DE2836098A1 - Offset printing press sheet insertion mechanism - has grips in cylinder trough interchangeable via slots in guide plate - Google Patents

Abstract

The mechanism gives accurate insertion of sheets in a rubber-to-rubber rotary offset printing press printing on both sides, having side and front stops and a guide plate from the latter ending shortly before the printing zone and in the tangental direction of this zone. A grip mechanism is accommodated in the trough of one rubber cylinder. The grip mechanism (11) moves in the trough (8) in such a manner in relation to the rubber cylinder (4) that the grips are interchangeable via slots in the guide plate (23), so as to engage with a sheet (18) when this is precisely in the rest position against the front stop (17), the grip supports (31) being roughly at the level of the sheet table (12). As the grips re-accelerate to the cylinder peripheral speed and simultaneously retract to the level of the periphery, they are guided so as to follow the line of the guide plate, their supports being at the level of the latter or above it.

Description

The invention relates to a convertible perfecting printing - sheet

offset rotary printing machine with a rubber-on-rubber printing unit and for such a machine a device for the precisely fitting insertion of those to be printed Sheet from the rest position into the perfecting printing unit.

For some years now, so-called beautiful and Reprint - machines prevailed. Such machines make it possible to print a sheet optionally only on one side or in one machine pass at the same time also to be provided with a back print, the so-called reverse print. Economic Reasons have been decisive for the success of these machines.

Are for example in a multi-color printing machine with several Printing units with a certain printing work not all printing units for a one-sided If multi-color printing is required, this can be done with a convertible perfecting machine (hereinafter referred to as the 54ji1 machine) which is the case with a normal machine Unused printing units in one machine pass for printing the back of the sheet, if necessary.

For the purpose of the transition from face printing to reverse printing are between the individual printing units of S + W machines facilities are available with which you have it in your hand, in the next following printing unit either the same or to have the opposite side of the sheet printed. Such changing facilities are often provided for two-color machines with one either one Sheet side with two prints or each of the sheet sides can be provided with a print. But there is also the possibility of such changing devices on machines with more printing units to be provided in any arrangement between the individual printing units. A special There is a need for machines that have the printing options 2/1, 2/0 or 1/1, where the first number is the number of straight prints and the second number indicates the number of possible reprints. - Well-known S + W machines use so-called Bend drums, with which a print sheet from the previous cylinder is sent to either its gripper edge or at the free end can be taken over. In the latter case then a turning of the bow takes place. An overview of the state of the art Such Bogenwendeeinrlc-; 7tungen is in "Deutscher Drucker", 1978, No. 15, pp 36-47 released.

Printing machines with sheet turning cylinders have the disadvantage that they usually require a total of 9 cylinders for two printing units, which makes the machine is very complex and expensive, Another disadvantage is that in the case of the printed sheet of finishing two gripper edges must be provided, and that the machines usually have to be reduced in speed for the perfecting, because despite the suction devices used as an alternative, the takeover of the sheet begins the second gripper edge of the free end is not possible with sufficient accuracy is in order to obtain a sufficient accuracy of fit with repeated reverse printing. the cited publication shows further difficulties with such known Machines can occur.

On page 46 of the same article is a construction proposal for a convertible S + W sheet-fed offset machine based on the rubber-on-rubber principle shown as it would be desirable from the printer's point of view. One such a machine would not require turning drums and the provision of a second one The gripper edge on the printed sheet could be omitted.

So far not resolved, however, is the way how to get an individual Can insert printed sheet into a rubber-on-rubber printing unit with an accurate fit1 without the sheet touches one of the two cylinders prematurely. Accordingly, the The above-mentioned illustration is also not an embodiment of an arch system but has simply by the word "attachment" to indicate at which point such Device should be located.

In web offset machines, which generally use the - rubber-on-rubber -Principle is worked, the introduction of the web into a printing unit does not cause any difficulties, since the web is under such a position in its entire passage through the machine Tension is that it is introduced tangentially into the printing zone of a printing unit without touching either cylinder prematurely. Are also at A roll-L offset machine does not require a gripper to attach the print carrier must hold one of the cylinders of the printing unit.

'A sheet-fed printing machine that, however, is close to the desired principle comes is the so-called perfector. It is an S + td machine with rubber-on-rubber printing unit for undemanding, monochrome printing work, with each of which a face print and a side print can be generated, with the Sheet insertion accuracy for the precisely fitting application of further prints. However, not sufficient. The perfector uses a so-called roller feeder, in which the stationary arch system only for pre-alignment of an arch serves. After swiveling up the front lay, the print sheet is rolled into the Print zone advanced, whereby it is passed through a metal sheet, which is up close the pressure zone is sufficient. The rollers push the print sheet a little higher than the cylinder circumferential speed just before the pressure zone in the open Gripper system of one of the cylinders, with stops on the cylinder between the grippers are provided that limit the advance of the sheet. This way is no Precise insertion of the sheet into the gripper system is possible, as the rollers hold the sheet often pull at an angle, so that it is either gripped at an angle by the grippers or in the one corner is compressed.

A changeover from two straight prints to one straight and one counterprint is also not possible with the perfector. The object of the present invention consists primarily in the sheet transfer with a rubber-on-rubber - SAW - printing unit from the sheet feeder to the rubber cylinder equipped with the gripper system design that the printed sheets in a precisely fitting transfer position without prior contact one of the blanket cylinders can be pulled into the print zone.

According to the invention, this object is achieved by a device as described at the outset designated type, which is characterized in that the gripper system in is movable in such a way relative to the blanket cylinder in the cylinder cavity, that the gripper through slots provided in the guide plate over the cylinder circumference can also emerge to a print sheet in absolute rest position on the front lay to take over, whereby the gripper pads are approximately at the level of the feed table are located, and that the gripper system in its subsequent re-acceleration on Cylinder circumferential speed and simultaneous return movement at cylinder circumference level is guided in its movement so that it is essentially the course of the Guide plate follows, whereby the gripper pads are each level with the surface of the guide plate are located or a little above, so that the print sheet over the guide plate without prior cylinder contact essentially in the tangential direction in the Print zone is pulled.

It is true that every gripper system that meets the above requirement is suitable for solving the object according to the invention, as particularly advantageous However, an embodiment has been found in which the gripper device within the cylinder recess of a rubber cylinder by means of swing arms on an eccentric cam-controlled offset parallel to the cylinder axis in the direction of the cylinder recess Rocking shaft is pivotally mounted in such a way that the rigidly attached to the swine arms Gripper supports from a point called the pressure position, at which the gripper supports rest on the front edge of the cylinder jacket and their contact surfaces with the cylinder surface are flush, via an apex position outside the cylinder circumference to an in near the rear edge of the cylinder jacket, referred to as the immersion position Point within the cylinder circumference and can be moved back again.

The guide plate is expediently curved so that it is guided along the circumference of the blanket cylinder containing the gripper system is-With such a gripper device, which because of their few relatively moved Parts is also suitable for the highest printing speeds themselves the gripper pads by a sufficient amount over the cylinder circumference so that they pass through the guide plate and the arch in the rest position on the front lay can take over.

The takeover position in which the gripper system is opposite the Front lay is at an absolute standstill, is expediently with the delayed Movement of the gripper system within the cylinder recess before the apex position of the gripper system so that it can still move a little after the sheet has been grasped raises further to better the recorded print sheet then in the slightly raised state to be able to pull off the feed table. The imaginary extended surface can thereby of the feed table the outer circumference of the curved guide plate a little bit cut so that the printed sheet is pulled over the guide plate a bridged certain hollow between these two components.

The slight lifting of the sheet from the feed table after it has been grasped The gripper system makes it possible to swivel one into the guide plate from below Provide pre-alignment flap, which is seen in the direction of the pressure zone around a a short distance behind the front lay and in the swiveled-in state only minimally above the feed table or

the guide plate protrudes. This arrangement makes it advantageous possible while drawing a sheet into the print zone, whereby this is easily lifted off the feed table, already against the next printing sheet to advance the pre-alignment flap so that after the previous one has disappeared Sheet from the feed table now only the front mark the pre-aligned sheet needs to push back a small amount in its precisely fitting investment position. This enables a denser overlapping of the printed sheets from the feeder, which in turn means a lower feed speed of the printed sheets towards the system has the consequence.

So that the print sheet does not have the opposite when it is drawn into the print zone Touches the rubber cylinder, it is advisable to provide brushes above the guide plate, which hold the printed sheet down on the guide plate when it is drawn into the print zone.

The device described can be in terms of their constructive Train space requirements very favorably in particular when the gripper system containing blanket cylinder compared to the counter cylinder has twice the circumference.

The object of the invention is also to provide a convertible S + W -Printing machine with a rubber-on-rubber printing unit to create the Sheets fit, lukewarm and without first touching one of the blanket cylinders in the print zone of the printing unit, and the compared to known convertible SMS - Printing machines, as well as compared to the previously unrealizable proposal on page 46 of the publication mentioned at the beginning shows an even simpler structure.

This task is carried out by a convertible StW printing machine initially identified type, which is characterized according to the invention, that one of the blanket cylinders is provided with a device for inserting the sheets is, as described above, that the one containing the gripper system Rubber cylinder is designed with double circumference and that another printing unit is provided, the rubber cylinder also against the one containing the gripper system Double circumference cylinder works.

The cylinder containing the gripper system is double circumference expediently designed so that it can be used as a blanket cylinder or as a pure impression cylinder convertible is.

Printing is possible with such a convertible S + W machine -ities 2/1, 2/0 and 1/1.

In the following the invention with reference to the attached Drawings described in detail.

The figures show: FIG. 1 a schematic section through a part a perfecting unit with an upper rubber cylinder and one with a Gripper system provided lower rubber cylinder with double circumference, in which the The gripper system is shown in its position submerged in the cylinder trough; FIG. 2 shows a representation similar to FIG. 1, but in which the gripper system is in The sheet take-over position is located at the sheet system; Fig. 3 shows a representation accordingly Figs. 1 and 2, in which the gripper system is in the printing position .; and 4 is a schematic side view of a convertible perfecting printing machine.

The partially shown in Figures 1 to 3 in a schematic section Perfecting printing unit has an upper cylinder 1 with a cylinder recess 2 (Fig. 3) and a rubber blanket 3 stretched on the cylinder.

The lower cylinder 4, which is designed with a double length, has a Cylinder jacket 5, its front edge 6 and its rear edge 7 between them one Limit cylinder recess 8. For the sake of clarity, there is one Cylinder axis 9 rotatably mounted lower cylinder 4, no rubber blanket shown.

As can be seen most clearly from Figures 1 and 3, is before Inlet gap between the two cylinders 1 and 4, a sheet system 10 is arranged and a gripper system 11 is provided within the cylinder trough 8 of the cylinder 4.

To further explain the individual parts of the arch system 10, so far these are shown, reference is made to FIG. The core of the arch system 10 is a feed table 12 which is carried by a cross member 13. On the left On the side of the traverse 13, the pulling rollers 14 and 15 are one (otherwise not in detail indicated) side mark indicated. There the page mark and with it the pulling rollers 14 and 15, the attachment of which is also not shown in detail, for reasons the format adjustment in a direction perpendicular to the plane of the drawing, at least in The feed table has to be adjustable in a certain area 12 a side cutout at this point, which is intended to indicate that the feed table is not shown hatched in this section. In his the hatched section extends closer to the cylinder jacket S However, the feed table 12 is at least over the entire width of the cylinder jacket 12, but preferably beyond this, so that the feed table in addition to both Sides of the cylinder in the (not shown) machine frame can be attached.

Above the left side of the feed table 12 is one about its axis pivotally mounted brand bar 16 arranged on its front page the front lay 17, which can be pivoted into the feed table 12, carries. The front lay takes effect in the swiveled-in state with some tongue-like provided at their lower end Extensions into corresponding slots in the feed table (see Fig. 2), so that a on the feed table 12 advanced printing sheet 18 (Fig. 2) with its leading edge can be brought to the stop against them, whereby the sheet 18 its accurately fitting Longitudinal alignment for the takeover by the gripper system 11 is obtained. The brand bar 16 is also provided with a cover mark 19 designed as a bent sheet metal, which is to hold down the advanced print sheet when it is placed against the front lay (Fig. 2) In addition to a front lay, the feed table 12 is also equipped with a pre-alignment flap 20 (Fig. 3) provided, which around a flasher in the order of only about 10 by means of a pivot shaft 21 with its front end 22 from below through recesses can be pivoted into the feed table 12. When swiveled in, it rises the pre-alignment flap 20 with its upwardly angled, hook-like ends 21 only slightly above the surface of the feed table 12.

The tongue-like extensions of the front lay 17 and the hook-like Ends 21 of the pre-alignment flap 20 engage in corresponding ones offset from one another Slots in the feed table 12 so that they do not interfere with each other when they both are in the swiveled-in state. The mutual arrangement of the front lay 17 and the ends 21 of the Vorrichtklappe 20 is such that the front lay in pivoted state is slightly, that is in the plane of the drawing to the right offset, located in front of the hook 21 of the Vorrichtklappe 20.

In the direction of the inlet gap between cylinders 1 and 4 the feed table 12 is continued in the form of a FGhrungsbleche 23, which to shortly before the pressure zone 24, in which the two cylinders are under pressure against each other roll off. The guide plate 23 is provided with slots that face the pressure zone 24 open open, and through which, as will be described further below, the grippers of the cylinder 4 can pass. Since the cutting plane of the drawing is through a runs such a slot, the guide plate 23 is not shown hatched. As can be seen from the figures, the guide plate 23 is curved and guided along close to the surface of the cylinder 4. From below to still For explanatory reasons, the surface of the feed table 12 does not run tangentially towards the guide plate, but the guide hole rises with its apex slightly above the level of the feed table 12.

As close as possible to the pressure zone 24 are above the guide plate 23 holding-down brushes 25 still firmly connected to the machine frame are arranged, which serve to bring a sheet to be drawn into the printing zone 24 into contact to hold with the guide plate.

In the following, that is now arranged in the cylinder recess 8 of the cylinder 4 Gripper system 11 is described in more detail. This gripper system essentially consists from swing arms 26, which on an oscillating shaft rotatably mounted in the cylinder 4 2? are attached. This rocking shaft is on the outside of the cylinder with a Provided curve control, which is indicated by dashed lines in Figures 1 to 3. The oscillating shaft 27 carries a cam follower roller 29 on a lever arm 28, which at a curve that is fixedly connected to the machine frame outside of the cylinder 4 30 expires.

The swing arms 26 can, as indicated in the embodiment, also be designed as a continuous plate, which at its upper edge with the gripper pads 31 is provided, which for this reason rigidly with the swing arms 26 are connected.

The swing arms 26 also carry a gripper spindle rotatably mounted on them 32, on which a number of gripper fingers 33 are fixedly attached.

The gripper spindle 32 carries each of the cylinder end walls adjacent Lever 34, which in turn are rotatably connected to articulated levers 35 with their opposite ends rotatably mounted in fixed points 36 of the cylinder end walls are.

From the different positions of the gripper systems in the figures 1 and 3 it can be seen that the gripper fingers through this articulated lever arrangement 33 open automatically when the oscillating shaft 27 moves the gripper system 11 into the position shown in FIG 1, the immersion position shown in the cylinder recess 8 pivots.

The eccentricity of the oscillating shaft 27 relative to the cylinder axis 9 and the length of the swing arms 26 or the distance of the Ereiferaufnagen 31 from the pivot point the oscillating shaft 27 are chosen so that the gripper system 11 from a printing position (Fig. 3 in which the gripper pads 31 are in contact with the front edge 6 of the cylinder jacket and the surface of the gripper pads is at the level of the cylinder circumference, via an apex position in which the gripper pads extend over the circumference of the cylinder also raise, can move into a diving position (Fig. 1) in which the gripper pads 31 and also the open gripper fingers 33 near the rear edge of the cylinder jacket 7 are located within the cylinder circumference. The control cam 30, by which the oscillating movement of the gripper system 11 is controlled is designed in such a way that that the gripper system in its pivoting back movement from the diving position into the Pressure position in or shortly before its apex position briefly to the absolute Standstill comes to a print sheet in this takeover position (Fig. 2) to take over the Vordermaike.

The mode of operation of that shown in FIGS. 1 to 3 will now be described below Device described: In the illustration of FIG. 1, this approaches after what has taken place Printing process and delivery of the printed sheet from its printing position into the immersion position Pivoted gripper system with open gripper fingers of the sheet system 10.

Un from the printing position of Figure 3 in the diving position of the figure 1 to get, the gripper system 11 must in its pivoting movement relative to the Cylinder rotation can be accelerated. The gripper system must be in this early get its diving position that it does not over when passing the arch system 10 the cylinder circumference protrudes more.

The gripper system is now out of the immersed position of FIG delayed compared to the cylinder rotation, whereby it is in its pivoting movement Towards the apex and the gripper pads 31 through the slots in the guide plate 23 and emerge beyond the cylinder circumference until the gripper pads 31 are at the level of the feed table 12 or even slightly above located- (takeover position of Fig. 2).

In this position, the gripper system 11 briefly reaches a absolute standstill in which the gripper fingers 33 are above the one on the front lay 17 Close the aligned press sheet. The front lay 17 is then pivoted away and the gripper system again accelerated absolutely, however, compared to the cylinder another relative delay is experienced until gripper pads 31 to rest against the cylinder jacket front edge 6 reach.

After detecting the printed sheet 18 (FIG. 2) and after pivoting it away the front lay, the gripper system still dips when it reaches its apex position somewhat farther out of the cylinder recess, whereby the detected printed sheet 18 is easy lifted from the feed table 12 and withdrawn from this and over the surface of the Guide plate 23 is pulled into the pressure zone, whereby he is by the brushes 25 is held down on the surface of the guide plate 23. The curvature of the Guide plate 23 is designed so that the gripper pads 31 at their Boiler acceleration to cylinder circumferential speed and when they are re-immersed to the cylinder circumference either exactly along the surface contour of the guide plate 23 or move on a slightly higher pivot line. This tour is necessary so that the printed sheet is not torn by the re-submerged gripper. Shortly before reaching the pressure zone, the gripper system takes its pressure position again a (Fig. 3) so that printing can begin.

While with the front lay swiveled up, the printed sheet 18 is still in the pressure zone is drawn in (FIG. 3), the pre-alignment flap 20 can already be in the feed table 12 swiveled in and a subsequent sheet 38 against the ends 21 of the Vorrichtklppe 20 are advanced. Has the previous sheet 18 finally leave the sheet feeder, the front lay 17 is returned to the feed table 12 swiveled in, with the leading edge of the following printed sheet 38 slightly pushes back into the final alignment position. The simultaneous alignment of one subsequent sheet, while the previous sheet was still drawn into the print zone will, 'will possible because the previous print sheet because of the elevation of the apex of the guide plate 23 over the plane of the feed table 12 lifts off the feed table 12 when it is drawn in, so that the The pre-aligning flap 20 swiveled in again shows the printed sheet that is just being pulled off 18 (Fig. 3) can not damage. Through this early alignment of each The following arch can have a denser arch scaling and a smaller one Feed speed can be worked, thereby also at high printing speeds there is enough time to align the sheets with the side mark.

It should be noted that the lower cylinder 4 in reality contains two diametrically opposed gripper systems 11, so that the one in FIG 1 printed sheet 37 shown on cylinder 4 from the print sheet 37 shown in FIG. The gripper system located in the lower half of the cylinder is held.

The device according to the invention, shown in FIGS. 1 to 3 allows a printed sheet to be precisely aligned with the front lay in absolute Standstill is taken over by the gripper system, and this arc along the surface of the guide plate to be drawn into the print zone without the sheet before printing begins can come into contact with one of the already colored cylinder surfaces. This alone makes it possible to create a printed sheet with an exact fit in a rubber-on-rubber - Printing unit can be printed on both sides at the same time, even at high printing speeds.

Although it would be conceivable for the device according to the invention also a to use differently designed gripper system, insofar as its gripper supports Raise the print sheet high enough above the cylinder circumference in the Standstill at the front lay can be taken over and the gripper supports then let it accelerate along the surface of the guide plate1 is most appropriate however, the gripper system shown is used for this, which is attached to swing arms about an oscillating shaft mounted eccentrically to the cylinder axis in the cylinder so that it can rotate is pivotable. The particular advantage of such a gripper system is that it depending on the formation of the diameter of its swing circle high enough above the Cylinder circumference can be raised and can still be used for the highest printing speeds is because it has relatively few masses to be moved relative to one another and the gripper pads can be rigidly connected to the swing arms. First that Relatively wide emergence from the cylinder circumference also makes it possible to that the gripper pads can pass through the feed table and below of the feed table in the immediate vicinity of the cylinder even the pre-alignment flap can be arranged. The one for a relatively high lifting of the gripper support surfaces Relatively short pivoting radius of the provided over the cylinder circumferential surface Swing arms and the associated large eccentricity of the swing shaft the cylinder axis also enable the formation of a relatively narrow one Cylinder recess, which means that the cylinder overall has the same format in terms of its diameter can be reduced.

In Figure 4 is a convertible perfecting printing machine with a rubber-on-rubber printing unit, which has an upper rubber cylinder 1 and a lower blanket cylinder 4 with double circumference, which two Includes gripper systems 11.

In front of the cylinders 1 and 4 is a sheet system 10 according to the Figures 1 to 3 arranged. A plate cylinder 39 and belongs to the blanket cylinder 1 to the Blanket cylinder 4 is a plate cylinder 40. In addition, behind blanket cylinder 1 on the double-sized cylinder 4, another printing unit with a rubber cylinder 41 and a plate cylinder 42 is arranged. The double-sized cylinder 4 can be with and operate without a blanket and in the second case can be used as a pure impression cylinder be used.

The printing unit 41, 42 and the plate cylinder 40 can each be switch on by applying pressure to the pressure magnets. This is how the print combinations are 2/0, 1/1 and 2/1 possible, whereby the first digit is the number of straight prints and the second digit indicates the number of reprints.

In the case of two straight prints, the plate cylinder 40 is taken out of operation, and it is printed with the printing units 1, 39 and 41, 42 alone, with the double large cylinder 4 can be driven without a rubber blanket. At a fair and a The printing unit 41, 42 remains out of operation. With two straight prints and All printing units are operated with a reverse printing.

About a delivery drum 43, the printed sheets are known Way fed to the boom.

Claims (9)

Convertible front and back printing sheet-fed offset rotary printing machine with rubber-on-rubber printing mechanism and device for precisely fitting the sheets in the printing unit patent claims 0 Vorfichtung for accurately fitting insertion to be printed Sheet from the rest position into a rubber-on-rubber perfecting printing unit Sheet-fed offset rotary printing machine, consisting of a sheet-fed system with feed table, Side mark, front lay and one in the direction of the print zone towards the The guide plate that follows the front lay and ends shortly before the print zone Surface in im essential tangential direction to the print zone runs out, and one in a cylinder recess of a rubber cylinder of the printing unit arranged gripper system, characterized in that the gripper system (11) in such a way relative to the blanket cylinder (4) in the cylinder trough (8) is that the gripper through slots provided in the guide plate (23) over the cylinder circumference are also interchangeable to a printed sheet (18) in the absolute rest position on the To take over the front lay (17), the gripper pads (31) on approximately the height of the feed table (12), and that the gripper system (11) at its subsequent re-acceleration to cylinder circumferential speed and simultaneous return movement at the cylinder circumference level in its movement sequence is guided so that it essentially follows the course of the guide plate (23), wherein the gripper pads (31) are each level with the surface of the guide plate (23) are located, or a little above, so that the printing sheet (18) over the guide plate (23) without previous cylinder contact essentially in the tangential direction in the pressure zone (24) is pulled. 2. Apparatus according to claim 1, characterized in that the gripper system (11) within the cylinder trough (8) of a rubber cylinder (4) by means of swing arms (26) on an eccentric to the cylinder axis (9) in the direction of the cylinder trough (8) offset in parallel, cam-controlled oscillating shaft (27) so pivotally attached is that the rigidly attached to the swing arms (26) gripper pads (31) of a point referred to as the pressure position, at which the gripper pads (31) are at the cylinder jacket front edge (6) and their contact surfaces with the cylinder surface are flush, over a vertex outside the cylinder circumference vu one lying on the rear edge of the cylinder matel (7), referred to as the immersion position Point within the cylinder circumference and back again. 3. Apparatus according to claim 1 or 2, characterized in that Above the guide plate (23) brushes (25) to hold down the printed sheet (18) are provided during its movement over the guide plate (23). 4. Device according to one of claims j to 3, characterized in that that the guide plate (23) is curved and close to the circumference of the gripper system (11) containing rubber cylinder (4) is guided along. 5. Device according to one of claims 1 to 4, characterized in that that the sheet system (10) in addition to the front lay (17) with a feed path the arch on the feed table limiting, in the arch worschubweg e: tnschwenkbaren Vorrichtklappe (20) is provided, the .8ogenanschlagpunkt (21) in the direction is just behind the front lay (17) seen on the pressure zone (24). - 6. Apparatus according to claim 5, characterized in that the Pre-alignment flap (20) can be swiveled into the guide plate (23) from below through slots is and in the swiveled-in state only so far above the surface of the guide plate (23) protrudes so that a sheet (18) gripped by the gripper system (11) even when it is swiveled in Vorrichtklappe (20) can be pulled off the feed table (12). 7. Device according to one of claims 1 to 6, characterized in that that the rubber cylinder (4) containing the gripper system (11) is opposite to the other Rubber cylinder (1) has twice the circumferential length. 8. Reversible perfecting printing - sheet-fed offset rotary printing machine with a rubber-on-rubber printing unit, characterized in that one of the rubber cylinders provided with a device for inserting the sheets according to one of claims 1 to 6 is, dao the gripper system (11) containing the blanket cylinder (4) with double Scope is formed, and that a further printing unit (41,42) is provided, its Blanket cylinder (41) also against the cylinder containing the gripper system (11) (4) works with double scope. 9. Convertible perfecting printing machine according to claim 8, characterized characterized in that the gripper system (11) containing the cylinder (4) with double Can be converted as a blanket cylinder and as an impression cylinder.