to any one of the preceding two claims, characterised in that at least one of the rollers (3, 4, 5, 6) is friction-driven.
4. The printing unit according to any one of the preceding claims, characterised in that the drive (11) which drives the ductor (9) comprises a drive regulator using which the position, speed, torque or a combination of these variables can be regulated.
5. The printing unit according to the preceding claim, characterised in that each group of driven rollers comprises one drive regulator each.
6. The printing unit according to any one of the preceding claims, characterised in that the printing unit further comprises at least one dampening unit, and at least one roller of the dampening unit belongs to a group of driven rollers.
7. A method for operating a printing unit according to any one of Claims 1 to 6, characterised in that the mode of operation of the ductor drive (11) and/or at least one of the intermediate drives (16, 17) can be altered in the course of production.
8. The method according to Claim 7, wherein the mechanical conditions are altered in steps when transitioning from one mode of operation to another mode of operation.
9. The method according to any one of the preceding two claims, wherein a lead is set between the rollers of an inking unit during printing operations.
10. The method according to the preceding claim, wherein the lead is set in accordance with the mode of production or the materials being used, such as inks.

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