Patent Application
20190232638
The present invention relates to a machine arrangement for the sequential processing of sheet-type substrates. The machine arrangement has multiple different processing stations. These multiple different processing stations each included a substrate guiding unit and a substrate processing unit. At least one of the processing stations has, as a substrate processing unit, at least one non-impact printing unit for printing each of the substrates. That processing station, which has the at least one non-impact printing unit, includes a printing cylinder. The respective non-impact printing unit is arranged on the periphery of the printing cylinder. The respective printing cylinder, in each case, is configured as one of a triple-sized or a quadruple-sized cylinder.
WO 2004/013704 A1 describes a digital printing machine for direct, contactless sheet-fed printing, which includes a digital printing couple that is format-free in the circumferential direction and which has a transport device downstream of the digital printing couple, the transport device having grippers for holding sheets on its periphery, and the transport device preferably having a plurality of transport cylinders and/or conveyor belts and/or impression cylinders.
EP 2 540 513 A1 describes a machine arrangement for the sequential processing of multiple sheet-type substrates, each having a front surface and a back surface, said machine arrangement comprising a first printing cylinder and a second printing cylinder, wherein at least one first non-impact printing unit for printing onto the front surface of the relevant substrate 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 surface of said substrate that has been printed by the first non-impact printing unit, are each located on the periphery of the first printing cylinder, and at least one second non-impact printing unit for printing onto the back surface of the relevant substrate and, downstream of the second non-impact printing unit in the direction of rotation of the second printing cylinder, a dryer for drying the back surface of said substrate that has been printed by the second non-impact printing unit, are each located on the periphery of the second printing cylinder, wherein the first printing cylinder transfers the substrate in question, the front surface of which has been printed and dried, directly to the second printing cylinder.
EP 1 440 351 B1 discloses a digital printing machine for direct, contactless sheet-fed printing, which has a transport device covered with a layer of elastic material on which a printing substrate is transported, the transport device having at least one gripper for holding the sheet on the periphery of the transport device and/or having a stop for positioning the leading edge of the sheet, said digital printing machine also having a digital printing mechanism which is format-variable in the circumferential direction of the transport device, wherein the distance between the highest point on the gripper and/or stop and the surface of the printing substrate to be printed during the printing operation is shorter than the distance between the surface of the printing substrate to be printed and the digital printing mechanism, and the highest point on the gripper and/or stop projects beyond the surface of the transport device that is not covered.
DE 10 2015 211 637 A1 discloses a device for transporting sheets through a printing unit that includes an inkjet printing cylinder and at least one transfer drum, in which each sheet is held on an inkjet printing cylinder and is transferred by a transfer of the leading edge from an upstream transfer drum; a tensioning roller is provided for crease-free positioning of the sheet on the inkjet printing cylinder.
DE 103 12 870 A1 discloses a digital printing machine for sheet-fed printing, having a digital printing mechanism which is format-free in the circumferential direction, an intermediate cylinder located downstream of the digital printing mechanism and coated at least partially with an elastic material, and an impression cylinder located downstream of the intermediate cylinder, wherein the impression cylinder is equipped with grippers for holding the sheet and the intermediate cylinder is provided with recesses on its periphery for receiving the grippers.
DE 10 2014 010 904 B3 discloses a device for the duplex printing of sheet-type printing substrates, in which the printing substrate is guided through more than 360° on an impression cylinder, wherein the active zone of an ink application unit, which has already printed the recto surface of the printing substrate on an impression cylinder upstream, is re-entered by the printing substrate, this time with its verso surface facing the ink application unit, wherein the ink application unit can preferably be pivoted between two impression cylinders arranged one downstream of the other, and wherein the pivotable ink application unit is, e.g. an inkjet print head.
DE 10 2009 000 518 A1 discloses a sheet-fed printing machine having a feed unit for loading sheets to be printed into the sheet-fed printing machine, and having at least one printing element and/or coating unit for printing the sheets with a static print image that is identical for all printed sheets, and having a delivery unit for discharging printed sheets from the sheet-fed printing machine, and having at least one printing unit that does not include a printing forme and that is integrated into the sheet-fed printing machine for printing the sheets, in particular with a dynamic, variable print image, wherein the or each printing unit that includes no printing forme is integrated into the sheet-fed printing machine, where it can be controlled on the basis of process parameters or operating parameters or order parameters or quality parameters.
DE 10 2009 002 580 A1 discloses a printing machine, in particular a sheet-fed offset printing machine, in which a sheet delivery base module is located downstream of a plurality of base modules that are arranged in a row and are each configured as a printing unit or coating unit, wherein the sheet delivery base module includes a printing cylinder that guides the sheet-type material, and an inkjet device for marking the printing substrate is disposed on the periphery of the printing cylinder of the sheet delivery base module.
DE 200 06 513 U1 relates to a sheet-fed rotary printing machine that includes a sheet feed unit, a sheet delivery unit, and a plurality of base modules, which are similar in terms of their basic structure and are arranged between the sheet feed unit and the sheet delivery unit, and which include a sheet guiding cylinder and a sheet conveying means and can be equipped with a printing unit, a coating unit, or a dryer unit; a multifunction module that includes a sheet conveying means and a sheet guiding cylinder is located between the last base module and the sheet delivery unit in the direction of sheet conveyance, and the multifunction module is prepared for the addition of multiple different auxiliary units, the multifunction module being equipped, e.g. for the addition of an inkjet marking unit.
DE 10 2016 207 398 B3, US 2009/0284561 A1, US 2009/0244237 A1, and US 2011/0205321 A1, all subsequently published, each disclose a machine arrangement for the sequential processing of sheet-type substrates, with the machine arrangement in each case including multiple different processing stations; at least one of the processing stations of each machine arrangement includes a non-impact printing unit that prints on each of the substrates, and said processing station which includes the non-impact printing unit has a printing cylinder, with the respective non-impact printing unit being located on the periphery of said printing cylinder.
U.S. Pat. No. 7,909,454 B2 discloses a printing machine for the sequential printing of sheet-type substrates, in which an inkjet printing unit is disposed on the periphery of a printing cylinder and a feed cylinder is located immediately upstream of the printing cylinder, and both the printing cylinder and the feed cylinder are equipped with grippers for holding substrates to be printed.
EP 2 610 064 A1 discloses an inkjet recording apparatus that includes: a) a conveyance device which has a moving suctioning surface for conveying a cut paper medium by suctioning the medium onto the suctioning surface, and suctioning holes that are arranged uniformly in the regions of the suctioning surface; and b) a recording head, which forms an image by ejecting ink by an inkjet method onto a surface of the medium which is conveyed by the conveyance device.
JP 2015 63 398 A discloses an inkjet recording device that includes a transport cylinder configured as a suctioning drum.
EP 2 752 380 A1 discloses a conveying device and image producing device, in which the conveying device comprises a drum having multiple suction fields.
The object of the present invention is to devise a machine arrangement for the sequential processing of multiple sheet-type substrates.
The object is achieved according to the invention by the provision of the machine arrangement having a double-sized or a triple-sized transfer drum or a corresponding feed cylinder located immediately upstream of the respective printing cylinder. Alternatively, a double-sized or a triple-sized transfer drum or a corresponding transport cylinder is located immediately downstream of the printing cylinder.
The advantages to be achieved with the invention will be clear from the following descriptions.
The solution described here can be used in a hybrid machine arrangement for the processing of sheet-type substrates, preferably in a hybrid printing machine that variably utilizes the high productivity of a conventional printing unit that prints, e.g., by an offset printing method or by a flexographic printing method or by a screen printing method, or the high productivity of a coating unit, in particular a finish coating unit, in combination with at least one non-impact printing unit configured, e.g. as an inkjet printer that prints variable printed images in a flexible manner, wherein both the conventional printing unit or coating unit and the non-impact printing unit are used in an ongoing inline production process, each at its optimum operating speed. 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 one of the printing units can be utilized, resulting in a flexible and efficient production of the packaging materials. Transporting sheet-type substrates by means of rotary bodies, in particular cylinders and gripper bars or gripper carriages, each of which transfers the sheet-type substrates in a gripper closure to the next subsequent processing station, as is known from 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 below.
In the drawings:
One common feature of all of the production lines shown in
In the following, it will be assumed by way of example that a sequence of rigid sheets, in particular, e.g. sheets of a paper, a single-ply or multi-ply paperboard, or a cardboard, as the printing substrate is processed in each case in the respective machine arrangement that includes multiple processing stations 01; 02; 03; 04; 06; 07; 08; 09; 11; 12, in particular to produce a packaging material. Paper, paperboard, and cardboard as printing substrates differ from one another in terms of their respective basis weight, referred to as grammage, i.e. the weight in grams of one square meter of printing substrate. In general, the aforementioned printing substrate having a basis weight of between 7 g/m2 and 150 g/m2 is classified as paper, substrate with a basis weight of between 150 g/m2 and 600 g/m2 is classified as paperboard, and substrate with a basis weight of greater than 600 g/m2 is classified as cardboard. Paperboards and cardboards in particular are used for producing folding cartons, as these materials are readily printable and are suitable for subsequent finishing or processing, such as coating and punching. In terms of fiber content, such paperboards and cardboards may, e.g. be wood pulp-free, low wood pulp-based, or wood pulp-based, or may contain recycled paper. In terms of structure, multi-ply paperboards and cardboards, e.g. corrugated cardboard, each have a top layer, an inlay, and forming the reverse side, a bottom layer. In terms of surface finish, paperboards and cardboards may be uncoated, pigmented, coated, or cast-coated, for example. The sheet format may range, e.g. from 340 mm×480 mm to 740 mm×1060 mm, with the first number in the format specification typically indicating the length of the sheets in the direction of transport T, and the second number indicating the width of the sheets orthogonally to the direction of transport 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 processing station 04, which is configured as offset printing unit 04. In cold foil application unit 03, a metallized coating layer, detached from a carrier film, is transferred to the printing substrate. By overprinting this coating layer, e.g. using an offset printing unit 04, a wide variety of metal effects can be achieved. Cold foil application unit 03 is advantageously configured, 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 the direction of transport 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 forme. A second printing couple 88 in the direction of transport T of the printing substrate is equipped with a foil transfer device which has the coating layer to be transferred. The foil 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 remain bonded 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, e.g. water-based 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 that is particularly absorbent, for example, and/or is to be prepared for printing with a non-impact printing unit 06 is fed from feed unit 01 to the next processing station 02, configured e.g. as a primer application unit 02, where at least one surface of said printing substrate is coated, e.g. with a water-based primer, in particular to seal said substrate prior to printing or varnishing. Priming involves providing the printing substrate with a base coating or initial coating, in particular to improve or enable the adhesion of a printing ink or ink that will subsequently be applied to the printing substrate. For this purpose, e.g. a white coating is applied to the substrate. Primer application unit 02 is formed, e.g. in conjunction with a printing couple 86 of a rotary printing machine and includes, e.g. a printing couple cylinder 82 cooperating with an impression cylinder 119 and having a forme roller 83, preferably in the form of an anilox roller 83, which 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 forme roller 83 (
The flexographic printing carried out by a processing station 04 configured, e.g. as a flexographic printing unit 04 is a direct letterpress process, in which the raised areas of the printing forme 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 forme, b) a printing cylinder, also called a forme cylinder, on which the printing forme is fixed, and c) an impression cylinder which guides the printing substrate.
Each processing station 04, configured 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 multiple printing couples 86, e.g. at least four, each printing couple 86 preferably printing with a different ink color, so that as the printing substrate passes through the flexographic printing unit 04 or the offset printing unit 04, it is printed in multiple colors, e.g. in four-color printing. In particular, the color shades yellow, magenta, cyan and black are used as printing ink colors. In an alternative embodiment of printing unit 04 for flexographic printing or offset printing, processing station 04, which prints at least one static print image onto each of the sheets, is configured as a printing unit 04 for printing by a screen printing method.
Once the printing substrate has been processed in the at least one non-impact printing unit 06, this printing substrate is fed, e.g. to a processing station 07 configured as a dryer 07, in particular as an interdeck dryer 07, said interdeck dryer 07 being configured for drying said substrate, e.g. using hot air and/or by irradiation with infrared or ultraviolet radiation, with a dryer that dries by ultraviolet radiation being embodied, e.g., as an LED dryer, and with 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 configured as a coating unit 08. Coating unit 08 preferably applies, e.g. a transparent or white or colored dispersion coating to the printing substrate, with dispersion coatings consisting essentially of water and binders (resins), along with surfactants for stabilizing these dispersions. A coating unit 08 for applying a dispersion coating to the printing substrate consists of either an anilox roller, a chamber doctor blade, and a forme roller (comparable to a flexographic printing couple), or a dipping roller and a forme roller. Full-surface and/or partial coatings, for example, are applied to the printing substrate by means of a printing forme, preferably based on photopolymerization. For full surface coatings, special coating plates made of rubber may also be used. In the transport path of the printing substrate, a processing station 09 configured, e.g. as a dryer 09 is located downstream of coating unit 08, said dryer 09 being configured to dry the printing substrate in question using hot air and/or by irradiation with infrared or ultraviolet radiation, with a dryer that dries by ultraviolet radiation being embodied, e.g. as an LED dryer. If the machine arrangement in question includes multiple 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 the direction of transport T of the printing substrate, in which case the interdeck dryer(s) 07 and the (final) dryer 09 may be structurally identical or may be structurally different 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 that is cured by UV-radiation, or a coating which is cured by UV-radiation, e.g. a gloss coating, is applied, said dryer 09 is equipped with a radiation source that generates ultraviolet radiation. Dispersion coatings allow more intense gloss and matte effects to be achieved than with classic oil-based coatings. Special optical effects can be achieved by 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.
Following the final drying step along its transport path, the printing substrate is fed, e.g. to a processing station 11, which performs further mechanical processing on the printing substrate, e.g. punching or creasing, and/or the separation of parts, in particular the stripping of usable blanks from their points of attachment in the preferably printed sheet. Each of the aforementioned further processing steps is carried out in or by a processing system 46. Further mechanical processing is preferably carried out in cooperation with a cylinder transporting the respective sheet. Thereafter, or directly from the final dryer 09 in the transport path of the printing substrate, the printing substrate advances to a delivery 12, which is the last processing station 12 in each of the production lines shown in
As 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 sheets based upon whether the printing ink to be applied to the sheet, in particular by the non-impact printing unit 06, is a water-based printing ink or ink, or is a UV-curing printing ink or ink. Thus, the respective machine arrangement is configured to print each of the sheets with a water-based printing ink or with UV-curing printing ink.
One advantageous machine arrangement, mentioned here by way of example, comprises multiple processing stations for processing sheets, with the multiple processing stations 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 being arranged one behind the other in the direction of transport T of the sheets for the inline processing of these sheets, wherein at least one of these processing stations 06 is configured as a non-impact printing unit 06, wherein a first processing station 01 located upstream of the non-impact printing unit 06 in the direction of transport T of the sheets is configured as a sheet feeder 01 or as a magazine feeder 01, wherein a processing station 08 located between the first processing station 01 and the non-impact printing unit 06 is configured as a first coating unit 08 for applying a coating to each of the sheets, wherein a first dryer 07 is located between the first coating unit 08 and the non-impact printing unit 06, wherein a first transport cylinder arrangement that includes at least one transport cylinder 39 is provided 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 the direction of transport T of the sheets, wherein a means 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 the direction of transport T of the sheets. A mechanical further processing unit 11 may additionally be located between the third dryer 09 and the delivery 12. In addition, e.g. a coating unit 03 for applying a cold foil is located upstream of the non-impact printing unit 06 in the direction of transport T of the sheets. Non-impact printing unit 06 preferably has multiple individually controlled inkjet printers along the transport path of the sheets. Within the active zone of the non-impact printing unit 06, the sheets are preferably guided, each lying flat on a transport device, wherein the transport device has a curved transport path for the sheets, at least within the active zone of non-impact printing unit 06, and the transport device is configured as a multi-sized printing cylinder 22 within the active zone of non-impact printing unit 06. In the direction of transport T of the sheets, upstream of non-impact printing unit 06, e.g. a transfer device is located, which transfer device aligns each of the sheets, e.g. 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, said transfer device including, e.g. a suction drum which 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 for transferring the sheets coming from the non-impact printing unit 06 to the second coating unit 08 is configured, for example, as a second transport cylinder arrangement having at least one transport cylinder 39.
Sheets are picked up from a pile in feeder 01, in particular sheet feeder 01, and are transported individually, spaced from one another, e.g. through the processing station 02; 03; 04, e.g. offset printing unit 04, disposed upstream of non-impact printing unit 06, at a first transport speed. Sheets that have been transferred from the processing station 02; 03; 04 which is configured, e.g. as offset printing unit 04 and is located upstream of non-impact printing unit 06 to the non-impact printing unit 06 are transported in this non-impact printing unit 06 at a second transport speed, with the second transport speed which is used in non-impact printing unit 06 typically being slower than the first transport speed used, e.g. in offset printing unit 04. To adjust the first transport speed which is used, e.g. in offset printing unit 04 to the typically lower second transport speed used in non-impact printing unit 06, e.g. the sheet gap existing between sheets that follow one another in immediate succession, i.e. the distance that is produced, e.g. by the width of a gripper channel for the sheets that are transported in the gripper closure, e.g. through offset printing unit 04, is preferably decreased as said sheets are being transferred, e.g. from offset printing unit 04 to non-impact printing unit 06, with such a decrease in distance amounting, e.g. to between 1% and 98% of the original distance. Sheets that follow one another in immediate succession are thus also transported spaced from one another in non-impact printing unit 06, but typically with a smaller sheet gap or at a shorter distance than, e.g. in offset printing unit 04, and consequently also at a lower 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 interdeck dryer 07 or dryer 09 and from there, e.g. by means of a feed table, to 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 the processing station 08; 09; 11, configured, e.g. as mechanical further processing unit 11 and located downstream of the non-impact printing unit 06, with the third transport speed typically being higher than the second transport speed and corresponding again, e.g. to the first transport speed used in particular in offset printing unit 04. Upstream of the mechanical further processing unit 11, the second transport cylinder arrangement is provided, for example, which picks up the sheets coming from the interdeck dryer 07 or dryer 09 and transports them to mechanical processing device 11. Also in the region of mechanical further processing unit 11, which includes, e.g. multiple processing systems 46 arranged in a row, a rotary body, in particular a cylinder, preferably a transfer drum 44, is provided, arranged between every two adjacent processing systems 46, for the purpose of transferring the sheets from one of the processing systems 46 arranged in a row to the next. One of processing systems 46 is configured, e.g. as a punching system, in particular a rotary punching system, while another processing system 46 is configured, e.g. as a creasing system. The processing system 46 in question is configured to carry 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 usable blanks that have been separated from said sheets are transported, e.g. by means of a chain conveyor 21 to delivery 12, where they are collected, preferably stacked.
The sheets are transported from the output of the processing station 02; 03; 04 configured, e.g. as offset printing unit 04 and located upstream of the non-impact printing unit 06, at least up to the output of interdeck dryer 07 or dryer 09, and preferably up to the beginning of the processing station 08; 09; 11 configured, e.g. as mechanical further processing unit 11 and located downstream of non-impact printing unit 06, in each case by means of a multi-component transport device, i.e. consisting of multiple modules, in particular transport units, arranged one behind the other in the direction of transport T of the sheets, the transport device preferably including a plurality of multi-sized transport cylinders 39. If necessary, an interdeck dryer 07 or a dryer 09 may also be provided between offset printing unit 04 and non-impact printing unit 06.
As is also clear from
As has already been mentioned, the above-described machine arrangements, each of which comprises multiple 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 configured for the purpose of processing sheets of different formats, i.e. of different lengths and/or widths. The typically rectangular sheets therefore differ, e.g. in terms of their respective length, with said length extending in the direction of transport T of said sheets. To avoid any decrease in the productivity of a machine arrangement when a processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 configured in particular as a non-impact printing unit 06 to which multiple sheets are fed in sequence is being used with comparatively shorter sheets, i.e. with sheets of smaller format than the larger format sheets that are otherwise processed in said machine arrangement, a method comprising the following steps is proposed:
A method for operating a transport device for feeding multiple sheets in sequence to a processing station 02; 03; 04; 06; 07; 08; 09; 11; 12, in which sheets of different lengths, said length extending in direction of transport T of said sheets in each case, are used for processing by 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 transported by the transport device spaced apart from one another, wherein the transport device impresses a transport speed onto each of the sheets to be transported, and wherein the distance between sheets that follow one another in immediate succession is kept constant for sheets of different lengths each extending in the direction of transport T of said sheets by adjusting the transport speed to be impressed by the transport device onto the sheet in question, the transport speed of each subsequent sheet in the direction of transport 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 preferably transported by the transport device spaced apart by a minimal distance, but typically by 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 the direction of transport T, i.e. between the trailing edge of a preceding sheet, said edge extending transversely to direction of transport T, and the leading edge of the sheet immediately following it, said edge extending transversely to the direction of transport T, ranges, e.g. between 0.5 mm and 50 mm, and is preferably less than 10 mm. When a shorter sheet will be processed after a longer sheet in the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 in question, the shorter sheet is accelerated by the transport device by increasing its transport speed. Conversely, a longer sheet is decelerated by the transport device by decreasing its transport speed when the longer sheet will be processed following a shorter sheet in the processing station 02; 03; 04; 06; 07; 08; 09; 11; 12 in question. As the 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 at its maximum when the sheets to be printed by said printing unit are fed to it in succession spaced apart by a constant minimal distance, regardless of their respective format. If a processing station 04 configured, e.g. as an offset printing unit 04 is located 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 that corresponds to the production speed of said offset printing unit 04, regardless of their respective format, in which case the transport speed specified for these sheets by the offset printing unit 04 is adjusted to the transport speed that corresponds to the processing speed of the non-impact printing unit 06, while said sheets are being transported by the transport device. If these sheets will also be fed to non-impact printing unit 06 spaced by a constant distance from one another, regardless of their respective format, longer sheets will be decelerated less than shorter sheets, although a decrease in their respective transport speeds will be necessary in any case since the processing speed of non-impact printing unit 06 is typically slower than the production speed of offset printing unit 04.
Each respective sheet is preferably held in a force-fitting and/or a form-fitting attachment by holding means, e.g. by suction air and/or by grippers, during its transport from one processing station 01; 02; 03; 04; 06; 07; 08; 09; 11; 12 to the next and/or also within said processing stations 01; 02; 03; 04; 06; 07; 08; 09; 11; 12, each of which is configured as a module, by the respective transport device, which comprises multiple transport cylinders one behind the other in the direction of transport T of the sheets.
In a preferred embodiment, the transport speed to be impressed upon the sheet in question is adjusted from a preferably electronic control unit located, e.g. on a control console of the machine arrangement, in which case the control unit performs the adjustment of the transport speed, in particular for the purpose of maintaining a constant distance between successive sheets, e.g. in a control loop. It is provided, for example, that a sheet that will be fed to mechanical further processing unit 11 is brought from the second transport speed to the third transport speed by means of rocking gripper 19 and, e.g. single-sized, transfer drum 31, meaning that the sheet in question is accelerated, in particular, by the rotation of transfer drum 31, controlled by the control unit.
The machine arrangement shown in
In turning device 23, turning is typically carried out based upon the principle of trailing edge turning. Turning device 23 may be configured, for example, as a three-drum turner or as a single-drum turner. In the three-drum turner, three substrate guiding cylinders are provided. In that case, for example, a single-sized or double-sized transfer drum, a preferably double-sized storage drum, and a preferably single-sized turning drum are provided in the direction of transport T of the substrates. A single-sized cylinder is able to accommodate one substrate of maximum format on its peripheral surface. In an offset printing unit, for example, a single-sized cylinder thus has the same diameter as a forme cylinder configured, e.g. as a plate cylinder, whereas a double-sized cylinder has a diameter of double size.
The turning drum is equipped in particular with a turning gripper system, in which case, the storage drum is equipped with at least one substrate holding system for each substrate-bearing lateral cylinder surface area. These substrate holding systems are preferably configured as a gripper system for gripping the leading edge of the substrate in the direction of transport T. Fixing elements for fixing the trailing area of a substrate in place are preferably also provided, each preferably configured as a system of suckers. The sucker systems are preferably connected to displaceable rear cylinder shell segments and are preferably displaceable circumferentially relative to the gripper systems on forward shell segments, so that substrates ranging from maximum to minimum format can be held in both their leading and their trailing areas on the storage drum in the straight printing mode and/or in the recto and verso printing mode. Substrate guiding elements for guiding the substrates can be situated below the storage drum and/or the turning drum. As a further refinement, a guiding doctor blade for guiding the substrate between the storage drum and the turning drum is assigned to turning device 23.
In the machine arrangement of
In the machine arrangement of
The machine arrangements shown in
A quadruple-sized printing cylinder 22; 38 has a diameter, e.g. of around 1,200 mm. A double-sized transfer drum 43 has a diameter, e.g. of around 600 mm. Below a transfer drum 43; 44 located upstream or downstream of the printing cylinder 22; 38, at least one comb sucker 33 which is equipped with a guide plate 42 is preferably provided (
It is possible for a dryer 07; 09 to be positioned inside a feed cylinder 43 that cooperates with a printing cylinder 22; 38, which dryer is then used for drying substrates being transported by said feed cylinder 43, e.g. substrates that have been primed upstream. A dryer 07; 09 of this type dries a substrate e.g. by irradiating it with infrared or UV radiation and/or using hot air.
In the preferred embodiment of the respective machine arrangement, each of the non-impact printing units 06; 37 is configured as an inkjet printing unit. Inkjet printing units of this type each have at least one nozzle bar. At least one nozzle bar preferably extends orthogonally to the intended transport path of the printing substrate or substrate, over the working width of the printing machine. The at least one nozzle bar preferably has at least one row of nozzles. The at least one row of nozzles, as viewed in a transverse direction, preferably has nozzle openings, i.e. ink outlet openings, positioned at regular intervals, for example, over the entire working width of the printing machine and/or the width of the barrel surface of the at least one first central cylinder, i.e. printing cylinder 22; 38. The nozzles are preferably distributed over multiple print heads. The surface of the respective print head that surrounds the nozzle openings is preferably called the nozzle surface.
Each nozzle bar preferably has at least one supporting member. The print heads of this nozzle bar are mounted on the supporting member directly or preferably indirectly, for example via positioning means and/or via connecting elements configured in particular as alignment means. The nozzle bar itself is preferably disposed such that it is movable, via at least one adjustment device, relative to a frame of the printing assembly, i.e. the processing station 06 in question, and/or relative to the axis of rotation of a central cylinder of the printing assembly. In a first embodiment, the adjustment path of the adjustment device points exclusively in one adjustment direction which has at least one component in a direction radial to the axis of rotation of the central cylinder and which is more preferably oriented exclusively radially to the axis of rotation of the central cylinder. In a second embodiment of the adjustment device, at least 75%, more preferably at least 90% of the entire length the adjustment path of the adjustment device points in an adjustment direction, at least one component of which points in a direction parallel to the axis of rotation of the central cylinder and which more preferably is oriented exclusively parallel to the axis of rotation of the central cylinder. In that case, however, a small portion of the travel path will preferably point in a radial direction, in order to avoid damage to the print heads.
The adjusting movement executed by the adjustment device serves, for example, to make print heads accessible for maintenance and/or cleaning operations and/or for the replacement of one or more individual print heads or groups of print heads. In particular, adjusting movements executed by the adjustment device can be used to allow temporary access to respective print heads by a cleaning device.
Multiple print heads are preferably arranged side by side in the transverse direction on the at least one nozzle bar, with the nozzle surfaces of said print heads being rectangular in shape, for example, but more preferably in the shape of a trapezoid and/or a parallelogram. Since individual print heads of this type typically are not fitted with nozzles up to the edge of their housing, the print heads must be arranged overlapping one another in the transverse direction. The at least one row of nozzles is preferably configured not as a single linear row of nozzles, but as the sum of multiple individual rows of nozzles, more preferably two, which are offset from one another in the circumferential direction. Various embodiments of such nozzle rows are possible.
In a first embodiment, for example, at least two and more preferably precisely two rows of print heads extending in the transverse direction are arranged offset from one another in the circumferential direction of the first central cylinder, preferably such that print heads arranged in succession in the transverse direction preferably belong alternatingly to one of the at least two rows of print heads, preferably alternating constantly between a first and a second of two rows of print heads. Two such rows of print heads form a double row of print heads.
In a second embodiment, the shapes of the print head housings are configured as matched with one another. For example, one nozzle surface of each print head, and/or at least one surface of the print head that delimits the print head in its ejection direction, has a shape that deviates from rectangular, and in particular has the shape of a preferably symmetrical trapezoid and/or of a parallelogram. This enables the nozzle surfaces of adjacent print heads to overlap in the transverse direction even when the print heads are arranged immediately adjacent to one another in the transverse direction, in particular without being offset from one another in a direction of transport T. Such a row of print heads is called a diagonally overlapping row of print heads, for example.
In particular, multiple rows of print heads, for example at least four double rows and more preferably at least seven double rows of print heads, or preferably at least four rows of diagonally overlapping print heads and more preferably at least seven rows of diagonally overlapping print heads, are arranged one behind the other in the circumferential direction with respect to the at least one first central cylinder, at least during printing operation, said print heads being aligned toward the at least one first central cylinder.
One coating medium, in particular a printing ink of a certain color, for example one of the colors black, cyan, yellow, and magenta, or orange, green, or purple, or a finish coating, for example a clear finish coating, preferably is and/or can be assigned to each double row of print heads or to each diagonally overlapping row of print heads. For example, two double rows of print heads or two diagonally overlapping rows of print heads are assigned to each coating medium. The at least one print head works to generate droplets of coating medium, preferably by the drop-on-demand method, in which droplets of coating medium are generated selectively, as needed.
During regular printing operation, all print heads are arranged fixed in place. This serves to ensure the permanent alignment of all nozzles in register in terms of color register and/or feed register. Some situations exist in which, apart from the movement by means of the adjustment device, a defined aligning movement of the print heads may be necessary. Said aligning movement of the print heads is preferably carried out by means of at least one positioning device.
At least one positioning device is preferably provided, which can be used to adjust the position of at least one print head, in particular the position of said print head relative to other print heads of the printing assembly and/or to other print heads belonging to the same nozzle bar, and/or the position of said print head with respect to the transverse direction and/or the position of said print head with respect to a pivot axis oriented parallel to its nozzle ejection direction. Preferably, multiple positioning devices are provided. For example, each print head may be assigned its own positioning device. Preferably, however, at least one such positioning device is assigned to multiple print heads collectively, in particular such that the positions of multiple print heads can be adjusted collectively by means of the common positioning device assigned to them, in particular in terms of their position relative to the common nozzle bar and/or relative to other print heads that are arranged on said common nozzle bar and/or in terms of their position with respect to the transverse direction and/or in terms of their position with respect to a pivot axis which is oriented parallel to their nozzle ejection direction.
The at least one positioning device has at least one base body, for example. The at least one print head is preferably located on the at least one base body. More preferably, multiple print heads, in particular at least three and preferably at least four print heads, are arranged on the at least one base body. The base body is preferably formed as a single integral unit.
Each respective print head is connected on one side to the base body and on the other side via at least one connecting element, for example. The at least one connecting element is configured, for example, as an alignment device. The alignment device can be used to align the respective print head, preferably individually, relative to the base body, in particular manually and/or in terms of the position of said print head with respect to the transverse direction and/or in terms of its position with respect to a pivot axis which is oriented parallel to the nozzle ejection direction of said print head. This enables preferably multiple print heads, in particular at least three and more preferably at least four print heads, to be aligned relative to the base body and thus also relative to one another.
These multiple print heads, in particular at least three and more preferably at least four print heads, and the base body preferably each represent a component of a first assembly unit. The print heads of the first assembly unit are aligned outside of the printing assembly relative to the base body and thus relative to one another, for example. This means that they can be aligned relative to the base body and thus also relative to one another using the appropriate tool and/or with the aid of a camera that records their relative positions and/or with particularly good accessibility. A first assembly unit which is aligned with particular precision is thereby produced.
The respective nozzle bar is preferably arranged supporting multiple such first assembly units. Each of these multiple first assembly units can preferably be adjusted in terms of its position relative to the supporting body of said nozzle bar by means of its own positioning device. Multiple positioning devices are therefore preferably arranged on one supporting body. Preferably, multiple first assembly units are arranged, at least indirectly via the positioning devices, on one supporting body, each assembly unit being adjustable in terms of its position relative to the supporting body, in particular by means of the multiple positioning devices. The print heads of two diagonally overlapping rows of print heads are arranged, at least indirectly via the positioning devices, on one supporting body, for example.
By moving the supporting body, all the print heads attached directly or indirectly thereto can then be moved, in particular without altering their alignment relative to one another.
To determine which print head or which group of print heads needs to be moved to what extent and in which direction in order to produce the optimum print result, at least one test print image is preferably printed and inspected. The result is used to determine settings for positioning devices, which are then adjusted manually and/or by means of respective positioning drives. The settings of the individual alignment devices are preferably determined and/or adjusted manually but may alternatively likewise be determined via at least one test print image.
Preferably, at least one sensor configured as a first printed image sensor is provided, in particular at a point along the transport path of the printing substrate downstream of the first printing unit. The at least one first printed image sensor is embodied, for example, as a first line camera or as a first surface camera. The at least one first printed image sensor is embodied, for example, as at least one CCD sensor and/or as at least one CMOS sensor. This at least one first printed image sensor and a corresponding evaluation unit, for example the superordinate machine controller, are preferably used for monitoring and/or regulating the actuation of all the print heads and/or double rows of print heads and/or diagonally overlapping rows of print heads positioned and/or acting one behind the other in the circumferential direction of the at least one first central cylinder of the first printing unit. In a first embodiment of the at least one printed image sensor, only a first printed image sensor is provided, the sensor field of which covers the entire width of the transport path of the printing substrate. In a second embodiment of the at least one printed image sensor, only a first printed image sensor is provided, which is configured as movable in the transverse direction. In a third embodiment of the at least one printed image sensor, multiple printed image sensors are provided, the respective sensor fields of which each cover a different region of the transport path of the printing substrate with respect to the transverse direction.
The positioning of pixels formed by droplets of coating medium, each originating from a respective first print head, is preferably compared with the positioning of pixels formed by droplets of coating medium, each originating from a respective second print head located downstream of the respective first print head in the circumferential direction of the at least one first central cylinder and/or in the designated direction of transport T of the printing substrate, and/or arranged in the direction transversely to the print head. This is preferably carried out regardless of whether these first and second print heads positioned and/or acting one behind the other in the circumferential direction of the at least one first central cylinder are processing the same or a different coating medium. The correlation of the positions of the printed images produced by different print heads is preferably monitored. If the same coating media are being used, the register-true merging of partial images is monitored. If different coating media are being used, the feed register or the color register is monitored. Quality control of the printed image is also preferably carried out based upon the measured values of the at least one printed image sensor.
At least one adjustment sensor is preferably provided. More preferably, at least two adjustment sensors are provided. The at least one adjustment sensor, and more particularly the at least two adjustment sensors, serve(s) to collect data regarding the adjustments of multiple print heads or groups of print heads, for example at least four, relative to one another. The at least one adjustment sensor or the at least two adjustment sensors is/are preferably optical sensors. Such relative adjustments are, for example, relative geometric positions of the print heads or groups of print heads and/or relative actuation times, in particular droplet ejection times of the print heads and/or groups of print heads. The relative adjustments are additionally or alternatively relative adjustments, for example, that affect at least one ink density and/or at least one area coverage and/or at least one point size of generated pixels. In the following, the relative adjustment is referred to geometric positioning and/or actuation times, in particular droplet ejection times. However, the described devices and/or processes also apply to the other relative adjustments mentioned, provided no contradictions arise therefrom.
The at least one adjustment sensor and in particular the at least two adjustment sensors are preferably configured at least as position sensors. The at least two adjustment sensors, in particular position sensors, are configured, for example, as cameras and/or CCD sensors and/or CMOS sensors. The at least two adjustment sensors, in particular position sensors, are preferably used to directly or indirectly detect the position and/or actuation of each of at least two print heads and/or groups of print heads relative to one another. For indirect detection, which is preferred, the at least one adjustment sensor, in particular the at least two adjustment sensors, preferably is/are arranged aligned and/or alignable toward the printing substrate and/or is/are arranged aligned and/or alignable toward the transport path provided for the transport of printing substrate, and/or is/are arranged aligned and/or alignable toward at least one transfer body.
The position of the target region of at least one newly positioned and/or repositioned print head relative to the position of the target region of at least one previously positioned print head and/or the position of the target region of at least one newly positioned and/or repositioned group of print heads relative to the position of the target region of at least one previously positioned group of print heads is preferably at least temporarily detectable. This is preferably accomplished by comparing the relative positions of pixels produced by the respective print heads on the printing substrate using a common adjustment sensor, in particular a position sensor. These relative positions of the pixels are preferably evaluated by means of an evaluation unit, for example the higher-level machine controller.
As at least one adjustment sensor, the above-described at least one first printed image sensor is used, for example. Preferably, however, adjustment sensors other than the above-described at least one first printed image sensor are used, for example adjustment sensors configured specifically for this task.
Following the installation and/or maintenance and/or replacement and/or cleaning of at least one print head and/or at least one group of print heads, a test print is preferably run to produce at least one printed test image, in which the print head to be newly positioned and/or repositioned and/or the group of print heads to be newly positioned and/or repositioned, and at least one print head serving as a reference or guiding print head transfer printing ink droplets or ink droplets onto the printing material or substrate. The at least one test print is preferably detected automatically by at least one adjustment sensor, for example the first printed image sensor. If a deviation of the actual position of the at least one newly positioned and/or repositioned print head or of the corresponding group of print heads from a target position is documented and detected based upon the at least one printed test image, the position of said print head or said group of print heads in the transverse direction and/or with respect to a pivot position is preferably adjusted automatically by means of the corresponding positioning device, and/or the actuation of the nozzles of said print head is preferably adjusted automatically with respect to the actuation time, in particular the droplet ejection time.
While preferred embodiments of a machine arrangement with printing unit for the sequential processing of sheet-type substrates, in accordance with the present invention, have been set forth fully and completely herein above, and 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.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2016 214 903.2 | Aug 2016 | DE | national |
| 10 2017 203 700.8 | Mar 2017 | DE | national |
This application is the U.S. National Phase, under 35 U.S.C. § 371, of PCT/EP2017/068774, filed Jul. 25, 2017; published as WO 2018/028980 A1 on Feb. 15, 2018, and claiming priority to DE 10 2016 214 903.2, filed Aug. 10, 2016 and to DE 10 2017 203 700.8 filed Mar. 7, 2017, the disclosures of which are expressly incorporated herein by reference in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/068774 | 7/25/2017 | WO | 00 |
