EP2202081A1 - Device for printing a sheet web - Google Patents

Abstract

The device has two rollers (34,54) rotated with a circumferential speed corresponding to a motion speed of a sheet web (16). The rollers are provided for tangential support plate of sheet web on its circumferential area over a predetermined angle area. A guiding device is provided for guiding the sheet web. The guiding device has two guiding units and two other guiding units.

Description

The invention relates to a device for printing a movable in its longitudinal direction, printable sheet web, in particular for use in connection with the production of book blocks.

From the DE 44 29 458 A1 is a variable-size web press known, which has two substantially spatially stacked rollers over which the sheet to be printed sheet is guided at a wrap angle of about 180 °. Each roller is associated with four ink jet printheads, which are directed substantially radially on the rollers and located in the region where the sheet web is passed over the rollers.

It is an object of the present invention to provide a device of the type mentioned, which works reliably and provides good print quality, in particular to achieve a high-precision web guide, and further preferably suitable for use in connection with the production of book blocks.

• zwei Walzen, die mit einer Umfangsgeschwindigkeit entsprechend der Bewegungsgeschwindigkeit der Bogenbahn rotieren und zur berührenden Auflage der Bogenbahn auf ihrer Umfangsfläche über einen vorbestimmten Winkelbereich vorgesehen sind,
• jeder Walze zugeordneten, berührungslos arbeitenden Druckköpfen, die beabstandet von der Umfangsfläche der zugehörigen Walzen angeordnet sind und zumindest im wesentlichen quer zur Umfangs- und Drehrichtung der zugehörigen Walze nebeneinander liegen, wobei die Druckkopfstirnseiten im wesentlichen tangential zur zugehörigen Walze und die Druckkopfmittelachsen im wesentlichen radial zur Umfangsfläche der zugehörigen Walze ausgerichtet sind,
• einer Führungseinrichtung zur Führung der Bogenbahn, wobei die Führungseinrichtung mindestens zwei erste und zwei zweite Führungsmittel aufweist, von denen ein erstes Führungsmittel und ein zweites Führungsmittel jeder Walze zugeordnet sind, das erste Führungsmittel mindestens eine an der Umfangsfläche der zugehörigen Walze anliegende Andruckrolle aufweist und das zweite Führungsmittel so ausgebildet ist, dass die Bogenbahn im wesentlichen tangential von der Umfangsfläche der zugehörigen Walze entlang eines tangentialen Wegabschnittes abgezogen wird, und wobei die Führungseinrichtung ferner zur Führung der Bogenbahn derart ausgebildet ist, dass bei Auflage auf der einen Walze die eine Seite der Bogenbahn und bei Auflage auf der anderen Walze die andere Seite der Bogenbahn bedruckbar ist,
• Mitteln zur Erzeugung einer gewünschten Bahnspannung in der Bogenbahn, und
• mindestens zwei Qualitätsmesseinrichtungen, von denen jede einer Walze zugeordnet und die Qualität der Bogenbahn nach deren Verlassen der Walze an einer Stelle ihres tangentialen Wegabschnittes ermittelt.

This object is achieved by a device for printing a moving in its longitudinal direction, printable sheet web, in particular for use in connection with the production of book blocks, with

• two rollers which rotate at a peripheral speed in accordance with the moving speed of the sheet and are provided for contacting the sheet sheet on its peripheral surface over a predetermined angular range,
• each non-contact printhead, spaced apart from the peripheral surface of the associated rollers and juxtaposed at least substantially transverse to the circumferential and rotational directions of the associated roller, the printhead faces substantially tangential to the associated roller and the printhead center axes substantially radial Peripheral surface of the associated roller are aligned,
• a guide means for guiding the sheet web, wherein the guide means comprises at least two first and two second guide means, of which a first guide means and a second guide means associated with each roller, the first guide means has at least one voltage applied to the peripheral surface of the associated roller pressure roller and the second Guiding means is formed so that the sheet web is withdrawn substantially tangentially from the peripheral surface of the associated roller along a tangential path portion, and wherein the guide means is further adapted to guide the sheet web such that when placed on one roller, the one side of the sheet path and when placed on the other roller, the other side of the sheet is printable,
• Means for generating a desired web tension in the sheet web, and
• at least two quality measuring devices, each associated with a roller and determines the quality of the sheet web after leaving the roller at one point of its tangential path section.

According to the invention for double-sided printing the sheet web is drawn over the peripheral surface of two web-driven rollers with a suitable radius to form a suitable wrap angle and printed by spaced to the sheet web and the peripheral surface in the circumferential direction concave and non-contact printing heads, the print head end faces tangentially and the Printhead centerlines are radially aligned with respect to the associated roller. For the maintenance of a predetermined web tension is the Arc path in each case introduced on the input side via a pressure roller to the peripheral surfaces of the rollers and deducted tangentially from the peripheral surface of the rollers on the output side. By using rollers as an abutment for the sheet web during printing and by generating a web tension in the sheet web fluttering or floating of the sheet web is avoided during printing, whereby a very good print quality can be achieved and blurred and bad print images are avoided.

Furthermore, it has been found that the tangential path section along which the sheet web is drawn tangentially from the peripheral surface of the rolls is optimally suited for checking the quality of the printed sheet web. Thus, the invention also proposes to provide at this point at least one quality measuring device, whereby the print quality can be further increased.

The device according to the invention is particularly suitable for use in connection with the production of book blocks in that they now - in departure from traditional printing methods - in a continuous and quasi-seamless process in a simple manner format flexible under a completely free and arbitrary design of the printed images let produce.

Preferred embodiments and further developments of the invention are specified in the dependent claims.

Preferably, at least one drying device is provided for drying the printed sections of the sheet web. With the help of the drying device blurring previously applied printed images can be effectively prevented. By using a drying device, an immediate further processing of the printed sheet web and thus a high production speed of the device can be achieved. For this purpose, the sheet web can advantageously be passed for drying at several drying means of the drying device for drying. If the two rollers are arranged spatially next to one another and the drying device is arranged spatially below the rollers, a particularly compact design can be realized.

In order to prevent blurring of the printed images initially applied in the first printing step on one side on the sheet web, it is advantageous to design the guide device such that the sheet web already passes or exits the drying device after leaving the first roller and before reaching the second roller this is passed through. In order to also blur the second printing step on the Furthermore, to avoid printed images applied to another side of the sheet web, it is also advantageous to further design the guide device in such a way that after leaving the second roll, the sheet web is guided past or through the drying device. Thus, the drying device may preferably have at least two drying units, one of which is arranged downstream of a drying unit downstream of a roller and the other drying unit downstream of the other roller.

Preferably, upstream of the first roller, a first web edge control device is provided for aligning the sheet web with respect to the first roller in parallel, which enables a plane-parallel alignment of the sheet web with respect to the print heads. To achieve a particularly compact design of the device, the web edge control device should preferably be arranged approximately spatially between the two rollers. In order to increase the web edge control and to achieve a high-precision web run, it is advantageous to provide a second web edge regulating device upstream of the second roller for the parallel alignment of the sheet web with respect to the second roller upstream.

A moistening device for moistening the incoming sheet web is preferably provided upstream of the first roller. The moistening device may be located upstream of the web edge control device.

The guide means may comprise at least two deflection means, of which a deflection means is associated with each roller and arranged so that the sheet web at an angle of greater than 0 ° and less than 180 ° relative to a formed with respect to the peripheral surface of the associated roller at the intersection with the guide roller Tangent is introduced. The deflection means expediently have a deflection roller. The deflection rollers may preferably be provided with a high-resolution angle measuring system.

Advantageously, the arrangement is such that the wrap angle for the sheet web on at least one roller between the deflection and the point at which the sheet web leaves the associated roller is about 180 °. In principle, however, other wrap angles are also conceivable.

Preferably, the pressure rollers should be pressed by a drive unit against the associated roller.

To determine the pressing force, at least one pressure roller should be provided with a corresponding measuring means.

Von Vortell is to provide at least one pressure roller with an elastic outer sheath.

For exact control of the circumferential speed, each roller is preferably associated with a direct drive which directly drives the associated roller, preferably has a servomotor and is provided with a high-resolution angle measuring system.

The pressure rollers can each form a traction drive with the associated roller, wherein the peripheral speed v _{2 of} the first roller is slightly lower than the peripheral speed v _{3 of} the second roller.

In a further preferred embodiment, the means for generating a desired web tension in the sheet path in the inlet region of the device, a first tensile means and in the outlet a second tension means and the two tension means are each driven by a drive such that the second tension means the sheet web in the conveying direction with a conveying speed v ₄ drives, which is slightly higher than the conveying speed v ₁ , which drives the first tension means the sheet web in the conveying direction. Thus, in the arcuate path between the first tensioning means in the entrance area and the second tensioning means in the exit area, a tensile stress is created which not only ensures safe guidance over the rollers but also along the remaining path of movement. In order to achieve freedom from slippage and a defined web elongation and elongation, v ₁ <v ₂ <v ₃ <v ₄ is preferred.

In a further preferred embodiment, the print heads are combined to form at least one group in which the print heads in a first row substantially transversely to the circumferential and rotational direction of the roller side by side and in a circumferentially and rotationally one behind the other second row substantially are arranged side by side transversely to the circumferential and rotational direction of the roller, wherein the print heads of the first row are arranged offset relative to the print heads of the second row. This makes it possible, on the one hand, to realize a custom printed image which is more complicated, reaching into edge regions of a book block page, and, on the other hand, if the sheet web is divided into several parallel partial webs on each partial web.

For this purpose, it is advantageous if the printheads of the first row overlap the printheads of the second row on both sides. In addition, the printheads of the first and second rows should preferably be arranged substantially at the same pitch.

In a further variant of the aforementioned embodiment, a plurality of groups of print heads in the circumferential and rotational direction of the roller are arranged one behind the other. This development has several advantages. On the one hand, this enables a printing of the sheet web offset in the conveying direction to be realized, with the result that a danger of moisture penetration due to a print media application can be minimized. On the other hand, a higher color quality can be achieved in the manner of multi-color printing. In view of the fact that the printing speed of the print heads is limited to a certain maximum depending on their design, this development can increase the printing speed and thus the productivity.

If the printheads are designed as jet printheads, preferably inkjet printheads, moving printing units can be avoided and a high degree of flexibility in printing can be achieved.

Preferably, the two rollers rotate in the opposite direction. This has several advantages. On the one hand, the sheet web withdrawn on the output side from the first roll can be brought to the second roll without twisting in such a way that the still unprinted other side of the sheet web is printed there. For this purpose, the guide device may optionally have at least one deflection roller or roller on which the sheet web is deflected after leaving the first roller and before reaching the second roller. Another advantage of this design is that the transport path for the sheet path between the two rolls can be kept short if necessary.

For maintenance purposes, it is advantageous if the printing heads associated with a roller are fastened together on a print head carrier which can be brought into a rest position away from the associated roller. Preferably, the print head carrier may be movably mounted approximately radially to the roller in a rest position.

Figur 1

eine schematische Seitenansicht einer Maschine zur Buchblockherstellung gemäß einer bevorzugten Ausführung der Erfindung;

Figur 2

eine schematische Draufsicht auf die Maschine von Figur 1;

Figur 3

eine vergrößerte schematische Seitenansicht auf einen Abschnitt der Maschine von Figur 1 von einer Bogenbahnabrollstation bis zu einer Bahnbefeuchtungsstation;

Figur 4

eine nochmals vergrößerte Seitenansicht einer Druckstation der Maschine von Figur 1;

Figur 5

eine gegenüber Figur 4 um 90° gedrehte Draufsicht auf die Druckstation;

Figur 6

eine ausschnittsweise perspektivische Darstellung einer Anordnung mit einer Andruckrolle, einer Walze und einer zwei hintereinanderliegende Reihen von Druckköpfen aufweisenden Gruppe von Druckköpfen;

Figur 7

eine schematische perspektivische Darstellung einer Anordnung mit einer Andruckrolle, einer Walze und zwei jeweils zwei Reihen aufweisenden Gruppen von Druckköpfen;

Figur 8

eine schematische perspektivische Darstellung einer Anordnung mit einer Andruckrolle, einer Walze und zehn jeweils zwei Reihen aufweisenden Gruppen von Druckköpfen; und

Figur 9:

eine ausschnittsweise Draufsicht auf eine bedruckte Bogenbahn.

Hereinafter, a preferred embodiment of the invention will be explained in more detail with reference to the accompanying drawings. Show it:

FIG. 1

a schematic side view of a book block making machine according to a preferred embodiment of the invention;

FIG. 2

a schematic plan view of the machine of FIG. 1 ;

FIG. 3

an enlarged schematic side view of a portion of the machine of FIG. 1 from a sheet launching station to a web moistening station;

FIG. 4

a further enlarged side view of a printing station of the machine of FIG. 1 ;

FIG. 5

one opposite FIG. 4 90 ° rotated top view of the printing station;

FIG. 6

a fragmentary perspective view of an arrangement with a pinch roller, a roller and a two successive rows of printheads having group of printheads;

FIG. 7

a schematic perspective view of an arrangement with a pinch roller, a roller and two groups each having two rows of printheads;

FIG. 8

a schematic perspective view of an arrangement with a pinch roller, a roller and ten each having two rows of groups of print heads; and

FIG. 9:

a fragmentary plan view of a printed sheet.

The in the FIGS. 1 and 2 essentially complete and in FIG. 3 In detail, the machine shown at the beginning contains a sheet-web delivery station 2, from the in FIG. 3 a frame 4 is shown, on which in the illustrated embodiment, a first support arm 6 for receiving a first roller 8 and a second support arm 10 for receiving a second roller 12 are arranged. The rollers 8, 12 are rotatably mounted on non-illustrated pivot, so-called. Mandrels, mounted on the support arms 6, 10 and thereby removably disposed thereon. The support arms 6, 10 are movably mounted on the frame 4 in the vertical direction and between an upper working position and a lower rest position movable so that they can be replaced in the lower rest position.

Each roll 8, 12 consists of a wound continuous sheet web, preferably of paper, which is unwound from the corresponding roll for the processing described in detail below. In this case, in the illustrated embodiment, only one role during operation is used, while the other role can be interchanged. So if the sheet has been completely deducted from a role is changed to the other role and then deducted from this arc the web, while the empty one role is replaced by a new full role. In order to avoid interruption of the current operation of the machine, the end of the sheet path of the one roller is connected to the beginning of the sheet path of the other role. For this purpose, the Bogenbahnabgabestation 2 a splicer 14, which is arranged in the illustrated embodiment on the frame 4 above the support arms 6, 10 and thus above the rollers 8, 12. The splicing process usually takes place at standstill, but can also be performed on the fly.

To bridge a possible need for Bogenbahnmaterial, for example, during the aforementioned splicing operation at a standstill, a Bogenbahnspeicher, not shown, is provided in the Bogenbahnabgabestation 2.

After leaving the Bogenbahnabgabestation 2 passes the sheet web, which is shown in the figures with the reference numeral "16", in a printing station 20, in which the sheet web 16 is printed with the desired printed images. At this point, it should be noted in addition that in the figures, the web running direction takes place from left to right.

The printing station 20 is in detail in the FIGS. 4 and 5 shown. As FIG. 5 can recognize, the printing station 20, a frame 22, on which the various, hereinafter described in detail units are arranged. To better represent these aggregates is in FIG. 4 the observer facing side of the frame 22 omitted for the sake of clarity.

Before entering the printing station 20 in the direction indicated by arrow A, the sheet web 16 passes through a first draw roller arrangement, which thus extends in the inlet area to the printing station 20 located. This draw roller assembly 24 is driven by a not-shown drive and acts upon the sheet web 16 with a first feed speed _V1. After entering the printing station 20, the sheet web 16 is guided over a plurality of guide rollers 26 to a web edge control device 28. Along this path section may be provided upstream of the web edge control device 28 optionally still a moistening device, which, however, is not shown in the figures. The web edge control device 28 has the task of aligning the sheet web 16 relative to the below-described printing devices transverse to the web direction so that, viewed in the transverse direction of the web running direction, the printed images are accurately positioned in the desired location.

After leaving the web edge control device 28, the sheet web 16 is guided via a guide roller 30 to a first guide roller 31 which rests on the circumference of a first roller 34 and is provided with a rotary encoder 33. The rotary encoder can preferably have a high-resolution angle measuring system (> 3600 l / rev, preferably 9000 l / rev). The first roller 34 is rotatably mounted on a bearing 35, which is supported on the frame 22 of the printing station 20 and has a rotary encoder 36 for determining the instantaneous rotational position of the first roller 34 and its rotational speed. The rotary encoder 36 preferably has a high-resolution angle measuring system (> 3600 I / U, preferably 36000 I / U). The first roller 34 is driven in the direction of the arrow B at a peripheral speed v ₂ by a direct drive 37, which has a servomotor (not shown) and is also seated on the frame 22. As FIG. 4 can be seen, the sheet web 16 runs in the illustrated embodiment with respect to the first roller 34 approximately radially to the first guide roller 31 and is deflected by this in the direction of the peripheral surface of the first roller 34.

Downstream of the first deflection roller 31 and thus at a certain angular distance from this, a first pressure roller 32 is provided, which also bears against the circumference of the first roller 34. From this first pressure roller 32, the sheet web 16 is pressed against the peripheral surface of the first roller 34 and thereby comes into abutment against the peripheral surface of the first roller 34. The first pressure roller 32 is pressed by an unspecified loader against the peripheral surface of the first roller 34. The application device can have, for example, an energy store such as a spring and / or an active drive. Alternatively, it is also conceivable that the sheet web 16 is not approximately radially and thus approximately at right angles to Peripheral surface at the location of the first pinch roller 32, but at a different angle of inclination introduce.

The first pressure roller 32 forms, together with the first roller 34, a kind of second tension roller arrangement which drives the arc web 16 resting on the circumference of the first roller 34 at the conveying speed v ₂ , which is slightly higher than the conveying speed v ₁ . Thus, while the first pinch roller 32 generates the sheet web 16 with a pressing force against the first roller 34 and thereby prevents slippage between the sheet web 16 and the circumference of the first roller 34, the first guide roller 31 ensures the desired wrap angle.

Namely, the sheet web 16 is pulled over about half of the circumference of the first roller 34 of the first guide roller 31 before it leaves the first roller 34 in the tangential direction again, so that in the illustrated embodiment, the wrap angle of the sheet 16 about the first roller 34 about 180 °. In principle, however, it is also conceivable to choose another wrap angle which is at least slightly smaller or slightly greater than 180 °. The rotational speed of the first roller 34 is chosen so that its peripheral speed is equal to the path speed of the arcuate path 16.

In particular FIG. 4 can be seen, in the illustrated embodiment, approximately halfway along its path over the circumference of the first roller 34, the sheet path 16 led to a printing unit 38 where the printing process takes place while the outwardly facing side of the sheet 16 is printed with the desired printed images , The first pressure roller 32 is disposed adjacent to the printing unit 38, so that in the illustrated embodiment, the first pressure roller 32 between the guide roller 31 and the printing unit 38 is located; Alternatively, it is also conceivable to store the first pressure roller 32 directly on the printing unit 38. To carry out the printing operation, the printing unit 38 has a plurality of non-contact printing heads 40, which are arranged at a distance from the peripheral surface of the first roller 34 and thus to the sheet web 16. Moreover, in the printheads 40, their printhead faces are substantially tangential to the peripheral surface of the first roller 34 and their printhead center axes are substantially radially aligned with the first roller 34. As FIG. 4 Furthermore, a plurality of print heads 40 are arranged one behind the other in the direction of rotation of the first roller 34 in accordance with arrow B and thus in its circumferential direction and in the web running direction of the sheet web 16.

As FIG. 6 can recognize which an arrangement of the first guide roller 31, the first roller 34 and the printheads 40, omitting the first pinch roller 32 by way of example from one opposite FIG. 4 In other perspectives, each print head 40 extends across the web travel direction only a fraction of the width of the sheet web 16, and the print heads 40 are combined into two web running successive rows 40R, which together form a group 40G. In this case, each row consists of a certain number of printing heads 40 located next to one another transversely to the web running direction and extends over the entire width of the sheet web 16. In addition, the print heads 40 of the two adjacent rows 40R of group 40G are offset relative to one another. This staggered arrangement of the print heads 40 is made in the illustrated embodiment so that each one print head 40 of a row 40R overlaps with its lateral ends, the ends of the print heads 40 of the other row 40R. As FIG. 6 Further, the printheads 40 of each row 40R are arranged at the same pitch, so each row 40R of printheads 40 has the same pitch. The staggered arrangement of the printheads 40 to each other takes into account the fact that each housing printhead 40 whose housing is wider than the effective pressure range transverse to the direction of web travel. Thus, on the one hand, if required, one can print over the entire width of the sheet web 16 continuous line and can be on the other hand more difficult to realize reaching into the edge regions of the sheet web 16 print images.

However, since each print head 40 can only operate up to a maximum frequency, the web running speed, which corresponds to the peripheral speed in the direction of the arrow B, would be limited to a maximum value. In order to be able to print even at a higher web speed, a plurality of groups 40G of printheads 40 are according to FIG FIG. 6 arranged in the web running direction one behind the other. In the example of FIG. 7 which also has an arrangement of the first guide roller 31, the first roller 34 and the printheads 40 omitting the first pinch roller 32 in the same perspective as FIG. 6 3, three consecutive groups 40G are provided with a total of six rows of printheads 40 at a speed three times that of using a single group 40G in accordance with FIG FIG. 6 to realize with only two consecutive rows, each print head 40 needs to print for a continuous line in the web running direction only every third point.

For full-color printing, one color is printed per group (comprising two consecutive rows 40R of printheads 40). Multiplied by the number of groups for the corresponding required speed, this then results in a corresponding number of required groups. FIG. 8 in which, in a different perspective to the FIGS. 6 and 7 an arrangement of the first pulley 31, the first roller 34 and the printheads 40 is shown omitting the first pinch roller 32 shows an example of a design for a full-color printing with ten groups.

In addition, the example of FIG. 8 It can also be seen that the printing unit 38 (FIG. FIG. 4 ) with their printheads 40 is not necessarily about in the middle between the first guide roller 31 and the point at which the sheet web 16 leaves the first roller 34 again, but that this also at another point along the path of the arc 16 over the circumference of the first roller 34 may be the case. In this connection, it should be noted that in order to achieve a high print quality, an arrangement which is substantially adjacent to the printing unit 38 directly in FIG FIG. 4 shown first pinch roller 32 is advantageous.

In the described embodiment, the printheads 40 used are jet printheads and preferably ink jet printheads.

The printing unit 38 is mounted so as to be movable radially relative to the first roller 34 on a holder 42 which is fastened to the frame 22. In this way, the printing unit 38 can be moved from a working position in which the print heads 40 occupy a relatively small distance from the peripheral surface of the first roller 34 and thus arc sheet 16 in a rest position in which the printing unit 38 and thus the print heads 40th have a significantly greater distance from the first roller 34 and release enough space for repair, maintenance and / or adjustments. Therefore, the printing unit 38 is mainly spent in the rest position when appropriate cleaning, repair, maintenance and / or adjustments must be made. In FIG. 4 the printing unit 38 is shown in its raised rest position.

As previously mentioned, the arcuate web 16 is drawn tangentially from the peripheral surface of the first roll 34. Responsible for this is a guide roller 44, which is arranged with respect to the first roller 34 so that the path leading from the first roller 34 for the sheet path 16 with respect to the peripheral surface of the first Roller 34 runs in the tangential direction, as FIG. 4 lets recognize. An arrangement of a first quality measuring device 46, which may have, for example, a high-speed stroboscope camera, not shown, and a so-called first table plate 47 is provided at this tangential path section at a position adjacent to the first roller 34. As FIG. 4 can recognize the arc path 16 between a front side of the first quality measuring device 46 and the first table plate 47, which extends approximately in the plane of the arcuate track 16, wherein the arcuate path 16 is at a minimum distance from the first table plate 47. As a result, a thin air cushion is formed between the first table plate 47 and the arc track 16, on which the arc track 16 slides over the first table plate 47. The first quality measuring device 46 serves to check the quality of the freshly applied print image on one side of the sheet web 16. For this purpose, in a very special way, the tangential path section after leaving the first roller 34, since there after removal from the first roller 34, the arcuate path 16 has a particularly straight course.

While in the illustrated embodiment, the tangential path portion of the first roller 34 to the guide roller 44 extends approximately vertically down, the sheet web 16 experiences a deflection in an approximately horizontal direction on this guide roller 44 and is guided by a drying device 50, in which the arc path 16 and thus prevents blurring of the previously applied printed images is prevented. Via further guide rollers 48, the sheet web 16 passes to a second deflection roller 51 and a second pressure roller 52, which both bear against a second roller 54. The second guide roller 51 is also provided with a rotary encoder 53. Upstream of the second deflection roller 51 may be provided another web edge control device similar to the web edge control device 28 in order to ensure highly accurate web travel with respect to the print heads 62 of the second printing unit.

The second roller 54 is also rotatably mounted on the frame 22 via a bearing 56, which has a rotary encoder 57 for determining the rotational position and the rotational speed of the second roller 54 and is also driven by a direct drive 58, which is arranged on the frame 22. In this case, the second roller 54 rotates in the direction of arrow C at a peripheral speed v ₃ . Associated with this second roller 54 is also a second printing unit 60, which has printing heads 62 and a holder 64, which is fastened to the frame 22, between a working position and a rest position is slidably mounted. In FIG. 4 is also the second printing unit 60 shown in its raised rest position. With regard to construction and function of the second guide roller 51 and the rotary encoder 53, the second pinch roller 52, the second roller 54, the bearing 56, the encoder 57, the direct drive 58, the printheads 62 and the holder 64 is based on the previously given detailed description of first guide roller 31 and its rotary encoder 33, the first pinch roller 32, the first roller 34, the bearing 35, the encoder 36, the direct drive 37, the print heads 40 and the holder 42 referenced. At this point it should be noted that measuring means for measuring the pressing force of the first and second pressure rollers 32, 52 may be provided.

Thus, with the aid of the print heads 62 on the second roller 54, a further printing operation takes place on the sheet web 16. Unlike on the first roller 34 but now the previously unprinted other side of the sheet web 16 is printed on the second roller 54. That the sheet web 16 now comes with its already printed one side into contact with the second roller 54, so that the previously unprinted other side is exposed for the printing process is achieved in the illustrated embodiment, that both rollers 34, 54 in the web running direction spatially one behind the other the second roller 54 is rotated in the direction of arrow C opposite to the direction of rotation of the first roller 34 and the sheet web 16 after leaving the first roller 34 via the guide rollers 44 and 48 along a curved path to the second roller 54 and there at the first Roller 34 facing side of the second roller 54 is brought into contact with the peripheral surface of the second roller 54. Thus, the second pressure roller 52 together with the second roller 54 forms a kind of third tension roller arrangement, which drives the sheet web 16 at the speed v ₃ in the web running direction. To achieve a defined tensile stress and thus elongation in the arcuate web 16, the speed v _{3 is} slightly higher than the speed v ₂ . Alternatively, it is also conceivable that both rollers 34, 54 rotate at exactly the same peripheral speed.

Similar to the guide roller 44, the guide roller 66 also serves to subtract the sheet path 16 tangentially from the second roller 54. Shortly after leaving the second roller 54, the sheet web 16 passes between a second quality measuring device 68 and an opposite second table plate 69 therethrough. Like the first quality measuring device 46, the second quality measuring device 68 also serves to check the quality of the print. Unlike the first quality measuring device 46, however, the second quality measuring device 68 has the task of improving the quality of the now to check on the second side of the sheet web 16 applied by the printheads 62 printed image.

After deflection on the guide roller 66, the sheet web 16 is returned by an additional drying device 50 via further guide rollers 70 back to the aforementioned drying device 50 to now perform a drying of the second roller 54 printed on the second side of the sheet 16 and a blur the previously on the second side of the print heads 62 applied print images to avoid. Incidentally, in this connection, it should be noted that the necessity of the drying devices 50 and their operation depends largely on the pressure medium discharged from the print heads 40, 62 and on the web speed of the sheet web 16.

After the sheet web 16 has passed through the drying device 50 again, it is deflected by guide rollers 72 and passed to another guide roller 74 to a second double roller assembly 76, which sits in the outlet of the printing station and through the rollers, the movement path 16 is passed before the sheet web 16th the printing station 20 leaves in the direction of arrow D. The two rollers of this double roller assembly 76 are driven by a drive, not shown. In this case, the tensile stress or feed force applied by the second draw roller arrangement 76 to the sheet web 16 is slightly greater than the tensile stress or feed force which is generated by the first draw roller arrangement 24 in the inlet region of the printing station 20. Due to this difference, a tensile stress or web tension arises in the sheet web 16 when it passes through the printing station 20. The first pull roller assembly 24 acts as a type of brake drive relative to the downstream driven pull roll assemblies formed by the first roller 34 / first pinch roller 32, the second roller 54 / second pinch roller 52 and the second pull roller assembly 76. The ratio of the speeds to each other according to the following inequality: $${\mathrm{<figure-callout\; id="1"\; label="v"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">v</figure-callout>}}_{\mathrm{1}}\mathrm{<}{\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">v</figure-callout>}}_{\mathrm{2}}\mathrm{<}{\mathrm{v}}_{\mathrm{3}}\mathrm{<}{\mathrm{<figure-callout\; id="4"\; label="v"\; filenames="imgf0003.png"\; state="\{\{state\}\}">v</figure-callout>}}_{\mathrm{4}}\mathrm{,}$$

In this way, in the sheet web 16, a defined tensile stress and thus a defined elongation or sheet elongation and also a slip freedom between the sheet web 16 and the rollers 34, 54 achieve, the differences between the individual speeds are at most in the per thousand range and in particular the increase in speed should each be about one per thousand.

By guiding the sheet web 16 over the rollers 34 and 54 and thus over a part arcuate curved path at a predetermined web tension on the printheads 40 and 62 over a particularly accurate positioning of the sheet web 16 relative to the printheads 40 and 62 can be realized and will flutter or swimming the sheet web 16 avoided, whereby printed images of particularly good quality can be produced at high production speed. For compliance with the web tension in the sheet web 16 along the embossed curvature forming circumference of the rollers 34 and 54 provide primarily the pinch rollers 32 and 52, via which the sheet web 16 are respectively introduced on the input side to the peripheral surface of the rollers 34, 54, while yes on the output side tangentially from the circumference of the rollers 34, 54 is subtracted. To assist in the generation of the web tension in the sheet web 16, the first and second twin roll assemblies 24 and 76 provide support to ensure that the sheet web 16 is under a predetermined tension substantially throughout its path through the printing station 20.

The evaluation of the measurement signals delivered by the measuring systems with respect to a web slip of the sheet web 16 relative to the rollers 34 and 54 takes place in a higher-level control device, which is not shown in the figures. If a web slip is detected, there is in particular the possibility to reduce the slip by changing the pressing force of the pinch rollers 32 and 52, to compensate for the slip by signals to a print head control, also not shown, for example, in the operating frequency of the print heads 40, 62 corresponding dead times be controlled to reduce the web speed of the arc path 16 or simply leave a corresponding warning message.

After leaving the printing station 20, the now printed sheet web 16 in the illustrated embodiment passes through a feed station 80, which supports the transport of the sheet web 16 in the web running direction.

Downstream of the feed station 80 in the illustrated embodiment is a refractive station 90, in which the sheet web 16 is broken on both sides and thus in both directions in order to eliminate any waviness caused by the printing process.

The arcuate web 16 then passes through a moistening station 100 which is designed to spray the arcuate web 16 with steam or a liquid mist in order to discharge an electrostatic charge which may be present in the arcuate path 16 to ground or ground. Alternatively or additionally, it is also conceivable to provide the moistening station 100, for example, for dispensing a fixing agent or dyes for the purpose of surface refinement.

The machine further has a longitudinal cutting station 110, which is arranged downstream of the discharge station 100. As FIG. 2 can be seen schematically, the longitudinal cutting station 110 includes a plurality of knives 112 which are arranged side by side transversely to the web running direction and thereby spaced from each other. The knives 12 are preferably designed as rotary drivable circular knives whose respective axis of rotation is oriented transversely to the direction of web travel. Further, the blades 12 are each positioned transversely positionable relative to the web running direction of the sheet web 16, whereby the distance between two adjacent blades 112 is adjustable from each other. Incidentally, the knives 12 can also be moved transversely in such a way that, if necessary, they can be moved out of engagement laterally from the curved path 16 into a rest position.

In the longitudinal cutting station 110, the sheet web 16 is cut by the knives 112 in the web running direction by a number of longitudinal cuts into a plurality of partial webs each corresponding to a desired width of a book block side. Due to the variable positionability of the individual blades 112 transversely to the web running direction of the sheet web 16, the distance between two adjacent blades 112 can be adjusted to the desired width of a book block page, resulting in a high format flexibility. Accordingly, if the width of the sheet web 16 is a multiple of the width of one side of the book block to be produced with the machine, a corresponding plurality of book blocks can be produced simultaneously in parallel.

As in FIG. 2 is further shown, the longitudinal cutting station 110 also includes a Randstreifenabsaugeinrichtung 114, with which the elimination of cut and not usable edge strip sections is possible.

Downstream of the longitudinal cutting station 110 is a transverse cutting station 120, in which the partial webs cut longitudinally by the preceding longitudinal cutting station 110 are cut simultaneously into sheets at a length corresponding to the height of a book block side, transversely to the conveying direction become. The cross cutting station 120 may have a cylindrical knife drum extending over the entire width of the sheet web 16 with a helical knife arranged inclined therewith relative to the axis of rotation of the knife drum; Alternatively, it is also conceivable to provide on the circumference of such a knife drum a plurality of opposite the axis of rotation of the cutterhead inclined blade extending, for example, according to the number of cut in the longitudinal cutting station 110 partial webs.

Subordinate to the cross cutting station 120 in the web running direction is a Schlechtbogenweiche 130, to which shoots a firing belt 132, which is led out transversely to the web running direction of the machine, such as FIG. 2 lets recognize. With the help of the Schlechtbogenweiche 130, which is not shown in detail in the figures, but only very schematically, are inferior sheets, which in particular have faulty printed images or splices or splices, or blank sheets discarded and provided on the weft tape 132 from the machine.

For this purpose, upstream of the Schlechtbogenweiche 130 an optical sensor, not shown in the figures is provided, which determines the number of passing sheets and determines whether the determined number of sheets corresponds to the number of pages formed by the sheets for the production of the book block, and auszusondernde Identified sheets and controls the bad arc switch 130 via a control device, not shown.

Downstream of the bad curve switch 130 is an overlapping station 140, in which the sheets delivered by the cross cutting station 120 are brought into an overlapping and thus shingled arrangement. For this purpose, the overlapping station 140 is provided with suitable delay means (not shown in the figures) for braking and overlapping the sheets.

The overlap station 140 is followed downstream by a collection station 150, which contains a plurality of adjacent compartments 152, which are located in FIG. 2 are shown schematically. These compartments 152 are each bounded laterally by side walls which are unspecified in the figures, which are adjustable transversely to the web running direction, so that the width of the individual compartments 152 can be adapted to the width of the sheets cut from the part webs. Thus, the side walls of the compartments 152 should be transversely conforming to the knives 112 of the slitting station 110, respectively be adjusted to the web running direction, so as to ensure that the side walls of the compartments 152 in the collection station 150 occupy the same transverse position as the corresponding blades 112 of the slitting station 110. In each of the bins 152, a stack of superimposed bows is set up in the collection station 150 which upon completion forms the desired book block, the bins 152 being arranged in a number corresponding to the number of sub-webs, thereby forming a corresponding plurality of parallel and book blocks Bow stacks are accumulated. At this point, for the sake of completeness, it should be noted that each sheet in the stack represents a book block page of the resulting book block, whereby page "1" of a book block is always deposited either to the top or to the bottom.

In addition, it should be noted at this point that the collecting station 150 may include pliers conveyors, not shown in the figures, wherein preferably each of the compartments 152 is associated with a pliers conveyor. The forceps conveyors serve to remove a stack accumulated in a finished book block from the respective compartment 152 by pinching a stack embodying a finished book block between the forceps heads of the forceps conveyor.

Adjacent to the collection station 150 is an intermediate buffer 160 for temporary storage of good and / or bad book blocks from the collection station 150.

As FIG. 2 Further, the collecting station 150 is followed by a conveyor belt 170, which transports the book blocks accumulated in the individual compartments 152 of the collecting station 150 to a binding station not shown in the drawings.

Besides, lets FIG. 2 still schematically recognize a cross conveyor 180, which is provided for a transfer of the book blocks by a gripper conveyor from the collection station 150 on the conveyor belt 170. The cross conveyor 180 may also comprise a circulating conveyor belt. In addition, the cross conveyor 180 acts not only toward the conveyor 170, but also toward the intermediate buffer 160 to temporarily interpose the book blocks from the collection station 150 in the intermediate buffer 160 as needed.

At this point, it should be noted in addition that for the consideration of different material qualities of the sheet web 16 used, the tensile forces of at least some used drive units should be monitored accordingly. In particular, a torque measurement is suitable for this purpose. The monitoring device, which is not shown in the figures, can preferably be designed for adaptive control of the drive units.

In FIG. 9 For example, a section of the sheet web 16 is shown, which is printed in the machine described above and further processed. The arc path 16 has an in FIG. 9 visible first surface or side 16a and one of these opposite surface or side, which in FIG. 9 directed away from the viewer and thus is not visible. Further, the arcuate track 16 has a length L (this dimension is, of course, many times longer than that in FIG FIG. 9 portion shown) and a width B, wherein the width B is a multiple (according to the example of FIG. 9 a triple) of a width FB of the page of a book block plus a double measure of the width EB of the edge portions and the length L is a multiple of a height FH of the page of a book block. In this connection, it should be pointed out again that an arc produced from the sheet 16 forms one side of a book block.

In the printed sheet 16 according to FIG. 9 is the one facing the viewer and thus in FIG. 9 visible first surface 16a were printed with the page contents of the odd-numbered pages "51", "53", "55", "57". On the viewer of FIG. 9 turned away and thus in FIG. 9 The contents of the even-numbered pages "52", "54", "56", 58 "have been printed corresponding to the non-visible second surface, in which example the printed image for the page" 52 "on the second surface of the sheet web 16 is the same Place the print image for the page "51" placed on the first surface 16a of the sheet 16, corresponding to the remaining pages "53" / "54", "55" / "56", "57" / "58 "etc. applies FIG. 9 recognize on the curved path 16 interrupted longitudinal lines X, which symbolize the section through the respective knife 112 of the longitudinal cutting station 110 in partial webs with the width FB. Also, in FIG. 9 shown broken cross lines Y, which indicate the section through the cross cutting station 120, whereby the partial webs are cut into finished sheets with the width FB and the length or height FH, from which then the respective book block with the width FB and the height FH is composed ,

Claims (17)

Device (20) for printing a printable sheet web (16) moved in its longitudinal direction, in particular for use in connection with the production of book blocks two rollers (34, 54) which rotate at a peripheral speed corresponding to the speed of movement of the sheet web (16) and are provided for contacting the sheet web (16) on its peripheral surface over a predetermined angular range, - each roller (34, 54) associated, non-contact printheads (40, 62) spaced from the peripheral surface of the associated roller (34; 54) are arranged and at least substantially transversely to the circumferential and rotational direction of the associated roller (34; 54) are juxtaposed with the printhead faces substantially tangential to the associated roller (34; 54) and the printhead center axes substantially radially aligned with the peripheral surface of the associated roller (34; 54), - A guide means for guiding the sheet web (16), wherein the guide means comprises at least two first and two second guide means (32, 44, 52, 66), of which a first guide means (32, 52) and a second guide means (44; The first guide means (32, 52) has at least one pressure roller resting against the peripheral surface of the associated roller (32, 54), and the second guide means is designed such that the arc track (16) in FIG substantially tangentially from the peripheral surface of the associated roller (34; 54) is drawn off along a tangential path portion, and wherein the guide device is further designed to guide the sheet web such that when resting on one roller (34) one side of the arc path (16 ) and when resting on the other roller (54) the other side of the sheet web (16) is printable, - means (24, 76) for generating a desired web tension in the sheet web, and - At least two quality measuring devices (46, 68), each associated with a roller (34; 54) and determines the quality of the sheet web (16) after leaving the roller at a position of its tangential path portion. Apparatus according to claim 1, having at least one drying device (50) for drying the printed sections of the sheet web (16), wherein in particular the two rollers (34, 54) approximately spatially next to each other and the drying device (50) spatially below the rollers (34, 54 ) are arranged. Apparatus according to claim 2, wherein the drying means comprises at least two drying units (50), one of which is arranged downstream of one drying unit (50) downstream of one roller (34) and the other drying unit (50) downstream of the other roller (54). Device according to at least one of the preceding claims, wherein upstream of the first roller (34) a first web edge control device (28) for parallel alignment of the sheet web (16) relative to the first roller (34) is provided, the first web edge control device (28) in particular approximately spatially between the two rollers (34, 54) is arranged. Apparatus according to claim 4, wherein upstream of the second roller (54) there is provided second web edge control means for aligning the sheet web (16) in parallel with the second roller (54). Device according to at least one of the preceding claims, in which upstream of the first roller (34) a moistening device for moistening the incoming sheet web (16) is provided upstream. Device according to at least one of the preceding claims, in which the guide device has at least two deflection means (31, 51) of which a deflection means (31; 51) is associated with each roller (34; 54) and arranged such that the arc track (16) at an angle of greater than 0 ° and less than 180 ° with respect to a tangent formed with respect to the peripheral surface of the associated roller (34; 54) at the point of intersection with the guide roller (31; 51), and preferably a guide roller (31; 51) having. Apparatus according to claim 7, wherein the arrangement is such that the angle of wrap for the sheet web (16) on at least one roller (34, 54) between the deflection means (31; 51) and the point at which the sheet web (16) the associated roller (34, 54) leaves, is about 180 °, wherein preferably each roller (34, 54) is associated with a direct drive, which drives the associated roller (34, 54) directly, preferably has a servo motor and preferably with a rotary encoder is provided. Device according to at least one of the preceding claims, in which the pressure rollers (32, 52) are pressed by a drive unit against the associated roller (34, 54) and in particular at least one pressure roller (32, 52) is provided with a measuring means for determining the pressure force and preferably has an elastic outer jacket. Device according to at least one of the preceding claims, wherein the pressure rollers (32, 52) with the associated roller (34; 54) each form a traction drive, wherein the peripheral speed v _{2 of} the first roller (34) is slightly lower than the peripheral speed v ₃ of second roller (54). Device according to at least one of the preceding claims, having an inlet and an outlet, wherein the means (24, 76) for generating a desired web tension in the arcuate web (16) in the region of the inlet a first tensile means (24) and in the region of the outlet second tension means (76) and the two tension means (24, 76) are each driven by a drive such that the second tension means (76) drives the sheet web (16) in the conveying direction with a conveying speed v ₄ , which is slightly higher than the conveying speed v ₁ is, with which the first tension means (24) drives the sheet web (16) in the conveying direction, wherein in particular v ₁ <v ₂ <v ₃ <v ₄ . Device according to Claim 11, in which the first and / or second tensioning means (24, 76) comprise at least one respective roller or roller, which is preferably provided with an elastic jacket, and preferably the first and / or second tensioning means (24, 76). is designed as a preferred drive, which has a measuring means for outputting a torque signal. Device according to at least one of the preceding claims, wherein on each roller (34, 54) the print heads (40, 62) are combined to form at least one group (40G) in which the print heads (40, 62) are arranged in a first row (40R ) substantially transversely to the circumferential and rotational direction of the roller (34; 54) side by side and in a circumferentially and rotationally one behind the other second row (40R) are arranged substantially transversely to the circumferential and rotational direction of the roller (34; 54) side by side wherein the printheads (40 "62) of the first row (40R) are offset from the printheads (40" 62) of the second row (40R). The apparatus of claim 24, wherein the printheads (40, 62) of the first row (40R) overlap printheads (40, 62) of the second row (40R) on both sides, respectively, and preferably the printheads (40, 62) of the first row (40R) and second row (40R) are arranged substantially at the same pitch and preferably a plurality of groups (40G) in the circumferential and rotational direction of the roller (34; 54) are arranged one behind the other. Device according to at least one of the preceding claims, in which the print heads (40, 62) are designed as jet print heads, preferably inkjet print heads. Device according to at least one of the preceding claims, in which the two rollers (34, 54) rotate in opposite directions (B, C) to one another and preferably the guide device has at least one deflection roller or roller (44 "48) on which the arc path ( 16) after leaving the first roller (34) and before reaching the second roller (54) is deflected. Apparatus according to any one of the preceding claims wherein the print heads (40; 62) commonly associated with a roller (34; 54) are mounted together on a print head carrier (38; 60) which is in a rest position remote from the associated roller (34; 54) can be brought and preferably moved approximately radially to the roller (34, 54) in the rest position.

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