Device for decurling a web of material, such as a paper web

Abstract

The invention relates to a device for decurling a web of material, such as a paper web, which device comprises: a first main roller; a second main roller arranged parallel to and at a distance of the first main roller, wherein the first main roller and the second main roller are arranged in a main plane; and a decurling roller arranged parallel to and between the first and second main roller, when viewed in a direction perpendicular to the main plane, wherein the spacing between the first main roller and the second roller is smaller than the diameter of the decurling roller.

Claims

1. A device for decurling a web of material comprising: a first main roller; a second main roller arranged parallel to and at a distance from the first main roller, wherein the first main roller and the second main roller are arranged in a main plane; a decurling roller arranged parallel to and between the first main roller and the second main roller, when viewed in a direction perpendicular to the main plane, wherein the decurling roller has an axis and wherein the axis is positioned below the main plane; wherein the decurling roller is supported only by the web of material passing over the main rollers such that the decurling roller is movable in a direction parallel to a radial and tangential direction of either the first main roller or the second main roller; and wherein there is spacing between the first main roller and the second main roller and the spacing is smaller than a diameter of the decurling roller.

2. The device according to claim 1, wherein at least one of the first main roller and second main roller is driven by a driver.

3. The device according to claim 1, comprising a guide plate having a fold and curved parts on both sides of the fold, wherein the fold extends into a pinch between the first main roller and the second main roller, and wherein a fold line is parallel to the main rollers.

4. The device according to claim 1, further comprising a housing having opposing walls, an inlet opening and an outlet opening for passing a web of material through the device, wherein each end of the decurling roller is positioned adjacent to an opposing wall of the housing.

5. A combination of a web of material and a device according to claim 1, wherein the web of material starts and ends on a side of the main plane opposite of a side where the decurling roller is positioned.

6. The combination according to claim 5, wherein the web of material extends along a surface of the first main roller, through a space between the first main roller and the decurling roller, then along a surface of the decurling roller, through a nip of the second main roller and along a surface of the second main roller.

7. A device for decurling a web of material comprising: a first main roller; a second main roller arranged parallel to and at a distance from the first main roller, wherein the first main roller and the second main roller are arranged in a main plane; a decurling roller arranged parallel to and between the first main roller and the second main roller, when viewed in a direction perpendicular to the main plane, wherein the decurling roller has an axis and wherein the axis is positioned below the main plane; wherein at least one conveyor belt runs along the first main roller, the decurling roller, and the second main roller; wherein the decurling roller is supported only by the web of material passing over the main rollers and the at least one conveyor belt such that the decurling roller is movable in a direction parallel to a radial and tangential direction of either the first main roller or the second main roller; and wherein there is spacing between the first main roller and the second main roller and the spacing is smaller than a diameter of the decurling roller.

8. The device according to claim 7, wherein a drive roller is provided parallel to the first and second main rollers, and wherein the at least one conveyor belt also runs along the drive roller.

9. The device according to claim 8, wherein the drive roller is fixed about and rotates about an axis and wherein the axis is movable in at least the direction perpendicular to the main plane to control tension in the at least one conveyor belt.

10. The device according to claim 8, wherein the drive roller is crowned.

11. The device according to claim 9, wherein the at least one conveyor belt has a width substantially equal to a length of the decurling roller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) These and other features of the invention will be elucidated in conjunction with the accompanying drawings.

(2) FIG. 1 shows a cross sectional view of a first embodiment of a device according to the invention;

(3) FIG. 2 shows a perspective view with partially cut-away portions of the device of FIG. 1;

(4) FIG. 3 shows a cross sectional view of a second embodiment of a device according to the invention; and

(5) FIG. 4 is a side view of one embodiment of a drive roller showing a crown.

DESCRIPTION OF THE INVENTION

(6) FIG. 1 shows a cross sectional view of a first embodiment 1 of a device according to the invention.

(7) The device 1 has two parallel main rollers 2, 3 arranged in a main plane 4. The main rollers 2, 3 are arranged at a distance of each other with a spacing S.

(8) A decurling roller 5 is arranged parallel to and between the first main roller 2 and the second main roller 3, when viewed in a direction perpendicular to the main plane. The diameter D of the decurling roller 5 is larger than the spacing S. Furthermore, the axis of the decurling roller 5 is positioned below the main plane 4.

(9) A web of paper P is guided along the top of the first main roller 2, along the bottom of the decurling roller 5 and back over the top of the second main roller 3.

(10) When the second main roller 3 is driven by a driver DR, the paper P will be pulled through the device 1 and the decurling roller 5 will be pulled up by the tension in the paper P, and will cause that the paper P is squeezed between the first main roller 2 and the decurling roller 5 and is squeezed between the second main roller 3 and the decurling roller 5.

(11) In theory the diameter D could be a little smaller than the spacing S, under the condition that the thickness of the paper P is sufficient such that the decurling roller 5 cannot pass the space between the main roller 2, 3. However, it is preferred that the diameter D is larger than the spacing S, such that it is ensured that the decurling roller 5 cannot pass the space between the main rollers 2, 3, independent from the paper thickness.

(12) FIG. 2 shows a perspective view with partially cut-away portions of the device 1 of FIG. 1.

(13) The device 1 has a housing 6 with an inlet opening 7 and an outlet opening 8. Due to the side walls 9, 10 the decurling roller 5 can only be supported by the paper P and will stay in axial position.

(14) FIG. 3 shows a cross sectional view of a second embodiment 20 of a device according to the invention. This device 20 has a first main roller 21, a second main roller 22 and a decurling roller 23 arranged parallel to and between the first main roller 21 and second main roller 22. Furthermore, the axis of the decurling roller 23 is positioned below the main plane of the rollers 21, 22.

(15) A drive roller 24 is arranged beneath the main rollers 21, 22 and the decurling roller 23. The drive roller 24 is fixed about an axis B and rotates about the axis B and is movable up and down as illustrated by the vertical arrow A.

(16) A conveyor belt 25 is wound along the top of the first main roller 21, beneath the decurling roller 23, over the second main roller 22 and under the drive roller 24. By driving the drive roller 24, all other rollers 21, 22, 23 will rotate, such that a web of paper P is taken along a part of the conveyor belt 25 path.

(17) By moving the drive roller 24 more down, the decurling roller 23 is pulled more firm against both main rollers 21, 22, while moving the drive roller 24 up will decrease the tension. In this way the amount of decurling can be controlled.

(18) A guide plate 26 is arranged over the main rollers 21, 22. The guide plate 26 has a fold 27 and curved parts 28, 29 on both sides of the fold 27, such that a web of material, such as a sheet of P can automatically be fed to the device 20.

(19) FIG. 3 shows a drive roller 24. In one embodiment, illustrated in FIG. 4, the drive roller is crowned.

(20) It should be noted that in each embodiment, the decurling roller 5, 23 is supported only by the web of material P passing over the main rollers 2, 3 and the main rollers 21, 22.