Abstract:
A guiding device for an areal printing material, the guiding device having an areal structure with a guide surface facing towards the printing material, and wherein the areal structure includes a supporting layer, and a surface layer is provided for forming the guide surface and covering the supporting layer; and a rotary printing machine equipped with the guiding device.

Description:
BACKGROUND OF THE INVENTION 
     FIELD OF THE INVENTION 
     The invention relates to a guiding device for an areal printing material with a substantially two-dimensional structure, such as a sheet material, the guiding device having a guide surface facing the printing material. The invention further relates to a sheet-processing machine, in particular a rotary printing machine, equipped with such a guiding device. 
     A guiding device of the aforementioned type is disclosed, for example, by the published German Patent Document DE 196 02 514 C1. As this document discloses, high requirements are placed on guiding devices for sheet printing materials, and in fact, particularly on the guide surface formed thereon. They must be made especially smooth. Guiding devices used by the applicant therefore have a high-gloss polished guide surface. This requires particularly careful procedures in the production and handling of a conventional guiding device and, therefore, involves the risk of a given rate of wastage. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a guiding device of the type mentioned in the introduction hereto, which can be produced with a possible wastage or reject rate that is considerably reduced. 
     With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a guiding device for an areal printing material, the guiding device having an areal structure with a guide surface facing towards the printing material, the areal structure comprising a supporting layer, and a surface layer is included for forming the guide surface and covering the supporting layer. 
     In accordance with another feature of the invention, the guiding device includes at least one support which, together with the supporting layer, forms a subassembly. 
     In accordance with a further feature of the invention, the support is trough-like in structure, has feed and discharge openings, and is otherwise closed by the supporting layer. 
     In accordance with an added feature of the invention, the support and the supporting layer are sealingly joined to one another. 
     In accordance with an additional feature of the invention, the support has a trough base formed with elevations, and the elevations are joined to the supporting layer. 
     In accordance with yet another feature of the invention, the support and a respective one of the elevations, on the one hand, and the supporting layer, on the other hand, are sealingly joined to one another and, in a region of a respective one of the elevations, are formed with apertures communicating with one another, the surface layer being formed with openings communicating with the apertures. 
     In accordance with yet a further feature of the invention, the guiding device comprises a chamber arrangement forming domes due to the elevations of the trough base. 
     In accordance with yet an added feature of the invention, the surface layer is provided with nozzles, a respective one of the nozzles, on the one hand, forming one of the openings in the surface layer and, on the other hand, extending into one of the apertures formed in the supporting layer, which communicates with one of the openings. 
     In accordance with yet an additional feature of the invention, a respective one of the nozzles forms a shaped region of the surface layer. 
     In accordance with a concomitant aspect of the invention, there is provided a rotary printing machine having a guiding device for an areal printing material, the guiding device having an areal structure with a guide surface facing towards the printing material, the areal structure comprising a supporting layer, and including a surface layer forming the guide surface and covering the supporting layer. 
     In one configuration of the guiding device according to the invention, the supporting layer forms an underlayer for the surface layer forming the guide surface, and therefore does not have to rest smoothly on the surface layer over the entire area. In particular, the surface layer, in preferred improved constructions thereof, is shaped so that, in spite of a relatively small layer thickness, it has a dimensional stability which is sufficient for the requirements and, for example, fixing lugs molded on integrally or in one piece, whereas according to a further development, at least one support is provided which, together with the supporting layer, forms a subassembly. 
     The supporting layer can have deformations, for example, which are directed away from the surface layer covering the supporting layer and are formed as beads, so that, in particular, in the case of one development, wherein a support is provided that is joined to the sheet-like structure via a fastening on the supporting layer, at the bottom of the respective bead, the most varied types of connections or joinings of the supporting layer to a support are possible, without affecting the guide surface in any way thereby. Instead, the surface layer forming the guide surface bridges over the aforementioned beads and/or other irregularities or discontinuities which may be in the surface of the supporting layer facing the surface layer. In particular, therefore, the supporting layer can be screwed or welded to a support, at the base of appropriate beads on the supporting layer, to form a subassembly. However, welding the supporting layer to a support is possible even without the formation of beads in the supporting layer, even in the case of a given build-up of corresponding welds on that surface of the supporting layer which faces the surface layer, because a build-up which may have an effect upon the course of the surface layer can be ground off before the supporting layer is covered by the surface layer. 
     In a configuration according to the invention of the guiding device mentioned at the introduction hereto, in particular, no increased requirements are thus placed on the supporting layer, to the extent that it is the condition of a surface of the supporting layer which is covered by the surface layer. 
     The process of producing the aforementioned subassembly, therefore, does not require any special measures to protect surfaces of the parts belonging to the subassembly. Appropriate measures are required only during the completion of the guiding device, by covering the supporting layer by the surface layer, and the further handling of the completed guiding device. In the event of any damage which may occur to the guide surface in the process, such damage is restricted to replacing the surface layer so that costs arising from any reject, wastage or spoilage are noticeably lower than in the case of rejects during the production of conventional guiding devices. 
     In an advantageous improvement, the support is trough-like, it has feed and discharge openings and is otherwise closed by the supporting layer. If, in addition, a support of such a construction and the supporting layer are preferably sealingly joined to one another, a chamber results, through which a cooling liquid can be pumped. A guiding device constructed in such a way is therefore suitable for guiding a sheet printing material along path sections wherein heat is transferred onto the guiding device from a dryer. 
     In a preferred improvement, the aforementioned trough-like support has a trough base provided with elevations, and the elevations are joined to the supporting layer. Therefore, even with a relatively thin-walled construction of the supporting layer and of the support, the subassembly formed therefrom proves to be relatively stable dimensionally. 
     If, according to a preferred development of the support, the supporting layer and a respective one of the elevations of the support are sealingly joined to one another, the supporting layer, on the one hand, and a respective one of the elevations, on the other hand, in the area thereof, are provided with apertures which communicate with one another, and openings which communicate with the apertures are provided in the surface layer, then the aforementioned cooling liquid, as it flows through the chambers formed by the supporting layer and the support, is advantageously ducted straightforwardly so that, on the supporting layer and on the support, areas that are not in contact with the cooling liquid are formed and surround a respective one of the apertures, so that the support and the supporting layer, and therefore also the surface layer, permit a throughput through the apertures thereof of a fluid which is separate from the cooling liquid. In this case, the elevations in the trough base preferably constitute cup-like depressions which are indented in the trough base from the outside thereof. 
     The aforementioned fluid is then preferably gaseous and is formed of ambient air in an available or in a conditioned state and, for the purpose of the ducting thereof, provision is moreover preferably made of a chamber arrangement through which the fluid flows during operation and which, due to the elevations in the trough base, forms domes. In this case, conditioned ambient air is to be understood in particular to mean that this air is, for example, dried and/or warm and/or carries powder with it. 
     Depending upon the use of the guiding device, the flow through the chamber arrangement takes place in such a manner that blown air flows out of the openings provided in the surface layer, or in such a manner that these openings are connected to a vacuum source, or in such a manner that a number of these openings are connected to a vacuum source while blown air emerges from the remaining openings. For the last case, the chamber arrangement is subdivided into corresponding excess pressure chambers and vacuum chambers. A chamber arrangement in the form of a multiplicity of separate individual chambers is preferably also provided for the case wherein the openings provided in the surface layer are penetrated, in particular, in groups, by different volume flows, it then being the case that a respective group of the openings communicates with at least one of the individual chambers. 
     In a further improvement, the surface layer is provided with nozzles. A respective one of the nozzles, on the one hand, forms one of the openings in the surface layer and, on the other hand, extends into one of the apertures communicating with one of the openings. These nozzles are furthermore preferably formed by shaping the surface layer, so that they are joined to the surface layer integrally or in one piece. Overall, therefore, a guiding device provided for a sheet printing material is produced by a manufacturing process which can proceed to the greatest possible extent without taking special account of surface qualities. This is because particular care with a view to the protection of surfaces is required only when forming the openings provided in the surface layer and when fitting or applying the surface layer to the supporting layer. 
     Because of the one-piece connection or joint between the nozzle and the surface layer, it is moreover possible to achieve a continuous transition between the guide surface and a region of the surface layer that forms a respective one of the nozzles. In particular, in the region of the nozzles, no joints or steps result, which otherwise would be inevitable if separate nozzles were to be inserted into the guiding device. 
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a guiding device for an areal printing material, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
    
    
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, wherein: 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a fragmentary diagrammatic side elevational view of a sheet-processing rotary printing machine embodying the invention, and showing a delivery section thereof; 
     FIG. 2 is a fragmentary sectional view of a guiding device for areal printing material, constructed in accordance with the invention; 
     FIG. 3 is a fragmentary, partly broken-away sectional view of the guiding device according to the invention, which is usable as a floating guide for a printing material guided thereover and is traversible by a cooling liquid flowing therethrough; 
     FIG. 4 is an enlarged fragmentary view of FIG. 3; and 
     FIG. 5 is a reduced top and two-side perspective view of the guiding device of FIG. 4, rotated approximately 45° counterclockwise. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Guiding devices for a sheet printing material are used both in web-fed rotary printing machines and in sheet-processing rotary printing machines and are preferably used in areas wherein the respective printing material is deflected as it passes through the respective machine. In this regard, sheet-processing rotary printing machines assume a special position, because a corresponding guiding device is provided therein also in order to guide the processed, i.e., printed and possibly varnished, sheets, on their path to a stacking station. 
     The following explanations are therefore based by way of example on a sheet-processing printing machine. 
     Referring now to the drawings and, first, particularly to FIG. 1 thereof, there is shown therein, accordingly, a section of a sheet-processing rotary printing machine, comprising a delivery  1  following a last processing station, which may be a printing unit or a post-treatment unit, such as a varnishing unit. In the exemplary embodiment at hand, the last processing station is a printing unit  2  operating with the offset process and having an impression cylinder  2 . 1 . The latter guides an areal printing material in the form of a respective sheet  3 , in a processing direction indicated by an arrow  5  representing the direction of rotation of the cylinder  2 . 1 , through a printing nip formed between the impression cylinder  2 . 1  and a blanket cylinder  2 . 2  cooperating therewith, and then transfers the sheet  3  to a chain conveyor  4  while opening grippers which are arranged on the impression cylinder  2 . 1  and which are provided for gripping the sheet  3  at a gripper edge located at a leading end of the sheet  3 . The chain conveyor  4  includes two conveyor chains  6 , one of which, respectively, revolves along a respective side wall of the chain delivery  1  during operation. A respective conveyor chain  6  in each case wraps around one of two, respectively, synchronously driven drive sprockets  7 , having axes of rotation which are mutually aligned and, in the exemplary embodiment at hand, is respectively guided over a deflection sprocket  8  which is located downline of the drive sprockets  7 , as viewed in the processing direction. Extending between the two conveyor chains  6  and carried thereby are gripper systems  9  having grippers  9 . 1 , which pass through gaps between the grippers arranged on the impression cylinder  2 . 1  and, in so doing, accept a respective sheet  3 , gripping the aforementioned gripper edge at the leading end of the sheet  3 , directly before the grippers arranged on the impression cylinder  2 . 1  open, transport the sheet over a guiding device  10 , illustrated very diagrammatically in FIG. 1, to a sheet brake  11 , and open thereat in order to transfer the sheet  3  to the sheet brake  11 . The latter imparts to the sheet  3  a deposition speed which is reduced with respect to the processing speed and, after the deposition speed has been reached, in turn, releases the sheet  3 , so that the respective, now decelerated or retarded sheet  3 , finally encounters leading-edge stops  12  and, being aligned against the latter and against trailing-edge stops  13  located opposite thereto, together with preceding and/or following sheets  3  forms a sheet pile or stack  14 , which is lowerable by a lifting mechanism to the same extent as the sheet pile or stack  14  grows. Of the lifting mechanism, only a platform  15  carrying the sheet pile or stack  14  and lifting chains  16 , which carry the platform  15  and are represented in phantom, are reproduced in FIG.  1 . 
     Along the paths thereof between the drive sprockets  7 , on the one hand, and the deflection sprockets  8 , on the other hand, the conveyor chains  6  are guided by chain guide rails, which consequently determine the chain paths of the chain strands. In the example at hand, the sheets  3  are transported by the lower chain strand, as shown in FIG.  1 . That section of the chain path through which the lower chain strand passes is followed by a guide surface  17  which is formed on the guiding device  10  and faces towards that chain path section. Between the guide surface  17  and the respective sheet  3  guided thereover, a supporting air cushion is preferably formed during operation. For this purpose, the guiding device  10  is equipped with blown-air nozzles which open into the guide surface  17 , the nozzles being discussed hereinafter in greater detail. 
     In order to prevent mutual adhesion between the printed sheets  3  in the sheet pile or stack  14 , a dryer  19  and a powdering device  20  are provided on the path of the sheets  3  from the drive sprockets  7  to the sheet brake  11 . 
     In order to avoid excessive heating of the guide surface  17  by the dryer  19 , the guiding device  10  is integrated into a coolant circuit, which will likewise be discussed hereinafter in greater detail. 
     The principle upon which the construction of the guiding device according to the invention is based is apparent from FIG. 2, the principle being that a supporting layer  21  is covered by a surface layer  24 , whereon the guide surface  17  is formed. Illustrated in FIG. 2 is a section  10 ′ of the guiding device  10 , that extends along the travel direction of the printing material  3 . The section  10 ′ includes a supporting layer  21  which, in accordance with a preferred construction, together with at least one support  22 ,  22 ′ connected thereto, forms a subassembly  23 . After constructing this subassembly  23 , the supporting layer  21  is covered by the surface layer  24 , whereon the guide surface  17  is formed. 
     It is believed to be readily apparent that, in every case, in the direction transverse to the travel direction of the printing material, the surface layer  24  extends at least over that extent,of the printing material disposed transversely to the travel direction. However, the transverse extent of the surface layer  24  and also the transverse extent of the supporting layer  21  expediently project beyond that of the printing material, and at the edges of the guiding device, which are therefore located outside the transverse extent of the printing material, a preferably detachable connection between the surface layer  24  and the supporting layer  21  is provided. Nevertheless, non-detachable connections between the surface layer  24  and the supporting layer  21  in the areas of the aforementioned edges thereof are likewise within the scope of the invention, an appropriate detachable or non-detachable connection preferably being made following the formation of the subassembly  23 . An appropriate connection between the surface layer  24  and the supporting layer  21  is, in particular, provided for the purpose of making the surface layer  24  follow a course having a trend that is predefined by the supporting layer  21 . In this connection, the term “trend”means that the surface layer  24 , in particular, bridges over local depressions in the supporting layer  21 . 
     In the exemplary embodiment of FIG. 2, local depressions in all the supporting layer  21  are present in the form of turned-up tongues  21 . 1  of the supporting layer  21 , and in the form of beads  25 , which can be cup-like or can extend over the supporting layer  21 , transversely with respect to the travel direction of the printing material, and form areas wherein it is possible to connect the supporting layer  21  to a support  22  or  22 ′ without having any effect upon the surface layer  24 . 
     In a further improvement, a combination of cup-shaped and elongated beads is provided. 
     As examples of possible types of connections, a bolt or screw connection to the support  22 , and a welded connection to the support  22 ′ are illustrated in FIG.  2 . 
     In exemplary embodiments reproduced in FIG. 2, the supports  22  and  22 ′, respectively, serve for assembling the guiding device  10 ′ in a rotary printing machine, such as is illustrated by way of example in FIG.  1 . For this purpose, turned-up edges  22 . 1  and  22 ′. 1 , respectively, are provided on the supports  22  and  22 ′, respectively, which, for example, with contact thereof with a respective side wall of the rotary printing machine, are fixed in the latter by screw connections. 
     In a non-illustrated construction, elongated beads extending transversely to the travel direction of the printing material are formed and, at the base thereof, fixing lugs molded on in one piece and corresponding to the turned-up edges  22 . 1  and  22 ′. 1 , respectively, are provided. 
     Sections of the guiding device  10  illustrated only in very simplified diagrammatic form in FIG. 1 are reproduced in extended form, by way of example, in FIG. 3 in the form of a section along the travel direction of the printing material and in accordance with a preferred embodiment. In this case, a supporting layer  21 ′ and a support  22 ″ connected thereto form a subassembly  23 ′ of a configuration which is special inasmuch as the support  22 ″ is trough-like, has a feed opening  26  and a discharge opening  27  and is otherwise closed by the supporting layer  21 ′. 
     The supporting layer  21 ′ and the support  22 ″ are further preferably connected tightly sealed to one another, so that a chamber is formed, which can be integrated into a cooling-liquid circuit via connecting pieces  28  connected on one side to the feed opening  26  and on the other side to the discharge opening  27 . 
     In addition, the trough-like support  22 ″ has a trough base  30  provided with elevations  29 . Between the elevations  29  and the supporting layer  21 ′ there is a connection which, among others, contributes a given dimensional stability to the subassembly  23 ′, even when the wall thicknesses of the supporting layer  21 ′ and the carrier  22 ″ are relatively small. 
     FIG. 4 is an enlarged view of one of the sections of the guiding device, which is disposed between end sections of the guiding device shown in FIG. 3, and offers a clearer view of special features thereof explained hereinbelow than may be seen in FIG.  3 . 
     These special features include, among other things, the fact that the aforementioned connection between the elevations  29  and the supporting layer  21 ′ is formed as a sealing connection. For this purpose, in this exemplary embodiment of FIG. 4, the elevations  29  projecting beyond the trough base  30  in the direction towards the supporting layer  21 ′ are formed as cup-like depressions indented into the trough base  30  from outside thereof, and connected to the supporting layer  21 ′ by an endless weld  31 . As explained hereinbefore, a connection or joint of this type has no problematic effect with regard to the quality of the guide surface  17  formed on the surface layer  24 , because the weld is preferably located in the base of a bead  32  formed in the supporting layer  21 ′, the base of the bead  32  being directed away from the surface layer  24 . 
     During a preferred manner of producing the weld  31  by a laser, the power thereof is set to a sufficiently high value that an entirely satisfactory joint or connection between the supporting layer  21 ′ and the elevations  29  is achieved. In this regard, it does not matter from which side the laser is directed onto the parts to be joined or connected thereby, because, both options regarding the bead do not give rise to any impairment which could have a detrimental effect upon the guide surface  17  of the surface layer  24 , which is completely unaffected by the welding operation. 
     The sealing joint or connection which has been mentioned hereinbefore and is otherwise provided between the supporting layer  21 ′ and the trough-like support  22 ″, i.e., joining or connecting the supporting layer  21 ′ to a circumferential rim of the support  22 ″, is preferably likewise produced by welding by a laser, but differing from as illustrated in FIG. 3, the supporting layer  21 ′ is provided with a bead which follows the circumferential rim and is directed away from the surface layer  24  and has a base wherein a corresponding endless weld extends. If such a bead were to be dispensed with, a local build-up of material, which might be produced on the supporting layer  21 ′ by the welding, would have to be removed, if it had a disruptive effect on the course of the surface layer  24 . 
     If, as mentioned hereinbefore, a coolant chamber  33  integrated in a cooling-liquid circuit is formed by the supporting layer  21 ′ and the trough-like support  22 ″, and if the elevations  29  are sealingly joined to the supporting layer  21 ′ by a respective one of the welds  31 , then a respective area enclosed by one of the welds  31  forms, in relation to a cooling liquid flowing through the coolant chamber  33 , an island which cannot be reached by the fluid and which is formed, as presented hereinbelow, for the case wherein a printing material is guided floatingly over the guide surface  17 . 
     The islands are distributed over the guiding device  10  in a given, here not illustrated arrangement, and are, respectively, provided with an aperture  34  in the supporting layer  21 ′, and an aperture  35  in the support  22 ″ communicating with the aperture  34 . Provided in the surface layer  24  are openings  36 , a respective one of which communicating with one of the apertures  34  provided in the supporting layer  21 ′ and therefore also with one of the respectively associated apertures  35  formed in the support  22 ″. In addition, a chamber device  37  is provided which is constructed so that the elevations  29  of the trough base  30  form domes of the chamber device  37 . As explained hereinbefore, the chamber device  37  preferably includes separate individual chambers  37 ′, respectively, including some of the elevations  29 . A configuration of this type is reproduced in FIG. 3, merely by way of example. Here, the elevations  29  belonging to one of the individual chambers  37 ′, respectively, follow one another perpendicularly to the plane of the drawing. The construction of the guiding device is not restricted, however, to this arrangement of elevations  29  and individual chambers  37 ′. 
     In this exemplary embodiment, a respective individual chamber  37 ′ is formed by a trough  38  which, at a trough rim  38 . 1  thereof, is joined to the trough-like support  22 ″ by that side of the trough base  30  which faces away from the supporting layer  21 ′. 
     A respective individual chamber  37 ′ is connectable via a connecting piece  37 ′. 1  communicating therewith, to a blower or a vacuum generator, as required, so that with regard to the configuration of the guiding device described hereinbefore, a respective opening  36  in the surface layer  24  is traversible by ambient air in one or the other opposite direction during operation without any further measures. 
     In this regard, in principle, lower requirements are made as to the tightness of the joint or connection between the trough rim  38 . 1  and the support  22 ″ than as to the respective joints or connections between the support  22 ′ and the supporting layer  21 ′. In particular, it is sufficient to screw the trough base  38 . 1  to the trough base  30  of the support  22 ″, with the interposition of a loop or O-ring seal, for example. For this purpose, as illustrated alternatively in FIG. 4, threaded bolts are welded onto the trough base  30  or threaded sockets are inserted into the trough base  30 . 
     In particular, for the case wherein an individual chamber  37 ′ is connected to a blower, an opening  36  through which air flows out of the individual chamber  37 ′, respectively, is formed at a nozzle  39 , with which the surface layer  24  is provided, and which extends into the apertures  34  and  35  assigned to the opening  36  and formed in the supporting layer  21 ′ and the support  22 ″, respectively. The nozzles  39 , respectively, form a shaped area of the surface layer  24  and, as indicated in FIG. 5, are produced by stamping and embossing. The arrow  40  in FIG. 5 indicates somewhat the main flow direction wherein an air flow generated by the aforementioned blower emerges from the nozzle  39 . In FIG. 4, the nozzle  39  is represented, in accordance with the course of the section line IV—IV in FIG. 5, and is oriented, in the travel direction of the sheets  3 , in accordance with the longitudinal section illustrated in FIG. 4 through a section of the guiding device  10  illustrated in very simplified diagrammatic form in FIG.  1 . However, this illustrates only one of the possible orientations of the nozzles  39 . Beyond this, there is also no restriction to the nozzles of the form reproduced by way of example in FIGS. 4 and 5. Within the scope of the invention, also included, in particular, are nozzle arrangements and shapes which, for example, produce a swirling flow. 
     Particularly in the case of the configuration of the guiding device  10  which has been integrated into a coolant circuit, the surface layer  24  and the supporting layer  21 ′ are formed of materials with good thermal characteristics, and the surface layer  24  is bonded to the supporting layer  21 ′ by a heat-resistant adhesive with a good thermal conduction property or characteristic.