PROCESSING MACHINE COMPRISING A RADIATION DRYER AND METHOD FOR OPERATING SAID DRYER
20210001621 ยท 2021-01-07
Inventors
Cpc classification
B41F23/0483
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
A processing machine includes a dryer device. In particular, the processing machine is a printable material- or sheet-processing or a substrate-processing machine, in particular a printing machine. A method for operating a drying device in such a processing machine is also provided. The processing machine addresses the problem of creating an alternative processing machine comprising a drying device or an alternative method for operating a drying device in a processing machine. In particular, the cooling in preferably high-performs dryers in processing machines, such as substrate, or printable material-processing machines, should be improved. Especially preferably the cooling of the underside of the underside of a UV emitter should also be further improved. The problem is solved by pairing a blast air system with the drying device, by the use of which blast air system, the ambient air flowing into the air inlet opening can be or is actively influenced at a distance from the radiation source.
Claims
1-50. (canceled)
51. A processing machine having a drying device (1), wherein the drying device (1) comprises a radiation source (2) accommodated in a housing (8), wherein shutters (9) are provided adjacent to the radiation source (2) in the housing (8), wherein the housing (8) has at least one air inlet opening (10) for ambient air (11) so that, once the ambient air (11) has entered the housing (8), it flows around the radiation source (2), and wherein the housing (8) has an air outlet opening (12) for exhaust air (11, 17), characterized in that, associated with the drying device (1) is a blower air system (13), by means of which the ambient air (11) flowing into the air inlet opening (10) is and/or can be actively influenced at a distance from the radiation source (2).
52. The processing machine according to claim 51, wherein the blower air system (13) has at least one air flow opening (16) that expels an air flow (17) at least approximately orthogonally to the direction of flow of the ambient air (11) flowing into the air inlet opening (10).
53. The processing machine according to claim 51, wherein the radiation source (2) is configured as an elongated UV emitter (2) having two electrodes (19) lying spaced apart from one another, each in one plane (E1, E2), wherein the elongated UV emitter (2) is arranged as a normal to the planes (E1, E2), and wherein the blower air system (13) generates air flows (17) exclusively in a region (B) that lies between the planes (E1, E2) or is bounded by the planes (E1, E2).
54. The processing machine according to claim 51, wherein the blower air system (13) has at least two opposing air flow openings (16) arranged adjacent to the air inlet opening (10).
55. The processing machine according to claim 51, wherein the blower air system (13) has one or more air flow openings (16) arranged outside of the air inlet opening (10).
56. The processing machine according to claim 51, wherein the blower air system (13) comprises a compressed air connection (18) and/or at least one air generator, in particular an axial fan (14), air ducts (15), and a plurality of air flow openings (16), and/or wherein the air outlet opening (12) is formed by an exhaust air duct (12) in the housing (8), which is connected to a suction air source and has one or more openings to the space surrounding the radiation source (2).
57. The processing machine according to claim 51, wherein the drying device comprises a UV module (1), which can be arranged in a delivery, in a drying tower, and/or as an interdeck dryer in a printing press and/or which is embodied as insertable into plug-in slots, and/or wherein the blower air system (13) is configured as an add-on module to be added on to a UV module (1) or as an auxiliary module for a UV module (1).
58. The processing machine according to claim 51, wherein the blower air system (13) has blower air openings (16), the opening gap of which is adjustable, in particular between 1 mm and 10 mm or between 2 mm and 6 mm.
59. The processing machine according to claim 51, wherein the blower air system (13) can be controlled by a control device based on the current emitter output of the radiation source (2) or can be regulated by a control device based on the current emitter output of the radiation source (2), which is determined by a sensor system.
60. A method for operating a drying device (1) in a processing machine, wherein the drying device (1) comprises a radiation source (2) extending inside a housing (8), wherein the radiation source (2) cooperates with shutters (9), wherein the housing (8) has at least one air inlet opening (10) for ambient air (11) so that, once the ambient air (11) has entered the housing (8), it flows around the radiation source (2), and wherein the housing (8) has an air outlet opening (12) for the exhaust air (11, 17) flowing around the radiation source (2), characterized in that a blower air system (13) associated with the drying device (1) actively influences or deflects the ambient air (11) flowing into the air inlet opening (10) before it reaches the radiation source (2).
61. The method according to claim 60, wherein the blower air system (13) directs an air flow or expels blower air (17), which restricts or constricts, in a region (B), the ambient air (11) flowing into the housing (8) through the air inlet opening (10).
62. The method according to claim 60, wherein the blower air system (13) directs an air flow or expels blower air (17), which, together with the inflowing ambient air (11), forms the cooling air and subsequently the exhaust air, wherein the proportion of the air flow volume introduced by the blower air system (13) is between 20% and 50% of the common cooling air flow volume or is at least approximately 33% of the common cooling air flow volume.
63. The method according to claim 60, wherein the blower air system (13) is switched on and/or switched off based on the output of the radiation source (2).
64. The method according to claim 60, wherein the blower air system (13) is switched on when an emitter output of at least approximately 120 to 140 W/cm is reached and/or is switched off when the emitter output drops below at least approximately 120 to 140 W/cm.
65. The method according to claim 60, wherein the blower air system (13) is operated in such a way that the effect of the blower air system (13) increases, in particular linearly or in a functionally dependent manner, up to the maximum output based on the emitter output, and/or wherein at an emitter output of at least approximately 200 W/cm, the effect of the blower air system (13) is at 100%.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] In the following, the invention will be explained in detail by way of example. The accompanying drawings schematically depict the following:
[0025]
[0026]
[0027]
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[0029]
[0030]
[0031]
[0032]
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[0034]
[0035]
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0036] In processing machines such as printing material processing machines, in particular printing presses or sheet processing machines, for example sheet-fed printing presses, in particular sheet-fed rotary offset printing presses, preferably in unit-based and inline configuration, substrates or printing materials are conveyed through the machine. In sheet processing machines, sheets of printing material, for example, are gripped at the leading edge by cylinders or by drums and are conveyed or transported through the machine as the cylinders rotate. The sheets of printing material are transferred between the cylinders in the gripper closure. In printing presses, the printing materials pass through various printing units along the conveying path, in each of which the materials are printed with a respective printing ink in accordance with the desired motif. Each of the printing units may comprise, for example, a plate cylinder, which is inked up by means of an inking unit with the printing ink to be used. This inked-up plate cylinder transfers the printing ink, in accordance with the motif, onto a blanket cylinder furnished with a rubber printing blanket, which cylinder forms a printing nip with a printing cylinder of a sheet-fed printing press, which printing cylinder conveys the sheet of printing material. As it passes through the printing nip, the corresponding motif is transferred from the inked-up rubber printing blanket of the blanket cylinder onto the sheet of printing material.
[0037] Downstream of the last printing unit of the printing press, the printed sheets of printing material can be delivered in a delivery of a sheet-fed printing press to form a delivery pile. The last printing unit can also be followed, for example, by one or more coating units, which furnish the printed sheets of printing material with a protective coating or gloss coating. UV inks are preferably used in the printing units and UV coatings are preferably used in the coating units. For recto-verso printing, a printing press may include a turning device. Alternatively, however, other printing methods, for example with variable motifs, can also be used. A drying device or an interdeck dryer in the machine is embodied, in particular, as a UV drying device and comprises one or more UV modules 1, for example.
[0038]
[0039] On the path to the delivery pile, the sheets 4 are guided past the UV modules 1 that dry or cure the sheets 4. The UV modules 1 each have UV emitters 2, the UV radiation of which is directed directly or via reflectors 3 onto the surface of the sheets 4. This UV radiation acting on the sheets 4 dries or cures the treated sheet surface, in particular the printed UV ink and/or the applied UV coating. Preferably, mercury vapor lamps are used as radiation sources in the UV modules 1. Additionally or alternatively, emitters with other wavelengths, such as infrared dryers, for example, can also be used. For example, plug-in slots can be provided in the machine or the delivery, into which the UV modules 1 can be inserted. The UV modules 1 can be fixed in these plug-in slots, thereby ensuring that the UV modules 1 can be replaced, e.g. if the UV emitter 2 becomes worn. The UV modules 1 operate in particular with exhaust air cooling.
[0040]
[0041]
[0042]
[0043] The ambient air, which is drawn in between the shutters 9 or reflectors 3 and the UV emitter 2, flows through the air inlet opening 10 that faces the substrate or printing material and thereby cools the UV emitter 2. The cooling air then flows out between the shutters 9 into the exhaust air duct 12 of the housing profile 8. For this purpose, the exhaust air duct 12 is preferably connected on one side to a suction air source that can be controlled or regulated, for example, which draws the exhaust air into the exhaust air duct 12. The exhaust air duct 12 preferably extends over the entire length of the UV emitter 2, so that the air heated at the UV emitter 2 can be drawn off into the exhaust air duct 12 through distributed openings. It can be provided, for example, that the exhaust air duct 12, which extends along the radiation source, in particular the UV emitter 2, can be connected to the space surrounding the UV emitter 2 via oblong holes that are spaced apart from one another. Said oblong holes are preferably dimensioned such that they differ from one another in terms of their aperture areas. In particular, the aperture areas of the oblong holes between the ends of an elongated UV emitter 2 are smaller in dimension than the oblong holes provided at the respective ends of the UV emitter 2. Very preferably, the aperture areas of the oblong holes between the ends of the elongated UV emitter 2 are dimensioned as steadily decreasing in size, in particular without local maxima, toward the suction air source of the exhaust air duct 12. More preferably, the aperture areas of the oblong holes associated with the ends of the elongated UV emitter 2 are dimensioned differently from one another, with the aperture area of at least one oblong hole at the end of the UV emitter 2 that faces the suction air source of the exhaust air duct 12 preferably having smaller dimensions than the aperture area of at least one oblong hole at the end of the UV emitter 2 that faces away from the suction air source of the exhaust air duct 12. The oblong holes that face the respective ends of the UV emitter 2 can also comprise two, three, or four oblong holes.
[0044] The air flows that result during operation with exhaust air cooling activated and with the blower air system 13 deactivated are depicted here generally or schematically. Cooling occurs above all on the upper side of the UV emitter 2, while the underside directed toward the processing material is cooled less than the upper side. Warming up can take place in this operating mode, for example. This can also be the operating mode, for example, during operation when the UV module 1 is operating at low output, for example, in particular when the glass tube temperature is low, for example when the emitter output is less than 140 to 120 W/cm.
[0045]
[0046] The blower air jets 17 generated by the blower air system 13 are aligned toward one another in one plane, in particular such that they influence, in particular restrict or constrict, the ambient air flow 11 flowing into the housing profile 8. The blower air jets 17 are preferably directed toward one another in one plane in such a way that they would preferably meet at the center of the air inlet opening 10, for example exactly below the UV emitter 2. The ambient air flow 11 is preferably influenced in such a way that the ambient air flow 11 cools the underside of the UV emitter 2, which faces the processing material or printing material, with increased intensity. In particular, the blower air system 13 generates a cross flow to the ambient air flow 11.
[0047]
[0048]
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[0050]
[0051] The cooling system or blower air system 13 of the radiation source, in particular of the UV emitter 2, has a maximum cooling capacity here exclusively in a cooling region B between the planes E1, E2 formed by the electrodes 19. A constant cooling output is preferably generated over the entire cooling region B, the cooling region B particularly preferably extending only between the mutually facing surfaces of the electrodes 19. However, the maximum cooling output in the cooling region B can be controlled or adjusted in terms of intensity or effect according to desired requirements. Adjacent to the cooling region B, in particular outside of the planes E1, E2, the cooling output of the cooling system or the blower air system 13 is reduced as compared with the maximum cooling capacity, or preferably is zero. The diameter of the glass body 20 in the present case is larger between the planes E1, E2 or in the cooling region B than in the edge regions. Outside of the planes E1, E2, the glass body 20, which surrounds the electrodes 19, tapers, with the tapered ends of the glass body 20 in particular bearing the pins 21 for establishing electrical contact with the electrodes 19. Physically, therefore, the electrodes 19 preferably lie largely outside of the cooling region B of the cooling system or blower air system 13. This embodiment is particularly preferably used in medium-format machines, such as sheet-fed printing presses. Medium format machines can be used to process processing material measuring at least approximately 1 m in width, for example.
[0052]
[0053]
[0054] Regarding the mode of operation: In order for the radiation source, in particular a UV emitter 2, to also be cooled well on its underside, air is preferably blown in on both sides, in particular beyond the irradiation range of the UV module 1. This air preferably meets at the center beneath the UV module 1, in particular approximately at the center of the UV emitter 2. The inflowing ambient air constricted by the blower air jets 17 in the UV module 1 is transported to the underside of the UV emitter 2. In this way, the underside of the UV emitter 2 is intensely cooled. Furthermore, cooling becomes more turbulent overall and the upper side of the UV emitter 2 is also cooled better. WALTER
[0055] The additional air is preferably introduced or blown in exclusively between electrodes 19 of the UV emitter 2 or over the length of the UV module 1. This can be accomplished by means of plates and/or blower air nozzles.
[0056] The air that is preferably introduced or blown in on both sides can be either a partial volume or at least nearly all of the cooling air acting in the UV module 1. Preferably, however, 80% to 50% of the cooling air is formed by the inflowing ambient air flow 11, and 20% to 50% of the cooling air is formed by the air introduced by the blower air system 13. In particular, a proportion of of the air or blower air 17 that is additionally introduced by the blower air system 13, and a proportion of of the inflowing ambient air flow 11 is sought.
[0057] For example, the UV emitter 2 can be operated at an output of between approx. 80 W/cm and approx. 200 W/cm. The blower air system 13 can also be activated or switched on dependent on the output. In particular, the blower air system 13 can be activated only after it reaches an average output, for example at approximately 120 to 140 W/cm. In that case, the blower air system 13 can be fully inactive or can be fully deactivated below an emitter output of, for example, 120 to 140 W/cm. For example, the blower air system 13 can be activated as soon as it reaches 120 to 140 W/cm. Preferably, the effect of the blower air system 13 can be increased as the emitter output increases. In particular, the blower air system 13 can begin to operate as soon as an emitter output of 120 to 140 W/cm is reached and can preferably be increased linearly or in a functionally dependent manner up to a maximum emitter output of 200 W/cm, so that at an emitter output of 200 W/cm, the blower air system 13 is operating at 100% output.
[0058] In the case of functionally dependent control, the blower air can be adjusted in particular according to a set of characteristics, which can have local maxima and/or minima, for example. In that case, the blower air can be adjusted on the basis of a curve established, for example, between 120 W/cm and 200 W/cm. A function for operating the blower air system 13 can be specified and/or modified based on the emitter output, in particular dependent on the machine. However, the effect of the blower air system 13 can also be adjusted individually and/or can also be embodied as controlled or regulated, for example, according to the emitter output. In that case, the current emitter output can be known to a control device, in particular the machine controller, or can be determined by a sensor system. By reducing the effect of the blower air system 13 or by switching off the blower air system 13 at a low emitter output, for example below 140 W/cm, a blow-out of the UV emitter 2 is reliably prevented.
[0059] While a preferred embodiment of a processing machine having a radiation dryer and a method for operating such a dryer is disclosed fully and completely hereinabove, it will be apparent to one of skill in the art that various changes can be made thereto, without departing from the true spirit and scope of the present invention, which is accordingly to be limited only by the appended claims.