Sheet-processing machine with a sheet transport system

Abstract

Sheet-processing machine with a sheet transport system (03), wherein the sheet transport system (03) comprises a cross member (09) carrying grippers movable in the transport direction (T), wherein the cross member (09) is arranged across the width of the machine, wherein actuators which can be controlled independently of one another are provided on both sides of the cross member (09), and wherein both actuators are designed as piezo actuators (13), characterized in that a sheet system is provided with a feed table (01) with feed marks (02) and a sheet transport system (03) designed as an oscillating system (03), wherein the piezo actuators (13) are assigned to the oscillating system (03).

Description

The invention relates to a sheet processing machine having a sheet installation with a sheet transport system.To protect a sheet-fed printing press against mechanical damage and to ensure stable sheet running and printing operation, a plurality of system control devices arranged over the sheet width are currently provided in the system region. These control the leading edge of the arc at specific machine angles. As information, these provide, for example, a yes / no statement, i.e. whether the arc to the machine angle is there or not. A statement as to the distance between the sheets and the tailline is generally not determined. These system checks are usually reflex light barriers and are arranged basically below the printing material. These emit light which is reflected by the detected sheet.From DE 10 2006 050 740 A1 a device for driving a sheet-fed system is known, wherein a first and a second drive unit, each connected by means of an output member, are assigned to a swing arm, and wherein the output members can be driven ahead or behind one another within a working cycle. This device is very large in size.DE 103 58 171 A1 discloses a device for conveying a sheet through a printing machine, wherein there is a possibility for changing the position of the rear edge of the sheets with respect to the front edge by means of piezoelectric actuators which are arranged on both sides between a suction gripper bridge and holders of the suction gripper bridge on an axis.DE 10 2005 046 097 A1 discloses a movable gripper bridge, wherein gripper systems can be controlled alternatively to a mechanical solution by computer-controlled linear motors or actuators, such as voice coil systems, piezoelectric, magnetostrictive, hydraulic or similar systems.The object of the invention is to provide an alternative sheet processing machine, in particular an alternative sheet installation with a sheet transport system. In particular, the position of the leading edge of the sheet should also be determined exactly.The object is achieved according to the invention by a device having the features of claim 1. Advantageous embodiments are evident from the dependent claims, the description and the drawings.The advantages which can be achieved with the invention consist in particular in that an alternative sheet-processing machine, in particular an alternative sheet system with a sheet transport system, is created. In particular, the position of the leading edge of the sheet is also determined exactly.It is particularly advantageous to correct the sheet or paper in the gripper in the oscillating unit and / or the feed drum in a sheet unit as a function of the position of the leading edge of the sheet. This makes it possible to improve the accuracy of the system passenger and thus the print quality of a sheet-fed printing press.An exemplary embodiment of the invention is illustrated in the drawings and is described in more detail below.The following are shown: FIG. 1 shows a sheet installation of a sheet-processing machine with a swing gripper; FIG. 2 shows a piezoelectric actuator for displacing the grippers of the oscillator shaft.FIG. 1 shows, for example, a section of a sheet system of a sheet-processing machine, in particular of a sheet-fed printing press, in this case specifically of a sheet-fed offset rotary printing press, preferably of aggregate and series construction. The sheet-forming system includes, among other things, a feed table 01 with feed marks 02, a vibrating system 03 and a feed drum 04 arranged downstream thereof, which is connected, for example, to a printing cylinder 05 of a first printing unit of the machine. The oscillator 03 has an oscillator 06 which is mounted on an oscillator shaft 07. The oscillator 06 preferably comprises a plurality of connecting webs 08. The connecting webs 08 can be connected to the oscillator shaft 07 in a rotationally fixed manner and arranged at a distance from one another over the machine width. The connecting webs 08 preferably delimit the oscillator 06 laterally. The connecting webs 08 receive a gripper shaft 09, which can be pivoted by means not shown. Gripper fingers are clamped on the gripper shaft 09 at a distance from one another, which correspond to gripper impacts. The gripper impacts are assigned, for example, to a gripper impact strip which is connected to the connecting webs 08. The oscillator shaft 07 is rotatably and preferably minimally translationally displaceable by a piezoelectric actuator, not shown, in particular accommodated in machine side walls.Drive units, not shown, implement a movement profile and a speed profile of the vibration system 03. In this case, within a working cycle which corresponds to the machine cycle, the oscillator 06 is moved in the direction of the application table 01. In a reversal or latching position, the oscillator 06 takes over a sheet aligned to the front edge of the feed marks 02 pivoted against the feed table 01 by guiding the gripper fingers against the gripper impacts and transports the sheet in the transport direction T to the following feed drum 04. For this purpose, the oscillator 06 is accelerated in such a way that the speed of the grippers is equal to the speed of a gripper system assigned to the feed drum 04. After the sheet transfer, the vibrator 06 is decelerated and, after passing through a further reversal position, is returned to the placing table 01. In this case, the oscillator 06 is accelerated in order to be decelerated again before entering the reversal position on the application table 01.The slip marks 02 preferably have cover marks oriented counter to a transport direction T and projecting beyond an applied sheet leading edge. Furthermore, a not-shown measuring device is provided for detecting the position of the leading edge of a sheet located on the placement table 01, which is connected to a control device, in particular the machine controller. Preferably, a transmitted light-based measuring method is applied to the application table 01. Preferably, a miniaraised transmitted light measuring device is used which is partly integrated in the cover mark or in the gripper of the oscillating system 03. This can be both the transmitter and the receiver. This transmitted light measurement principle permits an exact position determination of the sheet leading edge.Particularly preferably, a photosensor can be installed in the cover mark. On the opposite side, i.e. in the placement table 01 and / or the front mark or placement mark 02, the light source, for example an LED, is then located. Alternatively, the arrangement of photosensor and light source is also possible in the opposite sense. The front edge of the sheet influences the light transmitted from the light source to the photosensor. The intensity of the incoming light is then the measure of the position of the front edge of the sheet. Thus, the sheet being drawn does not interfere with the measuring operation. For example, the integration of the measuring device takes place in the moving cover mark or in the mark transmission. However, other measuring methods to be integrated into the trademarked transmission are also possible, for example a CCD line. The integration of the measuring device into the oscillation system 03 is also possible. This eliminates the covering action of the peeling sheet.If the measuring device is activated and if the position of the leading edge of the sheet placed on the slip marks 02 is detected by the latter, in the case of a position of the leading edge which is defective, the latter can be corrected before the transfer to the gripper system of the slip drum 04. For this purpose, the actual position of the leading edge applied to the slip marks 02 is detected by the measuring device, an actual value characterizing the actual position is generated and this is supplied to the control device, in particular machine control, for evaluation. If the actual value does not correspond to a setpoint value stored in the control device, which characterizes the setpoint position, a setpoint value is determined and a control command is output to one or both piezoelectric actuators for adjusting the oscillation system 03, for example the oscillator 06, after sheet transfer. By independently actuating one or both piezoelectric actuators, the gripper shaft 09 is inclined with the gripper fingers together with the gripper impact strip carrying the gripper impacts. In this case, an inclination is effected to such an extent that the desired position of the sheet held by the grippers with respect to the front edge can be realized and thus transferred to the gripper system of the feed drum 04. After the transfer of the sheet to the feed drum 04, the piezoelectric actuators and thus also the gripper shaft 09 with the grippers are returned to their initial position for the acceptance of a subsequent sheet.FIG. 2 shows the functional principle of an adjustable stop for the correction of the sheet or paper in the gripper of the oscillating unit 03. Preferably, at a frame point such as on the support table 01 or contact box, an adjustable stop bolt 10 is provided for the oscillating system 03, which is supported in the frame 11 for example via an abutment 12. Between the abutment 12 and the stop bolt 10 at least one piezoelectric element 13 is arranged as a piezoelectric actuator, which is connected to the control device, in particular the machine control, and can be controlled by the latter. The stop bolt 10 is held by a spring element 14 in contact with the piezoelectric element 13. The one or more piezoelectric elements 13 are arranged and designed for displacement and thus for adjusting the stop bolt 10. The stop bolt 10 interacts with the oscillating system 03 for translatory displacement. In particular, the piezoelectric element 13 acts on the bearing of the vibrator 06, in particular the vibrator shaft 07. The translatory movement of the oscillator mounting can be, for example, up to 0.2 mm, in particular up to 0.1 mm. The piezoelectric actuator or the piezoelectric element or elements 13 on the opposite machine side can be designed identically or functionally identical.As regards its mode of operation: An exact position determination of the sheet leading edge can take place over the entire region from the contact of the sheet to the gripper closure of the oscillating contact 03. The determined measured values of the sheet position are used to regulate mechanical setting values for the further sheet travel. The result from the determination of the position of the sheet leading edge, in particular by the measuring device integrated into the cover mark, is preferably used to influence the sheet section or the quantity of paper in the oscillating system 03 arranged downstream in such a way that the sheet section or the quantity of paper on the first printing cylinder 05 is constant independently of the position of the sheet leading edge with respect to the feed line.Regulation can be effected in particular by means of the adjustable stop bolts 10 for the oscillating system 03 in their position on the placement table 01 on the operating side and the drive side of the machine. During the sheet travel, the measurement marks preferably determine the position of each sheet leading edge on the drive side and the operating side and that particularly preferably directly before the gripper closure of the oscillating system 03. In accordance with the position determined by the control device, in particular the machine control, the stop bolt 10 on the drive side and / or the operating side is adjusted by the piezoelectric elements 13, so that the oscillating system 03 thereby holds more or less sheets or paper. A piezoelectric element 13 has, in particular, a very fast reaction time, for example approximately 1 ms. This adjustment makes it possible to minimize the scattering of the sheet or paper in the gripper in the first printing cylinder 05 and thus also in the cylinders following it. In principle, an adjustment range of approximately 0.1 mm to 0.2 mm of paper change in the oscillating unit 03 can be achieved. The oscillating system 03 can be adjusted both parallel and on one side with respect to the feed line during the course of the sheet.List of reference characters01 Placing table 02 Placing mark 03 Vibrating system 04 Placing drum 05 Pressure cylinder 06 Vibrator 07 Vibrator shaft 08 Connecting web 09 Gripper shaft 10 Stop bolt 11 Frame 12 Abutment 13 Piezoelectric element 14 Spring element T Transport direction

Claims

Sheet-processing machine having a sheet transport system (03), wherein the sheet transport system (03) comprises a cross-member (09) carrying grippers movable in the transport direction (T), wherein the cross-member (09) is arranged over the width of the machine, wherein actuators which can be controlled independently of one another are provided on both sides of the cross-member (09), and wherein both actuators are designed as piezoelectric actuators (13), characterized in that a sheet contact is provided having a contact table (01) with contact marks (02) and a sheet transport system (03) designed as an oscillating contact (03), wherein the piezoelectric actuators (13) are assigned to the oscillating contact (03).Sheet processing machine according to claim 1, wherein the piezoelectric actuators (13) are assigned to a vibrator shaft (07) of the vibration system (03).Sheet processing machine according to claim 1 or 2, wherein the piezoelectric actuators (13) are arranged and configured for the translatory displacement of a bearing of an oscillator shaft (07) of the oscillator system (03) relative to a frame (11) of the arc system.Sheet processing machine according to claim 1, 2 or 3, wherein a control device for actuating the piezoelectric actuators (13) is provided independently of one another, wherein the control device is connected to a measuring device in the sheet system and wherein the measuring device operates according to the transmitted light measuring principle.Sheet processing machine according to claim 1, 2, 3 or 4, wherein one or the control device is connected to a measuring device arranged in a registration mark of a slip mark (02) of the sheet installation.Sheet processing machine according to claim 1, 2, 3, 4 or 5, wherein the piezoelectric actuators (13) are designed as a displacement path of up to 0.1 mm or piezoelectric elements (13) executing up to 0.2 mm.Sheet-processing machine according to Claim 1, 2, 3, 4, 5 or 6, wherein a piezoactuator (13) is supported on the frame (11) of the sheet contact by means of an abutment (12) and interacts with a displaceable stop bolt (10).Sheet-processing machine according to Claim 1, 2, 3, 4, 5, 6 or 7, wherein a piezoactuator (13) is connected to one or to the stop bolt (10), and the stop bolt (10) is held in contact with the piezoactuator (13) by a spring element (14).Sheet processing machine according to Claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein the sheet installation has a feed drum (04), which is connected to a printing cylinder (05) of a printing unit arranged downstream of the sheet installation.

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