EP0722415B1 - Process and device for forming and moving stacks of printed sheets - Google Patents

Abstract

The invention relates to a process and a device for forming stacks of printed documents or similar sheets (9). The sheets (9) are either advanced individually or separated from a printed web (2) by tearing or cutting and pushed over one another in such a way that the next sheet (9) is placed in staggered array beneath the previous one (9). The stack (10) is formed by the fact that the staggered sheets (9) meet a stop (11). In order to save the maximum of time during the displacement of a complete stack (10) a gap (25) is formed between the last sheet (9) of a stack (10) and the following one before the sheets (9) are staggered. As soon as the last sheet (9) has reached the stacking position, the stop (11) is shifted from its stop position so that the stack (10) is moved away by the conveyor (20). The stop (11) is then moved back into its stopping position and the next stack (10) is formed.

Description

The invention relates to methods and devices for forming and moving stacks of printed sheets, in which the sheets are shingled and stacked, according to the features listed in the preamble of claim 1.

Such an arrangement is known from DE-A-1 436 485. It is about conveying, counting and stacking pamphlets in order to form piles with a constant predetermined number of pamphlets. The individual publications are first scaled in ascending order. Ascending desquamation is understood to mean that the front edge of the subsequent publication comes to lie over the rear edge of the preceding publication.

When scaled documents hit a stacking stop in such a manner, the stack is formed from top to bottom, as is known from US-A-4,265,443, which has some disadvantages. It is therefore desirable to form the stack from the bottom up. This goal is achieved by the previously known arrangement according to DE-A-1 436 485 in that the ascending scaled publications on a drum through 180 ° are turned and thus fed to the attack. this measure is extremely space-consuming and costly.

From DE-A-1 436 485 it is also known to form a gap between two adjacent documents with a rake which intervenes in the shingled documents, which is then scanned by a control unit in order to stack only the group of sheets located between the gaps. This arrangement leads to the counting of a predetermined number of sheets and accordingly to the formation of sheets of the same height.

From WO 93/15006 it is known to form stacks from bottom to top by the sheets arriving individually and at a distance from one another passing through a station which periodically raises the rear sheet margin in order to form descending grouped sheets. As soon as a stack of a predetermined height is formed, the next sheet is stopped by a stop, on which a small partial stack is then formed. During this time, the previous stack of sheets is removed and the stack position for the subsequent group of sheets is cleared. The briefly stopped partial stack then reaches the actual stacking position by removing the stop.

The disadvantage of this measure is that the gap formation in the area of the already scaled leaves must take place from above. This requires control which signals must pick up from the shingled last sheet of a stack and must actuate the stop to form a gap between the individual shingled sheet groups. Such gaps are unsafe because they create the danger of also holding the last sheet in front by friction.

In contrast, the invention is concerned with a problem deviating from the prior art.

In the field of modern data processing, it is namely required to prepare the data, information and the like printed on single sheets or on endless webs ready for dispatch by separating and stacking single sheets from the sheet web. A special problem arises from the condition of stacking only sheets belonging to a certain group, then moving the stack and forming a new stack for another group of sheets. If the data carriers are to be stacked in a sequence in such a way that the first sheet is on top, there is the requirement to form the stack from bottom to top.

With this document processing, it is important to form stacks of different heights, depending on how many documents have to be assigned to the individual transaction.

The invention is therefore based on the object of further developing the previously known measures so that one is able to stack and process groups of documents with different numbers of documents in a simpler manner. It is left open whether the receipts must be fed in as individual cuts or separated from a sheet.

This object is achieved with the characterizing features of patent claim 1.

The leaf groups are then separated before the leaves are flaked. This measure has the advantage that, at the same time as the leaf groups are separated, the stack formation is also controlled with a simple sequence control.

In a preferred embodiment, a sheet web is assumed, from which the sheets are separated by cutting, tearing or the like.

In this case, it proves to be expedient to create the gap by interrupting the feed of the sheet web for the separation process of the individual sheets. This is advantageously done by creating the gap by briefly interrupting the separation process.

It has proven to be expedient here if the sequence control is activated by marking the last sheet belonging to a certain group of sheets.

The aim of the invention is to move the stack of a certain group of sheets as quickly as possible to another stack in the same place another group of leaves. Such conditions arise in particular when single sheets or an endless web are printed in a printer and then stacks of all such receipts must be formed, which are intended for a recipient, for example invoices, transfers, account statements or other documents.

A preferred device for carrying out the method according to the invention consists in the features of claim 6.

"Descending descending group of leaves" is understood to mean a measure in which the following leaf comes to lie offset under the preceding leaf. This measure has the advantage that the first sheet of a certain sheet group also comes to lie at the top of the sheet stack. As a result of this descending scaling, it is sufficient that the stop only a short distance, for. B. 10 to 15 mm, but at least one sheet thickness protrudes beyond the conveying plane of the sheets, because the only thing that matters is to stop the sheets lying at the bottom in the sheet stack.

This leads to an advantageous embodiment of the invention, according to which the stop with a drive element arranged off the conveyor path, for. B. switching shaft, can be connected so that it projects upright in its stop position between the belts of a belt conveyor and comes to rest in its inactive position by rotating the switching shaft or the like below the conveyor line. If, in the sense of the invention, the stop is brought out of the conveyor line by twisting or shifting, the previously formed stack can be displaced, ie transported away, by the continuously rotating conveyor. Once the stack moves away the position of the stop has exceeded, the stop is brought back into its stop position so that the next stack can be formed within a very short time.

Instead of a control shaft, sliders, levers or the like can be used.

In an advantageous embodiment of the invention it is provided that, following a take-off conveyor for the individual sheet, a ramp which rises obliquely up to the conveying plane of a subsequent belt conveyor and a short distance thereafter an entraining roller arranged against the belt conveyor are arranged, the distance between the ramp and the driver roller is shorter than the sheet length extending in the conveying direction.

Such an arrangement is known from CH-PS 418 366. However, it is about flaking leaves so that they can be folded afterwards. Stacking is not provided in this prior art.

With the device according to the invention it is possible to shed the sheets arriving one behind the other for another purpose. As the follower roller grips and advances the sheet sliding over the ramp, the rear portion of the sheet is brought into an inclined position by the ramp, which makes it possible to guide the front area of the following sheet below the rear area of the preceding sheet.

The individual sheet can be separated from the sheet web in various ways. It is expedient, for example, if the withdrawing conveyor in a ripper has a higher conveying speed than the feeding conveyor. This creates a tensile force in the web, which is able to tear off the single sheet, if a predetermined tear line is predetermined by perforation or the like in the web. However, the single sheet can also be separated from the sheet web by a cross cutter or the like.

In a further embodiment of the invention it is provided that a web loop is provided between a web printer and the separating device for forming the sheets. The purpose of this web loop is to form a web buffer, namely when the feed of the web is briefly interrupted in order to gain time for moving a finished stack of sheets. The web printer should not be shut down during this phase. As a result, the web conveyor in the printer pushes the web into a loop from which the web material is pulled out again by temporarily conveying the take-off conveyor.

This measure does not apply if printed single sheets are to be stacked. Then a buffer is formed from the scale section, which enables a gap to be created.

If, according to the invention, a flat hold-down device is placed against the belt conveyor at a distance approximately corresponding to the length of a sheet, it is possible to convey the incoming sheet under the stack with a sufficiently large frictional force, which can have a considerable height. Depending on the sheet stiffness, the stack can hold up to 3000 sheets. The hold-down device increases the friction of the sheet underneath against the belt conveyor, so that when the sheet is pushed under the stack, no jam or sheet bulging can occur.

It is also expedient if one or more groups of balls which extend transversely to the conveying direction and are rotatably mounted in sockets are placed against the belt conveyor. These keep the overlapping sheets in contact with the conveyors and prevent the sheets from shifting when stacked.

Finally, the subject of the invention is a measure in which the stop and one of the conveyors for the sheet web or the single sheets are connected to a sequence control which stops the conveyor until the end of the stack formation until there is a gap between the last sheet of the stack to be formed and the subsequent sheet is created and which swings the stop as soon as the last sheet has reached the stack position.

Figur 1:

eine schematische Seitenansicht einer Stapelvorrichtung mit aneinander gereihten Gruppen zum Bedrucken, Schuppen, Stapeln und Versetzen von Blättern, insbesondere Belegen

Figur 2:

eine schematische Seitenansicht der Vorrichtung zum Schuppen und Stapeln von Blättern in vergrößerter Darstellung

Figur 2a:

eine schematische Seitenansicht einer Vorrichtung zum Abtrennen der Blätter von einer Bahn durch Abreißen und

Figur 3:

eine schematische Darstellung der Vorrichtung gemäß Figur 2 in verschiedenen Verfahrenssituationen.

These and other features of the invention emerge from the drawing. In it, the invention is shown schematically and for example. Show it:

Figure 1:

is a schematic side view of a stacking device with groups lined up for printing, flaking, stacking and moving sheets, in particular documents

Figure 2:

a schematic side view of the device for flaking and stacking sheets in an enlarged view

Figure 2a:

is a schematic side view of a device for separating the sheets from a web by tearing and

Figure 3:

a schematic representation of the device according to Figure 2 in different process situations.

In the example in FIG. 1, it is shown that the device suitable for carrying out the method according to the invention can be designed in a plurality of assemblies arranged one behind the other.

A sheet web (2) provided with predetermined tear lines is printed in a printer (1). In this way it is possible, for example, to print account statements, invoices, transfers or other receipts in succession on an endless web, which creates the problem of stacking receipts intended for one recipient, for example, without confusing receipts for other recipients .

The sheet web (2) leaves the printer (1) to form a loop (3), the meaning of which will be described later. The leaf web (2) then arrives in a separating device (5), where it is transferred to a linear conveyor section (4). In this separating device (5), the single sheet or the single document is separated from the endless sheet web (2) and taken over by a take-off conveyor (6). This take-off conveyor (6) conveys the separated sheet into a scale-forming device (7), the details of which are shown in FIG. The purpose of this scale-forming device (7) is to push the subsequent sheet under the end of the previous sheet, in order to ensure that the first sheet of a certain group of sheets comes to lie at the top of a stack.

The descaled leaves (9), descending in this way, are now brought together to form a stack (10), for which purpose a stop (11) is provided, which the conveyor section (4) e.g. protrudes upwards and against which the leading sheet edges of the individual sheets (9) abut. As soon as the stack (10) of a certain group of sheets is finished, the stop (11) is moved out of its stop position, so that the stack (10) by a conveyor (20) (see FIG. 2) on which the stack of sheets (10 ) while sitting on the stack, can be moved. (12) denotes a stack buffer and (13) a stack bundle, which are intended to feed the individual stacks (10) as required for further processing.

In the example in FIG. 2, it is assumed that the individual sheets (9) are separated from the sheet web (2) by a cross cutter (14). It has proven to be expedient to shut down the sheet web (2) during the cross cutting process, which can be done, for example, by briefly stopping the drive of the cross cutter (14) with its conveying elements, not shown.

The descaling of the sheets (9) is carried out between the take-off conveyor (6) and a driving roller (16), which is set against a belt conveyor (19). For this purpose, a ramp (15) is provided which overlaps the conveying plane of the belt conveyor (19) in an inclined manner. The sheet guided over this ramp (15) is therefore deflected when the front one End of sheet is detected by the driving roller (16). Then the rear sheet area (17) of the sheet (9) is inclined upwards, so that the front sheet area (18) of the next sheet is pushed under the rear area of the preceding sheet.

The sheets (9) scaly in this way are first moved forward by the belt conveyor (19) and then subsequently by the belt conveyor (20). In order to ensure the position of the scaly leaves, several balls (24) are provided in rows in the embodiment of FIG. 2 and are rotatably guided in sockets (25). These sockets (25) have, for example, the shape of transverse strips, which can be designed so that they can be swiveled up in order to allow access to the scaly leaves (9).

The stack (10) to be formed is achieved in that a stop (11) (or several stops one behind the other) protrudes upward through the belt conveyor (20), it being assumed that the belt conveyor (20) consists of several, spaced apart arranged, circumferential belts. The stop (11) protrudes only a short distance beyond the conveyor section (4), because it only needs to limit the sheets in the feed at the bottom. Below the conveyor level of the belt conveyor (20) there is a control shaft (21) to which the stop (s) (11) are attached. By turning this switching shaft (21), the stop (11) comes out of its stop position into an ineffective position, so that the stack (10) formed on the belt conveyor (20) can be moved by the belt conveyor (20).

At a distance corresponding to the length of the sheet, there is a hold-down device (22) in front of the stop (11) which, by means of a spring, acts against the continuously rotating belt conveyor and the sheets (9) on it is pressed. This hold-down device (22) ensures that the rear region (17) of a sheet (9) can be pushed under this stack (10) without creasing against the load of the stack (10).

FIG. 2a shows a variant of FIG. 2 with regard to the separation process. The separating device (5) has two pulling roller pairs (27) and (28) which are arranged at a distance from one another, of which the pair of pulling rollers (27) has a lower conveying speed than the pair of pulling rollers (28). Consequently, the sheet web (2) between the pairs of pull rollers (27, 28) is subjected to a tensile stress, which leads to the separation of the single sheet along an existing transverse perforation.

In order to form sheet stacks (10) with a certain number of sheets (9), there must be a gap (26) between the last sheet (9) of the preceding stack (10) and the first sheet (9) of the subsequent stack (10) (see FIG. 3b) are formed before the descaling of the leaves (9) takes place.

In the example in FIG. 2, the gap formation is caused by the cross cutter (5) with its drive elements being stopped briefly while the printer (1) continues to work and conveys the web (2) into the loop (3). The interruption lasts until the last sheet (9) of the preceding sheet group can no longer be obtained from the first sheet (9) of the subsequent sheet group when the separation process with web conveyor is resumed.

In the example of FIG. 2a, the pairs of pull rollers (27) and (28) are stopped in order to form a gap (26) between the groups of sheets. In this case, the already torn first sheet (9) of the subsequent sheet group is still in the area of influence of the pair of pull rollers (28). When this sheet is at a standstill, its front edge has not yet reached the take-off conveyor (6) of the scale-forming device (7).

While the leaf web (2) is at a standstill in the area of the separating device (6), the loop (3) according to FIG. 1 is of course enlarged. In order to eliminate this degree of enlargement, the pairs of pull rollers (27) and (28) are briefly driven at a higher conveying speed when the drive interruption ends, until the original normal operating state has been reached again.

The scale formation of the sheets (9) according to FIG. 2 presupposes that the belt conveyor (19) rotates more slowly than the take-off conveyor (6) or the pair of pull rollers (28).

The position of the driving roller (16) can be adjusted parallel to the conveying direction of the sheets and can be adapted to the length of the sheet (9). The distance between the discharge conveyor (6) and the driving roller (16) is slightly larger, for. B. 5 mm than the length of the sheet (9).

The distance between the pairs of pull rollers (27) and (28) is also greater than the length of the sheet (9). The function of the pair of pull rollers (28) could also be taken over by the discharge conveyor (6).

The movement of the stop (11) and the arrangement (which creates a gap (26) between the shingled leaves (9)) are in a specific relationship to one another, which is achieved by a sequence control according to the invention. The individual phases of this control are shown in FIG. 3 with the individual positions 3a to 3h.

In position 3a it is shown that a single sheet (9) is separated from the sheet web (2) and that the preceding sheets (9) are scaled in such a way that the following sheet (9) is below the end of the preceding sheet (9) comes to rest. At the end of the conveyor section (4) there is a stop (11) on which the stack (10) forms. With (19, 20) a conveyor is shown schematically, through whose upper conveyor run the individual stop (11) protrudes. In the example in FIG. 3b, it is indicated that a gap (26) is formed after the control device according to the invention has recognized when the last sheet (9) was caught by the driving roller (16). The conveyor (19, 20) conveys this last sheet (9) up to below the stack (10) while the separation process for the subsequent sheet (9) is briefly interrupted, thereby creating the gap (26). This gap (26) is decisive in order to gain time for moving the stack (10).

This phase is reached in position 3c. The gap (26) has migrated to the stack (10) because the supply of single sheets was briefly interrupted beforehand, while the conveyors (19, 20) are constantly rotating. It can be seen that the gap (26) is formed between the end of the stack and the front edge of the next sheet (9). If the stop (11) is brought into the position of the position 3d, the stack (10) can be moved without the subsequent sheets (9) needing to be stopped. As can be seen from position 3f, the stop (11) returns to the stop position after passing the stack (10), so that the gap (26) is sufficient to rest the leading edge of the next sheet (9) at the stop (11) to be able to stop. This measure is shown in position 3g so that a new stack (10) corresponding to position 3h can be formed.

The actuation of the stop (11) and the brief stopping of the separating device (6) or another conveyor for the sheet web (2) can be marked by a mark, e.g. Imprint which is placed on the last sheet (9) intended for a specific stack.

The arrangement according to the invention is not limited to the use of leaf webs (2). Rather, one can also assume a sheet stack of greater height in order to pull the cut sheets from there, to scale them and to stack them.

In any case, the gap (26) is always formed before the flakes of the leaves (9). This has the advantage that sheet stacks (10) can be formed for very specific sheet groups with quite different numbers of sheets. Depending on the marking of the last sheet (9) belonging to a sheet group, it is easier to form the gap before the shingling process than if - as in the prior art - the gap formation in the flaky association of the sheets had to be carried out.

PARTS LIST

1

printer

2nd

Scroll of leaves

3rd

loop

4th

Conveyor line

5

Separator

6

Deduction conveyor

7

dandruff device

8th

Stacking device

9

sheet

10th

stack

11

attack

12th

Stacking buffer

13

Stacking

14

Cross cutter

15

ramp

16

Driving roller

17th

rear leaf area

18th

front leaf area

19th

Belt conveyor

20th

Belt conveyor

21

Selector shaft

22

Hold-down

24th

Bullet

25th

Frame

26

gap

27

Pull roller pair

28

Pull roller pair

Claims (15)

1. Process for forming and moving stacks (10) of sheets (9), especially printed sheets, in which the sheets (9) are conveyed in descendingly imbricated sheet groups, between each of which a gap (26) is situated, up to a stop (11), at which the stack (10) forms from the bottom upwards, the stop (11) being briefly removed from its stop position for the purpose of freeing the formed stack (10) and transporting it away, in dependence on the position of the gap (26) situated between the sheet groups, by means of a sequence control and the gap (26) between the sheet groups being formed along a linear conveying section (4), characterised in that the sheets (9) for the formation of sheet groups in dependence on a preset number of sheets are imbricated only after formation of the gap (26).
2. Process according to Claim 1, characterised in that the sheets (9) are separated off from a printed sheet web (2) and then divided into the sheet groups, imbricated and stacked along the linear conveying section (4).
3. Process according to Claim 2, characterised in that the gap formation is effected by brief interruption of the separating operation.
4. Process according to Claim 1 or one of the subsequent claims, characterised in that the gap formation and the movement of the stop (11) are carried out by means of a sequence control of the drive members without interruption of the printing operation.
5. Process according to Claim 1 or one of the subsequent claims, characterised in that the sequence control is activated by a mark on the last sheet (9, 17) belonging to a specific sheet group.
6. Apparatus for carrying out the process according to Claim 1 or one of the subsequent claims, in which, at the end of a conveying section (4) for descendingly imbricated sheet groups, between each of which a gap (26) is situated, there is arranged a stop (11) which projects above the conveying plane and at which the sheet stack (10) forms from the bottom upwards, and in which there is provided a sequence control, which reacts in dependence on the position of the gap (26), for the brief removal of the stop (11) in order to transport the fully formed stack (10) away, characterised in that there is arranged along a linear conveying section (4) an arrangement for the formation of gaps (26) between the arriving sheets (9), which are not yet imbricated, for the purpose of distancing sheet groups with a preset number of sheets, and therebehind there are arranged an apparatus for the descending imbrication of the sheets (9) and the stop (11) for the formation of the sheet stack (10).
7. Apparatus according to Claim 6, characterised in that the arrangement for the formation of gaps (26) between the sheets (9) comprises a controlled drive for the brief stoppage of the separating apparatus (5) for a printed sheet web (2).
8. Apparatus according to Claim 7, characterised in that, following a drawing-off conveyor (6) for the individual sheet (9), there are arranged a ramp (15) which rises obliquely above the conveying level of a following band conveyor (19) and, a short distance thereafter, a driver roller (16) which is set against the band conveyor (19), the distance between the ramp (15) and the driver roller (16) being shorter than the sheet length extending in the conveying direction.
9. Apparatus according to Claim 8, characterised in that the drawing-off conveyor (6) has a greater conveying speed than the following band conveyor (19).
10. Apparatus according to Claim 8, characterised in that the driver roller (16) is adjustable parallel to the conveying direction.
11. Apparatus according to Claim 7, characterised in that a cross cutter (14) or a tearing-off arrangement for perforated sheet webs (2) is provided for separating off the sheets (9) from the sheet web (2).
12. Apparatus according to Claim 7 or one of the subsequent claims, characterised in that a web loop (3) is provided between a web printer (1) and the separating apparatus (5) for the formation of the sheets (9).
13. Apparatus according to Claim 6 or one of the subsequent claims, characterised in that a flat hold-down means (22) is set against the belt conveyor (20) in front of the stop (11) at a distance corresponding approximately to the length of a sheet (9).
14. Apparatus according to Claim 6 or one of the subsequent claims, characterised in that one or more groups of balls (24) extending transversely to the conveying direction and rotatably mounted in holders (25) are set against the band conveyor (19, 20).
15. Apparatus according to Claim 6 or one of the subsequent claims, characterised in that the stop (11) and the drawing-off conveyor (6) are connected to a sequence control which briefly stops conveying means in order to end the stack formation until a gap (26) has arisen between the last sheet (9, 17) of the stack (10) to be formed and the following sheet (9, 18), and which swings the stop (11) away as soon as the last sheet (9, 17) has reached the stacking position.

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