Patent Grant
10486416
This application is the U.S. National Stage, under 35 U.S.C. 371, of PCT/EP2017/059890, filed Apr. 26, 2017; published as WO 2017/186772A1 on Nov. 2, 2017, and claiming priority to DE 10 2016 207 397.4, filed Apr. 29, 2016, the disclosures of which are expressly incorporated herein by reference in their entireties.
The present invention relates to a device for overlapping sheets. The device utilizes at least one blower module and one infeed table. A plurality of sheets are guided, in succession, and are spaced from one another on the infeed table, in the same direction of transport, into a region of the blower module. A blower nozzle is arranged in the blower module on the side thereof facing the infeed table. A blowing direction of the blower nozzle is oriented parallel to the infeed table and is opposite to the transport direction of the sheets.
From JP 2001-39 604 A, a device for overlapping sheets, having at least one blower module and one infeed table, is known, wherein a plurality of sheets are fed on the infeed table in succession, spaced from one another and in the same direction of transport, into the region of the blower module, wherein a blower nozzle is arranged in the blower module, on the side thereof that faces the infeed table, and the blowing direction of the blower nozzle is aligned parallel to the infeed table, opposite the direction of transport of the sheets.
From DE 196 43 600 A1, a method for influencing sheets that are being conveyed overlapping one another to a printing machine is known, wherein the sheets are transported by means of conveyor belts into the region of front and/or side lay marks, and each sheet to be aligned is held by additional means, which act on the region in which the sheet to be aligned overlaps with next sheet in the sequence, in an operative connection with the next sheet in the sequence, which is forcibly guided by conveyor belts, in such a way that a movement with at least three degrees of freedom of the sheet to be aligned can be realized.
From DE 10 2004 007 404 A1, a method for guiding sheets to a sheet-processing machine is known, in which the adhesive force between two successive sheets in an overlapping stream is reduced by lifting the trailing edge of the first sheet.
Known from DE 10 2010 041 453 A1 is a sheet-fed printing machine having an infeed table for conveying sheets in an overlapping sequence to a first printing mechanism of the sheet-fed printing machine, wherein a sheet to be aligned can be placed on the infeed table on feed marks, and above the overlapping sequence, a sheet guidance mechanism is provided, which has at least one blower unit, by means of which an air flow onto the trailing edge of the sheet to be aligned can be generated, wherein at least one device for lifting the trailing edge of the sheet to be aligned is assigned to the infeed table, said device being located beneath the overlapping sequence of sheets.
From EP 0 792 742 A1, a device for guiding sheet-type material within a printing machine is known, having a guide surface arranged beneath the sheet-type material and having nozzles arranged in zones within the guide surface, wherein a first zone extends along the longitudinal axis of the guide surface and a second and a third zone are each arranged to the side of the first zone, wherein the nozzles arranged in the first zone are in the form of blower nozzles, the blowing direction of which is directed substantially in the sheet transport direction, and wherein the nozzles arranged in the second and third zones are in the form of blower nozzles, the blowing direction of which is directed substantially away from the longitudinal axis of the guide surface toward the lateral edges of the guide surface, wherein blower air can be supplied to the nozzles of the first zone separately from the nozzles of the second and third zones.
From EP 1 757 450 A2, a sheet-fed printing machine is known, having a feeder for printing sheets to be printed, in which case the feeder removes sheets from a feed pile, and having at least one printing unit and/or varnishing unit for printing the printing sheets, and having a delivery for discharging printed sheets, and having at least one device for corona treatment of the printed sheets, to increase the surface tension of the printed sheets and thus the wettability of the same with printing ink and/or varnish, wherein a) the feeder is embodied as a single-sheet feeder, which separates the printing sheets removed from the feed pile in such a way that said sheets can be conveyed without overlap in the region of a conveyor table located downstream of the single-sheet feeder as viewed in the direction of conveyance of the printing sheets, b) the conveyor table comprises at least two conveyor systems arranged one behind the other as viewed in the direction of conveyance of the printed sheets, wherein a plurality of corona treatment devices are arranged in the region of the conveyor table and can be used to subject the printing sheets to a full-surface corona treatment on the upper side and the underside of each, c) as viewed in the direction of conveyance of the printing sheets, downstream of the conveyor table, an overlapping device is positioned, which generates an overlapping stream of partially overlapping printing sheets from the printing sheets being conveyed without overlap in the region of the conveyor table, and d) the printing sheets can be fed in the form of an overlapping stream across a feed table positioned downstream of the overlapping device as viewed in the direction of conveyance of the printing sheets, to a printing unit or varnishing unit.
From EP 2 540 513 A1, a machine arrangement for the sequential processing of a plurality of sheet-type substrates each having a front side and a reverse side is known, said machine arrangement including a first printing cylinder and a second printing cylinder, wherein on the periphery of the first printing cylinder, at least one first non-impact printing unit for printing the front side of the substrate in question is provided, and downstream of the first non-impact printing unit in the direction of rotation of the first printing cylinder, a dryer for drying the front side of the substrate in question, which has been printed by the first non-impact printing unit, is provided, and wherein on the periphery of the second printing cylinder, at least one second non-impact printing unit for printing the reverse side of the substrate in question is provided, and downstream of the second non-impact printing unit in the direction of rotation of the second printing cylinder, a dryer for drying the reverse side of the substrate in question, which has been printed by the second non-impact printing unit, is provided; the first printing cylinder and the second printing cylinder are arranged forming a common roller nip, and in this common roller nip, the first printing cylinder transfers the substrate in question, which has been printed and dried on its front side, directly to the second printing cylinder.
From DE 103 12 870 A1, a digital printing machine for sheet-fed printing is known, having a digital printing couple with free format in the peripheral direction, an intermediate cylinder which is at least partially coated with an elastic material and is connected downstream of the digital printing couple, and an impression cylinder connected downstream of the intermediate cylinder, wherein the impression cylinder has sheet-holding grippers, and the intermediate cylinder has recesses for receiving the grippers, arranged on its periphery.
From DE 10 2014 010 904 B3, a device for printing on both sides of sheet-type printing substrates is known, in which the printing substrate is guided through more than 360° on an impression cylinder, with the printing substrate arriving with its reverse side in the operative region of an ink application unit, by which the printing substrate has already been printed on its front side on an impression cylinder upstream, the ink application unit preferably being pivotable between two successive impression cylinders, and the pivotable ink application unit being, e.g. an inkjet print head.
From DE 10 2005 021 185 A1, a device for applying opaque white or an effect coating layer is known, wherein the effect coating layer is dried or cured after application and is subsequently overprinted; one or more inkjet print heads are provided within a printing machine, the one or more inkjet print heads for applying the opaque white or the effect coating layer directly onto the printing substrate or indirectly onto the substrate with an intermediate layer therebetween being arranged or arrangeable upstream of the infeed to or within the printing machine along the transport path of the printing substrate.
From DE 10 2009 000 518 A1, a sheet-fed printing machine is known, which comprises a feeder for loading sheets to be printed into the sheet-fed printing machine, at least one printing unit and/or coating unit for printing the sheet with a static print image which is identical for all the sheets, a delivery for channeling printed sheets out of the sheet-fed printing machine, and at least one printing unit that operates without a printing form, integrated into the sheet-fed printing machine, for printing the sheets with a variable, in particular dynamic print image, wherein the or each form-free printing unit is integrated into the sheet-fed printing machine such that it can be controlled dependent upon process parameters or operating parameters or print order parameters or quality parameters.
From EP 2 657 025 A1, a sheet conveying device is known, which comprises the following components: a first conveyance unit comprising a first holder, which holds one edge of a sheet and conveys the sheet held by the first holder; a second conveyance unit comprising a second holder, which holds the one edge of the sheet and conveys the sheet held by the second holder; a third conveyance unit, wherein the third conveyance unit comprises a third holder that holds the other edge of the sheet being conveyed by the first conveyance unit, and conveys the sheet being held by the third holder; an independent drive unit that independently drives the first conveyance unit; a device drive unit that drives the entire device including the second conveyance unit and the third conveyance unit; and a control unit that controls the independent drive unit to adjust the speed at which the third conveyance unit conveys the sheet in one direction, based on the dimensions of the sheet, wherein the first conveyance unit comprises a rotatably mounted transport cylinder, and the independent drive unit comprises an independent drive motor that drives the transport cylinder independently of a device drive system, wherein the third conveyance unit is mounted so as to be pivotable between a receiving position, in which the third conveyance unit receives the sheet from the first conveyance unit, and a transfer position, in which the third conveyance unit transfers the sheet to the second conveyance unit, and with a further inclusion of a fourth conveyance unit, located on an upstream side of the transport cylinder in a sheet conveyance direction, comprises a fourth holder, which holds one edge of the sheet and transfers the sheet held by the fourth holder to the first holder of the transport cylinder, wherein the control unit controls the independent drive motor to adjust the rotational speed of the transport cylinder to coincide with the dimensions of the sheet in the direction of conveyance, so that the other edge of the sheet being conveyed by the transport cylinder is opposite the third holder when the third conveyance unit is detected in the sheet receiving position, and the fourth holder of the fourth conveyance unit is opposite the first holder of the first conveyance unit once the sheet has been transferred to the third holder.
From DE 10 33 225 A, a sheet feeder for printing machines is known, in which continuous belts travel above a vacuum space, said space being closed off and the vacuum being active only in openings (suckers) in the belt opposite the paper pile or individual paper sheets, so that the sheet is carried along by the belts, wherein the belts are made of wear-resistant steel, wherein adjacent to and behind the sucker points, blower openings (chambers, tubes, slots) are preferably located, which cause the sheets to separate and to float by means of blower air.
From DE 44 13 089 A1, a method for the overlapped feeding of sheet-type printing substrates into a printing machine using a conveyor table is known, in which compressed air flows continuously underneath the overlapped stream, opposite the direction of conveyance of the printing substrate being fed in over the conveyance table.
From DE 40 12 948 A1, a conveyor table for guiding sheets to a printing machine is known, having at least one suction chamber to which an axial fan is attached, along with perforated suction belts circulating about said fan over suction openings in the conveyor table, wherein parallel to the suction belts, openings are provided in the conveyor table which are separated from the suction chamber and are connected to the surrounding environment.
From DE 20 2004 006 615 U1, a device on a conveyor table, preferably on a suction belt table, is known, for transporting sheet-type material in a stream of sheets lying in an overlapping arrangement from a sheet feeder to a sheet processing machine, in particular to a rotary sheet-fed printing machine, having one or more conveyor belts, for example suction belts to which suction air can be applied, which are drivable and are guided continuously about the conveyor table, and having a blower device, which blows air underneath the stream of sheets, outside of the guide region of the conveyor belts, and in the area where guide regions of the conveyor table are located laterally and parallel to the conveyor belts, wherein, at least in the guide regions on the outer side of the conveyor belts, a plurality of individual ventilation openings distributed substantially over the entire surface of the guide regions is provided, and wherein a blower air infeed is provided, such that it is at least partially coupled for ventilation openings in such a way that blower air can be applied essentially to partial areas or to the entire surface of the guide regions, wherein the ventilation openings, preferably in the region of the outlet-side end of the conveyor table, are embodied as nozzles, each aligned from the center of the conveyor table toward the lateral edges.
From DE 101 57 118 A1, a device for braking printed sheets in the delivery of a sheet-fed printing machine and having a sheet brake that operates using suction air is known, wherein the sheet brake is connected via a system of lines and at least one valve to a vacuum generator, so that at the outer radius of the sheet brake, vacuum pressure can be applied to the suction area, wherein at least one sensor for determining the position of the printed sheet and a control device connected downstream are provided, and the valve can be actuated by the control device in response to signals from the at least one sensor.
From DE 10 2009 048 928 A1, an inkjet printer for printing on sheet-type substrates is known, the printer having the following components: a) a printing unit transport device which has at least one revolving printing unit conveyor belt, guided over rollers and having openings, and a suction chamber device, located beneath the printing unit conveyor belt, wherein the printing unit conveyor belt or the printing unit conveyor belts has/have a dedicated drive unit, which impresses/impress a speed on the conveyor belt(s), b) an inkjet printing device located above the upper drum of the printing unit conveyor belt, which is guided approximately horizontally, c) a transport device having at least one revolving belt, disposed upstream of the printing unit transport device in the direction of transport of the printing sheets/printing substrates, wherein the conveyor belt(s) has/have a dedicated drive unit that impress/impresses a speed upon the conveyor belt(s), wherein the ratio of the speed of the printing unit conveyor belt or printing unit conveyor belts of the printing unit transport device to the speed of the conveyor belt or conveyor belts of the transport device situated upstream of the printing unit transport device is selected such that the printing sheets or printing substrates for all sheet formats provided for the inkjet printer come to rest end to end or spaced by a slight distance of up to 10 mm on the printing unit conveyor belt or printing unit conveyor belts.
From DE 101 41 589 B4, a method for operating a sheet processing machine is known, in which the sheets are displaced in the direction of transport and are treated in multiple processing stations, wherein the speed of displacement of the sheets is individually adjustable, wherein the speed of a given sheet is adjusted to the processing step to be carried out in the respective processing station, and wherein the speed of the sheet is different in at least two of the processing stations. In this case, the processing output of the individual processing stations during a certain period of time may be the same, or the processing output of a first processing station may be higher or lower than the processing output of a second processing station upstream or downstream during a certain period of time.
From DE 10 2004 014 521 B3, a device for transporting sheets in printing machines from the printing couples to the sheet delivery pile is known, said device consisting of at least one gripper carriage guided bilaterally on chain tracks and having gripper systems for gripping and guiding the sheets, wherein the gripper carriage follows a rectilinear guide path above the sheet delivery pile, and after depositing a sheet onto a sheet pile is guided along a radius of curvature within a turning region, said device further consisting of leading edge grippers for gripping the leading edges of the sheets and for depositing the sheets onto the sheet delivery pile, wherein a gripper carriage support is provided only on the rectilinear guide path above the sheet delivery pile and in the turning region.
From U.S. Pat. No. 2,198,385 A, a gripper carriage is known, which is supported centrally via a cam follower on a cam disk in the area of transfer from the last sheet guiding cylinder to the gripper carriage, for the purpose of achieving a register-true transfer of the sheet.
The object of the invention is to provide a device for overlapping sheets.
The object is attained according to the invention by the positioning of the infeed table beneath the blower module. In the blower module, on the side thereof that faces the infeed table, a plurality of blower nozzles are arranged, one behind the other, in the transport direction of the sheets. The blowing direction of the each of the blower nozzles is oriented parallel to the infeed table and is opposite the transport direction of the sheets.
The advantages to be achieved with the invention will be apparent from the following explanations.
In addition, the described solution can be used in a hybrid machine arrangement for processing sheet-type substrates, preferably in a hybrid printing machine, which uses the high productivity of a conventional printing system, e.g. for printing in an offset printing process or in a flexographic printing process or in a screen printing process, or the high productivity of a coating device, in particular a coating unit, variably in combination with at least one non-impact printing unit, e.g. embodied as an inkjet printer, for flexible printing of variable print images, wherein both the conventional printing system or the coating unit and the non-impact printing unit are used in a running production operation inline, each at the operating speed that is optimal for it. A hybrid machine arrangement of this type is highly advantageous, in particular for the production of packaging materials, e.g. sheets for the production of folding cartons, because the strengths of each of the printing systems are utilized, resulting in a flexible and efficient production of packaging materials. For instance, rigid sheet-type substrates, in particular, can advantageously be printed in a flat state and a horizontal position in a non-impact printing unit. The length of a linear transport device can be adapted with less effort to a different number of printing couples or printing stations (color separations) and (intermediate) dryer configurations, e.g. for water-based or UV-curing printing inks or inks, than would be possible with a rotary transport device involving cylinders. Moreover, with a linear transport device, when sheet-type substrates of variable format lengths are used, a constant sheet gap between sheet-type substrates being transported in immediate succession and spaced from one another can be more easily realized. On the other hand, transporting sheet-type substrates by means of rotational bodies, in particular cylinders and gripper bars or gripper carriages, in each case with the sheet-type substrates being transferred in the gripper closure to the next processing station, as is known with sheet-fed offset printing machines, ensures the highest possible register accuracy.
Exemplary embodiments of the invention are illustrated in the drawings and will be described in greater detail in the following.
Shown are:
Common to all of the production lines shown in
In the following, it will be assumed by way of example that in each machine arrangement having a plurality of processing stations 01; 02; 03; 04; 06; 07; 08; 09; 11; 12, a sequence of, in particular, rigid sheets, e.g. of a paper, a single-ply or multi-ply paperboard or a cardboard as printing substrate is processed, in particular to produce a packaging material. Paper, paperboard and cardboard as printing substrates differ from one another in terms of grammage, i.e. the weight in grams of one square meter of the printing substrate. In general, the aforementioned printing substrate having a grammage of between 7 g/m2 and 150 g/m2 is considered to be paper, substrate having a grammage of between 150 g/m2 and 600 g/m2 is considered to be paperboard and substrate having a grammage of more than 600 g/m2 is considered to be cardboard. For producing cartons, paperboards are used in particular, as these are readily printable and are suitable for subsequent finishing or processing, such as varnishing and punching. In terms of fiber content, these paperboards are, e.g. pulp-free, contain small amounts of pulp, or are pulp-containing, or contain recycled paper. In terms of their structure, multi-ply paperboards have a cover layer, an inlay, and a backing on the reverse side. In terms of surface finish, paperboards may be, e.g. uncoated, pigmented, coated or cast-coated. The format of such sheets ranges, e.g. from 340 mm×480 mm to 740 mm×1060 mm, with the first number of the format specifications typically indicating the length of the sheet in the transport direction T and the second number indicating the width of the sheet, orthogonally to the transport direction T.
In the block diagram of
If the processing station 03 immediately following feeder 01 is the cold foil application unit 03, the sheet is then typically transported from there to the processing station 04 embodied as an offset printing unit 04. In cold foil application unit 03, a metallized coating layer, detached from a carrier film, is transferred to the substrate. By overprinting this coating layer, e.g. with an offset printing unit 04, a wide variety of metal effects can be achieved. Cold foil application unit 03 is advantageously embodied, e.g. as integrated into offset printing unit 04, with two additional printing couples 87; 88 being provided in offset printing unit 04. In the first printing couple 87 in transport direction T of the printing substrate, a special adhesive is applied to the printing substrate, i.e. to the sheet, by means of a standard printing form. A second printing couple 88 in transport direction T of the printing substrate is equipped with a film transfer device which has the coating layer to be transferred. The film bearing the coating layer is guided from an unrolling station into a printing nip between a transfer cylinder and a printing cylinder that cooperates with said transfer cylinder and is brought into contact with the printing substrate. Coloring in the coating layer is provided by an aluminum layer and a protective coating layer, the coloring of which influences the color effect. The transfer layers bond to the substrate by adhesion of a bonding layer onto which the adhesive layer is printed. The carrier film is then rolled up again. After the cold foil transfer, overprinting with conventional printing inks and with UV and hybrid inks is possible inline, in particular in offset printing unit 04, to produce various metallic color shades.
A printing substrate which is, e.g. particularly absorbent and/or which is to be prepared for printing with a non-impact printing unit 06 is fed from feeder 01 to the next processing station 02, embodied e.g. as a primer application unit 02, for coating at least one surface of this printing substrate with, e.g. a water-based primer, in particular to seal said substrate prior to printing or varnishing. This priming involves providing the printing substrate with a base coating or initial coating, in particular to improve or enable the bonding of a printing ink or ink that will subsequently be applied to the printing substrate. Primer application unit 02 is formed, e.g. in conjunction with a printing couple 86 of a rotary printing machine and has, e.g. a printing couple cylinder 82 cooperating with an impression cylinder 119 and having a form roller 83, preferably in the form of an anilox roller 83, that is or at least can be thrown onto said printing couple cylinder 82, along with at least one doctor blade 84, in particular a chamber doctor blade system 84, extending in the axial direction of the form roller 83 (
The flexographic printing carried out by a processing station 04 embodied, e.g. as a flexographic printing unit 04 is a direct letterpress process, in which the raised areas of the printing form are image-bearing, and which is frequently used for printing packaging materials made from paper, paperboard or cardboard, metallized film, or a plastic, such as PE, PET, PVC, PS, PP or PC, for example. Flexographic printing uses low viscosity printing inks and flexible printing plates made of photopolymer or rubber. A flexographic printing unit 04 generally includes a) an anilox roller used for inking up the printing form, b) a printing cylinder, also called a form cylinder, on which the printing form is fixed, and c) an impression cylinder which guides the printing substrate.
Each processing station 04, embodied as a flexographic printing unit 04 or as an offset printing unit 04, which prints at least one static print image onto each of the sheets, preferably has a plurality of printing couples 86, e.g. at least four, each printing couple 86 preferably printing in a different printing ink, so that as the printing substrate passes through the flexographic printing unit 04 or the offset printing unit 04, it is printed in each case with a multicolor print, e.g. a four-color print. In particular, yellow, magenta, cyan and black inks are used as the printing inks. In an alternative embodiment of printing unit 04 for flexographic printing or offset printing, processing station 04, which prints each of the sheets with at least one static print image, is embodied as a printing unit 04 that prints in a screen printing process.
After the printing substrate has been processed in the at least one non-impact printing unit 06, said printing substrate is fed, e.g. to a processing station 07 embodied as an intermediate dryer 07, this intermediate dryer 07 being configured to dry the substrate in question, e.g. by irradiation with infrared or ultraviolet radiation, the type of radiation being dependent, in particular, on whether the printing ink or ink applied to the printing substrate is water-based or UV-curing. After intermediate drying, the printing substrate is fed, e.g. to a processing station 08 embodied as a coating unit 08. coating unit 08 applies, e.g. a dispersion coating to the printing substrate, with dispersion coatings consisting essentially of water and binders (resins), along with surfactants to stabilize these dispersions. A coating unit 08 for applying a dispersion coating to the printing substrate comprises either an anilox roller, a chamber doctor blade and a form roller (comparable to a flexographic printing couple), or a dipping roller and a form roller. Full-surface and/or partial coatings, for example, are applied using a printing form, preferably based on photopolymerization. For full surface coatings, special coating plates made of rubber may also be used. Downstream of coating unit 08 in the transport path of the printing substrate, a processing station 09 embodied, e.g. as a dryer 09 is arranged, said dryer 09 being configured for drying the printing substrate in question by irradiation with infrared radiation or with hot air. If the machine arrangement in question has a plurality of dryers 07; 09 along the transport path of the printing substrate, the dryer denoted by reference symbol 09 is preferably the last of this plurality of dryers 07; 09 in transport direction T of the printing substrate, in which case the intermediate dryer(s) 07 and the (final) dryer 09 may be structurally identical or may be configured differently from one another. If a printing substrate to be dried by ultraviolet radiation is fed to dryer 09, i.e. a printing substrate to which a printing ink or ink which is cured by UV-radiation, or a coating which is cured by UV-radiation, e.g. a gloss coating, is applied, this dryer 09 is equipped with a radiation source for generating ultraviolet radiation. Dispersion coatings allow more intense gloss and matte effects to be achieved than with classic oil-based varnish. Special optical effects can be achieved using effect pigments in the coating. Primer application unit 02, cold foil application unit 03 and coating unit 08 may be combined under the term coating unit 02; 03; 08.
After drying, the printing substrate is fed, e.g. to a processing station 11, which performs further mechanical processing of the printing substrate, e.g. punching or creasing, and/or the separation of parts, in particular the stripping of blanks from their linkage points in the preferably printed sheet. Each of the aforementioned further processing steps is carried out in or by a processing mechanism 46. Further mechanical processing is preferably carried out in cooperation with a cylinder that transports the respective sheet. Thereafter, or directly from dryer 09, the printing substrate travels to a delivery 12, which in each of the production lines shown in
As is illustrated in
Production lines illustrated by way of example in
At least one of the processing stations 01; 02; 03; 04; 07; 08; 09; 11; 12 cooperating with the at least one non-impact printing unit 06 is selected for inclusion in the processing of the sheets based upon whether the printing ink to be applied to the sheet, in particular with the non-impact printing unit 06, is a water-based printing ink or ink, or as a UV-curing printing ink or ink. The respective machine arrangement is therefore configured to print each of the sheets with a water-based printing ink or with UV-curing printing ink.
Additional machine arrangements that will be described in detail in conjunction with
One advantageous machine arrangement, mentioned here by way of example, comprises a plurality of processing stations for processing sheets, wherein a plurality of processing stations 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 are arranged in succession in transport direction T of the sheets for the inline processing of these sheets, wherein at least one of these processing stations 06 is embodied as a non-impact printing unit 06, and wherein a first processing station 01 situated upstream of the non-impact printing unit 06 in transport direction T of the sheets is embodied as a sheet feeder 01 or a magazine feeder 01, wherein a processing station 08 located between the first processing station 01 and the non-impact printing unit 06 is embodied as a first coating unit 08 for applying a coating to each of the sheets, wherein between the first coating unit 08 and the non-impact printing unit 06 a first dryer 07 is located, wherein a first conveyor belt 17 is arranged for transporting the sheets from the first dryer 07 to the non-impact printing unit 06, wherein a second dryer 07 is located downstream of the non-impact printing unit 06 in transport direction T of the sheets, wherein a device for transferring the sheets coming from non-impact printing unit 06 to a second coating unit 08 is provided, wherein a third dryer 09 is located downstream of the second coating unit 08, and wherein a delivery 12 for the sheets is located downstream of the third dryer 09 in transport direction T of the sheets. A mechanical further processing unit 11 may also be arranged between the third dryer 09 and the delivery 12. Additionally, e.g. a coating unit 03 for applying a cold foil is located upstream of the non-impact printing unit 06 in transport direction T of the sheets. Non-impact printing unit 06 preferably has a plurality of individually controlled inkjet printers along the transport path of the sheets. In the operative zone of non-impact printing unit 06, the sheets are preferably each guided horizontally and lying flat on a transport device 22, wherein in each case, transport device 22 has a linear transport path or a curved transport path for the sheets, at least in the operative zone of non-impact printing unit 06, the curved transport path being formed by a concave or convex arcuate line lying in a vertical plane and having a radius within a range of 1 m to 10 m. In transport direction T of the sheets, upstream of non-impact printing unit 06, e.g. a transfer device is located, wherein the transfer device aligns each of the sheets, at least in terms of its axial register and/or its circumferential register, true to register relative to the print position of non-impact printing unit 06, the transfer device having, e.g. a suction drum 32 that holds each of the sheets by means of suction air. This machine arrangement is configured in particular for printing each of the sheets with a water-based printing ink or with a UV-curing printing ink. This machine arrangement is configured, in particular, for producing various packaging materials. The device used for transferring the sheets coming from non-impact printing unit 06 to the second coating unit 08 is embodied, e.g. as a rocking gripper 19 and a transfer drum 31 cooperating with rocking gripper 19.
The sheets picked up from a pile in feeder 01, in particular in sheet feeder 01, are transported individually, spaced apart from one another, through offset printing unit 04 at a first transport speed. The sheets transferred from offset printing unit 04 to non-impact printing unit 06 are transported in this non-impact printing unit 06 at a second transport speed, the second transport speed used in non-impact printing unit 06 typically being slower than the first transport speed used in offset printing unit 04. To adapt the first transport speed used in offset printing unit 04 to the typically slower second transport speed used in non-impact printing unit 06, the sheet gap, for example, between immediately sequential sheets, i.e. the distance produced, e.g. as a result of a gripper channel width for the sheets transported in the gripper closure through offset printing unit 04, is preferably reduced during the transfer of these sheets from offset printing unit 04 to non-impact printing unit 06, with such a reduction in distance ranging, e.g. between 1% and 98% of the original distance. Immediately sequential sheets are thus also transported spaced apart from one another in non-impact printing unit 06, but typically with a smaller sheet gap or with a shorter distance than in offset printing unit 04, and consequently also at a slower second transport speed. This second transport speed is preferably maintained when sheets that have been printed in non-impact printing unit 06 are transported first to an intermediate dryer 07 or dryer 09 and from there, e.g. by means of a feed table 18, on to a mechanical further processing unit 11 and on to delivery 12. However, the sheets can also be brought from their second transport speed to a third transport speed, if required, e.g. by mechanical further processing unit 11, in which case the third transport speed is typically faster than the second transport speed and again corresponds, e.g. to the first transport speed used in offset printing unit 04. In mechanical further processing unit 11, e.g. a second rocking gripper 19 is provided, which picks up the sheets coming from intermediate dryer 07 or dryer 09 from feed table 18, and transfers these, e.g. to a second transfer drum 31, located in the region of mechanical further processing unit 11, after which the sheets are transported, e.g. by means of a gripper closure, through the region of mechanical further processing unit 11. In the region of mechanical further processing unit 11, which includes, e.g. a plurality of processing mechanisms 46 arranged in a row, a rotary body, in particular a cylinder, preferably a transfer drum 44, is provided, in each case arranged between two adjacent processing mechanisms 46, for the purpose of transferring the sheets from one of the processing mechanisms 46 arranged in a row to the next. One of processing mechanisms 46 is configured, e.g. as a punching mechanism, while another processing mechanism 46 is configured, e.g. as a creasing mechanism. The processing mechanism 46 in question is configured for carrying out the mechanical further processing of the sheets preferably in cooperation with a cylinder for transporting the respective sheets. Once they have been processed mechanically, the sheets and/or the blanks that have been separated from them are transported, e.g. by means of a second chain conveyor 21 to delivery 12, where they are collected, preferably stacked.
The sheets are transported from the output of offset printing unit 04 at least up to the output of intermediate dryer 07 or dryer 09, preferably on to the start of mechanical further processing unit 11, in each case by means of a multi-part transport device 22, i.e. consisting of a plurality of modules, in particular transport units, arranged one after the other in transport direction T of the sheets, wherein transport device 22 transports each of the sheets oriented lengthwise in transport direction T and preferably lying horizontally flat, at least in the operative zone of non-impact printing unit 06 situated between offset printing unit 04 and intermediate dryer 07 or dryer 09, along a linear transport path. The linear transport path and the flat horizontal transport are preferably continued during transport of the sheets through the intermediate dryer 07 or dryer 09 situated downstream of non-impact printing unit 06. If necessary, an intermediate dryer 07 or a dryer 09 may also be located between offset printing unit 04 and non-impact printing unit 06.
In the operative zone of the non-impact printing unit 06 located between offset printing unit 04 and intermediate dryer 07 or dryer 09, a second revolving conveyor belt 27 is preferably provided, on which the sheets are transported in succession, each preferably lying flat horizontally, along a linear transport path. The transfer device is arranged in particular between first conveyor belt 17 and second conveyor belt 27. Also preferably provided in the operative zone of intermediate dryer 07 or dryer 09 is a third revolving conveyor belt 28, on which the sheets received from non-impact printing unit 06 are transported in succession, each preferably lying flat horizontally, along a linear transport path. The third conveyor belt 28 transfers the sheet which has been transported through the intermediate dryer 07 or dryer 09 to feed table 18, from which the sheets are transported in succession, preferably to mechanical further processing unit 11. The first conveyor belt 17, the second conveyor belt 27 and the third conveyor belt 28 preferably transport the sheets within the same, e.g. horizontal transport plane 29, in particular configured as a flat surface. The transport device 22 for transporting sheets in a machine arrangement composed of processing stations, each for processing sheets, thus comprises at least three transport units, specifically the first gripper system 16 or the first chain conveyor 16, the first conveyor belt 17 and the second conveyor belt 27. The first chain conveyor 16 and the first conveyor belt 17 are arranged so as to cooperate for the purpose of transferring a sequence of sheets from a first processing station to a second processing station, preferably immediately following the first processing station in transport direction T of the sheets. The sequence of sheets is transferred from the first conveyor belt 17 to the second conveyor belt 27, which belongs to the next processing station. A third conveyor belt 28 is preferably also provided, in which case the sequence of sheets is transferred from the second conveyor belt 27 to the third conveyor belt 28, which belongs to a third processing station, preferably immediately downstream of the second processing station in transport direction T of the sheets. If the transport paths of the first conveyor belt 17 and/or of the second conveyor belt 27 or optionally of the third conveyor belt 28 are not aligned linearly and/or are not aligned horizontally, the conveyor belts 17; 27; 28 of transport device 22 each transport the sheets along a curved transport path, in particular along a concave or convex arcuate line, lying in a vertical plane and having a radius of at least 1 m, preferably having a radius ranging from 2 m to 10 m, in particular having a radius ranging from 3 m to 5 m. Each of conveyor belts 17; 27; 28 is preferably embodied as a suction belt conveyor, i.e. as a conveyor belt having at least one suction chamber 26 for suctioning a respective sheet during its transport. With the conveyor belts 17; 27; 28 that have a plurality of suction chambers 26 along the transport path provided for the sheets, these suction chambers 26 are preferably controllable individually and/or preferably independently of one another in terms of the action of their respective suction air. Along the curved transport path, a plurality of individually controlled non-impact printing units 06 are preferably arranged, each of the plurality of non-impact printing units 06 being embodied, e.g. as an inkjet printer. The conveyor belts 17; 27; 28 of transport device 22 each consist, e.g. of a plurality of parallel individual belts, arranged side by side orthogonally to the transport path intended for the sheets, and thus each extending lengthwise to the transport path intended for the sheets. In contrast to gripper system 16, a conveyor belt 17; 27; 28 is to be understood as a gripperless transport device, in which the conveyor belt 17; 27; 28 in question is configured as revolving continuously between at least two deflecting devices.
With a machine arrangement having a plurality of processing stations for processing sheets, in which in transport direction T of the sheets a plurality of processing stations 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 are arranged in succession for the inline processing of these sheets, wherein at least one of these processing stations 06 is embodied as a non-impact printing unit 06, e.g. a first alignment device is situated upstream of the first processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 in transport direction T of the sheets, said first alignment device aligning each of the sheets true to register, at least in terms of its axial register and/or in terms of its circumferential register, relative to a processing position of the first processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12. Also situated between non-impact printing unit 06 and a processing station 01; 02; 03; 04; 07; 08; 09; 11; 12 located downstream of non-impact printing unit 06 in transport direction T of the sheets is, e.g. an additional alignment device, said additional alignment device aligning each of the sheets true to register, at least in terms of its axial register and/or in terms of its circumferential register, relative to a processing position of the processing station 01; 02; 03; 04; 07; 08; 09; 11; 12 located downstream of non-impact printing unit 06.
Suction drum 32, located in particular in the transfer device, is also used, e.g. to adjust the transport speed of the sheets to be transferred from offset printing unit 04 to non-impact printing unit 06. Since the second transport speed used in non-impact printing unit 06 is typically slower than the first transport speed used in offset printing unit 04, suction drum 32 first decelerates the sheets fed to it in succession at the first transport speed by offset printing unit 04 by the leading edge of each sheet first striking the at least one stop 34; if necessary, the suction drum then aligns the sheets, which are held by suction, at least laterally, i.e. in response to a corresponding position signal from the first sensor 33 that indicates a need for correction, by an axial movement of suction drum 32, which holds the sheet in question, and then accelerates or decelerates the gripped sheet by a rotation of said suction drum 32 to the second transport speed required in the non-impact printing unit 06, and the sheet in question is released by suction drum 32, e.g. when said sheet reaches the second transport speed, after which suction drum 32 is brought to its rotational and/or axial operating position required for it to grip the next sheet. Suction drum 32 thus preferably rotates, e.g. non-uniformly in each of its revolutions. Position information about the leading edge of the sheets, which is necessary for controlling the rotational position of suction drum 32, is provided by an angular position sensor 47, e.g. disposed on a sprocket 24, or alternatively by an angular position sensor of offset printing unit 04, in particular of the printing machine.
As has already been mentioned, the above-described machine arrangements, each of which has a plurality of processing stations 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 for processing sheets and at least one transport device for transporting these sheets, are provided for processing sheets of different formats, i.e. of different lengths and/or widths. The typically rectangular sheets therefore differ, e.g. in terms of length, the length thereof extending in transport direction T of these sheets. To avoid any loss in the productivity of a machine arrangement using a processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 embodied in particular as a non-impact printing unit 06 to which sheets are fed sequentially, with comparatively shorter sheets, i.e. with sheets of smaller format than larger format sheets that are otherwise processed in said machine arrangement, a method having the following steps is proposed:
A method for operating a transport device for feeding a plurality of sheets sequentially to a processing station 02; 03; 04; 06; 07; 08; 09; 11; 12, in which sheets of different lengths, each extending lengthwise in transport direction T of these sheets, are used for processing by means of the same processing station 02; 03; 04; 06; 07; 08; 09; 11; 12, wherein the sheets to be fed in succession to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 are each transported by the transport device spaced apart, wherein the transport device impresses a transport speed onto each of the sheets to be transported, wherein the distance between immediately sequential sheets for sheets of different lengths extending in transport direction T of these sheets is kept constant by an adjustment in the transport speed to be impressed by the transport device onto the sheet in question, wherein the transport speed of the subsequent sheet in transport direction T is adjusted relative to the transport speed of the sheet immediately preceding it. In this method, the sheets to be fed in succession to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 in question are each transported by the transport device, preferably at a minimal distance, but typically at a distance not equal to zero, in order to achieve and/or maintain a high level of productivity of the processing stations 02; 03; 04; 06; 07; 08; 09; 11; 12. The distance between successive sheets in transport direction T, i.e. between the trailing edge of a preceding sheet extending transversely to transport direction T and the leading edge of the sheet immediately following it, extending transversely to the direction of transport T, lies e.g. within a range of between 0.5 mm and 50 mm, and is preferably less than 10 mm. If a sheet of shorter length will be processed in the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 in question following a sheet of greater length, the shorter sheet is accelerated by the transport device by increasing its transport speed. Conversely, a sheet of greater length is slowed down by the transport device by decreasing its transport speed when the sheet of greater length will be processed in the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 in question following a sheet of shorter length. As a processing station 02; 03; 04; 06; 07; 08; 09; 11; 12, a non-impact printing unit 06 is preferably used, the productivity of which is generally greatest when the sheets to be printed by it are fed to it in succession at a constant minimum distance, regardless of their respective format. If a processing station 04 embodied, e.g. as an offset printing unit 04 is situated upstream of the non-impact printing unit 06 in the machine arrangement in question, sheets printed in the offset printing unit 04 are fed to the transport device at the transport speed corresponding to a production speed of this offset printing unit 04, regardless of their respective format, wherein this transport speed defined for these sheets by the offset printing unit 04 is to be adapted during their transport by the transport device to the transport speed corresponding to the processing speed of the non-impact printing unit 06. If these sheets will be fed at a constant distance from one another, regardless of their respective format, to non-impact printing unit 06, sheets of greater length are decelerated less than shorter sheets, but in any case, a reduction in the respective transport speeds may be necessary because the processing speed of non-impact printing unit 06 is typically slower than the production speed of offset printing unit 04.
The respective sheet is preferably held by the transport device in a force-locking manner, e.g. by suction air, during its transport. The respective transport speed is preferably impressed onto each sheet by suction rings 76 of a suction drum 32 engaging onto said sheet, or by at least one continuously revolving suction belt 52; 78. In the preferred embodiment, the transport speed to be impressed onto the sheet in question is set by a preferably electronic control unit, wherein the control unit sets the transport speed, in particular to maintain the constant distance between successive sheets, in a control loop, as described above e.g. in conjunction with the rotational position control of suction drum 32, or e.g. in conjunction with a control device to which, e.g. optical sensors 33; 36 are connected, as will be described in greater detail in the following.
If the machine arrangements described above, each of which has a plurality of processing stations 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 for the processing of sheets and at least two transport devices for the transport of these sheets, are used for transporting and processing pliable sheets, i.e. sheets of low rigidity, in particular thin sheets that cannot transmit shear forces, so that shear forces acting on such a sheet cause the sheet to undulate, then it is difficult to feed this type of sheet to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 in question in a target position designated for said processing station 02; 03; 04; 06; 07; 08; 09; 11; 12.
Proposed, therefore, is a method for sequentially feeding a plurality of sheets into a processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 for processing each of said sheets, in which a first transport device, located upstream of the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 in transport direction T of the sheets feeds each of the sheets to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 at a first transport speed in a thrusting movement, wherein during the thrusting movement, the first transport device holds the respective sheet to be fed to said processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 with at least one holding element, wherein the sheet in question fed to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 is gripped by a second transport device associated with said processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 and is transported in the gripped state at a second transport speed, wherein the first transport speed of the first transport device is slower than the second transport speed of the second transport device, wherein the holding element in question of the first transport device releases the sheet in question to be fed to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 only after the second transport device has gripped said sheet which has been fed to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 and has begun to transport said sheet. A non-impact printing unit 06 is preferably used as a processing station 02; 03; 04; 06; 07; 08; 09; 11; 12. The sheets are each transported in the first transport device and/or in the second transport device in particular in the same transport plane 29. A first, in particular continuously revolving conveyor belt 17 is used, for example, as the first transport device, and/or a second, in particular continuously revolving conveyor belt 27 is used as the second transport device, said conveyor belts 17; 27 each being embodied, e.g. as a suction belt. In an alternative embodiment of the holding elements, each of these is embodied as a suction ring 76 of a suction drum 32. A holding force is exerted by the relevant holding element of the first transport device onto the respective sheet to be fed to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12, said holding force being greater, at least briefly, than a tensile force simultaneously acting on said sheet, which is exerted by the second transport device. The first transport device preferably holds each sheet to be fed to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 with the at least one holding element by means of a force-locking connection, e.g. by means of suction air. With the proposed method, the sheet to be fed to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 is acted on by a tensile force and is thereby tautened despite the thrusting movement carried out by the first transport device. After the actual position of each of the sheets in the transport plane 29 has been checked, and if a deviation of the actual position from a target position intended for the sheet in question in the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 is detected, after the position of said sheet has been corrected, the sheets are preferably each transferred in the intended target position to the second transport device.
Therefore, preferably on the device for transferring the sheets, e.g. to mechanical further processing unit 11, a method for arranging sheets in an overlapping position in a transfer device located between a first processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 and a second processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12, which follows the first processing station in transport direction T of the sheets, is carried out, in which the sheets to be overlapped are transported in succession in a transport plane 29, each lying individually, from the first processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 to the transfer device, and in which a trailing edge in transport direction T of each of the sheets coming from the first processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 is lifted relative to the transport plane 29 exclusively by means of blower air, and a subsequent sheet is pushed underneath the trailing edge of the sheet preceding it. The blower air preferably acts with at least 50% of its intensity in the direction of a surface normal in the transport plane 29 opposite the force of gravity. Advantageously, it is provided that additional blower air is blown opposite transport direction T of the sheets, substantially tangentially from above, at an acute angle of, e.g. 0° to 45° formed with the transport plane 29, i.e. said blower air is blown onto the surface of the sheets that faces away from transport plane 29 onto the sheets to be transported to the transfer device. In that case, the additional blower air directed opposite the transport direction T of the sheets emerges from a guide surface that forms a converging acute angle of, e.g. 0° to 45° with the transport plane 29 of the sheets, wherein nozzles, in particular, for emitting the blower air are arranged in the guide surface. The blower air acting opposite the force of gravity in the direction of the transport plane 29 is preferably pulsed by the control unit. Each sheet to be transported from the first processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 to the subsequent second processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 is held in transport plane 29 by means of suction air preferably acting in the leading half of the sheets in transport direction T. The suction air used to hold the sheets to be transported from the first processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 to the subsequent second processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 in transport plane 29 is preferably pulsed by the control unit. In the preferred embodiment, the effective width, directed orthogonally to the transport direction T of the sheets, of the blower air acting opposite the force of gravity, in the direction of transport plane 29, and/or the effective width of the additional blower air directed opposite the transport direction T of the sheets and/or the effective width of the suction air holding the sheet to be transported from the first processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 to the subsequent second processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 downstream in transport plane 29 is adjusted in each case dependent upon the width of the sheet directed orthogonally to the transport direction T of the sheets. In that case, the setting of the effective width of the blower air acting opposite the force of gravity in the direction of the transport plane 29, and the setting of the additional blower air directed opposite the transport direction T of the sheets and the setting of the suction air holding the sheets to be transported from the first processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 to the subsequent second processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 in transport plane 29 are each carried out by the control unit, coupled mechanically or electrically, e.g. coupled via mechanical gearing, by means of a single adjustment device. This adjustment device is controlled by the control unit, e.g. automatically, dependent upon the format of the specific sheets to be transported from the first processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 to the subsequent second processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12.
For the overlapping arrangement of the sheet-type substrates, in particular the sheets 51, preferably each being embodied as a printed sheet, a device for overlapping sheets 51, also referred to in the following simply as overlapping device 132, is provided in the region, i.e. the operating region, of the transfer device located, in particular, in one of the above-described machine arrangements (
Overlapping device 132 is illustrated by way of example in
In the transport direction T of sheets 51, in a region between infeed table 18; 134 and the side of blower module 133 that faces said infeed table 18; 134, a baffle plate 141 is arranged upstream of the first blower nozzle 136 or the first blower nozzle row, said baffle plate 141 shielding the leading edge of a sheet 51 that immediately follows a sheet 51 that has been lifted by the blower air from at least one of blower nozzles 136; 137, against the suction effect induced by the blower nozzles 136; 137 arranged in blower module 133. The sheet 51 that has been lifted off of infeed table 18; 134 by at least one of the blower nozzles 136; 137 or blower nozzle rows channels the blower air streaming out of the at least one blower nozzle 136; 137 and conducts this blower air across the surface of baffle plate 141 that faces blower module 133. Baffle plate 141 preferably has a concave curvature at its end located in the blowing direction, which curvature gives the blower air a flow-off direction facing away from, i.e. directed away from, the infeed table 18; 134. Baffle plate 141 keeps the leading edge of the sheet 51 immediately following a sheet 51 that has been lifted by the blower air coming from at least one of blower nozzles 136; 137 from being influenced until the trailing end of the lifted sheet 51 exposes the blower nozzle 136 or row of blower nozzles first reached by said sheet 51 as a result of its own forward movement or advancement in transport direction T. To prevent the leading edge of the sheet 51 that immediately follows a sheet 51 that has been lifted by the blower air coming from at least one of blower nozzles 136; 137 from being lifted prematurely by the action of the blower nozzle 136; 137 or row of blower nozzles exposed by the trailing end of the sheet 51 preceding it, the blower air of the blower nozzle 136; 137 or row of blower nozzles in question is switched off by means of the associated valve 138; 139, based upon the forward movement or advancement of the sheet 51 currently lifted off of the infeed table 18; 134, which immediately precedes a sheet 51 located between baffle plate 141 and infeed table 18; 134. A sheet 51 that has been lifted by the blower nozzles 136; 137 or rows of blower nozzles is lifted above the infeed table 18; 134 as a result of the suction effect (Venturi effect) created by the respective blower air, at a specific floating height SH, e.g. measured as a distance from the side of the blower module 133 that faces the infeed table 18; 134, the floating height SH being dependent upon the intensity of the blower air and/or upon the weight of the sheet 51 in question and/or upon the transport speed of the sheet 51 in question. To prevent sheets 51, e.g. of heavy weight and/or high transport speeds, from vibrating and beginning to flutter as they are transported above the infeed table 18; 134, in the region between infeed table 18; 134 and the side of the blower module 133 that faces said infeed table 18; 134, a shield plate 142 that acts as a stop for the lifted sheet 51 is preferably provided, said shield plate 142, which is arranged, e.g. at an acute angle to the side of the blower module 133 that faces the infeed table 18; 134, being in the form of an air-permeable grate. The sheet 51 that has been lifted by the suction from the blower air and laid against the shield plate 142 is guided there in a smooth movement, i.e. without fluttering, in its transport direction T along said shield plate 142. In the infeed table 18; 134, at least in a region opposite the blower module 133, a plurality of holes 143 or openings 143 are preferably provided, through which air flows under the currently lifted sheet 51 for the purpose of pressure equalization. These holes 143 are configured, e.g. as circular, having a diameter d143 within the range of a few millimeters.
The transport device described with reference to
The speed of revolution v of the suction belt 52 in question is adjusted by the preferably digital control unit 61, which executes a program, and which has a drive 62 that places this suction belt 52 in motion. Said control unit 61 preferably also controls or regulates the aforementioned synchronization of the vacuum pressure in the second suction chamber 59 in the transport direction T of sheet 51 with the passage over said chamber of the perforated surface 57 of this suction belt 52 which is covered by sheet 51, e.g. by means of a valve 67. The preferably controllable valve 67 is located, e.g. in a line that connects the second suction chamber 59 to a pump (not shown), e.g. controlled by control unit 61. The drive 62, preferably embodied as an electric motor, acts, e.g. on at least one of the deflecting rollers 53. The drive 62 for adjusting the speed of revolution v of the suction belt 52 in question is preferably controlled by control unit 61. Control unit 61 preferably sets a discontinuous speed of revolution v of the suction belt 52 in question, i.e. the speed of revolution v of the suction belt 52 in question is accelerated or decelerated in phases, in contrast to an otherwise uniform speed, by the control of drive 62.
In each case, at least one register mark 63 is provided at least at one point on the suction belt 52 in question. In conjunction with the transport device, a sensor 54 that detects the register mark 53 in question is provided and is connected to the control unit 61. The speed of revolution v of the suction belt 52 in question is adjusted by control unit 61, preferably dependent upon a difference, determined, e.g. by control unit 61, between a first signal s1 generated by sensor 64 and corresponding to an actual speed of revolution and a second signal s2 corresponding to a target speed of revolution. The second signal s2, which indicates the target speed of revolution of the revolving suction belt 52 in question, is tapped, e.g. from a higher-level machine controller (not shown). Sensor 64, which detects the register mark 63 in question, is arranged in particular in the region of a slack run 66 of the suction belt 52 in question. The sensor 64 that detects the register mark 63 in question is configured as a sensor 64 for detecting the register mark 63 in question, e.g. optically or inductively or capacitively or electromagnetically or ultrasonically. Register mark 63 is configured, corresponding to the respective embodiment of sensor 64, e.g. as an optical signal surface applied to the suction belt 52 in question, or as a magnetic strip on the suction belt 52 in question, or as a recess or perforation in the suction belt 52 in question, or as a body that is located in the suction belt 52 in question and emits a signal. The time at which the speed of revolution v of the suction belt 52 in question is regulated, which is carried out by control unit 61, is preferably synchronized with the passage of the perforated surface 57 of the suction belt 52 in question, which is covered by the sheet 51 to be transported.
In a further variant, the transport device for the sequential transport of individual sheet-type substrates or sheets 51 has at least one stationary suction chamber 58; 59 which has a preferably table-shaped surface 69 in the region of the taut run 54, in which case a single, in particular at least partially perforated continuously revolving suction belt 52 is preferably arranged moving, in particular sliding, across this surface 69 during transport of the sheet-type substrate in question, i.e. preferably a sheet 51, the suction chamber 58; 59 in question being covered by the table-shaped surface 69 in the region of the taut run 54 of the suction belt 52. This table-shaped surface 69 is implemented, e.g. as a tabletop. This suction belt 52 holding the sheet 51 in question during its transport is arranged in particular centered with respect to the width b51 of the sheets 51, oriented orthogonally to the transport direction T, and/or centered with respect to the width b69 of the table-shaped surface 69, oriented orthogonally to the transport direction T. The width b52 of the suction belt 52 oriented orthogonally to transport direction T is narrower than the width b51 of the sheets 51 in question to be transported, oriented orthogonally to the transport direction T and is also narrower than the width b69 of the table-shaped surface 69 oriented orthogonally to transport direction T. The width b52, oriented orthogonally to the transport direction T, of suction belt 52 is, e.g. only 5% to 50% of the width b51, oriented orthogonally to transport direction T, of the sheets 51 and/or the width b69, oriented orthogonally to transport direction T, of the table-shaped surface 69 so that during its transport, the sheet 51 in question does not rest on suction belt 52 with its full surface, in particular with its two lateral regions extending orthogonally to transport direction T.
To allow the sheet 51 in question to slide with as little friction as possible during its transport across the table-shaped surface 69 that covers the at least one suction chamber 58; 59, at least one blow-suction nozzle 68 is positioned in at least two of the regions of the table-shaped surface 69 across which the suction belt 52 does not pass. The flow of air emerging from the respective blow-suction nozzle 68 preferably is or at least can be controlled, e.g. in terms of its intensity (i.e., in terms of its pressure and/or its flow rate) and/or its duration, wherein the blow-suction nozzle 68 in question allows air to flow against the underside of the sheet 51 in question during the transport thereof, whereby an air cushion is or at least can be created between the underside of the relevant sheet 51 to be transported and the table-shaped surface 69. In the preferred embodiment, each of the blow-suction nozzles 68 is configured as a Venturi nozzle, with the Venturi nozzle suctioning a lateral region of the relevant sheet 51 to be transported by applying vacuum pressure in the direction of the table-shaped surface 69. Each of the blow-suction nozzles 68 is preferably located in the table-shaped surface 69.
The transport device having the center suction belt 52 and blow-suction nozzles 68 in the edge region for the sequential transport of individual sheet-type substrates can be used advantageously when the sheets 51 to be transported are surface-coated and these surface-coated sheets 51 still in their wet state are removed by means of the above-described transport device, e.g. by a chain conveyor 16. The proposed solution not only enables the elimination of additional suction belts 78 that would be arranged parallel to the centrally arranged suction belt 52, it also avoids those problems that could be solved by synchronizing these additional suction belts 78 to the centrally arranged suction belt 52.
Moreover, with the blow-suction nozzles 68, the leading edge of each of the sheets 51, after being released by the gripper carriage 23 in question, is moved from the level of a gripper striking plane to a floating plane just above the table-shaped surface 69, i.e. a few millimeters, and the respective leading edge of the sheet 51 in question released by the gripper remains at the level of the table-shaped surface 69. Without the blow-suction nozzles 68, when sheets 51 are being transported at a high speed, e.g. of more than 10,000 sheets per hour, there is a risk that the released leading edge of the sheets 51 in question, or when sheets 51 are being transported in an overlapped arrangement, the leading edge of said sheets that has been thrust free, may be lifted up by a blade of air and raised again. In addition, with pliable sheets 51 or substrates, with which internal transverse forces are transmitted to only a limited extent from the center belt to the outer edge regions of the substrate in question, the conveyance component of each of these outer edge regions is supported by the air friction caused by the air flow LS.
With a chain conveyor 16, the sheet-type substrates 51 are each transported individually by a gripper carriage 23 moved along a movement path (
In conjunction with the machine arrangements described above, the following method can advantageously be used for operating a transport device for feeding individual sheet-type substrates 51 sequentially to a processing station 02; 03; 04; 06; 07; 08; 09; 11; 12, in which, by means of a monitoring device that cooperates with the transport device, the actual position of each substrate 51 in its transport plane 29 is determined mechanically before said substrate reaches the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12, and is compared automatically with a target position intended for the substrate 51 in question in said processing station 02; 03; 04; 06; 07; 08; 09; 11; 12. If the actual position deviates from the target position, the substrate 51 in question is aligned by a transport element of the transport device, the movement of which is controlled by the control device, such that the substrate 51 in question assumes its target position intended for this processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 before it reaches said processing station 02; 03; 04; 06; 07; 08; 09; 11; 12. In a highly advantageous variant, the substrate 51 in question is thereby aligned solely by the transport element, in each case in the transport plane 29, both in transport direction T and transversely thereto and about a fulcrum lying in the transport plane 29. This means that, in this variant for operating the transport device, no mechanical stops, in particular, are involved in the alignment of the substrate 51 in question. The processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 to which the substrate 51 in question is fed and is aligned with respect to its target position is preferably embodied as a non-impact printing device. The substrate 51 in question is preferably held by the transport element in a force-locking connection, e.g. by means of suction air, or by clamping, and is aligned in this operating state, held by the transport element, with respect to the target position intended for this substrate 51 in the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12. A suction drum 32 or a suction belt 52; 78 is used, in particular, as the transport element. The transport element transports each of the substrates 51 individually. The monitoring device includes, e.g. the control unit and at least one of the, e.g. optical sensors 33; 36 connected to it, each of the sensors 33; 36 being embodied, e.g. as a lateral edge sensor and/or as a leading edge sensor, for detecting the actual position of the substrate 51 in question. The target position, with respect to which the substrate 51 in question is to be aligned, is or will be stored in the control unit and/or, e.g. stored, preferably such that it can be modified, e.g. by means of a program. The transport element is driven by a first drive which moves the substrate 51 in question in its transport direction T, and by a second drive which moves the substrate 51 in question transversely to its transport direction T, and by a third drive which rotates the substrate 51 in question about the fulcrum located in the transport plane 29, with these drives, each of which is embodied, e.g. as a motor, in particular as a preferably electric servomotor, each being controlled by the monitoring device, i.e. by the control unit thereof. The transport element is driven by its three drives, in particular simultaneously. The substrate 51 in question is fed by the transport device at a transport speed that is not equal to zero to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12, and in the event of a deviation of the actual position from the target position, the substrate is preferably aligned while maintaining this transport speed. If the transport element is embodied as a suction belt 52; 78, the transport speed at which the substrate 51 in question is fed to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 in question corresponds, e.g. to the speed of revolution v of said suction belt 52; 78.
One exemplary embodiment for carrying out the aforementioned method for operating a transport device for the sequential feeding of individual sheet-type substrates 51 to a processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 is shown in
A further method for operating a device for transporting sheet-type substrates 51 likewise uses a transport element for conveying the substrate 51 in question in its transport plane 29, wherein the transport element feeds the substrate 51 in question true to register to a processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 downstream of the transport element in the transport direction T of the substrate 51 in question, this processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 being embodied, e.g. as a non-impact printing unit 06. A suction drum 32 having a plurality of suction rings 76 arranged side by side axially and each embodied as a holding element, or an arrangement of multiple suction belts 52; 78, each revolving lengthwise relative to the transport direction T of the substrate 51 in question and arranged side by side transversely to the transport direction T of the substrate 51 in question, is used as the transport element. The transport element for transporting the substrate 51 in question therefore always uses a plurality of holding elements arranged spaced from one another transversely to its transport direction T, the substrate 51 in question being held in a force-locking connection by at least two of these holding elements in each case up to an output position with respect to the transport plane 29. The output positions of all of the holding elements for holding the substrate 51 in question in a force-locking connection are all located on the same straight line 103. The transport element is used to adjust the diagonal register of the substrate 51 in question. The diagonal register of the substrate 51 in question is adjusted by adjusting a rotational angle β of this straight line 103 about a pivot axis 94 which is perpendicular to the transport plane 29, wherein the rotational angle β of this straight line 103 is adjusted, according to the diagonal register of the relevant substrate 51 to be adjusted, by means of an actuation, triggered by a control unit, of a single mechanical coupling element, which acts simultaneously on all the holding elements holding the substrate 51 in question in a force-locking connection, whereby the respective output position of at least one of the holding elements holding the relevant substrate in a force-locking connection is adjusted by means of the mechanical coupling element acting on the holding element in question. The holding elements that hold the substrate 51 in question in a force-locking connection each impress a transport speed onto the substrate 51 in question that differs from holding element to holding element, wherein the transport speed impressed by the respective holding element onto the substrate 51 in question is dependent in each case on the output position set for the respective holding element. As a mechanical coupling element, e.g. a linear gear element with rocker arms and/or with geared mechanical linkages is used, with each of the holding elements that holds the substrate 51 in question in a force-locking connection being assigned either a rocker arm or a geared mechanical linkage.
The proposed method for operating a device for transporting sheet-type substrates has the advantage that, for adjusting the diagonal register in the transport device, an oblique positioning of the transport element in question does not occur and therefore, a lateral register and/or axial register of the substrate in question that have, e.g. already been adjusted, cannot be adversely affected by the adjustment of the diagonal register. Instead, between the holding elements of the transport element that are involved in the adjustment of the diagonal register, a differential speed which is dependent upon the respective position of the holding element in question is adjusted by actuating a single adjustment drive, thereby aligning the substrate in question according to the desired diagonal register. The use of only a single actuating drive for adjusting the diagonal register has the advantage that a synchronization of different drives, each acting on one of the holding elements, or the adjustment of these to match one another is not required, thereby eliminating a source of error and enabling a highly precise adjustment of the diagonal register.
In one preferred embodiment of this method, the actual position, in its transport plane 29, of the substrate 51 to be fed true to register to the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 is determined by means of a monitoring device connected to the control unit before said substrate reaches the transport element, and is compared with a target position intended for the substrate 51 in question in the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12, and in the case of a deviation of the actual position from the target position, the control unit controls a drive 93 for adjusting the mechanical coupling element such that when all of the holding elements holding the substrate in question in a force-locking connection reach their respective output positions, the substrate 51 in question assumes its intended target position with respect to the diagonal register in the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12.
One exemplary embodiment for carrying out the latter method for operating a device for transporting sheet-type substrates 51 will now be explained in reference to
The variant of the embodiment according to
The machine arrangement shown in
The third transport device 128 for transporting the substrate in question within the operative zone of the first non-impact printing unit 06 and the second transport device, having at least one drawing element, for transporting the substrate in question within the operative zone of the second non-impact printing device 127 preferably each have an independent drive 129; 131, each of these independent drives 129; 131 being embodied, e.g. as a preferably electrically driven motor, the respective speed and/or angular position of which is or at least can be controlled, wherein these independent drives 129; 131 that influence the respective movement behavior of the transport devices in question synchronize or at least are capable of synchronizing the printing of the substrate in question on the front thereof by the first non-impact printing unit 06 and on the reverse side thereof by the second non-impact printing unit 127.
In one preferred embodiment, the first dryer 121 for drying the primer applied to the front side of the substrate in question is located, e.g. in the region of the impression cylinder 119 (
In one particularly advantageous embodiment of the transport device in question having gripper carriages 23, a plurality of belts are preferably arranged between immediately sequential gripper carriages 23, at least lengthwise along the transport direction T of the substrate in question, the substrate in question held by the gripper carriage 23 in question being supported with at least a part of its surface on said belts preferably arranged parallel to one another, for the purpose of stabilizing said substrate during transport. Belts arranged between sequential gripper carriages 23 along the transport direction T of the substrate in question are arranged, in particular, spring-loaded, or are made of a flexible material.
In a further preferred embodiment, gripper carriages 23 are guided, at least within the operative zone of the first non-impact printing unit 06 and/or within the operative zone of the second non-impact printing unit 127, by means of at least one guide element 71 arranged along the path of movement of the gripper carriage 23 in question, for the purpose of stabilizing their respective movement paths (
The machine arrangement illustrated in
In the machine arrangement according to
On the periphery of the impression cylinder 119 which has the first primer application unit 02, e.g. a dryer 121 is positioned, typically immediately downstream of the first primer application unit 02, for drying the front side of the substrate in question which has been primed by said first primer application unit 02, and/or on the periphery of the impression cylinder 119 which has the second primer application unit 126, e.g. a dryer 122 is positioned, typically immediately downstream of the second primer application unit 126, for drying the reverse side of the substrate in question which has been primed by said second primer application unit 126. The dryer 121 for drying the primer applied to the front side of the substrate in question and/or the dryer 122 for drying the primer applied to the reverse side of the substrate in question, and/or the dryer 123 for drying the substrate in question which has been printed on the front side by the first non-impact printing unit 06 and/or the dryer 124 for drying the substrate in question which has been printed on the reverse side by the second non-impact printing unit 127 are each embodied as a dryer for drying the primed and/or printed substrate in question using hot air and/or by irradiation with infrared or ultraviolet radiation. In one particularly preferred embodiment, the dryer 121; 122; 123; 124 for drying the primed and/or printed substrate in question by irradiation with infrared or ultraviolet radiation is embodied as an LED dryer, i.e. as a dryer that uses semiconductor diodes to generate the infrared or ultraviolet radiation.
Moreover, in the machine arrangement shown in
After being transported through the second printing cylinder, the substrate in question, which has been printed on both sides, is then preferably transported by means of a transport device, e.g. to a delivery 12, and is deposited onto a pile in delivery 12. The transport device connected downstream of the second printing cylinder is embodied, e.g. as a chain conveyor, and as the substrate in question is being transported through this transport device, before being deposited in delivery 12, the substrate is dried again, preferably on both sides, by at least one dryer 09. In some production lines, the plan may be to print the substrate in question, which has been printed on the front side by the first non-impact printing unit 06 and/or has been printed on the reverse side by the second non-impact printing unit 127, on one or both sides with additional printing inks, in particular special colors, and/or, e.g. to finish it by an application of varnish. In this latter case, at least one additional, e.g. a third printing cylinder or preferably at least one additional cylinder pair, composed of a third printing cylinder and a fourth printing cylinder, is provided downstream of the second printing cylinder and upstream of the transport device for transporting the substrate in question to delivery 12, on which at least one additional, e.g. third and/or fourth printing cylinder, one additional printing unit, in particular one additional non-impact printing unit, or at least one varnishing unit 08 is arranged in a manner similar to the arrangement associated with the first printing cylinder and/or the second printing cylinder, in each case optionally with an additional dryer. All of these juxtaposed printing cylinders then form a continuous transport path for the substrate in question in the machine arrangement in question, in which this substrate is then transferred from one printing cylinder to the next. The substrate in question can be processed, in particular printed, on both sides, without the need for a turning device for the substrate in this machine arrangement. The proposed machine arrangement is thus highly compact and inexpensive.
The machine arrangement shown in
While preferred embodiments of a device for overlapping sheets, in accordance with the present invention, have been set forth fully and completely hereinabove, it will be apparent to one of skill in the art that various changes could 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.
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| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/059890 | 4/26/2017 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2017/186772 | 11/2/2017 | WO | A |
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| Number | Date | Country | |
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| 20190070846 A1 | Mar 2019 | US |
