Dryer unit for a printing machine and printing machine

Abstract

A dryer unit (26), especially an intracolor dryer unit, for a printing machine is presented. It comprises a web inlet edge (34) and a web outlet edge (36) being substantially parallel to one another and defining a drying area (28) therebetween. Additionally, an air inlet and a first air outlet (38) being connected to the air inlet in an air-ducting manner are provided. The first air outlet (38) is positioned adjacent to one of the web inlet edge (34) and the web outlet edge (36) and a middle axis of the first air outlet (38) is inclined towards the respective other of the web inlet edge (34) and the web outlet edge (36) with respect to the drying area (28). Furthermore, a printing machine is described, comprising an impression drum, at least two ink application units and at least one dryer unit (26) as described above.

Claims

1. A dryer unit for a printing machine, the dryer unit being adapted for applying a flow of air to a moving web and comprising: a web inlet edge and a web outlet edge, being substantially parallel to one another and defining a drying area therebetween, an air inlet adapted for receiving air to be applied to the web, a first air outlet being connected to the air inlet in an air-ducting manner, and a second air outlet being connected to the air inlet in an air-ducting manner, wherein the first air outlet is positioned adjacent to one of the web inlet edge and the web outlet edge and wherein a middle axis of the first air outlet is inclined towards the respective other of the web inlet edge and the web outlet edge with respect to the drying area, and wherein the inclination of the middle axis towards the web outlet edge with respect to the drying area and the inclination of a middle axis of the second air outlet towards the web inlet edge with respect to the drying area is an angle of at least 45° up to 90°, wherein the dryer unit has a substantially triangular cross section when regarded in a direction of the web inlet edge or the web outlet edge, the substantially triangular cross section including a triangle top and a triangle basis, wherein the drying area is located adjacent to the triangle basis of the substantially triangular cross section, wherein the first air outlet is connected to the air inlet via a first air distribution duct being positioned adjacent to a first triangle side edge running from the triangle top to the triangle basis, wherein the second air outlet is connected to the air inlet via a second air distribution duct being positioned adjacent to a second triangle side edge running from the triangle top to the triangle basis, and wherein a middle axis of the first air distribution duct and a middle axis of the second air distribution duct correspond to a shape of the substantially triangular cross section so that a distance between the middle axis of the first air distribution duct and the middle axis of the second air distribution duct increases in a direction from the triangle top to the triangle basis.

2. The dryer unit according to claim 1, wherein the first air outlet is positioned adjacent to the web inlet edge and its middle axis is inclined towards the web outlet edge with respect to the drying area and wherein the second air outlet is positioned adjacent to the web outlet edge and the middle axis of the second air outlet is inclined towards the web inlet edge with respect to the drying area or vice versa.

3. The dryer unit according to claim 1, wherein the dryer unit comprises a third air outlet being connected to the air inlet in an air-ducting manner, wherein the third air outlet is oriented substantially orthogonally to the drying area and is positioned between the web inlet edge and the web outlet edge.

4. The dryer unit according to claim 3, wherein the first air outlet and/or the second air outlet and/or the third air outlet substantially extend over the entire width of the dryer unit, wherein the width is oriented in parallel to the web inlet edge or the web outlet edge.

5. The dryer unit according to claim 3, wherein the cross section comprises an upper portion and a lower portion, wherein the lower portion is located adjacent to the triangle basis of the cross section and the upper portion is located adjacent to a triangle top of the cross section, and wherein an air inlet duct is located in the upper portion, the air inlet duct being substantially parallel to the web inlet edge or the web outlet edge.

6. The dryer unit according to claim 5, wherein the third air outlet is connected to the air inlet duct via a third air distribution duct being positioned centrally inside the triangle.

7. The dryer unit according to claim 3, wherein the cross section comprises an upper portion and a lower portion wherein the lower portion is located adjacent to the triangle basis of the cross section and the upper portion is located adjacent to a triangle top of the cross section, wherein an air suction duct is located in the lower portion, the air suction duct being substantially oriented parallel to the web inlet edge or the web outlet edge, and wherein the air suction duct communicates with the drying area via at least one air suction opening in an air-ducting manner.

8. A printing machine comprising: an impression drum, at least two ink application units being located on a circumference of the impression drum and being adapted for applying ink to a web being located on the impression drum, and at least one dryer unit according to claim 1, wherein the at least one dryer unit is positioned between the two ink application units, and wherein the drying area is oriented substantially parallel to a tangent of the impression drum.

9. A dryer for a printing machine, the dryer comprising: a first air distribution duct to channel a first flow of air from an air inlet; a second air distribution duct to channel a second flow of air from the air inlet; a first air outlet connected to an outlet of the first air distribution duct to receive the first flow of air and expel the first flow of air toward a middle axis of the dryer; and a second air outlet connected to an outlet of the second air distribution duct to receive the second flow of air and expel the second flow of air toward the middle axis of the dryer, wherein a distance between a middle axis of the first air distribution duct and a middle axis of the second air distribution duct increases in a direction away from the air inlet along the middle axis of the dryer.

10. The dryer of claim 9, wherein: the first air distribution duct is adjacent to a first side edge of the dryer, and the second air distribution duct is adjacent to a second side edge of the dryer.

11. The dryer of claim 9, further comprising: a third air distribution duct to channel a third flow of air from the air inlet; and a third air outlet connected to an outlet of the third air distribution duct to receive the third flow of air and expel the third flow of air along the middle axis of the dryer in a direction substantially parallel to the middle axis of the dryer.

12. The dryer of claim 9, further comprising: an air suction duct to suction air expelled by the first air outlet and the second air outlet, the air suction duct between the first air distribution duct and the second air distribution duct along the middle axis of the dryer.

13. The dryer of claim 12, further comprising: a third air distribution duct to channel a third flow of air from the air inlet; and a third air outlet connected to an outlet of the third air distribution duct to receive the third flow of air and expel the third flow of air along the middle axis of the dryer in a direction substantially parallel to the middle axis of the dryer.

14. The dryer of claim 13, wherein the third air distribution duct separates the air suction duct into two halves.

15. A dryer for a printing machine, the dryer comprising: a first air distribution duct to channel a first flow of air from an air inlet along a first side of a substantially triangular shape, the substantially triangular shape including the first side, a second side, and a third side connecting the first side to the second side, wherein the third side substantially corresponds to an area to be dried by the dryer; a second air distribution duct to channel a second flow of air from the air inlet along the second side of the substantially triangular shape; a first air outlet connected to an outlet of the first air distribution duct to receive the first flow of air and expel the first flow of air toward a midpoint of the third side of the substantially triangular shape; and a second air outlet connected to an outlet of the second air distribution duct to receive the second flow of air and expel the second flow of air toward the midpoint of the third side of the substantially triangular shape.

16. The dryer of claim 15, wherein: the first air distribution duct is adjacent to a first side edge of the dryer, and the second air distribution duct is adjacent to a second side edge of the dryer.

17. The dryer of claim 15, further comprising: a third air distribution duct to channel a third flow of air; and a third air outlet connected to an outlet of the third air distribution duct to receive the third flow of air and expel the third flow of air toward the midpoint of the third side of the substantially triangular shape in a direction substantially orthogonal to the third side of the substantially triangular shape.

18. The dryer of claim 15, further comprising: an air suction duct to suction air expelled by the first air outlet and the second air outlet, the air suction duct between the first air distribution duct and the second air distribution duct.

19. The dryer of claim 18, further comprising: a third air distribution duct to channel a third flow of air; and a third air outlet connected to an outlet of the third air distribution duct to receive the third flow of air and expel the third flow of air toward the midpoint of the third side of the substantially triangular shape in a direction substantially orthogonal to the third side of the substantially triangular shape.

20. The dryer of claim 19, wherein the third air distribution duct separates the air suction duct into two halves.

Description

(1) The invention will now be explained with reference to embodiments which are shown in the attached drawings. In the drawings,

(2) FIG. 1 shows a printing machine according to the invention being equipped with several dryer units according to the invention,

(3) FIG. 2 shows key elements of a printing unit of the printing machine of FIG. 1 in a schematic illustration,

(4) FIG. 3 shows a first embodiment of a dryer unit according to the invention in a sectional view III-III of FIG. 5,

(5) FIG. 4 shows a detail IV of the dryer unit of FIG. 3,

(6) FIG. 5 shows the dryer unit of FIG. 3 in a cross sectional view V-V of FIG. 3,

(7) FIG. 6 shows a second embodiment of a dryer unit according to the invention in a cross sectional view VI-VI of FIG. 8,

(8) FIG. 7 shows a detail VII of the dryer unit of FIG. 6, and

(9) FIG. 8 shows the dryer unit of FIG. 6 in a cross sectional view VIII-VIII of FIG. 6.

DETAILED DESCRIPTION

(10) FIG. 1 shows a printing machine 10, which is a flexographic printing machine in the examples shown.

(11) It comprises a web feeding unit 12, where a web of carrier material may be stored before the printing process takes place, a printing unit 14 adapted for printing on the web of carrier material, and a storage unit 16, where printed web is stored after the printing process.

(12) The printing machine 10 also comprises a main dryer 18 adapted for drying printed web of carrier material after the printing process.

(13) Further details of the printing unit 14 may be seen in FIG. 2.

(14) As a central element the printing unit 14 comprises an impression drum 20, which is coupled to three ink application units 22a, 22b, 22c, each of which is adapted to apply an ink of a different color to a web 24. The ink application units 22a, 22b, 22c are located on a circumference of the impression drum 20.

(15) Between each of the ink application units 22a, 22b and 22b, 22c a dryer unit 26 is provided respectively. In the example shown all dryer units 26 are designed as so-called intracolor dryers, which are adapted for drying printed web of carrier material between the application of inks of different colors.

(16) In other words, the ink applied to the web 24 by the ink application unit 22a is dried by the dryer unit 26 interposed between ink application unit 22a and 22b. The ink applied to the web 24 by the ink application unit 22b is dried by the dryer unit 26 being interposed between ink application unit 22b and 22c.

(17) The traveling direction of the web 24 is indicated by arrows 29.

(18) It is understood that the number of ink application units 22a, 22b, 22c and the number of dryer units 26 has been chosen for illustrative purposes only.

(19) The dryer units 26 respectively define a drying area 28, which is oriented substantially parallel to a tangent of the impression drum 20.

(20) Every dryer unit 26 has an air inlet duct 30, which is connected to a central air supply system. This way, warm and dry air is fed to the dryer units 26, which apply it to the drying area 28. As a consequence thereof, ink on the web 24 moving through the drying area 28 is dried.

(21) Furthermore, every dryer unit 26 has an air suction duct 32, which is connected to a central air suction system adapted for extracting air from the dryer unit and the drying area 28.

(22) A first embodiment of the dryer unit 26 is illustrated in FIGS. 3 to 5.

(23) In the cross sectional view of FIG. 3 the dryer unit 26 has a substantially triangular cross section when regarded in the direction of a web inlet edge 34 or a web outlet edge 36 thereof. The drying area 28 is located adjacent to a triangle basis of this cross section.

(24) Both the web inlet edge 34 and the web outlet edge 36 extend substantially parallel to a middle axis 20a of the impression drum 20. Consequently, the web inlet edge 34 and the web outlet edge 36 also are substantially parallel to each other. The drying area 28 is located between the web inlet edge 34 and the web outlet edge 36.

(25) In the vicinity of the web inlet edge 34 moving web 24 enters the drying area 28 associated with the respective dryer unit 26. In the vicinity of the web outlet edge 36 the moving web 24 leaves the drying area 28.

(26) The air inlet duct 30 is supplied with air via an air inlet being an air duct interface on the outer surface of the dryer unit 26.

(27) The air inlet is connected to a first air outlet 38 and a second air outlet 40 in an air-ducting manner.

(28) The first air outlet 38 is positioned adjacent to the web inlet edge 34.

(29) It comprises a middle axis 38a which is inclined towards the web outlet edge 36 with respect to the drying area 28.

(30) The second air outlet 40 is positioned adjacent to the web outlet edge 36 and has a middle axis 40a which is inclined towards the web inlet edge 34 with respect to the drying area 28.

(31) Consequently, both the first air outlet 38 and the second air outlet 40 have middle axis 38a, 40a which are inclined towards a central section of the drying area 28 at an angle α.

(32) As can best be seen from a combination of FIGS. 5 and 6, the first air outlet 38 and the second air outlet 40 substantially extend over the entire width of the dryer unit 26.

(33) The triangular cross section of the dryer unit 26 may be subdivided into an upper portion 26a and a lower portion 26b, wherein the lower portion 26b is located adjacent to the triangle basis and the upper portion 26a is located adjacent to a triangle top.

(34) The air inlet duct 30 is located in the upper portion 26a, wherein the air inlet duct 30 is substantially parallel to the web inlet edge 34 or the web outlet edge 36.

(35) The first air outlet 38 is connected to the air inlet duct 30 via a first air distribution duct 42 being positioned adjacent to a triangle side edge running from the triangle top to the triangle basis. The flow of air inside the first air distribution duct 42 is illustrated by arrows 44.

(36) The second air outlet 40 is connected to the air inlet duct 30 via a second air distribution duct 46 being positioned adjacent to a triangle side edge running from the triangle top to the triangle basis. The flow of air inside the second air distribution duct 46 is illustrated by arrows 48.

(37) The air suction duct 32 is located in the lower portion 26b of the triangular cross section, wherein the air suction duct 32 is substantially parallel to the web inlet edge 34 or the web outlet edge 36.

(38) The air suction duct 32 communicates with the drying area 28 via at least one air suction opening 50 in an air-ducting manner. The air suction flow is illustrated by arrows 52.

(39) A second embodiment of the dryer unit 26 is shown in FIGS. 6 to 8. In the following, only the differences with respect to the first embodiment will be explained.

(40) In a first aspect the dryer unit 26 according to the second embodiment differs from the first embodiment in that it has a third air outlet 54 being connected to the air inlet in an air-ducting manner.

(41) The third air outlet 54 is oriented orthogonally to the drying area 28 and is positioned between the web inlet edge 34 and the web outlet edge 36. The middle axis of the third air outlet 54 is indicated by reference sign 54a.

(42) In the example shown, the third air outlet 54 is positioned substantially in the middle between the web inlet edge 34 and the web outlet edge 36. It extends over the entire width of the dryer unit 26.

(43) Like the first air outlet 38 and the second air outlet 40 the third air outlet 54 is connected to the air inlet duct 30 via a third air distribution duct 56 being positioned centrally inside the triangular cross section.

(44) The air flow through the third air distribution duct 56 and the third air outlet 54 is illustrated by arrow 58.

(45) The third air distribution duct 56 separates the air suction duct 32 into two halves 32a, 32b.

(46) In a second aspect the dryer unit 26 according to the second embodiment differs from the first embodiment in that the air suction openings 50 are oriented substantially parallel to the drying area 28.