DE102019105629B3 - Printing machine with an inkjet system and with a transport device - Google Patents

Abstract

The invention relates to a printing press with an inkjet system that preferably prints a water-based ink and with a transport device that in particular transports a non-absorbent printing material, in which opposite outer edge areas of print nozzle fields arranged in a print head of the inkjet system have a lower print resolution compared to the center area when the printing process is carried out a process of the relevant printhead directed laterally to the feed direction of the printing material and its corresponding positioning can be used.

Description

The invention relates to a printing press with an inkjet system and with a transport device according to the preamble of claim 1.

Through the DE 10 2015 203 423 A1 A device for processing a substrate is known, with at least one device for contactless application of a printing ink and / or a coating material to the substrate and with a device in a feed direction relative to the at least one device for contactless application of the printing ink and / or the coating material on the substrate moving conveyor with an endless, preferably rotating load carrier, the at least one device for contactless application of the printing ink z. B. is each designed as a printing head in an inkjet printing process, the at least one device for contactless application of the printing ink and / or the coating material in particular in each case movable transversely to the feed direction of the substrate resting on the load carrier, in particular remotely positionable, for. B. is arranged motorized. The substrate to be processed is e.g. B. as a printed sheet of paper or a plastic or as a particularly metallic board or as a flat body with at least one flat processing surface.

Through the DE 10 2017 207 007 A1 A method for printing non-absorbent substrates with a water-based ink is known, in which ink drops are applied to the respective substrate, in which the ink is applied to the substrate in question with at least one inkjet print head, in which the ink drops during a bidirectional movement of the Push button and / or the substrate in question are applied to the same.

Through the US2006 / 0284910A1 there is known an image forming apparatus provided with a recording head obtained by overlapping and arranging a plurality of short recording heads with a unidirectional nozzle array of ink jet nozzles to eject ink from the ink jet nozzle based on a value of an image signal and form an image, comprising an overlap correction control unit for controlling the driving of the ink jet nozzles according to a phase difference in an ink jet nozzle position between the overlapping short recording heads to correct the optical density of an image formed on an overlapping part of the recording heads; and a correction control unit for the optical density characteristic for controlling the drive of the ink jet nozzles independently of the overlap correction control unit in accordance with a recording optics for the optical density of a nozzle arrangement consisting of the ink jet nozzles.

Through the US2008 / 0158295A1 There is known an ink jet head comprising a nozzle assembly having a plurality of nozzles, the nozzle assembly comprising a first nozzle group arranged in a center thereof and second nozzle groups arranged further outside than the first nozzle group, and wherein distances between the nozzles of the second Nozzle groups are larger than the distances between the nozzles of the first nozzle group.

Through the US2011 / 0273729A1 A fluid ejection device is known comprising a first row of nozzles having nozzles configured and arranged to eject a fluid onto a medium, the nozzles being arranged in a prescribed direction, the first row of nozzles being configured to form a first band image, while facing a first spot on the medium; a second row of nozzles having nozzles configured and arranged to eject a fluid onto the medium, the nozzles being arranged in the prescribed direction, the second row of nozzles being configured to produce a second band image while being at a second location faces the medium; a third row of nozzles with nozzles configured and arranged to eject a fluid onto the medium, the nozzles being arranged in the prescribed direction, and the third row of nozzles configured to generate a third band image while it is a third Spot facing the medium; a memory section configured to store a dither mask used in a halftone process for converting input data consisting of a plurality of arranged pixels into dot data representing dot on / off states, the dither The mask has edge regions, the regions being arranged on both edge sections in the prescribed direction and a central surface which is a surface on a central section in the prescribed direction and having a plurality of arranged threshold values; and a control section configured to form an image based on the point data, in which an edge section that is to one side in the prescribed direction in the first band image overlaps an edge section that is to the other side in the prescribed direction in the second band picture.

The invention has for its object to provide a printing press with an inkjet system and with a transport device in which the Nozzle fields of the print head of the inkjet system can be used in an improved manner.

The object is achieved by the features of claim 1. The dependent claims relate to advantageous developments and / or refinements of the solution found.

The advantages that can be achieved with the invention are, in particular, that the print quality is improved. Further advantages are mentioned in connection with the description of the exemplary embodiment.

An embodiment of the invention is shown in the drawings and is described in more detail below.

• 1 eine Druckmaschine mit einem Inkjetsystem und mit einer Transporteinrichtung;
• 2 eine mehrere Düsenfelder aufweisende Druckkopfplatte eines Druckkopfes des Inkjetsystems;
• 3 eine Prinzipskizze für das Bedrucken eines Rundkörpers mit dieser Druckmaschine.

Show it:

• 1 a printing press with an inkjet system and with a transport device;
• 2nd a print head plate of a print head of the inkjet system having a plurality of nozzle fields;
• 3rd a schematic diagram for printing a round body with this printing machine.

1 shows a perspective view of a printing machine in an exemplary and very simplified manner 01 with an inkjet system 02 and with a transport device 03 , the inkjet system 02 at least one preferably digital, programmed control unit 04 and at least one print head controlled to perform a printing operation 06 ; 07 ; 08 ; 09 and one the printhead in question 06 ; 07 ; 08 ; 09 with respect to one from the control unit 04 predetermined print position z. B. positioning means using at least one linear drive 11 has, which from the control unit 04 predetermined printing position with reference to one of the transport device 03 transported, e.g. B. arcuate printing material 12th is specified. The inkjet system 02 is designed such that it is connected to at least one of the control unit 04 predetermined print position a contact fluid on the relevant print head 06 ; 07 ; 08 ; 09 facing preferably flat surface of the printing material 12th applies, a printing ink or an ink or a varnish can be used as the respective printing fluid. In the in the 1 illustrated embodiment has the inkjet system 02 several, e.g. B. four print heads preferably arranged together in the same housing 06 ; 07 ; 08 ; 09 on, with these printheads 06 ; 07 ; 08 ; 09 preferably printing fluids differing in color on the printing substrate 12th are applied or are at least applicable, e.g. B. the process colors magenta, cyan, yellow and black. In the particularly preferred embodiment, the printing fluid is in each case water-based and in particular in the form of a water-based ink. The inkjet system 02 However, as an alternative or in addition, at least one other solvent-based pressure fluid or a pressure fluid that is hardened by ultraviolet radiation can be designed to print. In the case of an inkjet system 02 with multiple printheads 06 ; 07 ; 08 ; 09 these are preferably parallel to one another in each case transversely to the longitudinal extent of the transport device 03 arranged in the same housing and by the positioning device 11 e.g. B. together, ie in a rigid network along a route S movable.

The substrate 12th is particularly in a flat position on the transport device 03 arranged on top and along a travel path relative to the at least one of the control unit 04 with reference to the substrate 12th predetermined print position positioned print head 06 ; 07 ; 08 ; 09 can be moved bidirectionally. The two opposite directions of feed T are in the 1 each indicated by an arrow. The transport device 03 is z. B. designed as a movable transport table or as a self-contained conveyor belt. The transport device points to the execution of their respective feed movements 03 at least one z. B. designed as an electric motor drive 13 on, the drive in question 13 preferably also from the control unit 04 is controlled. The movable transport table can also, for. B. be moved by a linear motor or by a chain drive. The substrate 12th is or is on the transport device 03 e.g. B. magnetically and / or held by a vacuum generated by a suction device.

The substrate 12th , which has a width extending transversely to its travel path B1 has, e.g. B. a non-absorbent surface to be printed on. In the preferred embodiment, at least this surface is e.g. B. formed from a metallic material. With the substrate 12th is it z. B. around a flat substrate, preferably around a sheet of metal z. B. in a format up to 1,000 mm x 1,200 mm, the substrate 12th a material thickness z. B. in the range between 0.1 mm and 0.5 mm. With the aforementioned format of the substrate 12th are its width B1 up to 1,000 mm and its length extending along the travel path L up to 1,200 mm.

The one from the control unit 04 predetermined printing position positioned or at least positionable Printhead 06 ; 07 ; 08 ; 09 has a transverse to the path of the substrate 12th shorter print width B3 ( 2nd ) than the width B1 of the substrate 12th on. Therefore, the printhead in question 06 ; 07 ; 08 ; 09 on one that is transverse to the path of the substrate 12th extending route S e.g. B. on or along at least one of the transport device 03 across their respective feed directions T preferably completely bridging traverse 14 bi-directional, what in the 1 is indicated by a double arrow. Because of its particular from the control unit 04 controlled with respect to the substrate 12th lateral movement is the printhead in question 06 ; 07 ; 08 ; 09 each by means of an associated positioning device 11 successively on at least two different ones from the control unit 04 predetermined print positions in the width range B1 of the substrate 12th positioned or at least positionable. The distance S along which the print head in question 06 ; 07 ; 08 ; 09 is bi-directionally movable, preferably corresponds in length to at least one transverse to the path of the printing material 12th extending width B2 the transport device 03 .

A printhead 06 ; 07 ; 08 ; 09 an inkjet system intended for an industrial printing process 02 points to the substrate 12th facing printhead plate 17th at least one pressure nozzle field 18th , preferably several, e.g. B. three to five or more arranged in a row pressure nozzle fields 18th on ( 2nd ), in each of these pressure nozzle fields 18th a plurality of individually controllable inkjet nozzles are arranged. It can be in a printhead 06 ; 07 ; 08 ; 09 on its printhead plate 17th also a plurality of rows, preferably arranged parallel to one another, each with a plurality of pressure nozzle arrays lined up in series 18th be provided. In the application at hand, this is at least one pressure nozzle field 18th or the at least one row of pressure nozzle fields 18th each transverse to the path of the substrate 12th arranged extending, which are transverse to the respective feed directions T , ie the path of the substrate 12th extending length of the at least one pressure nozzle field 18th or the corresponding length of the row of pressure nozzle fields in question 18th a maximum print width B3 of the print head concerned 06 ; 07 ; 08 ; 09 Are defined. In practice it is the case that the pressure nozzle field in question 18th or each of these rows of pressure nozzles 18th of the print head concerned 06 ; 07 ; 08 ; 09 each z. B. is trapezoidal and that in these pressure nozzle fields 18th each on their two, perpendicular to the path of the substrate 12th opposite edge areas R1 ; R2 in each case a lower print resolution than in its itself between these two edge areas R1 ; R2 arranged center area M having. For example, due to the arrangement of the respective inkjet nozzles, the maximum achievable print resolution is in the middle area M of the relevant pressure nozzle field 18th 600 dpi (dots per inch), whereas on the two opposite edge areas R1 ; R2 each preferably the same print resolution of at most 300 dpi, that is, only half of that in the middle area M of the relevant pressure nozzle field 18th maximum achievable print resolution is achievable. With an arrangement of several pressure nozzle fields arranged in a row 18th are neighboring pressure nozzle fields 18th formed such that their respective mutually facing edge regions R1 ; R2 during the execution of a print process to the maximum possible print resolution as in the middle area M of the relevant pressure nozzle field 18th complete. This design variant consists in the lack of a supplementary border area R1 ; R2 from an adjacent pressure nozzle field 18th in the outer edge areas arranged in the same row R1 ; R2 basically not, which is why this outer has a lower print resolution than in the middle area M having marginal areas R1 ; R2 of the pressure nozzle fields 18th of the print head concerned 06 ; 07 ; 08 ; 09 To avoid a reduced print quality when executing a printing process have so far remained unused. A reduced print quality e.g. B. in the form of an unprinted strip or in the form of a strip formed by superimposing two areas each printed with full print resolution and thus saturated with length along the travel of the printing material 12th the arrangement of the pressure nozzle fields is more constructive 18th in the printhead 06 ; 07 ; 08 ; 09 relevant circumstances and / or due to insufficient accuracy in the positioning of the printhead in question 06 ; 07 ; 08 ; 09 and / or according to thermal in particular on the inkjet system 02 and / or on the transport device 03 influences usually even if printed areas on the substrate 12th corresponding to the the unused outer edge areas R1 ; R2 of the pressure nozzle fields 18th of the print head concerned 06 ; 07 ; 08 ; 09 spare printing width B3 of the print head concerned 06 ; 07 ; 08 ; 09 can even be put together seamlessly. For example, the usual temperature control of the pressure nozzle fields 18th having printhead plate 17th due to the thermal influence of an inaccuracy in the positioning of the print head in question 06 ; 07 ; 08 ; 09 up to the order of 100 µm, what im on the substrate 12th generated print image leads to visible quality defects.

This problem is countered here in that the print head in question 06 ; 07 ; 08 ; 09 the first is the substrate 12th printing process from the positioning device 11 at a specific from the control unit 04 predetermined printing position is positioned such that a first edge region R1 of a pressure nozzle field 18th this printhead 06 ; 07 ; 08 ; 09 at this predetermined printing position on the surface of the transport device 03 transported substrate 12th is arranged printing along its travel path, and that the print head in question 06 ; 07 ; 08 ; 09 in the case of a second, the same surface of the relevant one from the transport device 03 transported substrate 12th printing process from the positioning device 11 on the print head concerned during the first printing process 06 ; 07 ; 08 ; 09 assumed printing position is positioned such that the first edge region R1 across the path of the substrate 12th opposite second edge area R2 the same pressure nozzle field 18th or another pressure nozzle field 18th of the pressure nozzle fields arranged in the same row 18th of the print head concerned 06 ; 07 ; 08 ; 09 at this specific printing position on the surface of the transport device that has already been printed during the first printing process 03 transported substrate 12th is arranged printing along its travel. With this solution, the substrate 12th along its travel path relative to that of the control unit 04 with reference to this substrate 12th predetermined print position positioned print head 06 ; 07 ; 08 ; 09 Repeatedly bidirectional. The substrate 12th becomes multiple times relative to the printing head arranged printing 06 ; 07 ; 08 ; 09 emotional. Here is the print head in question 06 ; 07 ; 08 ; 09 formed in such a way and / or by the control unit 04 controlled that the substrate 12th either only when moving in the same feed direction T or alternatively during its movement in each of its two opposite feed directions T each can be printed. The specific one from the control unit 04 with respect to that of the transport facility 03 transported preferably sheet-shaped printing material 12th predetermined print position can e.g. B. the longitudinal to the path of the substrate 12th extending line of symmetry of this substrate 12th or the transport device 03 be.

A printing press designed in accordance with the proposed solution has the advantage that the preferably water-based printing fluid flows from the outer edge regions R1 ; R2 of the pressure nozzle field 18th or the pressure nozzle fields 18th of the print head concerned 06 ; 07 ; 08 ; 09 with each printing operation, in each case in partial quantities on the surface, in particular non-absorbent, of the transport device concerned 03 transported substrate 12th is applied. Because one of the outer edge areas R1 ; R2 of the pressure nozzle field 18th or the pressure nozzle fields 18th of the print head concerned 06 ; 07 ; 08 ; 09 on the non-absorbent surface of the transport device in question 03 transported substrate 12th applied amount of z. B. water-based pressure fluid tends to run. It is therefore advantageous to remove the preferably water-based pressure fluid from the edge regions mentioned R1 ; R2 in partial quantities on the surface of the transport device in question, in particular a non-absorbent surface 03 transported substrate 12th apply and if possible after each printing process z. B. to dry and / or harden at least briefly by introducing heat, so that bleeding of the pressure fluid is avoided.

The printhead in question 06 ; 07 ; 08 ; 09 is at its second the same surface of that of the transport device 03 transported substrate 12th printing process from the positioning device 11 on the print head concerned during the first printing process 06 ; 07 ; 08 ; 09 assumed printing position, in particular then with a control unit 04 Correction value set with regard to this substrate 12th predetermined print position positioned when the first margin area R1 across the path of the substrate 06 ; 07 ; 08 ; 09 opposite second edge area R2 the same pressure nozzle field 18th or another pressure nozzle field 18th of the pressure nozzle fields arranged in the same row 18th of the print head concerned 06 ; 07 ; 08 ; 09 at this specific printing position on the surface of the transport device that has already been printed during the first printing process 03 transported substrate 12th is arranged to print along its travel path to disturbances z. B. compensate by manufacturing tolerances and / or thermal effects. This further development of the proposed solution also has the advantage that it extends over the entire width B1 of the substrate 12th uniform print resolution and / or uniform print quality can be produced.

3rd illustrates the idea of the invention in a sketch if the printing material 12th is designed as a round body. The round body, which is preferably to be printed on its outer surface, is on one with the transport device 03 the printing press 01 connected or molded there holding device and is at least during the printing process about its longitudinal axis 16 set in rotation by a drive. The rotation of the round body corresponds to the feed of a z. B. arcuate with the transport device 03 transported substrate 12th , so that the travel of the z. B. sheet-shaped printing material 12th is replaced by the circumference of the round body. The holding device holding the round body to be printed, in particular on at least one of its end faces, is, for. B. formed as a mandrel or as a clamping device. The rest of the way the inkjet system works 02 and the transport device 03 having printing machine 01 also corresponds to the printing of at least one printing material designed as a round body 12th the description that goes with this press 01 already based on the 1 and 2nd was given.

Reference list

01

Printing press

02

Inkjet system

03

Transport device

04

Control unit

05

-

06

Printhead

07

Printhead

08

Printhead

09

Printhead

10th

-

11

Positioning device

12th

Substrate

13

drive

14

traverse

15

-

16

Longitudinal axis

17th

Printhead plate

18th

Pressure nozzle field

B1

Width ( 12th )

B2

Width ( 03 )

B3

Print width ( 06 ; 07 ; 08 ; 09 )

L

Length ( 12th )

M

Middle area ( 18th )

R

Edge area ( 18th )

S

route

T

Feed direction

Claims (10)

Printing machine with an inkjet system and with a transport device, a) wherein the inkjet system (02) has at least one control unit (04) and at least one print head (06; 07; 08; 09) controlled for the execution of a printing process and one the relevant print head (06; 07 ; 08; 09) with reference to a positioning device (11) that positions the print position specified by the control unit (04), the print position specified by the control unit (04) being specified with reference to a printing material (12) transported by the transport device (03) b) the printing material (12) transported by the transport device (03) along a travel path relative to the printing head (06; 07; 08; positioned by the control unit (04) with respect to the printing material (12); 09) can be moved bidirectionally, c) wherein the printing material (12) has a width (B1) extending transversely to its travel path, d) the one on the above printhead (06; 07; 08; 09) has a shorter printing width than the width (B1) of the printing material (12) transversely to the travel path of the printing material (12), e) the print head in question (06; 07; 08; 09) on a cross-section to the travel path of the printing material (12 ) arranged distance (S) bidirectionally movable and by means of the positioning device (11) different in at least two sequentially positioned in each case by the control unit (04) predetermined pressure positions in the region of the width (B1) of the printing substrate (12) or is at least positionable) f wherein characterized in that the relevant print head (06; 07; 08; 09) has at least one print nozzle field (18) extending transversely to the path of the printing material (12), g) the relevant print nozzle field (18) or each of these arranged in a row (18) of the relevant printhead (06; 07; 08; 09) at each of its two edge areas (R1; R2) opposite one another transversely to the travel path of the printing material (12) in each case a lower print resolution than in its between these two edge areas (R1; R2) arranged center area (M), h) the relevant printhead (06; 07; 08; 09) during a first printing process printing on the printing material (12) by the positioning device (11) at a specific one specified by the control unit (04) The printing position is positioned such that a first edge region (R1) of a printing nozzle field (18) of this printing head (06; 07; 08; 09) at this predetermined printing position on the surface of the printing material (12) transported by the transport device (03) lengthways to it Travel path is arranged to print, i) and wherein the relevant printhead (06; 07; 08; 09) in the case of a second printing operation (12) printing the same surface of the printing material (12) transported by the transport device (03) from the positioning device (11) on the at the first printing process from the relevant print head (06; 07; 08; 09) is positioned in such a way that the first edge area (R1) is transverse to the Ve travel path of the substrate (06; 07; 08; 09) opposite second edge area (R2) of the same printing nozzle field (18) or another printing nozzle field (18) of the printing nozzle fields (18) of the relevant print head (06; 07; 08; 09) arranged in the same row at this specific printing position already on them during the first printing process, the printed surface of the printing material (12) transported by the transport device (03) is arranged so as to print along its travel path. Printing press after Claim 1 , characterized in that the printing material (12) is arcuate and / or that the printing material (12) is arranged in a flat position on the transport device (03) and / or that the printing material (12) on the transport device (03) is magnetic and / or is held by a negative pressure generated by a suction device and / or that the printing material (12) is designed as a sheet metal plate and / or that the transport device (03) is designed as a movable transport table or as a self-contained transport belt. Printing press after Claim 1 , characterized in that the printing material (12) is designed as a round body. Printing press after Claim 1 or 2nd or 3rd , characterized in that the surface to be printed on the printing material (12) transported by the transport device (03) is non-absorbent and / or the printing material (12) has a width (B1) of up to 1,000 mm transverse to its transport direction (T) . Printing press after Claim 1 or 2nd or 3rd or 4th , characterized in that the print head in question (06; 07; 08; 09) with its second printing process, printing the same surface of the printing material (12) transported by the transport device (03), from the positioning device (11) to the printing device from the positioning device (11) during the first printing process Print head (06; 07; 08; 09) is then positioned with a correction value set by the control unit (04) with regard to the print position specified with reference to this printing material (12) if the first edge region (R1) is transverse to the travel path of the Printing material (06; 07; 08; 09) opposite second edge area (R2) of the same printing nozzle area (18) or another printing nozzle area (18) of the printing nozzle areas (18) of the relevant printing head (06; 07; 08; 09) arranged in the same row this specific printing position on this surface of the transpo printed by the transport device (03) already printed during the first printing process rtiert printing material (12) is arranged printing along its travel path. Printing press after Claim 1 or 2nd or 3rd or 4th or 5 , characterized in that the inkjet system (02) has a plurality of print heads (06; 07; 08; 09), with these print heads (06; 07; 08; 09) printing fluids differing in color being applied to the printing material (12) or at least can be applied, the plurality of print heads (06; 07; 08; 09) of the inkjet system (02) being arranged in the same housing and being movable together along the path (S) by the positioning device (11). Printing press after Claim 1 or 2nd or 3rd or 4th or 5 or 6 , characterized in that the inkjet system (02) is designed to print at least one solvent-based pressure fluid or a water-based pressure fluid or a pressure fluid that is hardened by ultraviolet radiation. Printing press after Claim 1 or 2nd or 3rd or 4th or 5 or 6 or 7 , characterized in that the respective print resolution in the edge regions (R1; R2) of the respective print nozzle field (18) opposite each other across the travel path of the printing material (12) is of the same size. Printing press after Claim 1 or 2nd or 3rd or 4th or 5 or 6 or 7 or 8th , characterized in that the respective print resolution in the edge regions (R1; R2) of the relevant printing nozzle field (18) opposite each other transversely to the travel path of the printing material (12) is half as large as the print resolution in which there is between these two edge regions (R1; R2) arranged center area (M). Printing press after Claim 1 or 2nd or 3rd or 4th or 5 or 6 or 7 or 8th or 9 , characterized in that the relevant print head (06; 07; 08; 09) is designed and / or controlled by the control unit (04) in such a way that the printing material (12) either only during a movement in the same feed direction (T) or is printed during its movement in each of two opposing feed directions (T).

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