EP0179361B1 - Device for marking stack portions on the stacking deck of a printing machine - Google Patents

Abstract

A device for use with a sheet stacker for developing a marking or identifying sheet to separate groups within the stack as the latter is being formed. The device is comprised of a paper stop member that is movable between two positions, one for defining the boundary of the primary stack and a second position, spaced outwardly of the stack boundary, at a point defining the position for the marking sheet.

Description

The present invention relates to an arrangement for marking individual pads or stacks of printed sheets on the deposit table of a printing press according to the preamble of claim 1.

When the production pressure, d. H. in the case of successive printing according to different templates, it can result that the individual partial stacks with the different print images lie directly on top of one another on the filing table, without the separating plane between the individual partial stacks being readily identifiable. There are therefore various proposals in the prior art for distinguishing these individual runs or partial stacks from one another. So the so-called swivel table storage is known, d. H. The tray table is pivoted slightly about its vertical axis when one edition is finished, so that the subsequent printed sheets of the next edition (or the partial stack formed from them) differ from the previously printed edition by a slightly different placement angle. The individual partial stacks can be easily distinguished from one another by alternately pivoting the pivoting table or pivoting it back. However, with such a swivel table shelf, it is not common to design the table as a lowering table. In addition, it is disadvantageous to have to carry out a not inconsiderable structural effort only with regard to the desired marking of the individual supports, namely to have to pivot the table and to provide the necessary adjusting mechanism.

It is also known to shoot between these shreds of paper to mark the individual editions. This has the disadvantage that the paper stack can become skewed and that additional equipment is required, i.e. that is, a special strip bullet must be provided at a suitable location on the machine, which can also lead to space problems. In addition, this solution can lead to particular difficulties if the storage table is not designed to be gradually lowered, so that the top of the stack is always at different locations.

British patents 1550146 and 2093807 describe marking devices in which the forward movements of the sheets coming out of the machine are alternatively limited by two different stops, so that the stack can be divided by individual sheets which protrude beyond the stack edge. In this case, electromagnets are provided for activating the respective front stop, which change its position relative to the rear stop.

Proceeding from this, it is the object of the present invention to achieve a clear marking of the individual supports or partial stacks on the storage table of a printing press with a reduced design effort compared to previously known solutions.

This object is achieved by a device with the features of the main claim. According to this, only a single stop is provided, which defines two path lengths for the sheets running out through a front and a rear part. If necessary, the position of the stop is only changed as a whole. This eliminates the need to control the change in position of one stop relative to the other stop, so that neither the control device is arranged in the immediate vicinity of the stops as in the aforementioned British patents nor - unless this is done - the control is carried out with complex transmission elements got to. This simplifies the design, particularly in the case of machines in which the sheet stack is not arranged centrally but on one of the outer sides of the printing press.

According to the teaching of claim 2, a further simplification is achieved. According to this, the length of the distance that the outgoing sheets travel over the stack is controlled by temporarily lowering the deposit table. The devices which are present anyway for executing the continuous lowering movement, including the control, are now also used for the purpose of marking. A separate control of the stop can thus be dispensed with.

Such a solution is particularly interesting for (offset) printing presses with automatic printing film or template change, in which different runs are produced by the printing press in rapid succession. The electronic control of the printing machine ensures that the position of the stop relative to the top of the stack is changed briefly in coordination with the printing film change, so that the path to a further fixed stop is cleared for a possibly unprinted printed sheet, so that a «separating sheet »Is inserted between two successive editions. The solution according to the invention is also interesting without automatic printing film or template change, if it is e.g. B. it is important to insert a separating sheet after a certain number of the same printed sheets stacked on the filing table, which does not even have to be unprinted.

• Fig. 1 zeigt den Ablagestapel oder Stapeltisch während des Druckens einer Auflage (Stapeloberseite auf Höhe N-N);
• Fig. 2 zeigt den Ablagestapel nach Beendigung einer Auflage (Stapelniveau um den Betrag X von Höhe N-N abgesenkt zum Längsversatz des Trennbogens);
• Fig. 3 zeigt den Ablagestapel vor Beginn der neuen Auflage (Stapelniveau wieder auf Höhe N-N angehoben; und
• Fig. 4 zeigt die kinematische Umkehrung der Ausführungsform nach den Fig. 1-3. Die Stapeloberseite behält immer das Niveau N-N bei, doch wird der Anschlag 2 bei Bedarf in vertikaler Richtung so verstellt (Magnet usw.), dass der Spalt Y zum Längsversatz des Trennbogens entsteht.

In the accompanying drawings, two exemplary embodiments of the present invention are shown in principle. The actual printing press is omitted, since the only important thing here is the storage table and the two stops and their arrangement or adjustability in relation to one another.

• 1 shows the storage stack or stacking table during the printing of a support (top of stack at NN);
• Fig. 2 shows the discard pile after completion of a run (stack level by the amount X of Height NN lowered to the longitudinal offset of the separating sheet);
• Fig. 3 shows the discard pile before the start of the new edition (stack level raised to NN; and
• 4 shows the kinematic reversal of the embodiment according to FIGS. 1-3. The top of the stack always maintains the level NN, but the stop 2 is adjusted in the vertical direction (magnet, etc.) if necessary, so that the gap Y for the longitudinal offset of the separating sheet is created.

Fig. 1 shows the filing table with the filing stack 4a thereon in the position during normal printing, i. that is, the storage table is gradually lowered in a manner known per se, so that the top of the stack is always approximately at the level N-N. The printed sheets transported by the discharge roller pair 5 of the printing machine (not shown) onto the storage stack shoot out in the direction of arrow 7 and then slide on the surface of the storage stack up to the stop 2, which has a stop front part 2 a and a stop rear part 2 b. The front stop part 2 a has a lower height than the rear stop part 2 b, d. that is, it extends less far down than the rear part 2 b. In the normal operating position shown in FIG. 1 while the printing is in progress, the sheet stacks shooting in slide up to the stop advantage 2 a. On the opposite side of the storage stack (left in Fig. 1) a reciprocating stacking slide 6 is provided in the usual way, which ensures the formation of a proper stack by pushing possibly rebounding printed sheets back against the stop from the stop 2, 2 .

The top of the stack is held at a level N-N by a sensor in a known manner. If this level is exceeded due to the continuous shooting sheet, the tray table 4 receives a command to drop to the specified height. This sensor can be, for example, a capacitive sensing element arranged in the stacking slide, which is part of the height control for the storage tables 4. To the extent that the top of the stack rises due to the printed sheets placed thereon, the control of the deposit table or the associated drive ensures a lowering of the deposit table during normal printing, so that the top of the stack always remains at the same height.

The stop 2 with its front part 2 and the rear part 2 b and their displacement in relation to the top of the stack represents the actual essence of the invention. On a holder 1, a stop 2 is fastened with the two stop parts 2 and 2b, which by the amount Z are offset from each other in the weft direction. The holder 1 is arranged to be horizontally displaceable - for example by being mounted on a horizontal rod 8 provided on the printing press - and can thus be set to different sheet lengths. The holder 1 has a pin 9 which engages in an elongated hole 10 in the actual stop 2 and thus arranges this stop 2 so as to be vertically displaceable. In Fig. 1 it is shown that the stop 2 rests with its front part 2a on a previously inserted separating sheet and thus limits the subsequent printing sheets in their forward movement on the filing stack. The stop 2 lies on the front part 2 with its own weight on the separating sheet protruding from the storage stack 4a. However, it is also easily possible to generate or increase this load, for example by spring action.

As can be seen from the drawings, the stop 2 with the front part 2 a and the rear part 2 b has approximately the shape of a fork lying in the drawing plane with two prongs, the front prong (front part 2 a) being somewhat shorter than the rear Tine (rear part 2 b).

In the embodiment of FIGS. 1-3, after completion of a support, the storage tables 4 are lowered by a control command by the amount X compared to the level NN, so that between the uppermost sheet of the storage stack 4a and the lower (horizontal) end of the stop front part 2 a a gap of height Y arises. A separating sheet that has been shot in, printed or unprinted at this point is only braked by the rear stop 2b offset by the amount Z in the weft direction, so that there is a clearly visible separation of the various supports on the storage table due to the separating sheet protruding in the longitudinal direction from the stack . As soon as the separating sheet is deposited on the stack, the deposit table 4 receives the control command “upwards”, i. That is, the storage table 4 with the storage stack 4a located thereon is moved upwards until the top of the stack with the one separating sheet thereon has returned to the height N-N (FIG. 3). In this case, the stop advantage 2 a is supported on the separating sheet 3 that has just been introduced, so that sheets subsequently deposited on the filing stack are stopped again by the stop front part 2 a.

The same effect can be achieved by a cinematographic reversal according to the exemplary embodiment in FIG. 4.

For the insertion of a separating sheet 3, the deposit table 4 is not lowered by the amount X as in FIG raised by the amount X (FIG. 4), in order to allow a gap of height Y to arise between the top of the stack and the lower horizontal end of the front stop part 2a. The next shooting, printed or unprinted sheet will then protrude again by the amount Z in the longitudinal direction from the filing stack, after which the stop 2 is then lowered again in such a way that the stop front part 2 a on the Separation sheet 3 rests (corresponding to Fig. 3). The temporary lifting of the holder 8 or the stop 2 connected therewith via an elongated hole can be effected by a magnet or the like and is not shown in detail.

Another possible embodiment (not shown) with the same effect is to design the holder 1 which is longitudinally displaceable on the rod 8 in such a way that it takes over the effect of the stop part 2b and the stop part 2a can be displaced or actuated in height on the holder 1 ( the latter in turn by a magnet).

As a further alternative, it is possible to arrange the front stop so as to be pivotable about an axis parallel to the front edge of the paper stack, in order in this way to bring this front stop out of operation for a short time, so that the individual supports can be marked simply by pointing forward without any other design effort protruding separating sheet is possible.

All that matters is the short-term relative displaceability between the first or front stop and the top of the stack, the second or rear stop being arranged in a fixed manner, although it can be adjusted to differently long printed sheets.

Claims (4)

1. Device for marking individual editions or stack portions on the stacking deck (4) of a printing machine, the stacking deck (4) being gradually lowerable for adaption to the increasing heights of the stacks ands being provided with a buffer on the stacking deck at the height of the stack upperside to limit the forward movement in the transport direction (7) of the printed sheets emerging from the printing machine, wherein the buffer (2) is provided with a front section (2 b) and a back section (2 b) and wherein the stack upperside, or the stacking table, respectively, and the buffer (2) are adapted to be momentarily displaced relative to one another to clear the way to the rear buffer section (2 b) for a printed or demarcation sheet being inserted.

2. Device according to claim 1, wherein the front buffer section (2 a) is non adjustable and the stack upperside or the stacking deck, respectively, is adapted to be momentarily lowered relative thereto.

3. Device according to claim 1, wherein the front buffer section is adapted for momentary shifting while at the same time the stack upperside, or the stacking deck, respectively, is unalterable in its height.

4. Device according to any one of the preceding claims, wherein the front buffer section (2a) is suspended for shifting in height by means of a lost motion connection (elongated hole 10) so as to provide dead weight load on the demarcation sheet.

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