GB2077235A

GB2077235A - Facilitating the opening of folded signatures for collation

Info

Publication number: GB2077235A
Application number: GB8113732A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-05-06
Filing date: 1981-05-05
Publication date: 1981-12-16
Also published as: FR2491831A1; DE3117419A1; FR2491831B1; IT1144340B; IT8167615A0; DE3117419C2; CH659035A5; GB2077235B

Abstract

To facilitate the opening of folded signatures prior to collation thereof, an electrostatic charge is provided on each stack 13 of sheets before the stack is folded into the signature 17. Thus sheet parts charged with the same polarity confront one another on the inside of the folded product. The stacks may be cut from a multi-layer, printed web after a charge has been applied to the web by a high tension electrode arrangement disposed transversely to the web between pinch roller pairs. <IMAGE>

Description

SPECIFICATION A method of collating bundles of electrically insulating substrate materials in the form of folded sheets In the collation of printed sheets of illustrated magazines, brochures comprising a large number of pages, and similar publications of rotary printing machines, the printed paper webs coming from the printing and slitting units are formed by means of deflectors, including for example turning bars, in a predetermined register relationship into a multiweb band in which successive pages of the printed product lie adjacent to one another. The multi-web band then passes through a first pair of sandwich rollers by which the paper webs are substantially prepressed against one another, and thereupon through a second pair of sandwich rollers by which the multi-web band is pulled tautly off the first pair of sandwich rollers.The taut multi-web band then passes through a slitting unit having a rotating cutter arrangement, by which the band is divided into individual packets of sheets of predetermined length or sheet size corresponding approximately to double the page width of the printed product. These individual packets of sheets then pass into a receiving or gathering cylinder in which the packets are held in "intermediate store". From the receiving or gathering cylinder the individual packets of sheets are passed to a folder, in which they are crossfolded (e.g. halved) to single page size(s), in which the printed pages lying innermost in the folded bundle and facing one another are formed by the outer surface of the outermost web nearest the fold in the multi-web band.

The folded bundles originating from an individual printing unit are then stream-fed by a conveyor belt to a stacker, in which they are held in "intermediate store" in a stacked manner, for example on pallets. Folded bundles containing the other printed pages of the printed product are similarly held in "intermediate store", for example on pallets, until finally all the folded bundles of the printed product are collated in a packet delivery station in the finished shop. The packet delivery station may for example be a so-called rotary conveyor, in which horizontal carriers in the form of "knives" are guided between belts.The folded bundles, which in the printed product are to be placed one above the other in accordance with the printed pages following one another from inside to outside, are laid by hand, or by means of mechanical feed devices, astride the "knives" in a collating machine in the finishing shop so as to follow one another in the correct order. The folded bundles are removed from the knives of the packet delivery station either by hand or likewise by means of automatic grippers. The folded bundles, which have thus been collated in a determined order to form a stack of bundles containing all the pages of the printed product, are thereupon fed, once again by hand or by means of a gripper device, to a stiching machine in which the stack of bundles is stiched together to form a brochure.

Finally, the brochure is uniformly trimmed (e.g. on three sides).

In order to ensure that the folded bundles produced by the folding machine will be received correctly on the knives of the packet delivery station and can there by formed into stacks of bundles, it is necessary for the folded bundles first to be "opened", that is to say the printed sheets, which have been folded once and are lying one above the other, must be brought back to a Vshape in such a manner that they can be placed without obstruction on the appropriate knife. This can be done with complete success only if on the one hand the printed sheet parts of the innermost sheet of the folded bundle have a definite tendency to separate, with the sheet parts diverging continuously in the outward direction from the fold, and if on the other hand the printed sheets of the folded bundles do not fan out and thus no longer hold together.

The invention therefore seeks to provide a method for the collation of bundles of electrically insulating substrate material sheets which have been folded once, whereby on the one hand the abovementioned tendency of the innermost sheet parts of the folded bundle to separate is forcibly induced, while on the other hand ail the sheets of substrate material in the folded bundle are temporarily held in mutual contact. The invention further seeks to apply the method in conjunction with a rotary printing machine for the purpose of collating bundles of folded sheet stacks.

The problem underlying the invention is solved by the method featured in the following claims.

The advantages of the steps taken in accordance with the invention consist in that, for example, individual sheet packets separated from a multi-web band of substrate material can be folded in half in such a manner that under the action of an electrostatic charge acting between the outermost sheets of the bundle the resulting folded bundle automatically opens in a V-shape, at least during an appropriate period of time or until it undergoes further processing, as a result of the repulsion of homopolar charges, and that the individual sheets of the folded bundle are held in mutual contact until the charge is removed or equalized.In the case of folded bundles of printed sheets of the kind initially mentioned above complete removal or equalization of the charge is effected at the latest when a printed product, which has been collated from a plurality of individual sheet packets, has been passed through an external contacting zone shortcircuiting the charge potentials. Every time another folded bundle opened out into a V-shape is placed on a folded bundle lying beneath it, opposite charge potentials come into contact with one another, so that a stable sheet structure results even if a continuous natural discharge to the environment, promoted by the humidity of the ambient air, takes place.

The invention is described below by way of example and with reference to the accompanying drawings, in which: Figure 1 shows schematically an installation for effecting the collation and electrostatic tacking of sheet paper webs and the diversion of a multi-web band into individual sheet stacks, Figure 2 shows a modified version of the electrode arrangement of Figure 1 shown in basic form, Figures 3A and 3B show an individual sheet stack (A) cut to length and in the state before its entry into the gathering cylinder, and the individual sheet stack after it has been formed into a folded bundle (B) in the folder, and Figure 4 shows schematically the collation of a number of different folded bundles on a horizontal rotary conveyor provided with knife-type carriers, the stiching of the collated folded bundles, and the removal of the residual charge from the outside of the finished printed product.

In Figure 1, 1 a-1 h designated a number (for example eight) of paper webs which have been printed on one or both sides and which are fed to respective deflector rollers 2 and 2' in a collecting roller train from the printing and slitting units of one or more rotary printing machines, optionally passing over deflector means such as turning bars, and the like. When they run onto the associated deflector roller 2, 2' of the collecting roller train the paper webs 1 a-1 h have their printing already in the register relationship desired for neighbouring pages in the finished printed product.The paper webs, which on leaving the collecting roller train are still only in loose mutural contact, then pass between a first pair of sandwich rollers 3,3, by which they are brought into close mutual contact and then from a multi web band 4, which in its further movement is guided between another pair of sandwich rollers, 5,5 is in the form of a motor-driven pair of draw off rollers, which through their frictional engagement with the outer paper webs 1 d and 1 h move all the paper webs 1 a-1 h through the preceding processing stages (not shown). The second pair of sandwich rollers 5,5 thus has a considerable stretching action on the individual paper webs of the multi-web band 4 and effects the smoothing of all the paper webs 1 a-1 h.

Between the two pairs of sandwich rollers 3,3 and 5,5 is mounted a charging electrode arrangement 6, which extends transversely to the multi-web band 4 and over the entire width of the latter, and which in the arrangement shown in Figure 1 contains two identical ionizing electrodes 7,7'. By means of feed lines 8,8' these electrodes are connected to the output terminals of a high tension direct current source (not shown). The ionizing electrodes 7,7' are preferably known pointed electrode devices, in which individual electrodes ending in sharp points of conical shape are fed through a common contact bar and are mounted in an accurately defined sequence and spacing relationship.The contact bar which feeds the pointed electrodes, and which is connected to the direct current source by the above-mentioned feed lines 8,8', has a rigid covering of electrically insulating material, which is in the form of a bar and which at the same time serves as carrier for the contact bar. The ionizing electrodes 7,7' serve to apply respective electrostatic charges of opposite polarity to the outermost paper webs 1 d and 1 h. The purpose of this step will be explained below.

It will be understood that instead of the abovementioned pointed electrode apparatus it is also possible to use charging electrode arrangements comprising wire or rod electrodes of any crosssection and electrode configuration. Instead of the insulated arrangement of the two ionizing electrodes 7,7' it may for safety and operational reasons be expedient to ground one pole of the direct current source and correspondingly also the respective electrode. An arrangement of this kind is shown in Figure 2. The grounded electrode 9 is in this case preferably a metal section having apprpriate inherent rigidity, or an electrode strip mounted on a carrier element. This insulated electrode 10 is expediently a pointed electrode apparatus of the kind described above, or a wire or rod electrode.The insulated electrode may selectively be connected to the positive or negative pole of the direct current source, while the associated opposite pole is connected with ground.

When use is made of two insulated electrodes a preferential polarization of the two electrodes, dependent on the design or mode of operation of the printing machine, may be necessary in certain circumstances.

Electrode arrangements of the kind shown in Figures 1 and 2 can easily be installed not only during the installation of a printing machine, but also subsequently, as they take up little space.

Since in addition they can be installed in a position on the path of the paper through the machine where good visibility is possible at least during makeready work, and usually also during printing, and since furthermore they require little attention, special measures for their installation are usually not required.

Through the application of electrostatic charges of opposite polarities to the outer surfaces of the multi-web band 4 a pressure effect is applied to the paper webs between them, whereby the paper webs of the multi-web band are held together at least during a period of time in which the completion of the printed product can normally be effected. It is thus possible for even individual stacks or packets of sheets which hold themselves together to be separated from the multi-web band 4. This is expediently effected with the aid of a rotating cutter arrangement" 1 1,1 1', by which dividing cuts 12 can be made through the multi-web band 4 at determined intervals. The sheet stacks 1 3 then pass into a receiving or collecting cylinder 14, the construction and mode of operation of which are known and which is followed by a conventional transfer device 1 5 for forwarding the stacks of sheets to a likewise conventional folder 1 6.

Because of the electrostatic bonding of the individual sheets in the stack of sheets they adhere so firmly to one another that there is no risk of the stack falling apart.

The sheet stacks 13, which for example may be polarised as shown in Figure 3A and which enter the receiving or collecting cylinder 14, are there delivered by stream feeding, with opposite charge polarities of the packets of sheets coming to lie on one another in each case. Since the charge potentials are practically equal in magnitude, there is substantially no discharge. In the folder 16, folded bundles 1 7 are formed therefrom by crossfolding, as shown in Figure 3B, forming two halves practically equal in size. These halves of the portion of paper web lying inwards on the fold side thus come to lie one against the other. Since these two halves now have the same polarity (the negative polarity in Figure 3A and 3B), the legs of the folded bundle 1 7 tend to open out.Since in addition the outsides of the folded bundles 1 7 also are at the same potential -- the opposite potential to that of the inside of the bundle, the folded bundles leaving the folder 1 6 in a stream feed arrangement on a conveyor belt 1 9 have a tendency to repel one another, so that they must be held down by hold-down means 18, for example pendulum-mounted rollers.

The resulting ease with which the folded bundles 1 7 leaving the folder 1 6 on the conveyor belt 19 in the direction of the arrow 20 (Figure 1) can be separated brings about a substantial improvement of output in the actual collation, in a manner known per se as schematically indicated in Figure 4, of the folded bundles 17 following one another from inside to outside in the finished printed product. The operation will be explained here solely in order to demonstrate the advantages of the method of the invention.

Figure 4 shows at the top three conveyor belts 19.1, 19.2, 19.n, corresponding to the conveyor belt 1 9 in Figure 1, on which conveyor belts folded bundles 17 under load from hold-down means 18 are delivered in the direction of the arrow 20 to stacking device 21.1,21.2,21.n. In finishing shops which are not fully automated the stacking devices 21.1--21.n are for example containers which stand on pallets and from which the folded bundles 1 7 containing the different printed pages are delivered, usually by hand, to the collating machine given the general reference 22.

Associated with the stacking devices 21.1-21.n, in known manner, are bundle separating devices and schematically represented conveyor means 23.1-23.n, which work in rhythm with the forward movement of a packet delivery system 26 shown in partial developed view. The packet delivery system 26 may be a rotary conveyor in which horizontal carriers known as knives 24.1--24.n are guided on belts 25. All details not necessary for the explanation of the advantages of the invention are omitted in the diagram in Figure 4.

The knives 24.1 -24.n of the packet delivery system 26 are timed in movement in such a manner that they arrive in succession at respective points in the collating machine 22 which are adjusted to the working of the stationwise organization of the stackers 21.1--21.n and the conveyors 23.1-23.n.

At the latest at the point where the empty knife 24.0 is situated a full stack of bundles must be lifted off either by hand or by mechanical means.

During the next cycle of movements the knife which is now empty passes to the point where it is designated 24.1. There it receives from the conveyor 23.1 the first folded bundle 1 7.1 comprising the innermost pages of the printed product. The repelling action of identical polarities of the electrostatic charge on the innermost sheet of the packet has the consequence that the legs of the V-shaped folded bundle stand apart in such a manner that the folded bundle can be faultlessly placed astride the previously empty knife. The individual sheets of the folded bundle also continue to adhere to one another, so that there are no difficulties with sheet end fanning out.

The next movement cycle then brings the knife to the point where it is designated 24.2, and there it receives from the conveyor 23.2 the second folded bundle 1 7.2, which because of the spreading-out of the legs of the bundle can once again be faultlessly placed astride the first folded bundle 17.1. The process is repeated for each successive movement cycle, until all the folded bundles of the printed product being produced have been placed one over the other. The collating machine obviously contains as many of the abovementioned stations 21.1--21.n, 23.1-23.n as there are folded bundles 17.1-1 7.n to be collated.It is also obvious that instead of folded bundles of the kind shown in Figures 1,2, and 3 it is also possible for individual sheets of a different material from that of the sheets of the folded bundles to be introduced into a collating machine, which individual sheets are optionally not electrostatically charged or chargeable.

From the station where the outermost folded bundle in the printed product has been placed in position the bundle stack 27, which is thus stratified in the form of an inverted V, then passes automatically in the direction of the arrows 28, 29 to a stiching and trimming machine 30. In this machine the folded bundles 17.1-1 7.n are stapled to form a brochure and trimmed on three sides. Finally, the completed printed products pass on a conveyor belt 31, for example to the dispatch room. Any harmful residual charge retained by the printed product can be discharged by means of a grounded electrical discharge device 32.

Claims

1. A method of collating bundles of electrically insulating substrate materials in sheet form which are stacked one on the other in a plurality of layers and which have been folded about a fold line extending transversely of the substrate sheets, wherein the sheets in a stack of substrate sheets are temporarily held electrostatically against one another in a packet before the folding by inducing opposite electrostatic charges on the two outermost sheets of the substrate stack and wherein the electrostatically tacked substrate sheet stack is fed to a folder in order to be folded therein to form a folded bundle in which two sheet-parts charged with the same polarity confront one another on the inside of the bundle.

2. The method of claim 1, in which a second folded bundle is placed on a first whereby the electrostatic charge on the outer sheet of the first folded bundle is of opposite polarity to that on the inner sheet of the overlying second bundle.

3. The method of claim 1 or claim 2 in which the bundle of sheets is formed from a plurality of webs of electrically insulating substrate material mechanically brought into contact and passed between an electrode arrangement to electrostatically tack the webs together prior to cutting the tacked webs into stacks.

4. The method of any preceding claim in which the sheets are printed paper.

5. A method of collating bundles of electrically insulating substrate materials in sheet form which are stacked one on the other in a plurality of layers and which have been folded in half about a fold line lying approximately halfway along the length of the substrate sheets, wherein the sheets in the stack of substrate sheets are temporarily held electrostatically against one another in packets before the folding by the application of opposite electrostatic charges to the two outermost sheets of the substrate stack and wherein the electrostatically tacked substrate sheet stack is fed by way of a collecting system and a feed system to a folder in order to be folded therein into two halves of practically equal size to form a folded bundle in which two half-sheets charged with the same polarity lie opposite one another on the inside of the bundle.

6. The application of the method as claimed in claim 5 in conjunction with a rotary printing machine in which, after passing through web cutters, printed paper webs coming from at least one printing unit are separated into sheet paper, webs and are fed by way of deflectors to a collecting system in order to form a multi-web band and the paper webs of this multi-web band are brought into close mutual contact by means of a press device acting on the two outermost sheet paper webs, this press device comprising a first pair of sandwich rollers and a second pair of sandwich rollers which second pair is spaced apart from the first pair in the direction of advance of the multi-web band in the printing machine and which second pair exerts on the multi-web band a stretching action in order to pull it out of the printing machine, wherein the electrostatic charge is applied by a high-tension electrode arrangement, which is disposed transversely to the multi-web band in the region of action of the press device, to the outermost sheet paper webs in the multi-web band, and wherein after passing through the second pair of sandwich rollers the multi-web band is divided into individual sheet stacks without substantially reducing the electrostatic charge.

7. An application as claimed in claim 6, wherein the high-tension electrode arrangement is disposed between the first pair of sandwich rollers and the second pair of sandwich rollers and at least that portion of the high-tension electrode arrangement which is disposed on one side of the multi-web band is an ionizing electrode provided with individual tips.

8. A method of forming a folded stack of printed paper sheets substantially as hereinbefore described with reference to Figures 1 and 3 or Figures 1 and 3 as modified by Figure 2 of the accompanying drawings.

9. A method of collating folded stacks of printed paper sheets substantially as hereinbefore described with reference to Figures 1 to 4 of the accompanying drawings.

10. A printing machine adapted to operate the method claimed in any of claims 1 to 5.