Drying device, system comprising a drying device and method for operating a drying device for drying between inking units of a printing machine

Abstract

The invention relates to a drying device (10) for a drying between inking units of a printing machine (1), with which a substrate (2) can be transported via rotating cylinders (3.1, 3.2, 3.3) and is printable with a coloring agent (4), with an air supply unit (11) for supplying of air (5) in direction of the substrate (2) in order to effect a drying of the coloring agent (4), a suction unit (12) for discharging the air (5), a control unit (20), which controls and/or regulates the air supply unit (11) in dependence of the operating parameters (B) in a way that altering drying areas (13.1, 13.2, 13.3) are adjustable at the substrate (2).

Claims

1. Drying device for a drying between inking units of a printing machine which is adjustable between the inking units, with which a substrate is transported via rotating cylinders and is printable with a colouring agent, with an air supply unit for supplying of air in direction of the substrate to effect a drying of a surface with the colouring agent, a suction unit for discharging the air, a control unit, which at least controls or regulates the air supply unit according to an estimation of drying time of the colouring agent based on a degree of gloss and a calculation of a weighted combination of at least one operating parameter, for altering drying areas of the substrate, wherein each of said at least one operating parameter is a member of a group consisting of: a position and a size of a colouring agent application at the substrate or at the cylinder, a layer thickness of the colour application at the substrate, a printing degree, a colour formulation of said colouring agent, a type of material of the substrate measured solvent amount in the air in the suction unit, and a transport speed of the substrate; and an optical sensor adapted to determine said degree of gloss of the applied colouring agent by measuring a reflection of light at the surface with the colouring agent during the operation of the printing machine.

2. Drying device according to claim 1, wherein the air supply unit is adjusted transversely to the transport direction of the substrate and comprises movable flaps, wherein an alternating flow direction is achievable for the discharge of the air from the air supply unit.

3. Drying device according to claim 1, wherein multiple modules are intended, which each comprise an air supply unit and a suction unit, wherein the modules are individually controllable by the control unit and wherein at least the volume flow or the temperature or the flow direction of the discharging air in the direction of the substrate of each module is individually adjustable.

4. System with a drying device for drying between inking units of a printing machine, by which a substrate is transportable via rotating cylinders and printable with colouring agents with an air supply unit for the supply of air in the direction of the substrate to effect a drying of the colouring agent, a suction unit for discharging of air, a measuring unit adapted to: use an optical sensor for a degree of gloss at the surface with the applied colouring agent by measuring a reflection of light during the operation of the printing machine; and a control unit, which at least controls or regulates the air supply unit according to an estimation of drying time of the colouring agent based on a degree of gloss and a calculation of a weighted combination of at least one operating parameter, for altering drying areas at the substrate, wherein each of said at least one operating parameter is a member of a group consisting of: a position and a size of a colouring agent application at the substrate or at the cylinder, a layer thickness of the colour application at the substrate, a printing degree, a colour formulation of said colouring agent, a type of material of the substrate, measured solvent amount in the air in the suction unit, and a transport speed of the substrate; wherein the printing machine comprises multiple inking units, wherein to each inking unit a drying device is assigned.

5. System according to claim 4, wherein said optical sensor is a camera unit directed to at least the substrate or to at least one cylinder.

6. System according to claim 4, wherein to the printing machine at least one paint container is assigned, in which the colouring agent is insertable, wherein a colour formulation code is read out of said paint container by an identification unit, said colour formulation code serves as an operating parameter for the control unit and wherein a substrate code is read out by another identification unit assembled at a carrier of the substrate, said substrate code serves as another operating parameter for the control unit.

7. System according to claim 4, wherein a heat exchanger is intended, which provides arising heat waste of the printing machine of the air supply unit.

8. Method for the operation of a drying device for drying between inking units of a printing machine, by which a substrate is transported via rotating cylinders and is printed with colouring agents with an air supply unit for the supply of air in the direction of the substrate to effect a drying of a surface with the colouring agent, a suction unit for discharging of the air, an optical sensor adapted to determine a degree of gloss of the applied colouring agent by measuring a reflection of light at the surface with the colouring agent during the operation of the printing machine, and a control unit, which at least controls or regulates the air supply unit according to an estimation of drying time of the colouring agent based on a degree of gloss and a calculation of a weighted combination of at least one operating parameter, for alternating drying areas at the substrate, wherein each of said at least one operating parameter is a member of a group consisting of: a position and a size of a colouring agent application at the substrate or at the cylinder, a layer thickness of the colour application at the substrate, a printing degree, a colour formulation of said colouring agent, a type of material of the substrate, measured solvent amount in the air in the suction unit, and a transport speed of the substrate; wherein the drying device is controlled in dependence from the colouring agent applied to the substrate.

9. Method according to claim 8, wherein said group is further consisting of a temperature of the air at least in the lion unit or in the air supply unit.

10. Method according to claim 8, wherein the drying device (10) is operated in a circulating air process or is operated in a circulated air process with a connectable fresh air process.

11. Method according to claim 8, wherein at least at the substrate or at a format cylinder or at an anilox roller of the inking unit of the printing machine the position and size of at least a colouring agent application or the drying time is determined via at least the reflexion of air at the surface of the format cylinder or at the anilox roller.

12. Method according to claim 8, wherein image data of a cliche of a format cylinder serve as operating parameters.

13. Method according to claim 8 for operating at least a system with a drying device for drying between inking units of a printing machine, by which the substrate is transportable via the rotating cylinders and printable with the colouring agents with the air supply unit for the supply of air in the direction of the substrate to effect a drying of the colouring agent.

14. The Drying device of claim 1, wherein said at least one operating parameter is a position and a size of a colouring agent application at the substrate or at the cylinder.

15. The Drying device of claim 1, wherein said at least one operating parameter is a layer thickness of the colour application at the substrate.

16. The Drying device of claim 1, wherein said at least one operating parameter is a printing degree.

17. The Drying device of claim 1, wherein said at least one operating parameter is a colour formulation of said colouring agent.

18. The Drying device of claim 1, wherein said at least one operating parameter is a type of material of the substrate.

19. The Drying device of claim 1, wherein said at least one operating parameter is measured solvent amount in the air in the suction unit.

20. The Drying device of claim 1, wherein said at least one operating parameter is a transport speed of the substrate.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) Further advantages, features and details of the invention result from the subsequent description, in which possible embodiments of the invention are described in detail in relation to the drawings. Thereby the features mentioned in the claims and the description can be essential for the invention each single for themselves or in any combination. It is shown:

(2) FIG. 1.1 a schematic drawing of the system according to the invention with the printing machine, which is configured with the printing unit between the inking units,

(3) FIG. 1.2 a further alternative of the system shown in FIG. 1.1,

(4) FIG. 1.3 a further embodiment of the system according to the invention according to FIG. 1.1,

(5) FIG. 2 a schematic drawing of the drying device, which is assembled behind a printing unit of a printing machine,

(6) FIG. 3 a schematic drawing of a drying device, which is configured with an air supply unit and a suction unit,

(7) FIG. 4 a further drawing of a drying device according to the invention with an air supply unit and a suction unit,

(8) FIG. 5 a further embodiment of the system according to the invention with a drying device and a measuring unit, which is assigned to the anilox roller,

(9) FIG. 6 a diagram from which the estimation of the drying speed can be evaluated,

(10) FIG. 7 a further schematic drawing of a system according to the invention with a drying device, which is in data communication with a control unit and a measuring unit,

(11) FIG. 8 a further view of a drying device shown in FIG. 7 and

(12) FIG. 9 a schematic drawing of a method according to the invention for the determination of an optimal drying capacity, which is assigned to each inking unit.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

(13) In FIGS. 1.1 to 1.3 a printing machine 1 according to the invention is shown respectively, which is configured from a plurality of inking units 7. In the shown figures five inking units 7.1 to 7.5 are shown exemplarily, wherein the amount of inking units 7 can vary, which does not affect the substantial matter of the invention.

(14) Between the inking units 7 a drying device 10 according to the invention is assembled respectively. The printing machine 1 transports a substrate 2, which can for example be a paper material, a paper sheet or a plastic film, etc., via rotating cylinders 3.1, 3.2, 3.3, wherein the inking units 7 apply a printing image on the surface of the substrate 2. Hereby, a colouring agent 4 is applied to the surface of the substrate 2 via rotating cylinders 3.1, 3.2, 3.3. In the shown embodiments each inking unit 7 is composed of an anilox roller 3.1 and a format cylinder 3.2, wherein the anilox roller 3.1 comprises the colouring agent 4 from the paint container 31. The printing machine 1 can however comprise further constructive embodiments concerning the type of rotating cylinder, the amount of cylinder, etc. The substantial matter of all embodiments according to the invention is however, that a drying device 10 according to the invention is assembled between the inking units 7, which is in dependence of the operating parameters controlled in a way that the altering drying areas 13 like they are shown for example in FIG. 8 are adjusted at the substrate 2, which is subsequently described in detail.

(15) Like it is explicitly shown in FIG. 2, FIG. 3, FIG. 7 and FIG. 8 the drying device 10 comprises an air supply unit 11 and a suction unit 12, which are integrated in an assembly unit in the present embodiment. The air supply unit 11 effects a supply of air 5 in the direction of the substrate 2 in order to achieve a selective drying of the inking unit 4 on the substrate 2. The air supply unit 11 comprises a supply channel 15, which proceeds in the centre towards the suction unit 12, which is responsible to discharge air 5. The air supply unit 11 comprises a supply channel 15 and the suction unit 12 in turn is configured with two spaced apart suction channels 16, wherein the supply channel 15 proceeds between the suction channels 16. During drying an evaporation arises of the solvents contained in the printing image. The air 5 is enriched with solvents, which are removed by the suction unit 12. A special feature of the invention is that the drying device 10 comprises a control unit 20, which in dependence of operating parameter B controls and/or regulates the air supply unit 11 and/or the suction unit 12 in a way that concerning the applied printing image corresponding drying areas 13 are established according to each inking unit 7 in order to achieve an optimized and selective drying at the substrate 2 between the respective inking units 7. Hereby, the energy requirement is significantly reduced during the operation of the printing machine 1 particularly because blank areas at the substrate 2 receive no or little drying by the drying device 10.

(16) In order to however effect an optimal drying between the inking units 7 a plurality of operating parameters B has to be taken into account, which are necessary for the determination of the optimal drying capacity L, which is subsequently described.

(17) According to FIG. 2, FIG. 4 and FIG. 8 the air supply unit 11 and the suction unit 12 is oriented transversely to the transport direction of the substrate 2. In the present embodiment the drying device 10, which is assembled from an air supply 11 and a suction unit 12, is configured rod-like. The width of the transport device 10 can be greater than the width of the substrate 2, which is shown in detail in FIG. 2.

(18) According to FIG. 4 it can be recognized that the air supply unit 11 comprises movable flaps 14, wherein different drying areas 13 are adjustable via the respective position of the flaps 14. Like it is schematically shown in FIG. 4 the drying device 10 comprises multiple modules 30.1, 30.2, 30.3, which each comprise an air supply unit 11 and a suction unit 12. The modules 30.1, 30.2, 30.3 can be individually controllable so that the volume flow and/or the temperature and/or the flow direction of the discharging air 5 is adjustable in the direction of the substrate 2 of each module 30.1, 30.2, 30.3.

(19) The flaps 14 can be assembled on the side of the drying device 10 facing the substrate 2 alternatively and/or additionally the flaps 14 can be assembled on the side of the drying device 10 facing away from the substrate 2. If the flaps 14 of a module 30 are in their closed position no discharging air occurs from the module 30. Via this flap control an efficient inking unit drying can be performed selectively over the width of the substrate 2 (see FIG. 8). Using operating parameters B the control unit 20 of the drying device 10 determines the drying capacity L of the drying device 10, which is shown schematically in FIG. 9. In order to perform an efficient drying between the inking units 7 it is initially required to provide the necessary operating parameters B, which are visualized in the reference sign 60. The following operating parameters B influence the drying or the adjustment of the drying capacity of the drying device 10: position and size of the colouring agent application at the substrate 2 and/or at the cylinder; drying speed of the colouring agent 4; layer thickness of the colour application at the substrate 2; printing degree, colour formulation of the colouring agent 4 and/or material of the substrate 2; degree of gloss of the colouring agent application at the cylinder 3.1 and/or at the substrate 2; solvent amount of the air 5 in the suction unit 12; transport speed of the substrate 2; temperature of the air 5 in the suction unit 12 and/or in the air supply unit 11.

(20) For example it is possible that a part of said operating parameters B are determined via a measurement according to the reference sign 50 (FIG. 9). Therefore a measuring unit 40 can be intended, which is for example configured with an optical sensor 41. The measuring unit 40 is according to FIG. 1.1 directed to the substrate 2 between the two inking units 7 respectively. The measuring unit 40 can determine the position and the size of the colour agent application at the substrate 2, which is shown schematically in FIG. 7. Subsequently this information is transferred to the control unit 20, which thereupon adjusts the drying device 10 according to the drying capacity L. At the same time it is possible that in dependence from other parameters the temperature of the air 5 flowing in the direction of the substrate 2 is adjusted and/or regulated within the drying device 10. According to FIG. 8 it is schematically shown that the system according to the invention is configured with a heat exchanger 35, which provides the resulting heat waste of the drying device 10 or the air supply unit 11 in the printing machine 1.

(21) Alternatively the measuring unit 40 can optically review the surface of the format cylinder 3.2 and/or the surface of the anilox roller 3.1, which is shown in FIG. 1.2 or 1.3. Via the recognized image data conclusions to the position and size of the printing image can be drawn between the inking units 7 so that the control unit 20 performs a corresponding control and regulation of the drying device 10.

(22) In a further embodiment according to FIG. 6 it is possible to determine the drying speed of the colouring agent 4 using a measurement of reflection of light at the colour surface of the anilox roller 3.1 and/or the format cylinder 3.2. The measuring unit 40 according to FIG. 1.2 or FIG. 1.3 determines the reflection of light wherein different drying speeds can be estimated by the control unit 20 using already existing measurement curves. In FIG. 6 three measuring points lying mainly on top of each other are shown exemplarily. The upper measuring point is on a drying function, which is associated with a slow drying speed. The middle drying function constitutes a normal drying speed. The lower drying function constitutes a high drying speed. Since the operating parameter of the drying speed is likewise a significant size for the influence of the adjusting drying capacity of the drying device 10 it can be meaningful to involve operating parameters according to the invention with a selective energy supply for the drying process.

(23) Via the measuring unit 40 further the printing degree, the gloss degree and/or the layer thickness of the colour application of the colouring agent 4 at the substrate 2 can be determined, which can be essential operating parameters B for the determination of the drying capacity L like just described. Likewise a solvent amount of the air 5 can be determined in the suction unit 12 via the measuring unit 40, wherein for example the drying speed and/or the necessary drying capacity L of the drying device 10 can be determined.

(24) Concerning FIG. 9 it is likewise possible that the operating parameters B at least partially are already available at the system according to the invention (see reference sign 51). For example it is possible that each paint container 31 of each inking unit 7 comprises an identification unit 32, which can be read out from a colour formulation code, which serves as an operating parameter B for the control unit 20. Hereby, the identification unit 32 can comprise a RFID chip, in which the colour formulation code is saved. Via the colour formulation code a corresponding consideration concerning the drying capacity L can occur. Likewise for the substrate 2 an identification unit can be intended in the system according to the invention, like for example at a carrier of the substrate 2 particularly at its wrap. The identification unit can further be assembled directly in or at the substrate 2, wherein a substrate code can be read out from the identification unit, which a control unit 20 comprises for the consideration of the drying capacity L.

(25) According to FIG. 1.2 it is possible that the measuring unit 40, which is assigned to the format cylinder 3.2 is movable and/or rotatable so that at another position the measuring unit 40 can also be directed to the substrate 2 and therewith to the printing image or can adapt a position, which can be optically analysed and/or monitored in the anilox roller 3.2.

(26) The colour formulation code can be read out via the identification unit 32 and can be transferred to the control unit 20.

(27) The acquisition of the necessary operating parameters (reference sign 60) can therewith occur according to the described methods 50, 51, 52 from FIG. 9. The input of operating parameters (reference sign 52) can for example occur by a not explicitly shown interface by the operator of the printing machine 1. Subsequently an optimal adjustment of the respective drying device 10 occurs by the control unit 20 in order to selectively and in an energy optimized manner dry the substrate 2 via the altering drying areas 13.

(28) In FIG. 5 mainly the embodiment according to FIG. 1.3 is shown, by which the drying device 10 is directed to a substrate 2 and at the same time the measuring unit 40 analyses the surface of the anilox roller 3.1, like already described. The optical verification of the surface of the anilox roller 3.1 can occur via a reflection sensor, gloss sensor or via a camera unit, particularly a line scan camera.

(29) Like it is schematically shown in FIG. 9 for each drying device 10 an individual determination of the drying capacity L occurs so that between the inking units 7 different drying areas 13 occur. This means that within the drying device 10 in dependence from the moving substrate 2 the drying areas 13 can vary according to FIG. 8, this means that the amount of the drying areas can increase or can decrease or the size of the drying areas can vary likewise. This is dependent from the previously mentioned operating parameters particularly from the position and size of the colouring agent application, the layer thickness of the colour application, the printing degree, the colour formulation of the colouring agent 4, the material of the substrate 2, the solvent amount of the colouring agent 4, the transport speed of the substrate 2 etc.

(30) According to the determined size of the drying capacity L, which has to be adjusted for each drying device 10, it can be necessary to additionally adjust the temperature of the air 5 in the air supply unit 11 and/or also to accordingly adjust the transport speed of the substrate 2.

(31) In a not explicitly shown embodiment it can be likewise intended that the control unit 20 is assembled central in and/or at the printing machine or in a drying device 10, which determines the necessary drying capacity L for all drying devices 10. Likewise it is possible that the measuring unit 40 and the drying device 10 are integrated in a common component.

REFERENCE SIGN

(32) 1 Printing machine 2 Substrate 3.1 Cylinder, anilox roller 3.2 Format cylinder 3.3 Pressure cylinder 4 Colouring agent 5 Air 7 Inking unit 7.1 Inking unit 7.2 Inking unit 7.3 Inking unit 7.4 Inking unit 7.5 Inking unit 10 Drying device 11 Air supply unit 12 Suction unit 13.1 Drying area 13.2 Drying area 13.3 Drying area 14 Flap 15 Supply channel 17 Suction channel 20 Control unit 30.1 Module 30.2 Module 30.3 Module 31 Paint container 32 Identification unit 35 Heat exchanger 40 Measuring unit 41 Optical sensor, camera 50 Measurement of operating parameters 51 Presence of operating parameters 52 Input of operating parameters 60 Acquisition of operating parameters 70 Determination of the drying capacity L B Operating parameter L Drying capacity