Drying device

Abstract

To provide a dryer device capable of efficiently drying the ink adhering to a web passing through a drying chamber and producing the whole thereof compactly and at a low cost.SOLUTION: A dryer device 1 includes a drying chamber 7 with an upper nozzle 9a and a lower nozzle 9b capable of blowing moistened air. A roller row 15 is constituted of a plurality of carrier rollers 8 arranged side by side from one end side toward the other end side of the drying chamber 7. The roller row 15, after guiding a web 1 from one end side to the other end side of the drying chamber 7 in an upper area of the respective carrier rollers 8, turns back the web 1 and guides the web 1 from the other end side to the one end side of the drying chamber 7 in a lower area of the respective carrier rollers 8.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a drying device for drying ink adhered to a continuously transported web. [Background technology]

[0002] Drying devices that dry ink adhered to a continuously transported web have been known in printing machines for gravure printing and the like. For example, a drying device disclosed in Patent Document 1 includes a transport unit that continuously transports the web and a drying unit with three box-shaped drying chambers horizontally arranged. The drying unit dries the ink adhered to the web by continuously transporting the web through the drying unit. The transport unit has a horizontal rotation axis and two upper and lower roller rows each consisting of a plurality of transport rollers arranged at a predetermined interval in a horizontal direction perpendicular to the rotation axis. The web is guided from one end to the other end of the drying unit in a region below the transport rollers in the lower roller row, and then folded back and guided from the other end to one end of the drying unit in a region above the transport rollers in the upper roller row. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-237548 Summary of the Invention [Problem to be solved by the invention]

[0004] The drying device of Patent Document 1 shortens the dimension from one end of the drying unit to the other by transporting the web while folding it back horizontally, thereby lengthening the time the web takes to pass through the drying unit and increasing drying capacity, but because the drying unit has two rows of rollers arranged vertically, the vertical width of the drying unit becomes wide, which causes a problem of the overall size of the device. Furthermore, having two rows of rollers increases the number of parts, which also causes a problem of increased costs.

[0005] The present invention has been made in view of the above points, and its object is to provide a drying device that can efficiently dry ink adhering to a web passing through a drying chamber, and that is compact overall and low cost. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention is characterized in that the web is conveyed in a drying chamber while being folded back by one roller train.

[0007] Specifically, the target is a drying device equipped with a drying chamber having one or more nozzles capable of blowing out heated air, and configured to dry ink adhering to a web by blowing air from the nozzles toward the web as the web passes through the drying chamber, and the following measures have been taken.

[0008] That is, the first invention is characterized in that the rotation axis extends horizontally and the rotary guide means has at least one roller row consisting of a plurality of conveying rollers arranged in a direction perpendicular to the rotation axis and at a predetermined interval from one end side of the drying chamber to the other end side, and the rotary guide means is configured to guide the web from one end side of the drying chamber to the other end side in one radial side region of each conveying roller in the roller row, and then fold the web back and guide the web from the other end side of the drying chamber to one end side in the radial other side region of each conveying roller in the roller row.

[0009] The second invention is characterized in that, in the first invention, the nozzle is arranged on the opposite side of the web from the roller row and at a position corresponding to the conveying roller.

[0010] The third invention is characterized in that, in the first or second invention, a suction roll is arranged upstream of the drying chamber and guides the web onto which ink has been transferred by an inkjet printing unit to the upstream end of the drying chamber, and the drying chamber is oriented so as to extend diagonally downward from one end to the other end.

[0011] A fourth invention is characterized in that in any one of the first to third inventions, one or more infrared heaters are arranged on the opposite side of the web from the row of rollers.

[0012] A fifth invention is characterized in that in any one of the first to fourth inventions, a drive source is provided that drives and rotates the transport rollers in the same direction in synchronization.

[0013] The sixth invention is characterized in that, in any one of the first to fifth inventions, the diameter of each conveying roller is set to gradually increase from one end of the roller row to the middle of the roller row, while the diameter is set to gradually decrease from the middle of the roller row to the other end of the roller row. [Effects of the Invention]

[0014] In the first invention, a plurality of conveying rollers arranged in a row can transport the web back and forth inside the drying chamber. Therefore, there is no need to arrange two rows of rollers, one above the other, as in Patent Document 1, so the drying device can be made compact overall while efficiently drying the ink adhering to the web. Furthermore, because there is no need to arrange multiple rows of rollers to transport the web back and forth, the number of parts can be reduced, resulting in a low-cost drying device.

[0015] In the second aspect of the present invention, the web is pushed by the air blown from the nozzles and is supported from the opposite side by the transport roller corresponding to that nozzle. This makes it difficult for the web to be stretched during transport, thereby preventing the occurrence of wrinkles in the web.

[0016] In the third aspect of the present invention, the web is wound around the suction roll, reducing the tension on the web after it passes through the suction roll. This reduces the likelihood of wrinkles forming on the web when the ink adhering to the web is dried in the drying chamber. This is particularly true when continuously transporting a plastic web, which is prone to wrinkles due to tension. Furthermore, because the drying chamber extends obliquely, even if the printing unit is an inkjet type and the web moves horizontally through the printing unit, the drying chamber can be designed to be tall, and the suction roll can be located between the drying chamber and the printing unit, allowing for a compact structure around the drying device. This prevents the printing unit from being positioned too high, making maintenance difficult.

[0017] In the fourth aspect of the present invention, the ink adhering to the web during transport can be dried more efficiently.

[0018] In the fifth aspect of the present invention, it is possible to prevent a decrease in the conveying speed due to frictional resistance or the like when the web passes through the roller row, and it is possible to stabilize the conveyance of the web through the roller row.

[0019] In the sixth aspect of the present invention, the contact area between the web and the transport rollers transported back and forth in the roller train is increased compared to when the diameters of the transport rollers in the roller train are constant, which makes it less likely for the web to meander during transport in the roller train, thereby achieving stable web transport. [Brief explanation of the drawings]

[0020] [Figure 1]1 is a schematic configuration diagram of a printing device incorporating a drying device according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a view corresponding to FIG. 1 according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a view corresponding to FIG. 2 according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the following description of the preferred embodiments is merely exemplary in nature.

[0022] First Embodiment of the Invention 1 shows a printing device 10 incorporating a drying device 1 according to a first embodiment of the present invention. The printing device 10 prints on a web W1 made of a long plastic material, and includes a web transport unit 20 that continuously transports the web W1.

[0023] The web transport unit 20 comprises a payout roll 2 located at the upstream end of the printing device 10, a winding roll 3 located at the downstream end of the printing device 10, an in-feed section 4 located downstream of the payout roll 2, and an out-feed section 5 located upstream of the winding roll 3, and the winding roll 3 winds up the web W1 that is paid out from the payout roll 2 and continuously transported while being guided by multiple guide rolls G1.

[0024] The in-feed section 4 has a pair of first feed rolls 4a that sandwich the web W1 and send it downstream by rotating, while the out-feed section 5 has a pair of second feed rolls 5a that sandwich the web W1 and send it downstream by rotating.By both first feed rolls 4a and both second feed rolls 5a rotating in tandem, it is possible to change the tension applied to the continuously transported web W1 before and after it passes through the in-feed section 4 and the out-feed section 5, respectively.

[0025] A so-called inkjet printing unit 6 is arranged downstream of the infeed section 4, and the printing unit 6 drips water-based ink onto the web W1, which is continuously transported horizontally, to adhere the ink to one side of the web W1.

[0026] A suction roll 16 is disposed downstream of the printing unit 6, which rotates to feed out the web W1 while sucking it through numerous suction holes (not shown) formed on its outer circumferential surface, and the suction roll 16 guides the web W1, which has been fed horizontally from the printing unit 6, by changing its direction diagonally downward. The suction roll 16 wraps the web W1 around an angle of approximately 15°, and the suction angle is approximately 10°, so that the difference in tension of the web W1 before and after it passes through the suction roll 16 is approximately 100 N.

[0027] A drying device 1 for drying ink adhering to the web W1 in the printing unit 6 is disposed downstream of the suction roll 16.

[0028] The drying device 1 includes a drying chamber 7 having a substantially rectangular parallelepiped shape, and the drying chamber 7 extends obliquely downward toward the downstream side of the device.

[0029] A first air intake port 7a is formed in the middle of the longitudinal direction at the lower part of the side wall of the drying chamber 7, while a second air intake port 7b is formed in the middle of the longitudinal direction at the upper part of the side wall of the drying chamber 7, and the first air intake port 7a and the second air intake port 7b serve as openings for supplying heated air into the drying chamber 7.

[0030] In addition, a first exhaust port 7c is formed on the upstream side of the device at the lower part of the side wall of the drying chamber 7, while a second exhaust port 7d is formed on the downstream side of the device at the lower part of the side wall of the drying chamber 7, and the first exhaust port 7c and the second exhaust port 7d are openings for discharging air from inside the drying chamber 7.

[0031] Furthermore, a third exhaust port 7e is formed on the upstream side of the device in the upper part of the side wall of the drying chamber 7, while a fourth exhaust port 7f is formed on the downstream side of the device in the upper part of the side wall of the drying chamber 7, and the third exhaust port 7e and the fourth exhaust port 7f are openings for discharging air from inside the drying chamber 7.

[0032] Inside the drying chamber 7, a rotation axis extends horizontally perpendicular to the longitudinal direction of the drying chamber 7, and a roller row 15 (rotation guide means) is arranged, consisting of a plurality of conveying rollers 8 arranged in a direction perpendicular to the rotation axis and at a predetermined interval from one end of the drying chamber 7 to the other end in the longitudinal direction.

[0033] The conveying rollers 8 of the roller train 15 are driven to rotate in the same direction in synchronization with each other by a drive source 14 that moves a chain belt in a circular motion.

[0034] The roller row 15 guides the web W1, which passes through the suction roll 16 and enters the drying chamber 7 from one end thereof, from one end to the other end of the drying chamber 7 in an upper region of each of the rotationally driven conveying rollers 8, and then wraps the web around the conveying rollers 8 located at the end of the roller row 15, thereby turning it back and guiding it from the other end to one end of the drying chamber 7 in a lower region of each of the rotationally driven conveying rollers 8. The web W1, which has been guided by the roller row 15, then jumps out of the drying chamber 7 from one end thereof, and is then guided by a plurality of guide rolls G1 toward the outfeed section 5.

[0035] At the top inside the drying chamber 7, a plurality of upper nozzles 9a, each having a substantially box shape and extending in a horizontal direction perpendicular to the longitudinal direction of the drying chamber 7, are disposed at positions corresponding to the respective conveying rollers 8. In other words, each upper nozzle 9a is disposed on the opposite side of the web W1 from the roller row 15.

[0036] Each upper nozzle 9a is connected to a second air intake port 7b, and the heated air supplied into the drying chamber 7 through the second air intake port 7b is blown out toward the web W1, which is continuously transported from one end of the drying chamber 7 to the other end, to dry the ink adhering to the web W1.

[0037] Furthermore, multiple mid-infrared heaters 11 are arranged at the top inside the drying chamber 7, one positioned between each of the upper nozzles 9a. That is, each mid-infrared heater 11 is arranged on the opposite side of the web W1 from the roller row 15, and irradiates mid-infrared rays to dry the ink adhering to the continuously transported web W1.

[0038] A plurality of lower nozzles 9b, each having an approximately box shape and extending horizontally perpendicular to the longitudinal direction of the drying chamber 7, are arranged at the bottom inside the drying chamber 7, and each lower nozzle 9b is positioned corresponding to a position between each conveying roller 8.

[0039] Each lower nozzle 9b is connected to a first air intake port 7a, and the heated air supplied into the drying chamber 7 through the first air intake port 7a is blown out toward the web W1, which is continuously transported from the other end of the drying chamber 7 to the one end, thereby drying the ink adhering to the web W1.

[0040] The air volume of each lower nozzle 9b disposed below the roller row 15 is set to be larger than the air volume of each upper nozzle 9a disposed above the roller row 15.

[0041] As shown in FIG. 2, the drying device 1 also includes a web transport unit 20 and a control means 12 connected to a drive source 14.

[0042] The control means 12 outputs drive signals to the web transport unit 20 and the drive source 14, respectively, to drive the web transport unit 20 and the drive source 14, thereby causing the web W1 to be continuously transported.

[0043] As described above, according to the first embodiment of the present invention, the web W1 can be transported back and forth inside the drying chamber 7 by the roller row 15 consisting of a plurality of transport rollers 8 lined up in a row in the drying chamber 7. Therefore, there is no need to arrange the roller rows in two rows, one above the other, as in Patent Document 1, and therefore the drying device 1 can be made compact overall while efficiently drying the ink adhering to the web W1. Furthermore, because there is no need to arrange the roller rows 15 in multiple rows to transport the web W1 back and forth, the number of parts can be reduced, and the drying device 1 can be made low-cost.

[0044] Furthermore, since each upper nozzle 9a is disposed at a position corresponding to each transport roller 8, the web W1 is pushed by the air blown out from each upper nozzle 9a, and the transport roller 8 corresponding to that upper nozzle 9a supports the web W1 from the opposite side. Therefore, the web W1 is less likely to be stretched during transport, and wrinkles, etc., can be prevented from occurring in the web W1.

[0045] Furthermore, by winding the web W1 around the suction roll 16, the tension of the web W1 after it passes through the suction roll 16 is reduced, making it less likely for wrinkles to form on the web W1 when the ink adhering to the web W1 is dried in the drying chamber 7. This is particularly true when continuously transporting a plastic web W1, which is prone to wrinkles due to tension. Furthermore, because the drying chamber 7 extends obliquely, even if the printing unit 6 is an inkjet type and the web W1 moves horizontally through the printing unit 6, the drying chamber 7 can be designed to be tall, and the suction roll 16 can be disposed between the drying chamber 7 and the printing unit 6. This allows for a compact structure around the drying device 1. This prevents the printing unit 6 from being positioned too high, making maintenance difficult.

[0046] Furthermore, since the volume of air blown out from each lower nozzle 9b located below the roller row 15 is greater than the volume of air blown out from each upper nozzle 9a located above, the web W1 located below the roller row 15 is strongly supported from below by the air blown out from each lower nozzle 9b, preventing the web W1 from drooping downward and being stretched, while also preventing the web W1 located above the roller row 15 from being pushed too hard by the air blown out from each upper nozzle 9a and being stretched.

[0047] Furthermore, since a plurality of mid-infrared heaters 11 are disposed above the roller train 15, the ink adhering to the web W1 during transport can be dried even more efficiently.

[0048] Furthermore, since the drive source 14 drives each conveying roller 8 to rotate synchronously in the same direction, it is possible to prevent a decrease in conveying speed due to frictional resistance, etc. when the web W1 passes through the roller row 15, thereby stabilizing the conveyance of the web W1 in the roller row 15.

[0049] Second Embodiment of the Invention 2 shows a printing apparatus 10 incorporating a drying device 1 according to a second embodiment of the present invention. This second embodiment is similar to the first embodiment except for the configuration of the roller train 15, so the same parts as those in the first embodiment are denoted by the same reference numerals, and only the other differences will be described.

[0050] That is, each conveying roller 8 of the roller row 15 of embodiment 2 is set so that its diameter gradually increases from one end of the roller row 15 to the middle of the roller row 15, while its diameter gradually decreases from the middle of the roller row 15 to the other end of the roller row 15.

[0051] As described above, according to the second embodiment of the present invention, the contact area between the web W1 transported back and forth in the roller row 15 and each transport roller 8 is increased compared to when the diameter of each transport roller 8 in the roller row 15 is constant. Therefore, meandering of the web W1 during transport in the roller row 15 is less likely to occur, and stable transport of the web W1 can be achieved.

[0052] Third Embodiment of the Invention 3 shows a printing apparatus 10 incorporating a drying device 1 according to a third embodiment of the present invention. This third embodiment is similar to the second embodiment except that it has two rows of rollers 15, one above the other. Therefore, the same parts as those in the second embodiment are denoted by the same reference numerals, and only the other differences will be described.

[0053] The drying chamber 7 of the third embodiment has two rows of rollers 15, one above the other, and a floating roll 13, which blows air from its outer circumferential surface, is disposed between each row of rollers 15 at one end of the drying chamber 7.

[0054] The upper roller row 15 guides the web W1, which passes through the printing unit 6 and enters the drying chamber 7 from one end to the other end of the drying chamber 7 in the upper area of ​​each rotating conveying roller 8, and then wraps it around the conveying roller 8 located at the end of the upper roller row 15, and guides it from the other end to the one end of the drying chamber 7 in the lower area of ​​each rotating conveying roller 8.

[0055] The floating roll 13 is configured so that the web W1 sent from the upper roller row 15 is wound around it, and the web W1 is turned back while being slightly floated by air, and is guided to the lower roller row 15.

[0056] The lower roller row 15 guides the web W1 sent by the floating roll 13 from one end to the other end of the drying chamber 7 in an upper region of each of the rotationally driven conveying rollers 8, and then wraps the web W1 around the conveying rollers 8 located at the end of the lower roller row 15, thereby turning it back and guiding it from the other end to one end of the drying chamber 7 in a lower region of each of the rotationally driven conveying rollers 8. Thereafter, the web W1 guided by the lower roller row 15 comes out of one end of the drying chamber 7, and then is guided by a plurality of guide rolls G1 toward the outfeed section 5.

[0057] As described above, according to the third embodiment of the present invention, even if the drying chamber 7 has a configuration in which a plurality of roller rows 15 are arranged vertically in parallel, it is possible to obtain the same effects as those of the first and second embodiments.

[0058] In the third embodiment of the present invention, two roller rows 15 are arranged in parallel, one above the other, but three or more roller rows may be arranged in parallel.

[0059] Furthermore, in the first to third embodiments of the present invention, the roller row 15 is inclined at an angle, but it may also be in a position where it extends horizontally, or it may be in a position where it extends vertically. When the roller row 15 extends vertically, the web W1 is guided to one side area and the other side area of ​​each transport roller 8 during reciprocating transport. That is, in the first to third embodiments of the present invention, the web W1 is guided to one side area and the other side area in the radial direction of each transport roller 8 during reciprocating transport.

[0060] Furthermore, in the first to third embodiments of the present invention, the lower nozzles 9b are positioned so as not to correspond to the transport rollers 8, but they may be provided at corresponding positions.

[0061] Furthermore, in the first to third embodiments of the present invention, the mid-infrared heater 11 is disposed only above the roller row 15, but it may also be disposed below the roller row 15.

[0062] Furthermore, in the first to third embodiments of the present invention, a plurality of mid-infrared heaters 11 are arranged in the drying chamber 7, but other types of heaters may be used, for example, a plurality of near-infrared heaters may be used.

[0063] Although the drying device 1 of the first to third embodiments of the present invention is applied to drying ink applied to the web W1 by the inkjet printing unit 6, it can also be applied to drying printing by other types of printing units, such as drying ink applied to the web W1 by a gravure printing unit. Furthermore, it can be applied to drying not only water-based ink but also oil-based ink. [Industrial Applicability]

[0064] The present invention is suitable for a drying device that dries ink that has been applied to a continuously transported web. [Explanation of symbols]

[0065] 1 Drying device 7 Drying room 8 Conveyor roller 9a Upper nozzle 9b Lower nozzle 11 Mid-infrared heater 14 Power Source 15 Roller row (rotation guide means) 16 Suction roll W1 Web

Claims

1. A drying device comprising: a drying chamber having one or more nozzles capable of blowing heated air; and configured to dry ink adhering to a web by blowing air from the nozzles toward the web while the web is being continuously conveyed through the drying chamber, a rotary guide means having a rotation axis extending horizontally and having at least one roller row made up of a plurality of conveying rollers arranged in parallel at predetermined intervals in a direction perpendicular to the rotation axis from one end side to the other end side of the drying chamber; the rotary guide means is configured to guide the web from one end side to the other end side of the drying chamber in one radial side region of each of the conveying rollers of the roller row, and then turn back the web and guide the web from the other end side to one end side of the drying chamber in the other radial side region of each of the conveying rollers of the roller row, In the radially one side region, the web comes into contact with the plurality of conveying rollers included in the roller row and is guided from one end side to the other end side of the drying chamber, and in the radially other side region, the web comes into contact with the plurality of conveying rollers that it has come into contact with in the radially one side region and is guided from the other end side to the one end side of the drying chamber.

2. A drying device comprising a drying chamber having one or more nozzles capable of blowing out heated air, and configured to dry ink adhering to a web by blowing air from the nozzles toward the web while the web is being continuously conveyed through the drying chamber, a rotary guide means having a rotation axis extending horizontally and having at least one roller row made up of a plurality of conveying rollers arranged in parallel at predetermined intervals in a direction perpendicular to the rotation axis from one end side to the other end side of the drying chamber; the rotary guide means is configured to guide the web from one end side to the other end side of the drying chamber in one radial side region of each of the conveying rollers of the roller row, and then turn back the web and guide the web from the other end side to one end side of the drying chamber in the other radial side region of each of the conveying rollers of the roller row, a suction roll disposed upstream of the drying chamber and guiding the web onto which ink has been transferred by an inkjet printing unit to the upstream end of the drying chamber; The drying device is characterized in that the drying chamber extends obliquely downward from one end to the other end.

3. A drying device comprising a drying chamber having one or more nozzles capable of blowing out heated air, and configured to dry ink adhering to a web by blowing air from the nozzles toward the web while the web is being continuously conveyed through the drying chamber, a rotary guide means having a rotation axis extending horizontally and having at least one roller row made up of a plurality of conveying rollers arranged in parallel at predetermined intervals in a direction perpendicular to the rotation axis from one end side to the other end side of the drying chamber; the rotary guide means is configured to guide the web from one end side to the other end side of the drying chamber in one radial side region of each of the conveying rollers of the roller row, and then turn back the web and guide the web from the other end side to one end side of the drying chamber in the other radial side region of each of the conveying rollers of the roller row, a driving source for driving the conveying rollers to rotate in the same direction in synchronization with each other;

4. A drying device comprising a drying chamber having one or more nozzles capable of blowing out heated air, and configured to dry ink adhering to a web by blowing air from the nozzles toward the web while the web is being continuously conveyed through the drying chamber, a rotary guide means having a rotation axis extending horizontally and having at least one roller row made up of a plurality of conveying rollers arranged in parallel at predetermined intervals in a direction perpendicular to the rotation axis from one end side to the other end side of the drying chamber; the rotary guide means is configured to guide the web from one end side to the other end side of the drying chamber in one radial side region of each of the conveying rollers of the roller row, and then turn back the web and guide the web from the other end side to one end side of the drying chamber in the other radial side region of each of the conveying rollers of the roller row, A drying device characterized in that the diameter of each of the conveying rollers is set to gradually increase from one end of the roller row to the middle of the roller row, and is set to gradually decrease from the middle of the roller row to the other end of the roller row.

5. A drying device according to any one of claims 1 to 4, The drying device is characterized in that the nozzle is disposed on a side of the web opposite to the row of rollers and at a position corresponding to the transport roller.

6. A drying device according to any one of claims 1 to 5, A drying device characterized in that one or more infrared heaters are arranged on the opposite side of the web from the row of rollers.

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