EP4360882A1 - Printing apparatus for iris printing - Google Patents

Abstract

The invention relates to a printing device (100), comprising- a first roller train (102) of a first inking unit for inking a first inking roller (104) with a first printing ink (202), the first inking roller (104) providing first image information,- a second roller train (106) of a second inking unit for inking a second inking roller (108) with a second printing ink (204), the second inking roller (108) providing second image information,- a plate cylinder (110) which comprises a printing plate (112) which is operatively connected to the first inking roller (104) and to the second inking roller (108) in such a way that the printing plate (112) of the plate cylinder (110) is inked with the first printing ink (202) and with the second printing ink (204), and- a rubber blanket cylinder (114) with a rubber layer (140) which is operatively connected to the plate cylinder (110) in such a way that the printing inks (202, 204) are transferred to the blanket cylinder (114) in order to subsequently transfer them to a substrate (200) which is passed through a gap which is present at least temporarily between the blanket cylinder (114) and an impression cylinder (116).

Description

The present invention relates to a printing device for implementing a multi-colour printing process. Such printing machines are already known from the prior art and are described, for example, in the publications DE 100 25 996 C1 or EN 10 2013 223 826 A1 Color mixing is usually only possible in the axial direction of the printing device, although color mixing in the circumferential direction would be desirable. Further state of the art is described in the publications EN 10 2017 202 381 A1 or EP 2 114 677 A2 described in which a mixing of scope is sought.

It is therefore the object of the present invention to provide an improved printing device.

This object is achieved by a printing device having the features of claim 1. The dependent claims contain further advantageous embodiments of the invention.

• einen ersten Walzenzug eines ersten Farbwerks zum Einfärben einer ersten Farbauftragswalze mit einer ersten Druckfarbe, wobei die erste Farbauftragswalze erste Bildinformationen bereitstellt,
• einen zweiten Walzenzug eines zweiten Farbwerks zum Einfärben einer zweiten Farbauftragswalze mit einer zweiten Druckfarbe, wobei die zweite Farbauftragswalze zweite Bildinformationen bereitstellt,
• einen Plattenzylinder, der eine Druckplatte umfasst, welche mit der ersten Farbauftragswalze und mit der zweiten Farbauftragswalze derart in Wirkverbindung steht, dass die Druckplatte des Plattenzylinders mit der ersten Druckfarbe und mit der zweiten Druckfarbe eingefärbt wird, und
• einen Gummituchzylinder mit einer Gummischicht, der mit dem Plattenzylinder derart in Wirkverbindung steht, dass die Druckfarben auf den Gummituchzylinder übertragen werden, um sie anschließend auf ein Substrat zu übertragen, welches durch einen Spalt hindurchgeführt wird, der zumindest zeitweise zwischen dem Gummituchzylinder und einem Gegendruckzylinder vorliegt.

The printing device according to the invention comprises in particular

• a first roller train of a first inking unit for inking a first inking roller with a first printing ink, wherein the first inking roller provides first image information,
• a second roller train of a second inking unit for inking a second inking roller with a second printing ink, the second inking roller providing second image information,
• a plate cylinder comprising a printing plate which is operatively connected to the first ink form roller and to the second ink form roller such that the printing plate of the plate cylinder is connected to the first printing ink and colored with the second printing ink, and
• a blanket cylinder with a rubber layer, which is operatively connected to the plate cylinder in such a way that the printing inks are transferred to the blanket cylinder in order to subsequently transfer them to a substrate which is passed through a gap which is present at least temporarily between the blanket cylinder and an impression cylinder.

The solution of the printing device according to the invention makes it possible to collect several printing inks on the printing form, and therefore on the printing plate of the plate cylinder, with the printing inks preferably being partially mixed in edge areas and transferred to the substrate via a printing blanket. The printing device creates a printing method that produces color mixtures within the printing process. In particular, true color mixtures in the circumferential direction to the machine transport direction are possible with the solution according to the invention. The first ink form roller is fed by the first inking unit and the first ink form roller provides first image information. The second ink form roller is fed by the second inking unit and the first ink form roller provides first image information. The two ink form rollers therefore also provide the image-forming information and in their own way represent part of the printing form.

The option whereby the first ink application roller comprises a rubber band formed with a plurality of first recesses is preferred. The first recesses form the non-image areas.

In an analogous manner, the preferred possibility is that the second ink application roller also comprises an elastic band which is formed with a plurality of second recesses that are complementary to the first recesses of the first ink application roller. Here too, the second recesses form non-image areas.

The first roller train with the first ink application roller and/or the second roller train with the second ink application roller preferably each implement a storage inking unit. However, it is possible to use a double inking unit for the additional iris printing. Both roller trains can also be designed as short inking units.

Preferably, the plate cylinder is provided with a printing plate that enables letterset printing. Offset printing can be provided as a further variant.

It has proven to be advantageous for the first ink application roller and the second ink application roller to have ink-absorbing regions that are at least partially complementary to one another.

It is possible for the image information introduced into the ink form rollers to be introduced into a rubber blanket provided with image information, which is applied to the roller core. This is one of several ways to introduce image information into the ink form rollers. The print image can therefore also be provided by a sleeve that is placed over the roller core.

In order to drive the individual rollers or cylinders of the printing device with sufficient precision, it has proven to be preferred that a first direct drive is assigned to the first ink form roller, that a second direct drive is assigned to the second ink form roller, that a third direct drive is assigned to the plate cylinder, that a fourth direct drive is assigned to the blanket cylinder, and that a control device is present which is set up to control the direct drives.

The communication between the drives and the control device is preferably realized by means of a data bus.

To achieve full-surface printing, it is advantageous if the printing plate of the plate cylinder is a full-surface printing plate without any recesses. However, full areas are not required. The printing plate only needs to carry the image information from both ink application rollers so that all colors can be absorbed and transported further.

However, it can be produced as a predetermined print image, namely when the printing plate of the plate cylinder is designed to form a print image with ink-receiving image areas and ink-repellent non-image areas.

The circumferential ratios between the individual rollers of the printing device are preferably fixed.

It has therefore proven to be advantageous if the ratio between the circumference of the first ink form roller and the circumference of the plate cylinder is essentially 1:1. Another whole-number ratio is also possible. Due to the possible swelling of the rubber materials involved during the printing process, deviations from this ratio can occur, which are compensated for by the direct drives.

It is also possible that the ratio of the circumference of the first ink form roller to the circumference of the plate cylinder is essentially 1:1. Another whole-number ratio is also possible. Due to the possible swelling of the rubber materials involved during the printing process, deviations from this ratio can occur, which are compensated for by the direct drives.

The same is also possible for the ratio of the circumference of the plate cylinder to the circumference of the rubber cylinder, which is also preferably 1:1. Another whole-number ratio is also possible. Due to the possible swelling of the rubber materials involved during the printing process, deviations from this ratio can occur, which are compensated for by the direct drives.

To produce a high-quality print image, angle synchronization may be a special requirement. For this reason, it is sensible if the control device is set up to control all direct drives and cause them to rotate synchronously.

In the case of set-up and cleaning processes, inking units can be disengaged. When subsequently engaging, it is advantageous if the control device is set up to cause the direct drives to move to a common zero position in order to start again in synchronous operation.

However, it is possible for the control device to be set up to control at least one of the direct drives of the ink forme rollers and to cause it to lead or lag behind another of the direct drives. This can also have a correspondingly positive effect on the printed image.

In order to realize a sinusoidal or sinusoidal circumferential friction, it is also advantageous if the control device is designed to allow at least one of the direct drives of the ink application rollers to alternately lead and lag behind another of the direct drives.

For a particularly high-quality print image, it is also useful if the control device is set up to control the direct drives of the first ink form roller and the second ink form roller in such a way that the first ink form roller and the second ink form roller maintain a circumferential register (in 360 degrees).

With the selected variants, it is also possible to create multi-colour print gradients with fluorescent colourants and dyes. In addition, the same colours can be used but with different hidden properties, for example with magnetic properties, with fluorescent properties or with IR-absorbing properties.

To achieve iris printing, it is ultimately particularly advantageous if the first ink application roller and the second ink application roller are designed in such a way that the first printing ink and the second printing ink are applied to the printing plate of the plate cylinder in abutting relationship with the color edges running into one another. This has proven to be particularly advantageous when printing valuable or security documents.

Catenaries are required to ensure that the roller and cylinder bodies are aligned parallel to one another when setting up the machine; they must therefore be taken into account. In addition, a bearer ring can be present on the plate cylinder or on the ink form rollers to prevent bearer rings.

Further features, properties and advantages of the present invention are described in more detail below using embodiments with reference to the attached figures. All features described so far and below are advantageous both individually and in any combination with one another. The embodiments described below are merely examples which do not, however, limit the subject matter of the invention.

The figures are not necessarily detailed or to scale and may be shown enlarged or reduced in size for clarity of illustration. Therefore, functional details disclosed herein are not to be interpreted in a limiting sense, but merely as an illustrative basis for providing guidance to one skilled in the art to variously employ the present invention.

Fig. 1

zeigt stark vereinfacht eine Druckvorrichtung,

Fig. 2

zeigt stark vereinfacht das Antriebskonzept der Druckvorrichtung aus Figur 1, und

Fig. 3

zeigt eine Illustration der einzelnen Schritte des Druckprozesses mit einer Druckvorrichtung nach den Figuren 1 und 2.

As used herein, the term "and/or" when used in a series of two or more elements means that any of the listed elements may be used alone, or any combination of two or more of the listed elements may be used. For example, if a composition is described as containing components A, B, and/or C, the composition may contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination.

Fig.1

shows a very simplified printing device,

Fig. 2

shows a highly simplified drive concept of the printing device from Figure 1 , and

Fig. 3

shows an illustration of the individual steps of the printing process with a printing device according to the Figures 1 and 2 .

In Figure 1 a printing device 100 for realizing an iris print is shown in a highly simplified manner. This printing device 100 comprises a first inking unit with a first roller train 102 for inking a first ink application roller 104 with a first printing ink 202. Furthermore, there is a second inking unit with a second roller train 106 for inking an ink application roller 108 with a second printing ink 204. The roller trains 102, 106 shown here are to be understood only schematically and can also have a different design. In addition, there can also be another inking unit with another ink application roller, so that there can also be more than two of the roller trains 102, 106 with a final ink application roller 104, 108.

The printing device 100 also includes a plate cylinder 110, which includes a printing plate 112, which is operatively connected to the first ink application roller 104 and to the second ink application roller 108 such that the printing plate 112 of the plate cylinder 110 is inked with the first printing ink 202 and with the second printing ink 204. Thus, a color mixture is already generated within the printing process itself, namely in the circumferential direction, in the axial direction and in 360 degrees to the drive direction of the individual rollers and cylinders. The printing device 100 also comprises a blanket cylinder 114 with a rubber layer 140, wherein the blanket cylinder 114 is also operatively connected to the plate cylinder 110 such that the printing inks 202, 204 are transferred to the blanket cylinder 114 in order to subsequently transfer them to a substrate 200 which is passed through a gap which is present at least temporarily between the blanket cylinder 114 and an impression cylinder 116.

The ratio of the circumference of the first ink form roller 104 and the circumference of the plate cylinder 110 is 1 in this case. This means that there is a 1:1 transfer between the first ink form roller 104 and the plate cylinder 110. The ratio of the circumference of the second ink form roller 108 and the The circumference of the plate cylinder 110 is 1 in this case, which also means that a 1:1 transfer of the second printing ink 204 from the second ink application roller 108 to the plate cylinder 110 prevails. Finally, the ratio of the circumference of the plate cylinder 110 and the circumference of the blanket cylinder 114 is also 1 in this case, so that a transfer of the ink from the printing plate 112 to the rubber layer 140 of the blanket cylinder 114 also takes place in a ratio of 1:1.

In Figure 2 is a schematic illustration of the drive concept of the printing device 100 from Figure 1 shown. The printing device 100 comprises a first direct drive 130, which is assigned to the first ink form roller 104. Furthermore, a second direct drive 132 is present, which is assigned to the second ink form roller 108. A third direct drive 134 is also assigned to the plate cylinder 110, with a fourth direct drive 136 being assigned to the blanket cylinder 114. The drive concept also provides a control device 138, which is set up to control the direct drives 130, 132, 134, 136. A data bus is present for communication between the drives and the control device 138. The control device 138 is in particular set up to control all direct drives 130, 132, 134, 136 and to cause the first ink form roller 104, the second ink form roller 108, the plate cylinder 110 and the blanket cylinder 114 to rotate at an angle synchronous. However, it may be desired for one roller to lead or lag behind another roller. Therefore, the control device 138 is also set up in such a way that at least one of the direct drives 130, 132 of the ink form rollers 104, 108 is controlled and caused to lead or lag behind another of the direct drives 134, 136, namely the direct drive 134 of the plate cylinder 110. It is possible to realize a sinusoidal circumferential friction. For this purpose, the control device 138 is also designed to alternately lead and lag at least one of the direct drives 130, 132 of the ink forme rollers 104, 108 relative to another of the direct drives 134, 136, namely the direct drive 134 of the plate cylinder 110.

In order to achieve a high-quality printing result, the control device 138 is further configured to control the direct drives 130, 132 of the first ink form roller 104 and the second ink form roller 108 in such a way that to control the first ink form roller 104 and the second ink form roller 108 to maintain a circumferential register.

In the illustration after Figure 3 the application of ink to the substrate 200 is shown in more detail in individual steps. In each case, a sectional view through the roller or cylinder in question and an adjacent top view or the corresponding print image are shown. It should be noted that the selected images and views are merely illustrative in nature and thus represent examples that could also have different designs.

First (at the very top) is the first ink application roller 104, from which the first printing ink 202 has already been absorbed. For this purpose, the first ink application roller 104 is provided with a roller cover that consists of a soft layer. For this purpose, a rubber cover 118 is provided in the present case, which is formed with a plurality of first recesses 120. Where the recesses 120 are present, no printing ink 202 is absorbed; the first printing ink 202 is only absorbed by the areas where the rubber cover 118 is located. In a top view, for example, the coloring of the first ink application roller 104 can be seen next to it.

The first ink application roller 104 and the second ink application roller 108 are in this case at least partially shaped complementarily to one another, so that there are also ink-absorbing regions shaped complementarily to one another.

For this reason, the second ink application roller 104 shown second (from the top) is also provided with a roller cover made of a soft layer. In the present case, the second ink application roller 108 comprises a rubber cover 122 formed with a plurality of second recesses 124 that are complementary to the first recesses 120 of the first ink application roller 104. The second printing ink 204 only adheres in the areas where the rubber cover 122 is present. The complementary design of the two ink application rollers 104, 108 can be seen from the view of the second ink application roller 108 on the right.

Since the first ink form roller 104 and the second ink form roller 108 are in operative connection with the printing plate 112 of the plate cylinder 110, the printing plate 112 of the plate cylinder 110 is inked with the first printing ink 202 and with the second printing ink 204, as shown by the illustration in third place (from the top) in Figure 3 can be seen. For this purpose, the first ink application roller 102 and the second ink application roller 108 are designed in such a way that the first printing ink 202 and the second printing ink 204 are applied abutting to the printing plate 112 of the plate cylinder 110 with intersecting color edges. In this way, an iris print is realized, as can be used for printing ID, valuables or security documents. To the right, two different designs of the printing plate 112 can be seen, with the upper printing plate 112 representing a full-surface printing plate without any recesses. Directly below this, an alternative printing plate 112 is shown, which is designed to form a printed image with ink-absorbing image areas 126 and ink-repellent non-image areas 128. The printing plate 112 with the printed image can also be seen in the illustration on the left, as can be seen by the two ink-receiving image areas 126 and the only ink-repellent non-image area 128.

The inking of the printing plate 112, whether provided with a printed image or not, is then transferred to the rubber layer 140 of the blanket cylinder 114, as shown by the illustration in fourth place (from the top). The blanket cylinder 114 then transfers the printed image to the substrate 200, as can be seen by the illustrations in fifth place (bottom).

With the printing device 100 according to the invention, it is possible to produce color mixtures, in particular for banknotes or security printing, during the printing process itself. It has been shown that in addition to the plate cylinder 110 as a printing form carrier, the two ink application rollers 104, 108 can also provide image-forming information due to their respective recesses 120, 124.

LIST OF REFERENCE SYMBOLS

100

Printing device

102

first roller train

104

first ink application roller

106

second roller train

108

second ink application roller

110

Plate cylinder

112

printing plate

114

Blanket cylinder

116

Impression cylinder

118

Rubber cover

120

first recesses

122

Rubber cover

124

second recesses

126

Image location

128

Non-image location

130

first direct drive

132

second direct drive

134

third direct drive

136

fourth direct drive

138

Control device

140

Rubber layer

Claims (15)

Printing device (100) comprising - a first roller train (102) of a first inking unit for inking a first inking roller (104) with a first printing ink (202), the first inking roller (104) providing first image information, - a second roller train (106) of a second inking unit for inking a second inking roller (108) with a second printing ink (204), the second inking roller (108) providing second image information, - a plate cylinder (110) comprising a printing plate (112) which is operatively connected to the first ink form roller (104) and to the second ink form roller (108) such that the printing plate (112) of the plate cylinder (110) is inked with the first printing ink (202) and with the second printing ink (204), and - a blanket cylinder (114) with a rubber layer (140) which is operatively connected to the plate cylinder (110) such that the printing inks (202, 204) are transferred to the blanket cylinder (114) in order to subsequently transfer them to a substrate (200) which is passed through a gap which is present at least temporarily between the blanket cylinder (114) and an impression cylinder (116). Printing device (100) according to claim 1, characterized in that the first ink application roller (104) and the second ink application roller (108) have ink-absorbing regions that are at least partially complementary to one another. Printing device (100) according to claim 2, characterized in that the first ink application roller (104) comprises a rubber covering (118) which is formed with a plurality of first recesses (120). Printing device (100) according to claim 3, characterized in that the second ink application roller (108) comprises a rubber coating (122) which is provided with a plurality of second recesses (124) formed complementarily to the first recesses (120) of the first ink application roller (104). Printing device (100) according to one of claims 1 to 4, characterized in that a first direct drive (130) is assigned to the first ink form roller (104), that a second direct drive (132) is assigned to the second ink form roller (108), that a third direct drive (134) is assigned to the plate cylinder (110), that a fourth direct drive (136) is assigned to the blanket cylinder (114), and that a control device (138) is present which is set up to control the direct drives (130, 132, 134, 136). Printing device (100) according to claim 5, characterized in that the communication between the direct drives (130, 132, 134, 136) and the control device (138) is realized by means of a data bus. Printing device (100) according to claim 5 or 6, characterized in that the control device (138) is designed to control all direct drives (130, 132, 134, 136) and to cause them to rotate synchronously and angularly synchronously. Printing device (100) according to one of claims 5 to 7, characterized in that the control device (138) is designed to cause the direct drives (130, 132, 134, 136) to move to a common zero position after an interruption in order to start there again in a synchronous run. Printing device (100) according to one of claims 5 to 8, characterized in that the control device (138) is set up to control at least one of the direct drives (130, 132) of the ink application rollers (104, 108) and to cause it to lead or lag another of the direct drives (134, 136). Printing device (100) according to one of claims 5 to 9, characterized in that the control device (138) is designed to allow at least one of the direct drives (130, 132) of the ink application rollers (104, 108) to alternately lead and lag behind another of the direct drives (134, 136). Printing device (100) according to one of claims 5 to 10, characterized in that the control device (138) is set up to control the direct drives (130, 132) of the first ink application roller (104) and the second ink application roller (108) such that the first ink application roller (104) and the second ink application roller (108) maintain a circumferential register. Printing device (100) according to one of claims 1 to 11, characterized in that the ratio of the circumference of the first ink application roller (104) and the circumference of the plate cylinder (110) is one. Printing device (100) according to one of claims 1 to 12, characterized in that the ratio of the circumference of the second ink application roller (108) and the circumference of the plate cylinder (110) is one. Printing device (100) according to one of claims 1 to 13, characterized in that the ratio of the circumference of the plate cylinder (110) and the circumference of the blanket cylinder (114) is one. Printing device (100) according to one of claims 1 to 14, characterized in that the first ink application roller (104) and the second ink application roller (108) are designed such that the first printing ink (202) and the second printing ink (204) are applied abutting to the printing plate (112) of the plate cylinder (110) with intermeshing color edges.

Images