EP3201000B1 - Device for coding printing sheets in a sheet-fed press - Google Patents

Description

The invention relates to a device for coding in a sheet-fed printing press according to the preamble of claim and a method according to the preamble of claim 10. In accordance with the offset printing principle sheetfed presses increasingly find pressure-free printing devices use, preferably with the customization of printed products produced by offset printing For example, barcodes, numbering or other markings is used. Such printing formless printing devices are also referred to as non-impact print (NIP) printing devices and can be embodied, for example, as inkjet printing devices which have at least one inkjet print head, wherein the or each inkjet print head according to the so-called continuous inkjet principle, The drop-on-demand inkjet principle, the thermal inkjet principle or any other inkjet principle can work. The pressure-formless or NIP printing devices can also be designed as laser printing devices.

From the DE 197 04 003 A1 a sheet-fed printing machine is known, in which a designed as an inkjet printing device or as a laser printing device, pressure-free printing device is integrated in an offset printing unit of the sheet-fed press. In this case, the pressure-formless printing device with respect to a sheet-guiding impression cylinder in the area after the passage of sheet is arranged by a pressure gap formed by the impression cylinder and a blanket cylinder. In the printing machine according to DE 197 04 003 A1 In particular, the printing of printed sheets with a high rigidity in the area of the inkjet printing device or laser printing device is problematic. This is due to the fact that such sheets in the region of the sheet trailing edge after leaving the nip tend to bounce and up so that the distance between the pressure-free printing device and the sheet can change abruptly, which is why the sheet can strike without corresponding guide elements against the pressure-free printing device and thus the sheets in the sheet trailing edge are not printed with the same quality as in the area of a sheet leading edge and / or a sheet center can.

To fix the sheets on the surface of the impression cylinder are in the DE 197 04 003 A1 Bow guide rollers proposed, however, cover areas of the sheet, which is why the press sheet in the printing machine according to DE 197 04 003 A1 can not be printed over the entire format width of the printing formless printing device. Furthermore, the arrangement of the pressure-free printing device in the region of the printing gap implies that impressions are made in the freshly printed printed sheets with the help of the pressure-free printing device, whereby the risk exists that the sheet guiding rollers used leave markings on the surface of the printed sheets and thus impair the achievable print quality.

Another sheet-fed press with a built-in pressure-free printing device is from the DE 195 14 259 A1 known, the pressure-formless printing device seen in the transport direction of the sheet seen behind the last offset printing unit and in the transport direction of the sheet seen before a boom of the sheet-fed press integrated into the same according to this prior art.

Furthermore, from the DE 10 2006 002 302 A1 a sheetfed press known. The sheet-fed press is equipped with a sheet feeder for the supply of printed sheets and one or more printing units for printing the sheets with a static, identical for all sheets printed image. In the sheet-fed printing machine, at least one pressure-formless printing device for printing on the printed sheet is further integrated with a print image that varies from sheet to sheet. This one or each of these pressure-free printing devices is integrated in the sheet feeder in the sheet-fed press. In the case of the use of a single sheet feeder, a printed sheet can be printed on a feeder table in its entire surface area. Furthermore, sensors are provided which detect the front and side edges of the sheet. As a result, the sheet position is defined and it can be made possible with respect to the positioning of the print pattern targeted static or variable from sheet to sheet printing by means of pressure-free printing device.

In this case, an installation position is preferred over an arranged before the sheet alignment investment sheet in a trained as a shed feeder sheet feeder. Furthermore, an installation position above a forward conveying direction in the contact sheet and serving the sheet feed conveyor table is preferred in a sheet feeder designed as a single sheet feeder.

From the DE 10 2009 000 523 A1 is a sheet-fed press with a feeder, at least one printing unit and / or coating unit for printing a static, identical for all printed sheet image, with a boom and at least one integrated in the sheet-fed press formless printing device for printing a variable from sheet to sheet variable print image. The pressure-free printing device is provided in the area of sheet leading cylinder, wherein the sheet leading cylinder for safe guidance of the sheet in the area of the printing devices are provided with adhesive means for planar flat guiding the sheet.

From the DE-PS 895 157 is the printing of addresses o. The like. On newspapers known. For printing addresses on newspapers, the newspapers are overlapping, so shifted against each other, promoted in a conveyor. They lie on each other like scales, so that only as much of the edges of the copies is released, as this corresponds to the pressure surface claimed by the address. The printing is done with the help of a text tape made of plastic, rubber, textile, paper or metal.

Out WO 2010/086204 A1 a sheet-fed printing machine is known, with a feeder for feeding sheet to be printed, with at least one printing unit and / or coating unit for printing the sheet with a static, identical for all sheets printed image, with a boom for discharging printed sheet from the sheetfed press, and with at least one inkjet printing device integrated in the sheet-fed printing machine is provided for printing a dynamic, changeable printed image. The or each inkjet printing device is controllably integrated in the sheet-fed printing machine depending on process parameters or operating parameters or order parameters or quality parameters and can be assigned to a feed table.

Out WO 2010/086265 A1 Another sheetfed press is known. In an aggregate for the cold foil transfer to the sheet-fed press, the improvement of the transfer process is achieved in that for applying the adhesive for the film transfer at least one inkjet printing device is arranged in the transport direction of the sheet before the coating unit. For this purpose, the inkjet printing device can be assigned to a sheet fed printing machine upstream investment table. document WO-A-2010/086204 discloses a sheet-fed press according to the preamble of claim 1.

Proceeding from this, the present invention has the object to provide a novel device for simple, flexible and secure coding of printed sheets in a sheet-fed press.

This problem is solved by a sheet-fed printing machine according to claim 1 and by a method according to claim 10. According to the invention, the or each pressure-formless printing device is integrated into the sheet-fed press in the area of the sheet feeder in such a way that each printed sheet can be coded by an upper side in a selectable range. According to the invention, the or each pressure-formless printing device is integrated into the sheet-fed press in the area of the sheet feeder such that each printed sheet can be coded from an underside in a selectable area.

According to the invention, the or each pressure-formless printing device is integrated in the sheetfed press in the sheetfed press that each sheet can be encoded in a selectable area, wherein a controller detects in connection with sensors the presence of sheet and the time to start a coding or numbering and controls. According to the coding or numbering is manually or automatically activated for production, after which the release of the pressure by a pressure-free printing device only takes place when a sensor has reported the presence of sheet in the printing area and or the presence of color-correct sheet in the printing area. In addition, another sensor must have reported a settable zero or start time for each of the sheets depending on the length of the print format.

For the purposes of the present invention, it is proposed to integrate the or each pressure-formless printing device in the area of the sheet feeder of the sheet-fed printing machine in the same. Accordingly, in the context of the present invention, the printing of printed sheets with the help of or any pressure-free printing device at a time, the before printing the sheet in which is preferably designed as an offset printing units printing units of the sheet-fed press. Since the printed sheets to be printed in the area of the sheet feeder are flat and not curved as in the area of the printing units of the sheet-fed printing machine, the printing formless printing devices can be arranged with a small distance to the sheet without rolling on the sheet to be printed Sheet guide rollers are required, which on the one hand affect the print quality and on the other hand limit the printable in the range of or any pressure-free device width of the sheet.

A method according to the invention when inserting printed sheets into a sheet-fed printing press uses one or more printing-form-free printing devices in conjunction with a ribbon feeder which processes a shingled stream of printed sheets on a conveyor table. If the printing devices are assigned to the printing sheet on the conveyor table in a printing position, wherein they can be assigned from below in the scale flow exposed rear sheet ends of the sheet from the top or the imbricated stream from below exposed front end of the sheet, the printing devices by manual or automatic control for production activated.
The release of the pressure by means of the printing device takes place when a sensor reports the presence of printed sheets and / or the presence of color-correct printed sheet in the printing area and if sensor reports a dependent on the length of the printing format zero or start time for the passage of each of the sheet.

In a further development, at least one characteristic is stored in a control device of the pressure-free printing device, which curve is formed as a function of the printing material parameters such as sheet format, sheet thickness, grammage, fiber direction and / or stiffness of the printed sheet. The pressure-formless printing device can be controlled on the basis of these characteristics and there is provided a data connection of the control device for reading in order data from a control of the sheet-fed press.

In a further development, the or each pressure-formless printing device can be embodied as an inkjet print head or laser printing device which is arranged to print the printed sheets in the imbricated stream over the entire exposed format width and / or exposed format length from the uppermost upper side.

In a further development, each inkjet print head or laser printer device can be arranged to print printed sheets in the imbricated stream over the entire exposed format width and / or exposed format length, wherein the inkjet printheads or laser printing devices comprise one or more, at least partial regions of associated with the conveyor table lying underside of the sheet releasing openings in the conveyor table.

In a further development, a plurality of successively arranged inkjet print heads or laser print heads can be provided, viewed side by side and / or in the transport direction of the print sheet, transversely to the transport direction of the print sheet, which are interconnected on the control side.

In a further development, printing devices can be removable from the sheet-fed printing machine and usable at another sheet-fed printing machine or within the same sheet-fed printing press at different installation positions.

In a further development, a drying device and / or a suction device can be arranged downstream of the pressure-formless printing devices in each case in the transport direction of the printed sheet.

In a further development, pressure-formless pressure devices can be arranged pivotably in the region of the sheet feeder with respect to the conveyor table.

Preferred developments of the invention will become apparent from the following description. Embodiments of the invention will be described, without being limited thereto, with reference to the drawings.

Fig. 1:

eine Bogendruckmaschine mit verschiedenen Einrichtungen,

Fig. 2:

eine schematische Darstellung einer erfindungsgemäßen Einrichtung an einer Bogendruckmaschine,

Fig. 3:

eine detailliertere schematische Ausschnittdarstellung der Einrichtung nach Fig. 2 und

Fig. 4:

ein Schaltungsschema zu einer erfindungsgemäßen Einrichtung nach den Figuren 2 und 3.

Showing:

Fig. 1:

a sheetfed press with various facilities,

Fig. 2:

a schematic representation of a device according to the invention on a sheet-fed press,

3:

a more detailed schematic sectional view of the device according to Fig. 2 and

4:

a circuit diagram of a device according to the invention according to the Figures 2 and 3 ,

Fig. 1 shows a schematic representation of a sheet-fed printing machine 10, wherein the sheet-fed printing machine 10 comprises a sheet feeder 11, a plurality of printing units 12 formed as offset printing units, a printing unit 12 downstream of the printing unit 12 and a downstream of the coating unit 13 boom 14. The sheet feeder 11 is used for feeding sheet to be printed in the first of the printing units 12 of the sheet printing machine 10 and comprises a sheet feeder 20 with a feeder stack and a sheet separating device 23, a conveyor table 19 and an abutment plate 22 in conjunction with a pregripper 21. Die Druckbogen werden Moves 12 and the coating unit 13 moves and printed there with a print sheet for all the same or unchanging and thus static printed image. In the area of the arm 14, printed signatures are discharged from the sheet-fed printing press to form a delivery stack 15. In the illustrated embodiment of the Fig. 1 the sheet-fed printing machine 10 according to the invention is designed as a so-called turning machine, which serves the double-sided printing of printed sheets in the so-called perfecting. A arranged between the first two printing units 12 transfer cylinder is this formed as a turning cylinder 16.

In the sheet-fed printing machine 10 according to the invention at least one pressure-formless printing device is integrated, which is preferably the printing of the printed sheet with a static or from sheet to sheet variable print image serves. For the purposes of the present invention, the or each pressure-formless printing device is integrated in the sheet feeder 11 in the sheet-fed press 10, wherein in Fig. 1 possible installation positions 17 and 18 are shown schematically for the or each pressure-formless printing device. In both installation positions 17 and 18, the printed sheets are printed in the area of the sheet feeder 11 via the or each pressure-formless printing device from above.

When transporting the printing sheet along the conveyor table 19, the sheets are flat or flat. It can be maintained a small distance between the or each pressure-free printing device and the sheet and thus a high print quality can be provided.

The sheet feeder 11 is formed as a so-called shingled feeder for conveying a scale flow S of sheet in the sheet running direction R on the conveyor table 19. Here, the installation position 17 for the printing device above an in Fig. 1 and 2 symbolically illustrated investment sheet 22 of the sheet-fed printing machine 10 are selected on the first of the printing units 12. In the area of the contact plate 22, the last printed sheet of the scale flow S is present individually, is aligned to the front and side edge and detected by a so-called pre-gripper 21 and the first of the printing units 12 of the sheet-fed printing machine 10. Since in this case the printed sheets on their surface are completely freely accessible, they can be printed by the printing formless printing device over the entire format width and format length with a static or from sheet to sheet variable print image.
In the installation position 17, however, results in a cramped installation position as a result of there existing Bogenausricht- and Bogenleitmechanismen. Furthermore, the respective first printed sheet is accelerated by the pre-gripper 21 there from the speed on the conveyor table to the machine speed of the printing unit 1. This requires complex measures for integration.

For a smooth integration and adaptation to the production needs, according to the invention in a sheet feeder designed as a bulkhead feeder 11 a pressure-formless printing device in the installed position 18 above the conveyor table 19 integrated into the sheet feeder 11.

In FIG. 2 the arrangement according to the invention is shown in overview. It shows the integration of a formed as an inkjet printhead 1 pressure-free printing device in the area designed as a suction belt conveyor table 19. The chosen embodiment is based on the fact that regardless of the format length of the sheet on the conveyor table 19 by the Unterschuppung the sheet in the shingled stream S always the The end of the sheet or the back flake length of each print sheet is visible from above and therefore also printable. Therefore, a corresponding control of the inkjet printhead 1 is required, which takes place via a controller 6. For the inkjet printhead 1 also a printhead mount above the conveyor table 19 is required. This can be designed to be static, displaceable or pivotable, so that the inkjet print head 1 can be positioned for production purposes and displaced from the working space for setup and maintenance purposes.

A product sensor 2 for detecting the presence of printed sheets on the conveyor table 19 can be arranged above or below the conveying surface of the conveyor table 19 as a reflection light scanner, laser probe, color scanner or other sensor recognizing a substrate on a receiving device for mounting.

To detect the functional position of the printed sheets on the conveyor table 19, a rotary encoder 3 is provided, which may have a measuring wheel with rubber studs, so that, if necessary, the forward movement of the printed sheets in the scale flow S can be identified and analyzed.

To define the printing process by the inkjet printhead 1, a sensor 4 is further provided for a pressure release. This one is in FIG. 2 the sheet separating device 23 (also referred to as suction head) assigned in the sheet feeder 20 above the feeder pile. Here, the sensor 4 is connected to one or more elements of the sheet separating device 23 and / or the sheet conveying via the conveyor table 19 in connection.

For circuit connection between the sensor 4 and the control devices, an input / output connection element is provided for mounting approximately in a control cabinet of the first of the printing units 12.

In this context, a printhead controller 6 with a device holder for operable positioning in the area of the sheet feeding device 11 is arranged. This can preferably take place in the area of operating devices of the sheet-fed printing machine 10 of the sheet feeder 20, which are often provided parallel to the conveyor table 19.

Finally, a control device 7 for operating the pressure-free printing device from an operating position on the boom 14 of the sheet-fed printing machine 10 with circuit for starting the inkjet printhead 1 and a control diode for indicating the activity or operational readiness of the inkjet printhead 1 may be provided.

In FIG. 3 the functionality of the inkjet print head 1 in conjunction with the sheet feeder 11 is shown in more detail.

Should a continuous numbering or sheet-related single coding of sheets be desired, then this can be done in different processes. The start of the sheet numbering or coding can be triggered by a so-called good sheet counter or by means of another corresponding signal. The programming can also be done by specifications when setting up the sheet-fed press 10. The numbering or coding may be set via the function of an arc inspection 24 in relation to the printed sheet. In a log of the sheet inspection 24 while the consecutive number can be displayed in the inspection result.

To carry out is therefore after Fig. 3 the following device in connection with the sheet feeder 20, the sheet separating device 23, both of which are not shown here, but at least provided with the conveyor table 19. An inkjet printing head 1 is provided in a central extension region above the conveyor table 19. In this case, the inkjet printhead 1 is directed approximately at the middle region of the underlying sheet of the sheet stream S.

It is assumed that regardless of the format length of the sheet on the conveyor table 19 always the rear end of each sheet in the scale flow S of upper is visible and therefore can be printed in any area of the scale flow.

Hereby, the processability of all print formats is made possible, since format lengths of the print sheets which can be processed in a single sheet-fed press can for example be between values of 340 mm and 740 mm.

The printing by the inkjet print head 1 should be triggered automatically and all printed sheets should be printed in the scale flow S, regardless of their format length. A manual intervention of the printer should be avoided.

The synchronization of the numbering or coding is then carried out with equipment which is provided as described below.

A sensor 2 is arranged in the region of the inkjet print head 1 above (or also below a control opening in the conveyor table 19) of the conveyor table 19 and observes whether a print sheet is present under the inkjet print head 1. If this is the case, the sensor 2 outputs an "arc" signal. As a sensor 2, a simple optical reflection sensor, a laser sensor, a color sensor or other sensor can be used for material detection, which is arranged above the conveyor table 19 and the surface of the conveyor table 19 is arranged scanning and an opening in the conveyor table 19 or a dark Surface is assigned to the conveyor table 19.

Sensor 2 is required in all modes, manual or automatic.

About a known from the machine control machine angle and a so-called insertion point adjustment of the sheet feeder 20 and the sheet separating device 23 is format dependent (according to the format length used) of the print start for the inkjet printhead 1 calculated and a corresponding control signal via a print head control 6 to the inkjet printhead 1 transmitted. The accuracy of the printing position is estimated here in the circumferential and lateral directions with approximately +/- 3 mm.

A trained as a wheel encoder rotary encoder 3 is assigned to a conveyor belt 9 of the conveyor table 19 below the conveyor table 19. The rotary encoder 3 outputs equidistant pulses with respect to the transport path of the conveyor belt 9 (e.g., 300 dpi = 84 μm steps). The speed modulation of the sheet transport from 32% to 168% (referred to as so-called sheet slowdown) per scale path is recorded synchronously here and also passed on to the inkjet print head 1, so that this is automatically taken into account.

The inkjet printhead 1 is mounted on a cross member provided in the sheet feeder 20 or placed above the conveyor table 19, and can be positioned longitudinally and transversely to the scale flow S. In the sheet transport direction R, however, the position can be provided invariably.

The zero position of each of the incoming on the conveyor table 19 printed sheet is reproduced by a sensor 4, which is assigned in this case a drive element of a conveyor belt 9 of the conveyor table 19. However, the sensor 4 can also be assigned to the sheet feeder 20 and in particular the sheet separating device 23.

In operation, the inkjet printhead 1 is driven by a combination of the signals from the sensors 2 and 4. Thus, a numbering or coding on the exposed end of a printed sheet is then carried out when the sensor 2 reports the presence of a printed sheet and when the sensor 4 emits the zero position signal for the sheet transport. The zero position signal depends on the format length of the printed sheets and is adjusted to this format length when setting up a print job. This setting can be done automatically based on the format lengths known in the sheet-fed printing press 10.

Since the Unterschuppung is set in a sheet-fed press 10 in their length, the case occurs, from a certain larger format length is a multiple coverage of sheet. Then the double numbering or coding of the first printed sheet should be avoided. This can be done by metrological means or when setting up the sheet-fed press 10 by appropriate settings.

If so-called pre-sheet is used to set up a print job, a distinction should be made between the pre-sheet and the printed sheet as a supporting sheet in addition to the numbering or coding. The headers can be counted, but not printed with a numbering / coding. The support sheets are but - about the documentation. labeled with a numbering / coding, such as the order number and a date.

Furthermore, counter readings for pre-run and overlay sheets should be displayed. Furthermore, the support sheets can be counted and marked in each case after 500 sheets with a strip.

Therefore, as an alternative to the product sensor designed as a sensor 2, a color sensor for detecting differently colored flow sheet can be used.

Furthermore, a function for defining a plurality of features can be defined, which are linked to the output signal of the color sensor. For example, in the case of a white substrate, the corresponding printed sheet could be numbered / coded, whereas with a colored or red substrate, for example, a non-printing meter can be stored. Both counters are displayed on the print head controller 6.

For example, the dependence of the format length applies the following example of a specific sheet-fed press 10:
With a format length of up to 568 mm, a printed sheet is always printed once. From an arc length of 568 mm, an additional sensor can be used so as not to double-label the first printed sheet. In such a case, a manual preselection is possible. In order to remain flexible, however, an additional sensor should be installed, which is activated in formats from 568 mm in length. Double labeling of the first sheet should be avoided.

When an inkjet printhead 1 is provided with a paint supply cartridge system, this embodiment offers the user a great advantage ease of handling, the cartridges are easily replaceable and interchangeable, and moreover, is also a minimum cleaning effort, since the cartridges can be cleaned very easily and quickly.

In FIG. 4 the connection of the pressure-free printing device is shown. The inkjet printhead 1 is coupled to a control unit (printhead controller) 6, from which all the on / off, timing, duration, and print pattern control signals are output to the inkjet printhead 1.

The control unit 6 is also provided with input / output devices. There, the printing process can be enabled or disabled on the control unit 6. Furthermore, output data for printing can be displayed on the control unit 6, such as counter readings.

In the control unit 6, the printing patterns in the form of

Furthermore, the control unit 6 of the rotary encoder / rotary encoder 3 is assigned, which determines the conveying speed of the scale flow S respectively the individual sheets on the conveyor table 19 based on the speed of the / the conveyor belts 9. With this data, the synchronization of the printing operation of the inkjet printing head 1 is made at the speed of the sheet on the conveyor table 19.

The control unit 6 is connected to the control cabinet of the first of the printing units 12, for example for power supply and control technology coupling with the machine control. Therefore, the activation and blocking of the inkjet printhead 1 in the printing process can also take place via the machine control of the sheet-fed printing press 10. Furthermore, the data output for logging the printing process on the inkjet print head 1 can also take place via a control station of the sheet-fed printing press 10. Thus, print contents of the inkjet print head 1, counter readings to the processed printed sheet or information on the process status can be transferred from the control unit 6 to the machine control for display on the control desk or for further processing.

Furthermore, in this cabinet, an input / output device is arranged as a circuit board 5, to which the other devices are connected to the controller.

First, the sensor 2 is connected to the input / output board 5 as a product sensor for the presence of printed sheets.

Furthermore, the sensor 8 is connected to the input / output board 5 for a color detection of the present printed sheet.

Finally, the sensor can also be connected to the input / output board 5 as a sensor 4 for outputting zero or start signals or for detecting the scale position of the scale flow S passing through the conveyor table 19. For the activation of the printing process on the inkjet print head 1. The sensor 4 is referred to here as a sensor on the suction head, where he, as already stated, also be connected to sheet conveying means such as the conveyor table 19 and can work together.

Finally, an on / off switch 7 for the operation of the inkjet printhead 1 from the arm 14 is connected to the input / output board 5.

Upon connection or activation of the process for numbering or coding on the control unit 6, two basic queries for releasing the inkjet print head 1 for printing are carried out in connection with the general printing process.

At the sensor 2 as a product sensor is detected whether ever sheet present in the inkjet printhead 1. Another query takes place with regard to the time for numbering / coding. This time is determined by the sensor 4. The sensor 4 outputs a so-called single-turn signal, which defines in relation to the transport position of the sheet a cyclically recurring for each sheet zero or starting point. This zero or start point can be shifted as needed by adjusting the sensor 4 relative to the actual machine angle zero. It is shifted in practice so far that this single-speed signal is always output from the sensor 4, when the beginning of a free area of each of the printing sheets conveyed in the shingled stream S via the conveying table 19 is opposed to the inkjet printing head 1.

In the event the sensor 2 reports sheet and the sensor 4 reports the zero or start point, the inkjet printhead 1 is released and he prints the pattern defined in the control unit on the sheet.

If, as an alternative to the sensor 4, the detection of the shed position a sensor 8 is used for color detection, this can exert an additional blocking function. In the control can be provided that when recognizing certain colors of a sheet no numbering / coding or a differentiated other coding should be made or that an encoding example, should be made only on white sheet. The blocking function corresponds in effect to the function of the sensor 2, which detects the presence of printed sheets.

Functionally, this corresponds to a behavior according to which the sensor 8 for color detection simulates the absence of printed sheets and thus prevents printing of the inkjet print head 1.

Furthermore, when printing by means of the inkjet printhead 1, a speed adjustment is made, which serves to ensure that when the conveying speed of the imbricated stream S is changed, a good print image is always produced by the inkjet printhead 1. Therefore, the signal of the rotary encoder 3 for the speed of the conveyor belts 9 is switched directly to the print head control unit 6 and processed there.

Finally, the connection of the inkjet printhead 1 is also possible from the boom 14 of the sheet-fed printing press 10. At an on / off switch 7 on the control panel of the boom 14, the printer therefore, if desired, the function numbering / coding basically turn on when all machine functions are ensured and the printing process is set up ready.

Such a connection can also take place, for example, when a good-sheet counter is switched on, the latter - possibly in conjunction with a device for sheet inspection 24 - registering the production of salable printed sheets.

The device according to the invention can therefore be summarized in its function as follows:
The numbering / coding facility allows each sheet to be individually numbered, inscribed or encoded for internal documentation and sheet traceability.

An inkjet printhead 1 is integrated for this purpose above the conveyor table 19 of a sheet feeder 11 for a sheet-fed press 10.

The signatures are fed through the conveyor table 19 (e.g., suction belt table) below the inkjet printhead 1 in the usual scaling as a scale flow S. The inkjet printhead 1 is in the area in front of the so-called sheet system with acquisition by the pregripper 21 and is therefore not exposed to the acceleration of the sheet in the first printing unit 12. Thus, the accessible area of a scale length can be individually labeled at the end of the sheet of each sheet.

The inkjet printhead 1 can also be positioned format variable. This is in principle necessary only in one direction transverse to the sheet transport direction R in the sheet plane, since in the sheet transport direction R any of the format length dependent area for printing by the inkjet printhead 1 can be controlled by signal technology.

The positioning of the inkjet print head 1 transverse to the sheet travel direction R and parallel to the sheet plane can be done manually or automatically.

An automated positioning is carried out by means of an actuator which is driven from data that are recorded or read with respect to the sheet width in the order setting in the machine control.

The positioning may in this case also be coupled with an adjustment of the position of a page mark, the latter being associated with the sheet side edge of the printed sheet and being arranged in the sheet feed device 11 and / or an abutment sheet 22 arranged there.

In connection with an apparatus for sheet inspection 24, the printed sheet number can be displayed in the inspection error log. This means that every faulty sheet can be sorted out of the stack afterwards.

With regard to the speed and resolution of the inkjet print head 1, it can be noted in principle that high speeds are permissible and achievable for sheet-fed printing presses. At slower speeds, however, a higher resolution of the inkjet printing is possible and thus a better print quality can be achieved.

As print objects to be processed with the system, static and variable data come into consideration. Here, for example, dates, times, sheet counts, barcodes or 2D codes can be printed. But there are also any other codings possible.

The printing is usually monochrome and is to be matched with regard to the printing ink used on the substrate. The printing ink is written in cartridges written on the inkjet printhead 1.

The triggering of the inkjet printhead 1 for triggering the printing of the codes or numbering can be carried out starting from an activation of a good sheet counter or by manual operation or according to a predetermined production scheme or by automatic control after a monitored run a number of flow sheets.

Furthermore, the activation for controlling the printing process should also be dependent on the inkjet print head 1 being in a printing position in association with the conveyor table 19. Only in the printing position, the functionality of the sensors 2 and 8 for the control of printing by means of the inkjet printhead 1 can be effectively used.

The printing position of the inkjet printhead 1 can therefore be detected with a position detection sensor on the pivot arm 27 or the traverse 26 or on the inkjet printhead 1 itself. Is one of the sensors 2, 8 arranged in mechanical coupling together with the inkjet print head 1 in the sheet feeder 20, then the printing position can also be determined via the sensors 2 and / or 8.

The layout of the numbering / coding to be printed on the sheet can be easily created on any PC or even directly on the control unit 6 of the inkjet printhead 1.

When changing the format of the sheet after a job change, the inkjet printhead 1 must be positioned in the sheet plane transverse to the sheet transport direction R on to be printed areas of the scale flow S. This can initially be done manually by the inkjet print head 1 on a traverse or with appropriate, already mentioned above facilities for detecting sheet position and sheet format are also provided automatically controlled.

Regarding the position of the numbering / coding with respect to the format length, the position of the zero or start signal is to be reset. This adjustment is made by adjusting the signal point of the sensor 4 to the beginning of the free surface of each signature in the scale flow S, which results from the reference to the change in format length. Also, this setting can be automated because the necessary data for the sheet size, sheet position and location of the numbering / coding on the sheet before the start of printing are known.

As an additional option, a facility for reading database contents may be provided. In doing so, the type, content and location of the numbering / coding in a database can be stored with reference to certain products. Thus, these data can be transmitted to a sheet-fed printing machine 10 with an inkjet printhead 1 via a conveyor table 19 of the sheet feeder 11 and used there for setting.

This also includes procedural information regarding the adjustment of the inkjet printhead 1 to the substrate depending on its thickness. Furthermore, the settings related to the printing ink can be considered here which can be influenced depending on the printing material with regard to the type and amount of ink to be applied.

The inkjet printhead 1, in its setting to the scale flow S, the sheet may be formed so that it is placed on a sliding member in the manner of a carriage on the sheet surface. Thus, a constant distance of the inkjet printhead 1 is achieved to the surface of the sheet.

Since the conveying speed of the printed sheets can change when conveying the printed sheets via the conveyor table 19 to the sheet-fed printing press, preferably at least one characteristic curve is stored in the control unit 6 of the inkjet printing head 1, which depends on substrate parameters such as the grammage and / or the fiber direction and / or or the stiffness of the sheet is configured. The inkjet printhead 1 is then driven based on one of these characteristics. The characteristic curves are determined in advance for printed sheets from different substrates.

In the sheet-fed printing machine 10, a plurality of juxtaposed inkjet printheads 1 and seen in the transport direction of the sheet can be seen integrally arranged several inkjet printheads 1 arranged one behind the other and array or matrix-like associated with each other and preferably interconnected on the control side.

The number of inkjet printheads 1 required transversely to the printing direction is defined primarily by the desired total printing width relative to the given printing width of each inkjet printhead 1 used.

The required number of inkjet printheads 1 in the sheet transport direction R of the sheet is, however, determined by the fact that the desired printing speed is greater than the given maximum printing speed of a single inkjet printhead 1 and in that several inks on the sheets using the inkjet printheads 1 should be applied. Furthermore, the number of inkjet printheads 1 in the sheet transport direction R of the printing sheet defined by the desired print resolution in relation to the given print resolution of each individual inkjet printhead 1 used.

According to an advantageous development of the present invention, the or each inkjet printhead 1 is removable from the sheetfed press, in such a way that the or each inkjet printhead 1 can be used on a different sheetfed press or within the same sheetfed press at different mounting positions. For this purpose, the or each inkjet printhead 1 has a supply side, namely mechanical or printing ink side, and a control side, namely electrical or electronic, interface, via which the or each inkjet printhead 1 to an ink supply system and / or to a control device of respective sheet-fed press can be connected.

When viewed in the direction of transport of the printing sheet, the printing formless printing device can preferably be followed by a drying device or hardening device and / or a suction device, the drying device drying the ink applied via the inkjet printing head 1 and the suction device sucking solvent vapors out of the inkjet printing head 1 applied ink is used.

Furthermore, a camera 25 may be connected to the inkjet printhead 1, which is directed onto the print area downstream of the inkjet printhead 1 and previously swept by the inkjet printhead 1. By means of the camera 25 so the printed codes or numbering can be detected and identified. This ensures that each sheet to be processed is numbered or coded, that there are no gaps in numbering or coding, and that there are no duplicate numbering or coding in the sheet to be processed in sequence.

The inkjet printhead 1 is pivotally mounted in the region of the sheet feeder 20 or the conveyor table 19, preferably on a Schenkarm 27, the direct or via crossbar 28 on a side frame of the sheet feeder 20 or the first of the printing units 12 attacks. As a result, the conveyor table 19 and the sheet feeder 20 are freely accessible for setup and the inkjet printhead 1 can be easily moved and maintained.

The arrangement of an inkjet printhead 1 'can also take place in an association with respect to a lower side U of the conveyor table 19. Then, the inkjet printhead 1 'is directed toward the beginning of the sheet in the imbricated flow S successive sheet, since at the time of Unterschuppung the beginning of a sheet of a subsequent sheet is below the sheet end of the leading sheet. For printing the codings or numbering of the signatures by means of the inkjet print head 1 ', one or more openings 28 are then provided in the conveyor table 19. In the assignment to this area of the conveyor table 19 is the respective front sheet end of the sheet to the side of the pressure sheet conveying suction belts 9 relatively smooth on the conveyor table 19 and can be printed without further guide means of the inkjet printheads or 1. So that the coding or numbering is not polluted, it is immediately dried or passed over a conveyor track 29, which allows drying without the print pattern can smear.

The also required here detection of the sheet position for controlling a timely coding or numbering process by means of the inkjet or printheads 1 is carried out according to the in the embodiment for printing from the top O of the scale flow S on the conveyor table 19th

LIST OF REFERENCE NUMBERS

1

Inkjet printhead, laser printer (pressure-free printer)

2

Cartridge Holder

3

Sensor / product sensor (reflection light scanner, laser probe, color sensor)

4

Rotary encoder (measuring wheel with mounting on conveyor belt)

5

Sensor for pressure release

6

Input / output connection element (control cabinet first printing unit)

7

Control unit / printhead control

8th

Triggering inkjet print head from the boom; On / off switch

9

Sensor color recognition (on the printed sheet)

10

Conveyor belt (designed as a suction belt)

11

Sheetfed

12

sheet feeder

13

printing units

14

coating unit

15

boom

16

delivery pile

17

turning cylinder

18

installation position

19

installation position

20

Conveyor table (version here as suction belt table)

21

sheet feeder

22

pregrippers

23

conditioning sheet

24

Sheet separating device

25

sheet inspection

26

Camera (sheet inspection only for inkjet printhead)

27

traverse

28

swivel arm

29

opening

30

conveyor track

R

Sheet running direction

S

Shingled stream of printed sheet

O

top

U

bottom

Claims (10)

1. A sheet-fed printing press, comprising a sheet-feeding device (11) for introducing printed sheets that are to be printed into the sheet-fed printing press, comprising at least one printing unit (12) and/or coating unit (13) for printing the printed sheets with a static printed image, which is identical for all printed sheets, comprising a discharging mechanism (14) for discharging printed sheets that have been printed from the sheet-fed printing press, and comprising at least one printing form-free printing device (1), which is integrated into the sheet-fed printing press, which can be arranged in the region of the sheet-feeding device (11) at different positions (17, 18) for printing the printed sheets with a printed image, which is static or is variable from printed sheet to printed sheet,
   characterized in
   that the or each printing form-free printing device (1), in conjunction with a sheet feeder, which processes a shingled stream (S) of printed sheets, faces an underside (U) of a conveyor table (19), which transports the shingled stream (S),
   and that the or each printing form-free printing device (1) is assigned with its effective surface, which yields a pressurization, to one or a plurality of regions of the printed sheets, which are exposed to the bottom in the shingled stream (S) on the conveyor table (19).
2. The sheet-fed printing press according to claim 1, characterized in that a control device (6) is provided, which is connected to a sensor (2) for detecting the presence of printed sheets opposite to the printing form-free printing unit (1), and comprising a sensor (4) for detecting a production time for controlling the printing form-free printing device (1).
3. The sheet-fed printing press according to claim 1 or 2, characterized in that at least one characteristic curve, which is a function of printing material parameters, such as the sheet format and/or the sheet thickness and/or the grammage and/or the fiber direction and/or the stiffness of the printed sheets, is stored in a control device (6) of the printing form-free printing device (1), wherein the printing form-free printing device (1) can be controlled on the basis of these characteristic curves, wherein a data connection of the control device (6) for reading in job data from a control system of the sheet-fed printing press is provided.
4. The sheet-fed printing press according to one or a plurality of claims 1 to 3, characterized in that the or each printing form-free printing device is embodied as inkjet printhead (1) of laser printing device, wherein the inkjet printhead(s) or the laser printing device(s) are arranged to print the printed sheets in the shingled stream (S) across the entire exposed format width and/or exposed format length.
5. The sheet-fed printing press according to one or a plurality of claims 1 to 3, characterized in that the or each printing form-free printing device is embodied as inkjet printhead (1) or laser printing device, wherein the inkjet printhead(s) or the laser printing device(s) are arranged to print the printed sheets in the shingled stream (S) across the entire exposed format width and/or exposed format length, wherein the inkjet printhead(s) (1) or the laser printing device(s) are assigned to one or a plurality of openings (28) in the conveyor table (19), which release at least partial regions of the underside of the printed sheets resting on the conveyor table (19).
6. The sheet-fed printing press according to claim 4 or 5, characterized in that the or each printing format-free printing device has a plurality of inkjet printheads (1) or laser printing devices arranged next to one another viewed transversely to the transport direction of the printed sheets and/or a plurality of inkjet printheads (1) or laser printheads (1) arranged in a row viewed in the transport direction of the printed sheets, which are connected to one another on the control side.
7. The sheet-fed printing press according to one or a plurality of claims 1 to 6, characterized in that the or each printing device (1) can be disassembled from the sheet-fed printing press such that the or each printing device (1) can be used on a different sheet-fed printing press or within the same sheet-fed printing press at different installation positions.
8. The sheet-fed printing press according to one or a plurality of claims 1 to 7, characterized in that a drying device and/or a suction device is arranged downstream from the or each printing form-free printing device (1) viewed in the transport direction (R) of the printed sheets.
9. The sheet-fed printing press according to one or a plurality of claims 1 to 8, characterized in that the or each printing form-free printing device (1) is arranged to be pivotable with respect to the conveyor table (19) in the region of the sheet feeding device (11).
10. A method for operating a sheet-fed printing press, comprising a sheet feeding device (11) for introducing printed sheets that are to be printed into the sheet-fed printing press, comprising at least one printing unit (12) and/or coating unit (13) for printing the printed sheets with a static printed image, which is identical for all printed sheets, comprising a discharging mechanism (14) for discharging printed sheets that have been printed, from the sheet-fed printing press, and comprising at least one printing form-free printing device (1), which is integrated into the sheet-fed printing press, which can be arranged in the region of the sheet-feeding device (11) at different positions (17, 18) for printing the printed sheets with a printed image, which is static or is variable from printed sheet to printed sheet, characterized in
    that the or each printing form-free printing device (1) is activated manually or automatically to produce, wherein the or each printing device (1), in conjunction with a shingled sheet feeder, which processes a shingled stream (S) of printed sheets, is arranged below the conveyor table (19) transporting the shingled stream (S) and is assigned to the leading sheet ends of the printed sheets, which are exposed from below in the shingled stream (S),
    that the release of the print by means of the printing form-free printing device (1) then only takes place when a sensor (2, 8) reports the presence of printed sheets in the printing region and or the presence of printed sheets with the correct color in the printing region and
    when a sensor (4) reports a zero or starting point for the passage of each of the printed sheets, which can be adjusted as a function of the length of the printing format and
    wherein numbers/codes, which are imprinted by means of a device for the sheet inspection (24) provided on the sheet-fed printing press are displayed in an error log by means of the or each printing form-free printing device (1).

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