Method for the control of the rotational speed for a drive device of a printing roll

Abstract

The invention relates to a method for the control of the rotational speed for a drive device (20) of a printing roll (10) with a resilient printing sleeve (12) of a flexo printing press (100) comprising the following steps: Determination of a first rotational speed (V1) of the printing roll (10) in the free wheeling without active drive device (20) with a first adjusting value (B1), Determination of a second rotational speed (V2) of the printing roll (10) in the free wheeling without active drive device (20) with a second adjusting value (B2), Generation of a control curve (30) of the rotational speed related to the adjusting value on the basis of the determination steps, Usage of the control curve (30) for the control of the rotational speed of the printing roll (10) with an active drive device (20).

Claims

1. A method for the control of rotational speed for a drive device of a printing roll with a resilient printing sleeve of a flexo printing press comprising the following steps: adjusting a first adjusting value such that in a crimping situation the printing roll is moved towards a counter printing roll and a printing gap lying in between the printing roller and the counter printing roller is decreased after banding of the resilient printing sleeve at the printing medium; subsequently crimping of the resilient printing sleeve occurs during an alteration of the first adjusting value to a second adjusting value, determination of a first rotational speed (V1) of the printing roll in a simulated neutral gear condition without an active drive device with the first adjusting value, determination of a second rotational speed (V2) of the printing roll in the simulated neutral gear condition without an active drive device with the second adjusting value, generation of a control curve of the rotational speed related to the first adjusting value and the second adjusting value on the basis of the determination steps, controlling of the rotational speed of the printing roll with an active drive device based on the control curve wherein the crimping leads to a variation of the rotational speed of the printing roll.

2. The method according to claim 1, wherein the control curve is generated at least sectionally as a linear course between the determined first adjusting value and the second adjusting value.

3. The method according to claim 1, wherein the method is used for a register-free print.

4. The method according to claim 1, further comprising the step of determination of a further rotational speed (Vx) of the printing roll in the simulated neutral gear condition without an active drive device with a further adjusting value (Bx).

5. The method according to claim 1, wherein the determination steps are performed continuously or substantially continuously in a continuous or substantially continuous alteration of the first adjusting value and the second adjusting value.

6. The method according to claim 1, further comprising the step of controlling a rotational speed of an anilox roll based on the control curve.

7. The method according to claim 1, wherein during the step of controlling of the rotational speed of the printing roll a constructive undersize of the diameter (D) of the printing roll is considered.

8. The method according to claim 1, wherein the control curve is saved in relation to the resilient printing sleeve and/or in relation to the printing roll.

9. The method according to claim 8, wherein the control curve is compared to the saved control curve.

10. The method according to claim 1, wherein the control curve is used to control the rotational speed of at least one further roll, the at least one further roll being an anilox roll and/or a counter printing roll.

11. A flexo printing press comprising a printing roll with a resilient printing sleeve and a control unit for the control of the rotational speed of the printing roll, wherein the control unit is configured performance using the method of claim 1.

Description

(1) Further advantages, features and details of the invention result from the subsequent description in which embodiments of the invention are described in detail in relation to the drawings. Correspondingly, a flexo printing machine according to the invention has the same advantages as have been extensively explained regarding a method according to the invention. It is schematically shown:

(2) FIG. 1 a first embodiment of a flexo printing press according to the invention,

(3) FIG. 2 the embodiment of FIG. 1 with the resilient printing sleeve in a crimped situation,

(4) FIG. 3 a first embodiment of a generated control curve,

(5) FIG. 4 a further embodiment of a generated control curve,

(6) FIG. 5 a further embodiment of a generated control curve and

(7) FIG. 6 a further embodiment of a generated control curve.

(8) In FIG. 1 an embodiment of a flexo printing press 100 according to the invention is shown schematically. This flexo printing press 100 comprises a counter printing roll 50, an anilox roll 40 and a printing roll 10. On the printing roll 10 a resilient printing sleeve 12 is arranged which can for example be configured as a printing plate. Further, a drive device 10 for example in form of an electric motor is intended which serves for the drive of the printing roll 10.

(9) Further, a control unit 60 is shown schematically which is coupled to the drive device 20 for the control of the rotational speed of the printing roll 10 via a data connection. Likewise, in FIG. 1 the curve of the printing medium 200 is shown.

(10) In FIG. 1 the flexo printing press 100 with an inking system from an anilox roll 40 and a printing roll 10 is shown schematically. This embodiment is a register-free print with a single colour. Naturally, further inking systems can be provided wherein for each inking system an anilox roll 40 and a printing roll 10 can be intended.

(11) In FIG. 2 the crimping situation is shown. Thereby, a crimping situation for the printing sleeve 12 is established between the printing roll 10 and the counter printing roll 50. During the conveyance of the printing medium 200 between both rolls 10 and 50 the supply in FIG. 2 occurs top down. The printing roll 10 is moved towards the counter printing roll 50 and the printing gap lying in-between is decreased. The printing medium 200 proceeds through this printing gap. After banding of the resilient printing sleeve 12 at the printing medium 200 subsequently a crimping of the resilient printing sleeve 12 occurs during an alteration of the adjusting value like it is schematically shown in FIG. 2. This crimping leads to a variation of the rotational speed of the printing roll 10. This variation leads to an increased wear out of the drive device 20 or to a slip at the printing medium 200 such that here a wear out at the printing medium 200 and at the resilient printing sleeve 12 can be determined. In order to prevent the crimping effect and the related problems the method according to the invention is performed like subsequently described.

(12) In a first point of time, with a first adjusting value B1, in a simulated neutral gear condition, without active drive device 20, the first rotational speed V1 of the printing roll 10 is determined. Subsequently, in a second adjusting value B2 a second rotational speed V2 of the printing roll 10 is determined. Accordingly, these two determined values are registered in the diagram which applies the rotational speed via the adjusting value. Examples for such diagrams and control curves 30 generated therefrom are shown in FIGS. 3 to 6.

(13) FIG. 3 is a particularly simple and cost efficient configuration of the generated control curve 30. Thus, here the at least demanded certain parameters for the first adjusting value B1 and the second adjusting value B2 are drawn in. In this embodiment the according rotational speeds V1 and V2 establish points in this diagram which are connected to one another along a line. Herein, a linear relation between the rotational speeds and the adjusting value is taken as a basis for the generation of the control curve 30. The corresponding generation of the control curve can be achieved accordingly with a simple and cost efficient generating algorithm. On the basis of this control curve 30 an adjustment or control of the rotational speed of the printing roll 10 occurs via an actively appearing drive device 20.

(14) In FIG. 4 a further variation of the control curve 30 is shown. In this variation a respective further rotational speed Vx is determined to two further adjusting values Bx in addition to the first adjusting value B1 and to the second adjusting value B2, respectively. The courses between the single parameter values in the diameter according FIG. 4 are again on a linear basis. Thus, differently inclined lines between the single data values are established like shown in the control curve 30 according to FIG. 4. In comparison to FIG. 3 the effort for the determination of the values is increased, however a higher accuracy with the generation of the control curve 30 is achieved. Alternatively or in combination an embodiment according to FIG. 5 can be chosen. Thus by the adjusting value, a step function can be specified to the additional values or data values in the diagram of the rotational speed.

(15) If the adjusting value is mainly continuously adapted or varied and the rotational speed at which it occurs is monitored continuously or mainly continuously, a completely free control curve 30 can be generated by recording this correlation. This is shown in FIG. 6. The calibration effort is thus the highest, however an ideal or optimized accuracy during the generation of the control curve 30 is achieved.

(16) The previous description of the embodiments describes the present invention only within the scope of examples. Naturally, single features of the embodiments as far as technically meaningful can be freely combined with one another without leaving the scope of the present invention.

REFERENCE SIGNS

(17) 10 Printing roll 12 Resilient printing sleeve 20 Drive device 30 Control curve 40 Anilox roll 50 Counter printing roll 60 Control unit 100 Flexo printing press 200 Printing medium B1 First adjusting value B2 Second adjusting value Bx Further adjusting value D Diameter of the printing roll V1 First rotational speed V2 Second rotational speed Vx Further rotational speed