EP0668161A1 - Device for transferring individual sheets to the printing cylinder of a rotary sheet printing press - Google Patents

Abstract

The transfer devices has sheet grippers (4) installed on the on the transfer cylinder (2) which have a front stop for the arriving sheets and are adjustable by a controllable positioning device (9,15) during each rotation of the transfer cylinder. The front stop on passing the transfer position, in which a sheet is transferred to the print cylinder, adopts a position through which the exact register of this sheet relative to the position of the printing plate printing it on the plate cylinder is adjusted. The sheet grippers are mounted on a positioning plate (3) located movably on the transfer cylinder and at each end of this plate an individually controllable positioning device (9,13,15) engages.

Description

The invention relates to a device for transferring individual sheets to the printing cylinder of a sheet-fed rotary printing press according to the preamble of patent claim 1.

Such a device is known from EP-A-0 467 832 by the same applicant. This device allows the position of a sheet during the transfer to the printing cylinder to be automatically adjusted to the position of the printing plate printing on it and fastened to the plate cylinder. This eliminates the need to adjust the printing plates themselves when they are clamped onto the plate cylinder at exactly the same angular intervals, which is tedious and time-consuming. Deviations from the actual exact mounting position of the printing plates are corrected in the device mentioned by the automatic adjustment of the arches on the transfer cylinder.

The conventional sheet transfer devices had in common that the incoming sheets are transferred to the printing cylinder in exactly the same rhythm, whereby the transfer point of the transfer cylinder at which the leading edge of the sheet is taken over by the grippers of the printing cylinder is always the same. In order to ensure that the distance between the front edge of the sheet and the start of printing, i.e. the free front edge of the sheet, is always the same width when printing on the sheets, care must be taken when attaching the printing plates to the plate cylinder that all printing plates are attached at exactly the same distance , that means an exact angular distance for a plate cylinder with two, three or four pressure plates of 180 °, 120 ° or 90 °. The condition that all printed sheets must have a front margin of the same size is particularly important in the case of security printing, particularly in the case of banknote printing, in which the sheets have a number of security prints arranged in rows and columns and are subsequently cut into individual security notes. Different widths of the front edges of the sheet, the front edge of which serves as the reference edge when cutting, therefore result in incorrect centering of the notes of value and thus in rejects.

With the known device according to EP-A-0 467 832 described at the outset, however, only a correction of the bow position in one or the other circumferential direction can be carried out, but the bow cannot possibly be set somewhat obliquely to the circumferential direction if a correspondingly oblique fastening position of the Printing plate on the plate cylinder that would require. This means that when the printing plates are attached to the plate cylinder, it is not important to have exactly the same angular spacing, but that the printing plates, whose front edges must be aligned exactly parallel to the axis of the plate cylinder, are exactly aligned with the axis.

The limitation of the adjustment possibilities in the known device to a parallel displacement of the sheets in the circumferential direction is based on the fact that the transfer cylinder has a drum that is adjustable in the circumferential direction relative to its shaft, on which the sheet rests, so that a rotation of the sheet obliquely to the circumferential direction this device is not possible.

The present invention has for its object to improve the known device of the type described in such a way that not only an adjustment of the arc in the circumferential direction, but also an adjustment of the arc somewhat obliquely to the circumferential direction is possible, in order thereby a possible inclination of the Plate cylinder attached printing plates to take into account. In addition, the structure of the device is to be simplified.

This object is achieved according to the invention by the features specified in the characterizing part of patent claim 1.

Since each of the two ends of the movably mounted positioning plate can be individually adjusted by a predeterminable amount during each revolution of the transfer cylinder, not only a displacement of an arc in the circumferential direction but also a rotation into an inclined position is made possible in a simple manner, namely when the two ends of the Base plate can be adjusted by different amounts. All that is needed is the movably mounted positioning plate with the sheet grippers and not, as in the known device, an entire drum to be adjusted relative to the cylinder shaft.

A preferred embodiment is described in claims 2 and 3.

Further expedient refinements, in particular a preferred embodiment of the control devices actuating the two actuating devices, result from the other dependent claims.

• Figur 1 die Anordnung des Uebergabezylinders am Druckzylinder einer Druckmaschine in der Bogenübernahmestellung und
• Figur 2 in der Bogenübergabestellung, wobei alle Einzelheiten des Uebergabezylinders und die Stelleinrichtungen fortgelassen wurden,
• Figur 3 eine schematische Darstellung der Anordnung nach Figur 1 in verkleinertem Masstab zusammen mit dem Plattenzylinder, der mit dem Druckzylinder zusammenwirkt,
• Figur 4 eine schematische Darstellung des im Axialschnitt gezeigten Uebergabezylinders, der Stelleinrichtungen und der Steuervorrichtungen, und
• Figur 5 eine schematische Darstellung in Richtung des Pfeils F nach Figur 4 und zwar in der Nullstellung und, strichpunktiert, in der maximal ausgelenkten Stellung des einen Stellgliedes, wobei zur besseren Verdeutlichung der Stelleinrichtung der Uebergabezylinder grösser als in Figur 4 gezeichnet wurde.

The invention is explained in more detail with reference to the drawings using an exemplary embodiment. Show it :

• Figure 1 shows the arrangement of the transfer cylinder on the printing cylinder of a printing press in the sheet transfer position and
• FIG. 2 in the sheet transfer position, all details of the transfer cylinder and the actuating devices having been omitted,
• FIG. 3 shows a schematic illustration of the arrangement according to FIG. 1 on a reduced scale together with the plate cylinder, which cooperates with the printing cylinder,
• Figure 4 is a schematic representation of the transfer cylinder shown in axial section, the actuators and the control devices, and
• Figure 5 is a schematic representation in the direction of arrow F of Figure 4, namely in the zero position and, dash-dotted, in the maximum deflected position of one actuator, the transfer cylinder being drawn larger than in Figure 4 for better clarification of the actuating device.

According to FIGS. 1 to 3, the transfer cylinder 2 of the device is arranged between a feed roller S and the printing cylinder D of a rotary printing press, in particular an intaglio printing press, the plate cylinder P (FIG. 3) of which cooperates with the printing cylinder D in a known manner. The directions of rotation of all cylinders are indicated by arrows in FIGS. 1 to 3.

The plate cylinder P has at least two printing plates, generally N printing plates, N being greater than 1. In the example considered, the plate cylinder P has four pressure plates, which are mounted at an angular distance of approximately 90 °, that is, they do not necessarily have to be adjusted to a fraction of a millimeter exactly at a 90 ° distance, and which may also have deviations from the parallelism of the axes. In Figure 3 are the four printing segments of the printing cylinder D and the plate cylinder P are indicated.

The sheets B are moved one after the other by the feed roller S over a schematically indicated feed table T and placed on the transfer cylinder 2, each incoming sheet being conveyed against the front stop 4a of the sheet grippers 4 articulated on the transfer cylinder 2 and from there to the transfer to the printing cylinder D is taken. The feed roller S can in particular be a known suction roller driven at a non-uniform speed. In the illustration according to FIG. 1, an incoming sheet B is just being picked up by the sheet grippers 4, and in the illustration according to FIG. 2 the front edge of the sheet B is transferred from the transfer cylinder 2 to the sheet grippers G2 of the printing cylinder D.

The transfer cylinder 2 carries out one revolution of the plate cylinder N revolutions, in the example considered four revolutions, and has a diameter which is 1 / N of the diameter of the plate cylinder P, in the example considered a quarter of this diameter. With each revolution, the transfer cylinder 2 conveys an arc.

In the example under consideration, the impression cylinder D and the plate cylinder P are of the same size, and the impression cylinder D, since there are four printing plates, has four printing segments covered with blankets and sheet grippers in front of each blanket, of which the grippers G1 in FIG. 1 and the ones in FIG Grippers G2 can be seen.

In the area of the feed roller S there is usually also a known front mark, not shown here, which serves to align an incoming sheet B and is then pivoted downward so that this sheet can be conveyed onto the transfer cylinder 2.

According to Figures 4 and 5, on which the feed roller S, system table T and pressure cylinder D are not shown, the transfer cylinder 2 with its shaft 1 is rotatably mounted in the machine frame 30 and is fixed by a shaft 32 on this shaft 1, which in the pressure cylinder - Gear engages, driven by the pressure cylinder at a uniform speed. The transfer cylinder 2 thus executes four revolutions when the plate cylinder P makes one full revolution. Since the impression cylinder D has the same diameter as the plate cylinder P, as is usually the case, this naturally corresponds to one revolution of the impression cylinder D. In principle, however, the impression cylinder can also have a different diameter than the plate cylinder, in particular a smaller diameter, the impression cylinder for example, can be exactly as large as the transfer cylinder.

The sheet grippers 4, which cooperate with a gripper or sheet support 4 ', are adjustably arranged on the transfer cylinder 2 for the respective adjustment of the position of the incoming sheets. For this purpose, the sheet grippers 4 are mounted on a positioning plate 3 which is movably mounted in the two side walls 5 and 6 of the transfer cylinder 2. For this purpose, the setting plate 3 has guide projections 3a and 3b at its two ends, which engage in guide slots 5b and 6b of the side walls 5 and 6. On these side walls 5 and 6 roller levers 9 and 10 are articulated, which in bearings 5a and 6a of these side walls are pivotable about axes parallel to shaft 1. These roller levers are provided with drivers 11 and 12 at their ends projecting into the transfer cylinder 2 and with rollers 13 and 14 at their other ends.

The drivers 11 and 12 engage between two stop parts 7 and 8 fastened to the setting plate 3, which run essentially parallel to the shaft 1 and lie opposite one another in the circumferential direction of the transfer cylinder 2. These stop parts 7 and 8 serve as a play-free guide for the drivers 11 and 12. The rollers 13 and 14 each engage in an annular guideway 15c or 16c, which is formed by two annular projections 15a, 15b and 16a, 16b, which are concentric with one another Actuator 15 or 16 is formed on one or the other side and surrounds the shaft 1. The two actuators 15 and 16 are each pivotably suspended by a pin 17 or 18 fastened to the device frame 30 above the shaft 1, so that they can be tilted about an axis lying parallel to the shaft 1. The arrangement is such that the rollers 13 and 14 can roll without play when the transfer cylinder 2 rotates in the annular guideways 15c and 16c.

With the help of the control devices described below, the actuators 15 and 16 can be pivoted individually about the pins 17 and 18 in a plane oriented perpendicular to the shaft 1, as a result of which, as explained below, the actuating plate 3 with its arc grippers 4 parallel to the body of the transfer cylinder 2 can be adjusted to the circumferential direction thereof or also in a position oriented obliquely to the circumferential direction.

Each of the actuators 15 and 16 has its own control device. Both control devices are constructed identically and each have a lever arm 19 or 20, which is attached to the area of the actuator 15 or 16 facing away from the pin 17 or 18. As shown in FIG. 4, the lever arm 19 is fastened with as many individually adjustable stops 19a to 19d as there are pressure plates on the plate cylinder, that is, four adjustable stops in the example considered. The individually adjustable stops 20a to 20d are correspondingly provided on the lever arm 20.

In Figure 4, the lever arms 19 and 20 are shown with their stops, for clarity, compared to their actual position, which is shown in Figure 5, rotated by 90 ° down. These stops 19a to 19d or 20a to 20d lie side by side and can interact with a control cam in the form of a cam 24a to 24d or 25a to 25d. All cams are seated on the shaft 23 which is rotatably mounted in the device frame 30 and have the shape of segments which each extend over an angle of approximately 360 ° / N, that is to say in the example considered, approximately 90 °. The angular distance between adjacent cams is 360 ° / N, in the example considered 90 °, so that during a quarter turn of the shaft 23, for example, the cam 24a or 25a can act on the stop 19a or 20a, while the other cams 19b to 19d or 20b to 20d are ineffective; in the following quarter rotation of the shaft 23, the cam 24b or 25b can then act on the stop 19b or 20b while the other cams are ineffective, etc.

The arrangement is such that the shaft 23 executes a quarter turn with the cams during a full rotation of the transfer cylinder 2. For this purpose, a gear 27 is attached to one end of the shaft 23, the diameter of which is four times as large as a gear 31 on the shaft 1 and is driven by this gear 31 by means of a toothed belt 26. In general, the shaft 23 executes 1 / N revolutions with the cams during a full revolution of the transfer cylinder.

The lever arm 19 with its stops 19a to 19d is, as shown in FIG. 5, by a tension spring 21 attached to the lever end, the other end of which is attached to the frame 30, in the direction of the cams 24a to 24d or in the direction of a fixed stop 22 drawn, which is attached to the frame 30. In the position shown in solid lines in FIG. 5, the lever arm 19 bears against the fixed stop 22 under the action of the spring 21, since all adjustable stops 19a to 19d assume a position which is sufficiently far from the cams 24a to 24d. This position of the lever arm 19 with the actuator 15 is referred to as the zero position, in which the annular guideway 15c is concentric with the axis 1 of the transfer cylinder 2.

5, the stop 19a assumes the position 15a '. In this position, it is adjusted so far in the direction of the cam 24a assigned to it that this cam pushes against this stop as it passes through its active position and pushes it back so far that the lever arm 19 with its actuator 15 relative to the zero position around the pin 17th is pivoted counterclockwise against the action of the spring 21. This dot-dash position should represent the maximum deflection.

The above description applies in the same way to the arrangement and function of the other actuator 16 with its lever arm 20, for which a corresponding tension spring and a corresponding fixed stop are provided, and for the interaction of the stops 20a to 20d with the cams 25a to 25d. Since the control of the two actuators 15 and 16 is independent of one another, one actuator can assume its zero position, while the other actuator is pivoted more or less from its zero position.

With each full revolution of the transfer cylinder 2, the actuators 15 and 16 are either left in their zero position or according to a predetermined program, which is defined by the individual setting of the adjustable stops 19a to 19d and 20a to 20d, or else around the fixed pin 17 or 18 adjusts, depending on whether or not a cam 24a to 24d or 25a to 25d pushes back the assigned adjustable stop 19a to 19d or 20a to 20d by a more or less large amount when it passes its effective position.

What is important is the position of the setting plate 3 at the moment in which the front edge of a sheet located on the transfer cylinder 2 is transferred to the sheet grippers of the printing cylinder D by opening the sheet grippers 4, as shown in FIG. The position of the sheet at this point in time determines the later registration-based adaptation of this sheet to the relevant printing plate of the plate cylinder. It is assumed in the following that the two positions shown in FIG. 5 are these positions when the sheet is transferred.

The zero position is selected such that any correction to the position of the arc need only be made in one circumferential direction. The maximum possible deflection is adapted to the size of the tolerance of the plate fastening, that is to say the experience of maximum inaccuracy when fastening the plates to the plate cylinder.

In the position of the transfer cylinder in which its sheet grippers 4 take over an incoming sheet, the actuators 15 and 16 and thus these sheet grippers are always in the zero position. If no correction of the bow position is required, the stop in question is set so that it is not touched by the cam in question. Therefore, when a sheet is transferred from transfer cylinder 2 to impression cylinder D, both actuators 15 and 16 remain in their rest position, as shown in solid lines in FIG. 5 for lever arm 19 with actuator 15, and guideways 15c and 16c are concentric with the cylinder axis 1. Therefore, there is no displacement of the setting plate 3 with the sheet grippers 4, and the sheet is not displaced on the transfer cylinder 2.

It is assumed that the following sheet must be shifted into a position inclined to the circumferential direction in order to correct the position, namely to the maximum inclined position. For this purpose, the following adjustable stop 19b is shifted in the direction of the cams by the maximum possible amount, as is shown in broken lines for the position 19a 'of the stop 19a in FIG. After the transfer cylinder 2 has made a full revolution and therefore the camshaft 23 a quarter revolution, the following cam 24b assumes its working position and causes one by pushing back the stop 19b maximum deflection of the lever arm 19 with the actuator 15. The other actuator 16, as will be assumed, remains in its zero position. Due to the deflection of the actuator 15, its guide path 15c is pivoted eccentrically to the cylinder axis 1 in the illustration according to FIG. 5 to the left. As a result, the setting plate 3 with the sheet grippers 4 is displaced in its one circumferential direction at its left end according to FIG. Therefore, the sheet transferred to the printing cylinder D has an inclined position which corresponds to the corresponding inclined position of the printing plate on the plate cylinder.

In an analogous manner, of course, by appropriately adjusting one of the stops 20a to 20d on the other side, the guideway 16c and thus the other end of the adjusting plate 3 can be displaced, so that the sheet is displaced obliquely in the other direction.

If the corresponding stops 19a and 20a, 19b and 20b etc. are adjusted by the same amount on both sides and are therefore pushed back by the same amount by the cams 24a and 25a or 24b and 25b etc. assigned to them, then this means that that the two actuators 15 and 16 are adjusted by the roller levers 13 and 14 by exactly the same amount in the same circumferential direction. This results in a pure parallel shift of the arch. Only if the two ends of the adjusting plate 3 are adjusted by different amounts due to different settings of the simultaneously effective stops 19a and 20a, 19b and 20b, etc., does this correspond to the adjustment of the arc in question into an inclined position.

The stops 19a to 19d and 20a to 20d individually adjusted so that each time the transfer cylinder is rotated, the position of the positioning plate 3 and thus the position of the sheet are individually corrected such that this sheet assumes the position required to achieve a perfect print register when the sheet is transferred to the impression cylinder. In this way, all sheets have a constant margin width between the leading edge and the start of printing after printing.

This individual setting of the stops 19a to 19d or 20a to 20d takes place in the example under consideration by the schematically illustrated adjusting screws 28a to 28d or 29a to 29d.

Such an adjustment of the stops can either take place before the start of the printing operation due to some test prints by hand, for example by means of the schematically illustrated adjusting screws, or servomotors are provided for this purpose, one of which is assigned to an adjustable stop. These servomotors are either operated by pressing a button on a control panel or are controlled as a function of the register deviations measured automatically by reading register marks. In the case of unprinted sheets, the register marks applied during printing are used for this purpose, the reading of which corrects the positions of the subsequent sheets. If the incoming sheets already have a first print, for example a background, then register marks applied in the first printing unit can be used for automatic register correction.

In general, it is sufficient to provide a maximum displacement of the adjusting plate 3 with respect to the transfer cylinder 2 of, for example, two millimeters, because the adjustment of the printing plates on the plate cylinder with a tolerance of at most two Millimeters is possible without difficulty or a lot of time.

The device according to the invention is not limited to the exemplary embodiment described, but rather permits a variety of constructive embodiments.

Claims (6)

Device for transferring individual sheets to the printing cylinder (D) of a sheet-fed rotary printing press, which has a plate cylinder (P) provided with N printing plates, N being an integer greater than 1, with a transfer cylinder (2) interacting with the printing cylinder (D), whose diameter is 1 / N of the diameter of the plate cylinder (P) and which makes N revolutions when the plate cylinder (P) makes one revolution, with sheet grippers (4) installed on the transfer cylinder (2), which have a front stop (4a) for the Arriving arches (B) and which are adjustable by a controllable adjusting device (9, 10, 15, 16) during each revolution of the transfer cylinder (2) such that the front stop (4a) when passing the transfer position, in which a sheet to the Printing cylinder (D) is passed, takes a position by which the exact register of this sheet with respect to the position of the printing plate printing on the plate ylinder (P) is set, characterized in that the sheet grippers (4) are mounted on a positioning plate (3) which is movably mounted on the transfer cylinder (2) and that at each end of this positioning plate (3) there is an individually controllable adjusting device (9, 11, 13, 15; 10, 12, 14, 16) which, with each revolution of the transfer cylinder (2), moves the relevant end of the positioning plate (3) by a predeterminable amount in the circumferential direction of the transfer cylinder (2) relative to the latter. Device according to claim 1, characterized in that each of the two actuating devices has an actuator (15; 16) which is arranged on the side of the transfer cylinder (2) and which extends around a fixed pin (17; 18) above the axis (1) of the transfer cylinder (2) is pivotally suspended in a plane oriented perpendicular to this axis, that this actuator (15; 16) has an annular guideway (15c, 16c) surrounding the axis (1) of the transfer cylinder (2) and that in each side wall ( 5; 6) of the transfer cylinder (2) each has a roller lever (9; 10) which is pivotally mounted, one end (13; 14) of which is guided in the aforementioned annular guide path (15c, 16c) without play when the transfer cylinder (2) rotates and the other end (11; 12) of which is set up to displace the relevant end of the positioning plate (3) when the aforementioned guideway is in an eccentric position with respect to the axis (1) of the transfer cylinder (2). Apparatus according to claim 2, characterized in that said roller lever (9; 10) is pivotable about an axis oriented parallel to the axis (1) of the transfer cylinder (2) in the side wall (5; 6) of this transfer cylinder and that this is on the setting plate (3) acting end of this roller lever is a driver (11; 12) which interacts with stop parts (7; 8) attached to the positioning plate (3) and used as a play-free guide. Device according to one of claims 2 or 3, characterized in that each actuator (15; 16) can be pressed under the action of a spring (21) against a fixed stop (22) which defines a zero position of this actuator. Device according to one of claims 2 to 4, characterized in that a lever arm (19; 20) is attached to each actuator (15; 16), on which N stops (19a to 19d; 20a to 20d) are arranged side by side, which individually can be adjusted by adjusting devices (28a to 28d; 29a to 29d), and that these adjustable stops with N cams (24a up to 24d; 25a to 25d) can cooperate, which are fastened on a common shaft (23) next to one another, opposite the relevant stops, and at an angular distance of 360 ° / N, the shaft (23) supporting the cams being rotated one full revolution of the transfer cylinder (2 ) Executes 1 / N revolution. Apparatus according to claim 5, characterized in that the individually adjustable stops (19a to 19d; 20a to 20d) are adjustable by means of adjusting screws (28a to 28d; 29a to 29d) or by means of servomotors which can be switched on manually or as a function of reading automatically register deviations measured by register marks are controllable.

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