DE102022105333A1 - Method for mechanically introducing at least one crease into a web-shaped or sheet-shaped printed printing material - Google Patents

Abstract

The invention relates to a method for mechanically introducing at least one creasing into a web-shaped or sheet-shaped printed printing material, wherein the printing material moved by a printing press passes through a creasing tool in order to introduce the relevant creasing in the printing press in the transport direction after it has been printed by a printing unit of the printing press, wherein the relevant creasing is introduced by the creasing tool on the surface of the printing material printed by the printing unit of the printing press, the relevant creasing being introduced in a heated area of the surface of the printing material, this area being on the transport path of the printing material at a distance of less than 2 m has been heated in front of the creasing tool to a depth of at least 5 µm and a maximum of 30 µm to a temperature between 50°C and 140°C.

Description

The invention relates to a method for mechanically introducing at least one crease into a web-shaped or sheet-shaped printed printing material according to the preamble of claim 1.

Through the WO 2017/041982 A2 a machine arrangement for the sequential processing of sheet-shaped substrates is known, the printing material being fed to further mechanical processing in this machine arrangement after it has been printed by an inkjet printing device and after drying of the substrate printed in this way, this further processing being carried out e.g. B. performs creasing and/or punching of the printed substrate.

It has been observed that when creasing is mechanically introduced into a web-shaped or sheet-shaped printed printing material, this printing material and/or an ink layer applied to it break. It has also been found that sometimes when creasing is mechanically introduced into a web-shaped or sheet-shaped printed substrate, an ink layer previously applied to it flakes off from a surface of the relevant printing substrate.

The invention is based on the object of creating a method for mechanically introducing at least one crease into a web-shaped or sheet-shaped printed printing material, which eliminates the aforementioned defects.

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

The advantages that can be achieved with the invention are, in particular, that the printing material and / or an ink layer applied to it do not break and an ink layer previously applied to the relevant printing material does not flake off from its surface if the at least one groove - as proposed according to the invention - on one to a depth of at least 5 µm and a maximum of 30 µm to the surface of the printing material heated to a temperature between 50 ° C and 140 ° C.

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

• 1 eine Druckmaschine mit mindestens einem in Transportrichtung des Bedruckstoffes nach einem Druckwerk inline angeordneten Rillwerkzeug;
• 2 ein Rotationsrillwerkzeug;
• 3 einen vergrößerten Ausschnitt aus dem gerillten Bedruckstoff;
• 4 ein Rillwerkzeug mit einem vorgeordneten Trockner.

Show it:

• 1 a printing press with at least one creasing tool arranged inline in the transport direction of the printing material after a printing unit;
• 2 a rotary creasing tool;
• 3 an enlarged section of the grooved printing material;
• 4 a creasing tool with an upstream dryer.

Based on 1 until 4 a method for mechanically introducing at least one creasing into a web-shaped or sheet-shaped printed printing material is explained, the printing material passing through a creasing tool for introducing the relevant creasing in a printing press in the transport direction after it has been printed by a printing unit of the printing press, the relevant creasing from Creasing tool is introduced onto the surface of the printing material printed by the printing unit of the printing press. Preferably, during a specific pass of the printing material through the printing press, several creasings are introduced simultaneously and/or together into the relevant printing material, these creasings being arranged next to one another, in particular parallel to one another, in particular transversely to the transport direction of this printing material.

1 shows, by way of example, a printing press 11 designed as a sheet-fed printing machine, in particular a sheet-fed rotary printing machine, with at least one creasing tool 13 arranged inline in the transport direction T of the printing material 12, which is designed here in the form of a sheet, after a printing unit 04. In the in the 1 In the embodiment variant of the printing press 11 shown as an example, in the transport direction T of the sheet-shaped printing material 12, several are in line one after the other, e.g. B. two creasing tools 13 arranged. These creasing tools 13 are preferably designed in such a way that they each produce at least one creasing 21 in the printing material 12 at different positions.

In the in the 1 In the embodiment variant of the printing press 11 shown, a supply of sheet-shaped printing material 12 - in short: sheets - is provided as a stack in a feeder 01. Sheets isolated from the stack are sequentially transferred using a transfer device, for example. B. first transferred to a primer application device 02, in which a liquid primer is applied to a surface 20 of the sheet for priming and / or to improve the adhesion for ink to be subsequently applied. The primer applied to the surface 20 of the sheets is then placed in a first dryer 03 of the printing press 11 dried. The primed sheets are then fed to a printing unit 04 of the printing machine 11. The printing unit 04 of the printing press 11 has z. B. a multiple-sized, in particular triple-sized, printing cylinder 05, which means that several, e.g. B. three sheets can be arranged. On the circumference of the printing cylinder 05, at a short distance from its lateral surface, at least one print head is arranged to apply ink to the surface 20 of the printing material 12 to be grooved using an inkjet printing process. Preferably there are several, e.g. B. at least four to seven such print heads are arranged one after the other, in particular in the transport direction T of the printing material 12, these print heads preferably applying ink in different colors to the relevant surface 20 of the printing material 12. The printing material 12 printed in this way is now dried in a second dryer 06 of the printing machine 11. In an advantageous embodiment variant of the printing press 11, a varnish unit 07 is arranged in the transport direction T of the sheet after the second dryer 06, with a varnish applied to the surface 20 of the sheet then being dried in a third dryer 08 of the printing press 11. The at least printed, preferably previously primed and also coated after printing printing material 12 is then fed to at least one further processing device 09, preferably also to several mechanical further processing devices 09 successive in the transport direction T of the sheets, each of these further processing devices 09 preferably each having a creasing tool 13. The sheets scored in this way are ultimately deposited in this printing press 11 in a stack arranged in a delivery 10, the delivery 10 being used for the transport of the sheets, for example. B. may have a chain conveyor 15.

In order to improve the creasing process, the printed surface 20 of the printing material 12, which is moved through the printing press 11 at a speed other than zero, is placed in particular immediately before creasing, ie preferably at a distance s ( 4 ) of less than 2 m before the respective creasing tool 13 engages in the printed surface 20 of this printing material 12 by means of at least a fourth dryer 14 in such a way that the at least one creasing 21 is heated to a depth t12 of at least 5 μm and a maximum of 30 µm is introduced to the surface 20 of the printing material 12 heated to a temperature between 50 ° C and 140 ° C ( 3 ). Therefore, the fourth dryer 14 in question is in the printing press 11 in the transport direction T of the printing material 12 on its transport path at a very short distance s from z. B. less than 2 m, in particular less than 1 m, in front of the relevant creasing tool 13.

A printing material 12 is preferably used, e.g. B. made of paper, of a single-layer or multi-layer cardboard or of cardboard, the printing material 12 being processed in particular into a packaging material. In the packaging industry, creasing is used e.g. B. for the production of folding boxes or cardboard boxes or beverage cartons. The printing materials paper, cardboard and cardboard differ in their respective basis weight, ie the weight in grams for one square meter of this printing material. The aforementioned printing material with a basis weight between 7 g/m ² and 150 g/m ² is generally considered paper, between 150 g/m ² and 600 g/m ² as cardboard and with more than 600 g/m ² as cardboard.

Grooving here means the creation of a break line pressed into the printing material 12. Creasing refers to a work process in which notches (creases) are mechanically made into a material containing paper, cardboard or cardboard, which allows the material to be folded more definedly and with less effort at the point processed in this way. The linear depression created in this way on the printing material 12 creates a bulge-like elevation on the opposite side ( 3 ). For reasons of labor economy alone, the creasing is advantageously carried out inline shortly after the printing material 12 has been printed. Creases are usually straight, in particular in the transport direction T of the printing material 12. However, they can also be non-linear, e.g. B. wave-shaped or in a direction at an oblique angle to the transport direction T of the printing material 12. Creasing can also be introduced into the printing material 12 continuously or discontinuously, ie in cycles.

To produce at least one creasing, the material designed here as a printed printing material 12 passes through at least one creasing tool 13. A distinction is made between rotating (rotary creasing tools) and vertically working (punching creasing tools) tools. Like from the 2 As can be seen from the example of a rotary creasing tool, there is a positive tool 16 (male) with a z. B. rotating, preferably annular elevation 18 and on the underside of the material to be grooved a negative tool 17 (female) with a groove 19 corresponding to the elevation 18, the between these two tools 16; 17 material passed through from the elevation 18 of the positive tool 16 against or into the groove 19 of the negative tool 17 (female) is pressed. The elevation 18 therefore has a larger outside diameter than the remaining outside dimensions of the (painting) tool 16. The (female) tool 17 can be fixed or, like the (male) tool 16, rotating.

It is preferably provided that the at least one groove 21 is introduced in an area 24 on a surface 20 of this printing material 12 that is heated to a depth t12 of 20% of a total thickness d12 of the printing material 12.

In order to keep the energy expenditure for heating the surface 20 of the printing material 12 as low as possible, it is preferably provided that the surface 20 of the printing material 12 is only partially and selectively in a strip-shaped area 24 with a width which is to be provided with the at least one groove 21 b24 is heated between twice and twelve times the intended groove width b21 ( 2 ). In this strip-shaped area 24, the groove 21 introduced there can have one of the previously mentioned shapes - straight or non-linear, continuous or discontinuous - or also successively different geometric designs.

A rotary creasing tool is advantageously used as the creasing tool 13 ( 2 ), which e.g. B. as a pair of cooperating creasing rollers 16; 17 is formed, these creasing rollers 16; 17 usually rotate in opposite directions, with the printed substrate 12 passing through one of these creasing rollers 16; 17 formed nip is passed through. The creasing rollers 16; 17 extend longitudinally to their respective rotation axis 22; 23 e.g. B. over an entire width b12 of this printing material 12 extending transversely to the transport direction T of the printing material 12 or at least over a part of this width b12.

In a preferred embodiment of the printing press 11, an ink is applied to the surface 20 of the printing material 12 to be grooved by its at least one printing unit 04 in an inkjet printing process. In particular, an ink containing at least one polymer is applied by the printing unit 04 of the printing machine 11 to the surface 20 of the printing material 12 to be grooved, the surface 20 of the printing material 12 to be grooved preferably having a glass transition temperature in the temperature range between 50 ° C and 140 ° C the ink containing the polymer is heated. At the glass transition temperature, the polymer begins to become soft and/or viscous.

The printed surface 20 of the printing material 12 is z. before it passes through the creasing tool 13. B. heated by hot air or by a flame or by irradiation with infrared radiation or by irradiation with a microwave. In this case, an amount of heat advantageously of a maximum of 1 kJ/m ² is introduced into the printed surface 20 of the printing material 12 before it passes through the creasing tool 13. With a larger amount of heat there is a risk that a e.g. B. printing material 12 consisting of a fibrous material such as. B. paper is damaged. A duration of action of the amount of heat to be introduced into the printed surface 20 of the printing material 12 depends on the amount of speed at which this printing material 12 is moved through the printing press 11 and thus also guided through the creasing tool 13.

Furthermore, e.g. B. provided that in the transport direction T of the printing material 12 after its passage through the creasing tool 13 and either before placing the sheet-shaped printing material 12 on a stack in the delivery 10 or before winding up the web-shaped printing material 12 on or into a roll in one Rewinder, the surface 20 of the relevant printed material 12, which is provided with at least one groove 21, is cooled to a maximum temperature between 40 ° C and 50 ° C, so that the z. B. the printing material 12 placed on the stack or the printing material 12 rolled up or into a roll is not blocked or glued.

Like from the 1 in connection with the 4 As can be seen, there is also a printing press 11 with at least one creasing tool 13, the creasing tool 13 being designed to introduce a crease 21 on the surface 20 of a printing material 12 moved by the printing press 11, in the transport direction T of the printing material 12 moved by the printing press 11 A dryer 14 which heats the printing material 12 is arranged on its transport path at a distance s of less than 2 m in front of the creasing tool 13. In the 4 A web-shaped printing material 12 is shown as an example. In the example of the 4 the printing press 11 is designed as a web-fed rotary printing press. The dryer 14 that heats the printing material 12 is z. B. arranged on the circumference of a transport cylinder ( 1 ).

Regardless of the embodiment of the printing press 11, the dryer 14 which heats the printing material 12 and is arranged in front of the creasing tool 13 is designed in such a way that it only partially heats the surface 20 of the printing material 12, namely in a strip-shaped area 24 to be provided with the relevant creasing 21, whereby This strip-shaped area 24 preferably has a width b24 directed transversely to the transport direction T of the printing material 12 moved by the printing press 11 wise between twice and twelve times the groove width b21 belonging to the relevant groove 21. The creasing tool 13 is preferably designed as a rotary creasing tool rotating about a rotation axis 22, this rotary creasing tool - as in the 2 shown as an example - e.g. B. from a pair of interacting around an axis of rotation 22; 23 rotating creasing rollers 16; 17 exists and the printing material 12 to be creased is passed through one of these creasing rollers 16; 17 formed nip is passed through. In the 4 Due to the top view shown of the printing material 12 to be creased, only the positive tool, ie the upper creasing roller 16 with a z. B. rotating elevation 18 can be seen. In the transport direction T of the printing material 12 moved by the printing press 11, several creasing tools 13 which groove the surface 20 of the printing material 12 can be arranged one after the other and/or transversely next to one another.

As before using the 1 explained, in the transport direction T of the printing material 12 moved by the printing press 11, at least one printing unit 04 which prints on the surface 20 of this printing material 12 in the strip-shaped area 24 to be provided with the relevant creasing 21 is preferably arranged in front of the creasing tool 13. The printing unit 04 in question is preferably designed as a printing unit 04 that prints an ink in an inkjet printing process onto the surface 20 of the printing material 12 to be grooved.

The dryer 14, which is arranged in front of the creasing tool 13 and heats the printing material 12, is z. B. designed as a dryer that heats the surface 20 of this printing material 12 by hot air or by a flame or by irradiation with infrared radiation or by irradiation with a microwave. In a particularly advantageous embodiment, the dryer 14 which is arranged in front of the creasing tool 13 and which heats the printing material 12 transversely to the transport direction T of the printing material 12 moved by the printing press 11 has a plurality of selectively activated heat sources 25, these heat sources 25 being controlled by a control unit 26 and selective, ie are activated as needed at the required position and/or preferably in the required intensity by this control unit 26. The intensity of the heat source 25 activated by this control unit 26 relates to the amount of heat introduced into the surface 20 of this printing material 12. In this way it is provided that the dryer 14 which heats the printing material 12 and which is arranged in front of the creasing tool 13 heats the surface 20 of this printing material 12 to a depth t12 of at least 5 μm and a maximum of 30 μm to a temperature between 50 ° C and 140 ° C . Also is z. B. provided that the dryer 14, which is arranged in front of the creasing tool 13 and which heats the printing material 12, is designed to introduce only a limited amount of heat of a maximum of 1 kJ/m ² into this printing material 12 in order to protect the printing material 12.

Reference symbol list

01

investor

02

Primer application device

03

first dryer

04

Printing unit

05

Printing cylinder

06

second dryer

07

Lacquerwork

08

third dryer

09

Further processing facility

10

Display

11

printing press

12

printing material

13

Creasing tool

14

fourth dryer

15

Chain conveyor

16

positive tool

17

negative tool

18

survey

19

Nut

20

surface

21

Creasing

22

Axis of rotation

23

Axis of rotation

24

Area

25

heat source

26

Control unit

b12

Width

b21

Groove width

b24

Width

d12

Total thickness

s

distance

t12

depth

T

Transport direction

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2017/041982 A2 [0002]

Claims (10)

Method for mechanically introducing at least one crease (21) into a web-shaped or sheet-shaped printed printing material (12), wherein the printing material (12) moved by a printing machine (11) is used to introduce the relevant crease (21) in the printing machine (11). Transport direction (T) passes through a creasing tool (13) after printing is carried out by a printing unit (04) of the printing press (11), the relevant creasing (21) being passed by the creasing tool (13) to that of the printing unit (04) of the printing press (11). printed surface (20) of the printing material (12), characterized in that the relevant crease (21) is introduced in a heated area (24) of the surface (20) of the printing material (12), this area (24). the transport path of the printing material (12) at a distance (s) of less than 2 m in front of the creasing tool (13) to a depth (t12) of at least 5 µm and a maximum of 30 µm to a temperature between 50 ° C and 140 ° C has been heated. Procedure according to Claim 1 , characterized in that the relevant creasing (21) is introduced into an area (24) on the surface (20) of the printing material (12) which is heated to a depth (t12) of 20% of a total thickness (d12) of the printing material (12). becomes. Procedure according to Claim 1 or 2 , characterized in that the surface (20) of the printing material (12) is only partially and / or selectively in a strip-shaped area (24) to be provided with the relevant creasing (21) and with a width (b24) between twice and twelve times the intended Groove width (b21) is heated. Procedure according to Claim 1 or 2 or 3 , characterized in that a rotary creasing tool is used as the creasing tool (13). Procedure according to Claim 1 or 2 or 3 or 4 , characterized in that the printing unit (04) of the printing machine (11) applies an ink in an inkjet printing process to the surface (20) of the printing material (12) to be grooved. Procedure according to Claim 1 or 2 or 3 or 4 or 5 , characterized in that an ink containing at least one polymer is applied by the printing unit (04) of the printing machine (11) to the surface (20) of the printing material (12) to be grooved. Procedure according to Claim 6 , characterized in that the surface (20) of the printing material (12) to be grooved is heated to a glass transition temperature of the ink containing the polymer in the temperature range between 50 ° C and 140 ° C, the polymer starting at the glass transition temperature, becoming soft and /or to become viscous. Procedure according to Claim 1 or 2 or 3 or 4 or 5 or 6 or 7 , characterized in that the printed surface (20) of the printing material (12) is heated by hot air or by a flame or by irradiation with infrared radiation or by irradiation with a microwave before it passes through the creasing tool (13). Procedure according to Claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8th , characterized in that a maximum amount of heat of 1 kJ/m ² is introduced into the printed surface (20) of the printing material (12) before it passes through the creasing tool (13). Procedure according to Claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8th or 9 , characterized in that in the transport direction (T) of the printing material (12) after it has passed through the creasing tool (13) and either before winding the web-shaped printing material (12) onto or into a roll or before depositing the sheet-shaped printing material (12) the surface (20) of the relevant printed material (12) provided with the relevant creasing (21) is cooled on a stack to a maximum temperature between 40°C and 50°C.

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