EP2657161B1 - Method and device for feeding individual stacks of sheets from a printer into an adhesive band machine - Google Patents

Description

The invention relates to a method and a device for automatically feeding individual loose stacks of sheets from a printing press into an adhesive binding machine, wherein the stacks of sheets from the printing press are staggered on a stack.

The use of digital printing opens up the possibility of producing individual print products. As a result, often only relatively small series of a particular type of book and book thickness are produced, so that this must be considered in the case of automation in terms of flexibility. After printing the individual pages of a respective printed product, these pages are fed to an adhesive binding machine, wherein it must be ensured that the respective desired, possibly even individualized cover is supplied to the respective print.

It must be ensured that the individual sheet stacks coming out of the printing press are fed to the perfect binding machine at a correspondingly high speed as continuously as possible, wherein the individual sheet stacks can have a height of 1.5 mm and above.

A generic device and an associated method is known from the published patent application EP 2 361 861 A1 known. This document discloses a method and apparatus for automatically feeding individual loose stacks of sheets from a printing press into an adhesive binding machine, the stacks of sheets coming from the printing machine stacked on top of each other by means of a horizontal transport means, whereby always the two upper stacks of sheets by means of positionable layer gripper are held at their respective supernatant and the topmost layer is withdrawn in the direction of the transport device. The respective stock gripper transfers the respective stack of sheets to a peel-off gripper, which deposits the stack of sheets at the speed of the transport device on a transport device leading to the perfect binding machine. By adjusting the individual movements of the gripper and the positioning of the respective upper stack can be achieved by the method and the apparatus, a continuous Entstapelungsablauf with which the respective sheet stack is subsequently processed in the adhesive binding machine.

Starting from the above-described prior art, the invention is based on the object to provide a method and an apparatus with which originating from a printing press stack of sheets that are offset from each other on a stack of each other, automatically an adhesive binding machine individually with significantly higher clock speed and less disturbances can safely be fed to the binding.

This object is achieved by a method and an apparatus having the features of the independent main claims. Further advantageous embodiments can be found in the respective dependent subclaims.

According to the invention, in the method in feature A, the top sheet stack is arranged at a defined height and in proximity to a horizontal conveying feeder. This can be done in such a way that the stack is arranged on the front side or laterally of the conveying feeder.

It is advantageous to arrange the stack with the sheet stacks thereon on the end face of the feed device in order to facilitate the feed in the transport direction. To arrange the upper stack of sheets defined, the entire stack can be positioned with the loose sheet stacks thereon in the amount and, if necessary, laterally so that the simplest possible transfer of the upper stack of sheets on the forwarding feed to the adhesive binding machine is possible.

After the positioning of the upper stack of sheets in the next feature B of the upper stack of sheets is pressed against the underlying sheet stack in a resting central area by means of at least one front in the withdrawal direction first holddown and additionally by means of at least one rear in the withdrawal direction second holddown. In this case, the upper and the lower second top sheet stack are fixed immovably in their position and orientation.

After operating the at least one front first and the at least one rear second holddown, in the next step according to feature C, the uppermost sheet of the second upper sheet stack located offset to the upper sheet stack will protrude from the stack by the offset transverse to the take-off direction Lateral supernatant held by at least two first or two second lateral holders, which are arranged in the withdrawal direction next to the stack, preferably horizontally displaceable, on different sides. For example, suction devices can be used as the holder. It is alternately used in each case the holder, which can act on the second upper stack of sheets on the supernatant.

Subsequently, according to feature D, the upper stack of sheets is grasped, in particular clamped, by means of a first lateral layer gripper or a second lateral layer gripper at the projection projecting through the offset. After releasing the at least one front first and rear second blank holder from the stack, the upper sheet stack of subtracted from the second upper stack of sheets, without affecting this and the remaining stacks of sheets. It is alternately used in each case the one layer gripper, which can grab the upper stack of sheets on the supernatant and which is opposite to the currently active holder on the stack. For a stripping operation, ply grippers and grips are always used paired, which are arranged on different sides of the stacking device.

According to the feature E of the method according to the invention, the upper sheet stack is released by releasing the at least one first and second hold-down and then the upper sheet stack only partially withdrawn in the stripping direction from the stack by means of the respective sheet gripper holding the upper sheet stack, wherein the at least two lateral first Retainer reliably prevent slippage of the sheet stack located under the upper sheet stack.

After the partial removal of the upper stack of sheets from the stack, the second upper sheet stack according to feature F of the method according to the invention is pressed against the stack of sheets underneath by means of the at least one rear second hold-down. This happens as soon as the upper stack of sheets has been pulled out below the at least one rear second hold-down. By this measure, all the leaves of the second upper stack of sheets are pressed against each other and against the underlying next stack of sheets, so that a shift is excluded. The protection is particularly effective when two or more rear second hold-down are used, which have the greatest possible distance from each other. Now, the upper sheet of the second upper sheet stack under the top sheet stack to be deducted is also released by removing the at least two first side holders from the second upper sheet stack. This happens in any case only when the at least one rear second hold-down acts on the second upper stack, ie presses this stack of sheets to the underlying stack of sheets of the stack, without the withdrawal of the upper stack of sheets is delayed.

After releasing the side clamps from the second upper sheet stack, the top sheet stack according to the feature G is completely withdrawn from the underlying sheet stack. Of the sheet gripper, which preferably engages the upper sheet stack in two places and preferably jammed, the withdrawn sheet stack is on the horizontally conveying feeder, such as a conveyor belt, deposits with a defined distance to the previous stack of sheets. Preferably, the ply gripper transports the stack of sheets at the same speed as the feeder. This ensures that the loose stack of sheets does not slip when placed on the transport device. After laying the ply gripper is ready to take another stack of sheets from the stack of the printing press. He is moved back towards the stack. At the same time, the sheet stacks lying on the feeding device are fed to the perfect binding machine.

According to feature H of the newly proposed method, the method steps with the characteristics A to F are repeated continuously, wherein the holding of the upper sheet of the respective second upper stack of sheets arranged offset to the upper sheet stack at the projecting from the stack by the offset supernatant, alternately by means of the first and second lateral clamps and the gripping of the upper sheet stack on the projecting by the projection projection according to means of the first or second lateral layer gripper takes place. In this case, in each case the left first layer gripper and the right first gripper or the right second layer gripper and the left second gripper, which are respectively arranged on different longitudinal sides of the stacking device, are used together in a stripping operation.

By the retainer and the sheet grippers are duplicated and are arranged in the withdrawal direction of the stack respectively left and right so that a simultaneous operation is easily possible, the cycle time can be significantly reduced. During the one layer gripper the withdrawn sheet stack moves to the leading to the perfect binder feed device, the other layer gripper can already take over the next upper stack of sheets from the stack of the printing press. For this purpose, after the transfer of the sheet stack to a sheet gripper according to feature A, the next sheet stack, which is now the upper sheet stack, again positioned at a defined height and proximity of the feeder.

Preferably, in order to grasp the upper stack of sheets, the respective layer gripper with a respective clamping rail is retracted into the intermediate space formed by the projection between the upper and lower next stack of sheets. Before that, after removing a sheet stack from the stack by the ply gripper, the stack for positioning the top sheet stack is moved up in a defined height. This improves the speed of destacking.

Advantageously, the stack is raised significantly before retraction of the respective clamping rail and brought into position to the respective retracting clamping rail, while the clamping rail is already moved to the stack.

In a favored variant of the method, the lower edge of the upper sheet stack is detected in the movement of the clamping rail and the stack raised so far that the clamping rail can move into the space between the upper sheet stack and the same position arranged next to the next sheet stack. When entering the intermediate space, the clamping rail, which is preferably wedge-shaped at the end entering the gap first, exerts on the projection of the upper respective sheet stack a vertically upward pressure, which raises the projection slightly and thus increases the gap upwards.

In one embodiment of the method, during the movement of the clamping rail, the lower edge of the upper stack of sheets is detected and the stack for example, raised so far that the clamping rail can move into the space without damaging the leaves on the supernatant.

The offset of the individual stacked loose stack of sheets usually takes place only in one direction, so that the supernatants of the stacks of sheets are always arranged at 180 degrees to each other. In principle, it is also possible for the stack of sheets to lie on one another in such a way that an offset to the sheet stack underneath takes place in two planar directions (x, y). Depending on the nature of the staggered stacking, the trigger may be made either transversely or longitudinally to the offset. In most cases, the stacks of leaves become a simple offset, i. have in only one planar direction. As a result, the stack with the individual sheet stacks has a defined contact edge in the direction of the horizontally conveying feed device. According to this preferred embodiment of the method, the stacks of sheets are drawn off from one another transversely to the offset of the stacks of sheets. According to this advantageous embodiment can be processed by the defined contact edge and the trigger transverse to the offset also slightly in the direction opposite to the contact edge direction variable formats.

The method thus running thus enables the desired continuous operation at high cycle speed and without slippage of the individual sheets of a sheet stack. In order to ensure sufficient speed, the stack is already brought into position for the removal of the next upper stack of sheets as soon as the previous stack of sheets has been pulled from the stack. In addition, preferably, the gripping of the upper sheet stacks is already performed when the preceding sheet stack is still supplied to the feeder. Advantageously, the pressing, the holding and gripping pneumatic and the necessary facilities are moved by means of servo motors back and forth.

• mindestens einen in Abzugsrichtung vorderen ersten Niederhalter und mindestens einen in Abzugsrichtung hinteren zweiten Niederhalter im Bereich des Stapels an dem die Blattstapel aufeinander liegen, die unabhängig voneinander betätigbar sind;
• mindestens zwei in Abzugsrichtung linke erste Festhalter und mindestens zwei in Abzugsrichtung rechte zweite Festhalter im Bereich des Stapels, die zum Festhalten des obersten Blattes eines unter dem abzuziehenden oberen Blattstapel befindlichen zweitoberen Blattstapels im Bereich der jeweiligen in Abzugsrichtung seitlichen Überstände ausgebildet und zumindest zeitweise positioniert sind, wobei die rechten und die linken Festhalter unabhängig voneinander betätigbar sind;
• jeweils einen in Abzugsrichtung links und rechts seitlich des Stapels angeordneten horizontal bewegbaren Lagengreifer, mit einer horizontal angeordneten Klemmschiene und einer darüber angeordneten Klemmeinrichtung zum Klemmen des dazwischen befindlichen Blattstapels an der Klemmschiene an seinem randseitigen Überstand;
• mindestens eine optische Detektiereinrichtung seitlich des Stapels, die mittels eines Lichtstrahls den Zwischenraum zwischen dem oberen und dem übernächsten darunter befindlichen Blattstapel detektiert und entsprechendes Signal zum entsprechenden Anheben des Stapels abgibt.

The inventive apparatus for automatically feeding individual loose stacks of sheets from a printing press into an adhesive binding machine comprises

• at least one first hold-down device in the withdrawal direction and at least one second hold-down device in the withdrawal direction in the region of the stack on which the stack of sheets lie on one another, which can be actuated independently of one another;
• at least two first arrester left in the withdrawal direction and at least two right in the withdrawal direction second retainer in the region of the stack, which are designed to hold the uppermost sheet of under the deducted upper stack of sheets second upper sheet stack in the respective withdrawal direction in the lateral projections and at least temporarily positioned wherein the right and left fasteners are independently operable;
• each one in the withdrawal direction left and right side of the stack arranged horizontally movable layer gripper, with a horizontally disposed clamping rail and an overlying clamping device for clamping the interposed sheet stack on the clamping rail at its edge supernatant;
• at least one optical detection device laterally of the stack, which detects by means of a light beam, the gap between the upper and the next but one underlying sheet stack and emits corresponding signal for corresponding lifting of the stack.

In this case, the optical detection device preferably has an optical waveguide from which bundled light emerges.

The inventive device for automatically feeding individual loose stacks of sheets from the printing machine in the perfect binding machine, wherein the stacks of sheets from the printing press on a stack offset from each other and form opposing supernatants, also has according to the prior art a vertically movable stack carrier on a Front side of the horizontally conveying feeder on.

The retaining device and the optical detection device can be designed to be movable or stationary in the withdrawal direction of the stack of sheets.

With the inventively designed method and the device, it is possible, individual sheet stack down to a thickness of 1.5 mm, which are staggered from one another provided by a printing machine on a stack, take down from this and bring it to the horizontal feeder, which then the individual stack of sheets continuously transported to an adhesive binding machine. The method allows a high number of cycles up to 7500 cycles per hour and more, the peculiarity is that the sheet stacks are offset from each other and can be different in thickness. Depending on the application, the individual sheet stacks may decrease in thickness from top to bottom or increase, with the knowledge of the approximate thickness of each sheet stack for the process is beneficial. In principle, however, it is also possible that sheet stacks of different thickness can be processed distributed in the stack.

An advantage of the proposed method or the corresponding device over the prior art is the significantly higher speed with which the respective upper sheet stack is fed to the horizontally conveying feed device for the perfect binding machine. This allows the perfect binding machine to operate at the highest possible speed without having to wait for stacks of sheets from the stacking device. Another advantage is that the stacking device is much less susceptible to interference than in the prior art, since at least the three upper stacks of sheets are fixed much better for the gripping and removal of the stack by the combination of hold-down with the holders.

The following are based on the FIGS. 1 to 6 The various steps in the stacking of individual stacks of sheets shown after they were provided in a stack of the printing press. The figures show in a perspective view schematically a stack with staggered sheet stacks and a horizontally conveying feeder in the respective sequence items explained in more detail below. Further features of the invention will become apparent from the following description of the embodiment of the invention in conjunction with the claims and the accompanying drawings. The individual features of the invention may be implemented on their own or in several different embodiments of the invention.

The FIGS. 1 to 7 show a stacking device 1 with a stack 3 of mutually offset sheet stacks 4 on a stack lifter 2. In the description and in the claims, the respective reference numerals are used without additional letters, when they relate generally to the individual designated objects. The stack of sheets 4 are arranged offset to one another, so that they have a common stop edge in the direction of a horizontally conveying feeder 5 in the form of a conveyor belt and the offset is given in this embodiment only in a planar direction. In principle, it is also possible that an offset in two planar directions can be processed according to the same principle. The deduction of the respective upper stack of sheets 4 takes place in a withdrawal direction transverse to the offset of the individual stack of sheets 4 to each other. The stack 3 is arranged in the embodiment on the front side of the conveyor belt 5.

The sheet stacks 4 of the stack 3 are designated for the following description with 4a to 4e, wherein the sheet stack 4e already on the conveyor belt 5 located sheet stack 4 denotes. In the FIGS. 1 to 6 are already on the conveyor belt 5 located sheet stack 4e not shown. The stack lifter 2 is capable of moving in the vertical direction to bring the respective upper sheet stack 4a into a defined position relative to the conveyor belt 5. The defined height is set by means of optical detection devices 7, which are only in the FIG. 1 symbolically represented. In this case, a lower edge 6 of the upper sheet stack 4a is detected. The stack lifter 2 is shown schematically in the figures. Due to the mobility in the height of the stack 3 is moved in the embodiment that the respective upper Sheet stack 4a is arranged with the lower edge 6 on the conveyor belt level or with a slight offset to the height of the transport device of a maximum of 0.5 mm above it to have as little height difference when removing the respective upper sheet stack 4a.

Furthermore, the stacking device 1 has two layer grippers 8, 9 which are arranged in the withdrawal direction to the left and to the right of the stack 3. The layer grippers 8, 9 are provided for withdrawing the respective upper stack 4a from the stack 3 and are movable from the stack 3 to over the conveyor belt 5. They stack sequentially in an alternating sequence sheet stack 4a from the stack 3 and pass it to the conveyor belt 5. By not shown in the figures sensors on both sides of the stack 3, the offset of the sheet stack 4a - 4d and the respective supernatants 10 detected and Control of the first left layer gripper 8 and the second right layer gripper 9 are used by means of the control device, also not shown.

The figures furthermore show two first hold-down devices 11, which are in the withdrawal direction, and two second hold-down devices 12, which are located in the withdrawal direction, and which are arranged in a central region 13 of the stack 3, in which the stack of sheets 4 lie on one another. The first and second hold-downs 11, 12 are independently movable upwards and downwards and press the sheet stacks 4 against each other and against the stack lifter 2. In addition, in the withdrawal direction to the stack 3, right first retainer 14 and left second retainer 15 above the supernatants 10th arranged the sheet stack 4, which are preferably movable in and against the withdrawal direction. The first and second clamps 14, 15 are independently controllable, associated with the projections 10 of the sheet stacks 4 and at least the uppermost sheet of the respective second upper sheet stack 4 b, which is located directly below the deductible sheet stack 4 a, immovably hold from above by For example, vacuum this with vacuum.

The layer grippers 8, 9 and the clamps 14, 15 are preferably combined to form a left and a right unit, each between the stack. 3 and the conveyor belt 5 and along the conveyor belt 5 are movable and store the respectively withdrawn sheet stack 4a after reaching the conveyor belt speed on the conveyor belt 5. The two units work with a time delay to each other in sequential order. The drive of these ply grippers 8, 9 or the movable clamps 14, 15 and the stack lifter 2 by means not shown servo motors. The hold-downs 11, 12 serve to press before and during the gripping of the upper stack 4a by the respective layer gripper 8, 9 on the respective upper sheet stack 4a and the second upper stack 4b arranged underneath and fix it therewith. The lateral clamps 14, 15 fix the second upper stack 4b when the downholders 11, 12, after clamping the upper sheet stack 4 by means of a sheet gripper 8, 9, for removing the upper sheet stack 4a from the sheet stack 4b from the stack 3.

FIG. 1 shows the conveyor belt 5 without already handed over sheet stack 4e, which were stored on the conveyor belt 5 by means of the layer grippers 8, 9. The first layer gripper 8 is located above the conveyor belt 5, the second layer gripper 9 immediately in front of the stack 3. The two second grips 15 connected to the first layer gripper 8 are located above the stack 3, which are two grips 14 connected to the other layer gripper 9 positioned behind the stack 3. The layer gripper 9 is opened and moves in the horizontal direction in the direction of the stack 3. For clamping the respective upper sheet stack 4a, the two layer grippers 8, 9 each have a clamping rail 17 and two controllable clamping holders 16. The clamping holders 16 are spaced apart from the clamping rail 17 in the open position gripper 8, so that the free space formed thereby can receive the projection of the upper sheet stack 4a. The clamping rail 17 of the sheet gripper 8 is arranged at the level of the space 18 between the projections 10 of the upper sheet stack 4a and 4b located directly below the second upper sheet stack 4b sheet stack, so that the sheet gripper 8 with the clamping rail 17 in the gap 18 against the withdrawal direction the sheet stack 4 can retract.

In this position, the front first hold-down 11 and the rear second hold-down 12 press the current top sheet stack 4a simultaneously.

In the FIG. 2 the clamping rail 17 of the right layer gripper 9 is fully retracted into the space 18 between the upper sheet stack 4a and the third upper sheet stack 4c.

In FIG. 3 the holding holder 15 of the left layer gripper 8 are placed on the projection 10 of the arranged under the upper sheet stack 4a sheet stack 4b. They fix at least the uppermost sheet of the sheet stack 4b against unintentional shifting when removing the upper sheet stack 4a. The right layer gripper 9 is in gripping position for the upper sheet stack 4a, ie the clamping rail 17 is fully retracted into the intermediate space 18. The clamp holders 16 for clamping the sheet stack 4a are activated. The layer gripper 9 holds the upper sheet stack 4a on the left in the withdrawal direction projection 10, which is clamped between the two clamping holders 16 and the clamping rail 17. The hold-down 11, 12 are according to the FIG. 1 positioned and pressing the stack 3 in the central region 13. The retaining bracket 14 of the right layer gripper 9 are spaced from the supernatant 10 of the upper stack of sheets 4a behind the stack 3 and in this position without function.

In FIG. 4 is the position and the state of the sheet grippers 8, 9 unchanged. The two retainers 15 of the left layer gripper 8 are still lowered and act on the second upper sheet stack 4b. They hold the uppermost sheet of the second upper stack 4b by suction. The front and rear hold-down 11, 12 are moved away from the stack 3 upwards and thus without function. Thus, the upper sheet stack 4a is released, so that the sheet gripper 9 can deduct the upper sheet stack 4a from the directly below stack 4b.

In the FIG. 5 the layer gripper 9 has already partially removed the upper sheet stack 4a from the stack 3. The upper sheet stack 4a is no longer under the two rear hold-downs 12. In this position of the sheet gripper 9, the two front hold-down 11 are without function. The two rear hold-downs 12 are lowered onto the second upper sheet stack 4b and press this sheet stack 4b against the stack of sheets 4c arranged underneath. In order to fix the rear in the withdrawal direction hold-down 12 not only the top sheet, but also the underlying leaves of the sheet stack 4b in addition. The upper sheet stack 4a can thus be completely removed from the stack 3 without influencing the second upper sheet stack 4b. While the right sheet gripper 9 moves with the gripped sheet stack 4a in the direction of the conveyor belt 5, the other left sheet gripper 8, which is formed in mirror image to the sheet gripper 9 and arranged on the stacking device 1, moves in the direction of the stack 3.

The FIG. 6 shows the top sheet stack 4a completely removed from the stack 3. The right sheet gripper 9 is located directly above the conveyor belt 5, the left sheet gripper 8 directly in front of the stack 3. The clamps 14, 15 are not active and are located above the stack. 3 The right layer gripper 9, which is located above the conveyor belt 5, can now be moved down to transfer the sheet stack 4a to the conveyor belt 5 (not shown in the drawing). The stack 3 now only has to be lifted by means of the stack lifter 2 so far that the clamping rail 17 of the left ply gripper 8 can enter the intermediate space 18 between the upper stack of sheets 4a (previously 4b) and the third upper stack of sheets 4c (previously 4d). The two front hold-down 11 are already back to the sheet stack 4b, now upper sheet stack lowered.

The further procedure for removing the upper sheet stack 4a from the sheet stack 4b (previously 4c) is analogous to the steps described above, now instead of the right sheet gripper 9 of the left sheet gripper 8 and instead of the left holder 15 now the right holder 14 are used. This alternate use occurs continuously with each cycle of stacking.

In the FIG. 7 the sheet stack 4a is off FIG. 6 stored on the conveyor belt 5 as a sheet stack 4e. The stack 3 now has an upper sheet stack 4a, formerly 4b, on which the overhang 10 is located on the side of the left sheet gripper 8. In this case, the layer gripper 8 instead of the layer gripper 9 stacks the upper sheet stack 4a from the stack 3 and transfers it to the conveyor belt 5. The stripping of the sheet stack 4a takes place in the FIGS. 1 to 6 illustrated steps, but the right layer gripper 9 with its retainers 14 temporarily holds the second upper sheet stack 4b, while the left position gripper 8 by means of the clamping rail 17 and the clamping holder 16, the sheet stack 4a subtracts from the sheet stack 4b.

Claims (6)

1. Method for the automatic supply of individual loose sheet stacks (4) from a printing machine into a binding machine, wherein the sheet stacks (4) from the printing machine lie one on top of the other, offset laterally, in a stack (3), perpendicular to the direction of removal, the respective upper sheet stack (4a) is arranged at a defined height and distance to a horizontally conveying supply device (5), the upper sheet stack (4a) is gripped by means of a gripper, is removed from the stack (3) in the direction of removal and is deposited on the supply device (5) at a defined distance to a preceding sheet stack (4e) and is transported onwards there, characterised by

   A arranging the upper sheet stack (4a) at a defined height and distance to a horizontally conveying supply device (5);

   B pressing the upper sheet stack (4a) onto the sheet stack (4b) situated thereunder, in a supporting central region (13), by means of at least one first front hold-down (11) in the direction of removal and additionally by means of at least one second rear hold-down (12) in the direction of removal;

   C holding the upper sheet (16) of the second uppermost sheet stack (4b), arranged underneath and in an offset manner to the upper sheet stack (4a), on the lateral protrusion (10) that projects from the stack (3) due to the offset, transverse to the direction of removal, by means of at least two first lateral holders (14) or by means of at least two second lateral holders (15), which are arranged on the right or left side of the de-stacking device (1) for the stack (3) in the direction of removal, wherein the respective holder (14, 15) is used which can act on the second uppermost sheet stack (4b) at the protrusion (10);

   D gripping the upper sheet stack (4a) on the protrusion (10) that projects due to the offset by means of a first lateral layer gripper (8) or a second lateral layer gripper (9), wherein the layer grippers (8, 9) are arranged to be moveable in the longitudinal direction on the left or right side of the stack (3) or the supply device (5) in the direction of removal, and wherein the respective layer gripper (8, 9) is used which can grip the upper sheet stack (4a) at the protrusion (10) and which lies opposite the currently active holder (14, 15) on the other side of the stack (3);

   E releasing the upper sheet stack (4a) by releasing the at least one first and second hold-down (11, 12); partially removing of the upper sheet stack (4a) from the stack (3) in the direction of removal by means of layer gripper (8, 9) that holds the respective upper sheet stack (4a);

   F pressing the second uppermost sheet stack (4b) onto the sheet stack (4c) situated thereunder by means of the at least one second rear hold-down (12), as soon as the upper sheet stack (4a) is pulled forward under the at least one second rear hold-down (12), and releasing the upper sheet (16) of the second uppermost sheet stack (4b) situated thereunder at the projecting protrusion (10) using the first or second lateral holder (14, 15) after the at least one second rear hold-down (12) presses the second uppermost sheet stack (4b) onto the sheet stack (4c) situated thereunder;

   G Completely removing the upper sheet stack (4a) from the sheet stack (4b) situated thereunder in the direction of removal and depositing it onto the horizontally conveying supply device (5); and

   H repeating features A to G, wherein the holding of the upper sheet (16) of the respective second uppermost sheet stack (4b), arranged underneath and in a displaced manner to the upper sheet stack (4a), at the protrusion (10) projecting laterally from the stack (3) due to the offset, occurs alternately by means of the first and second lateral holders (14, 15), and the gripping of the upper sheet stack (4a) at the protrusion (10) projecting due to the offset, occurs correspondingly by means of the first or second lateral layer gripper (8, 9), wherein the first left layer gripper (8) and the first right holder (14) or the second right layer gripper (9) and the second left holder (15), which are arranged on different longitudinal sides of the de-stacking device (1) are used respectively in the removal procedure.
2. Method according to claim 1, characterised in that to grip the upper sheet stack (4a), the respective layer gripper (8, 9) with a respective clamping rail (17) is inserted into the intermediate space (18) formed by the protrusions (10) between the upper sheet stack and a sheet stack situated thereunder (4a, 4c).
3. Method according to claim 2, characterised in that the stack (3) is lifted before the insertion of the respective clamping rails (17) and is brought into position towards the respective inserting clamping rails (17), if the clamping rails (17) are already able to be moved towards the stack (3).
4. Method according to claim 3, characterised in that, during the moving of the clamping rails (17), the lower edge (6) of the upper sheet stack (4a) is detected and the stack (3) is lifted so far that the clamping rails (17) can be inserted into the intermediate space (18).
5. Device for the automatic supply of individual loose sheet stacks (4) from a printing machine into a binding machine, wherein the sheet stacks (4) from the printing machine lie one on top of the other, offset laterally, in a stack (3) and form protrusions opposite one another, having

   - a stack carrier (2) that is able to move in the vertical direction on a front side of a horizontally conveying supply device (5);

   - detection devices (7) for the detection of the intermediate space (18) between the sheet stacks (4a, 4c) in the region of the protrusions (10);

   - at least one hold-down (11, 12) for the respective sheet stack (4a, 4b, 4c);

   - at least one layer gripper (8, 9) to grip the respective upper sheet stack (4a) on the respective protrusion (10) projecting from the stack (3) due to the offset and for moving the respective upper sheet stack (4a) in the direction of the supply device (5);

   - at least one optical detection device (7) lateral to the stack (3), which detects the intermediate space (18) between the upper and the next uppermost sheet stack situated thereunder (4a, 4c) and emits a corresponding signal for the corresponding lifting of the stack (3);
   characterised by,

   - at least one first front hold-down (11) in the direction of removal and at least one second rear hold-down (12) in the direction of removal in the central region of the stack (3), on which the sheet stacks (4, 4a, 4b, 4c, 4d) lie one on top of the other, wherein the first and second hold-downs (11, 12) are able to be actuated independently of one another;

   - at least two first left holders (15) in the direction of removal and at least two second right holders (14) in the direction of removal in the region of the stack (3), which are positioned to hold the upper sheet (16) of a second uppermost sheet stack (4b), situated underneath the upper sheet stack (4a) to be removed, in the region of the respective lateral protrusions (10) in the direction of removal at least temporarily and are able to be actuated independently of one another;

   - a horizontally movable layer gripper (8, 9) arranged respectively to the left and right and laterally to the stack (3) in the direction of removal, having a respective horizontally arranged clamping rail (17) and a clamping device (16) arranged thereover to clamp the sheet stack (4a) situated therebetween on the clamping rails (17) at its protrusion (10);
6. Device according to claim 5, characterised in that the optical detection device (7) has a light conductor, from which emanates focused light.

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