EP0287563A1

EP0287563A1 - Perforation method and blanket for rotary printing machine provided with a perforation device, for example for offset machine.

Info

Publication number: EP0287563A1
Application number: EP19870900174
Authority: EP
Inventors: Gilbert Orsi
Original assignee: Individual
Current assignee: Individual
Priority date: 1985-12-24
Filing date: 1986-12-23
Publication date: 1988-10-26
Anticipated expiration: 2006-12-23
Also published as: WO1987003844A1; FR2591943B1; DE3674807D1; EP0287563B1; AU6839087A; FR2591943A1

Abstract

Blanchet pour machine d'impression rotative, par exemple pour machine offset, équipée d'un dispositif de perforage, caractérisé en ce que ledit blanchet (10) est pourvu d'au moins une gorge (11) s'ouvrant sur sa face d'impression (10a) et dans le fond de laquelle est logée une barrette ou lamelle (12) réalisée dans un matériau dur et non compressible, cette barrette comportant une face supérieure (12a) contre laquelle sont destinés à venir en pression les éléments perforants ou coupants (15d) des filets perforants (15) fixés sur le cylindre d'impression (5), ou cylindre de pression, ou de marge, de la machine, lors du processus d'impression. L'invention vise également le procédé de perforage utilisant le blanchet défini ci-dessus, en association avec au moins un filet perforant (15) fixé sur le cylindre d'impression de la machine.Blanket for rotary printing machine, for example for offset machine, equipped with a perforating device, characterized in that said blanket (10) is provided with at least one groove (11) opening on its face printing (10a) and in the bottom of which is housed a bar or lamella (12) made of a hard, non-compressible material, this bar comprising an upper face (12a) against which the perforating or cutting elements are intended to come under pressure (15d) perforating nets (15) fixed on the printing cylinder (5), or pressure cylinder, or margin, of the machine, during the printing process. The invention also relates to the perforation process using the blanket defined above, in association with at least one perforating net (15) fixed on the printing cylinder of the machine.

Description

Punching method and bLanchet for rotary printing machine equipped with a punching device or accessory. for example for offset machine.

The present invention relates to a blanket for a rotary press machine, such as a sheet or continuous offset machine, equipped with a perforating device.

It also targets the perforation process using this blanket.

IT is known (FR-A-2 479 094) to use, to carry out pre-punching perforations on sheets of paper being printed, threads or perforated strips of removable sheets on the print cylinder of rotary printing machines such as offset machines, teeth or cutting blades of these threads or perforating strips being strongly pressed against the blanket fitted to the blanket cylinder of said machines, during the printing process, so as to perforate the sheet of paper passing between said printing cylinder and said blanket cylinder.

This perforating system, which is easy to implement as required, however has serious drawbacks.

One of these drawbacks arises from the fact that the rubber blanket is prematurely put out of use, due to the penetration of the teeth of the puncturing threads into the soft material thereof, the slots or holes resulting from this penetration constituting tear primers which can harm the regular tension of said blanket on the blanket cylinder.

However, the most annoying drawback of this method of pre-cutting sheets of paper is in The fact that the teeth or cutting elements of the perforating threads penetrating into the tender material of the blanket, create blisters, at the level of the perforations, on the face of said sheets opposite to the penetrating face. The sheets of paper tend to bend slightly at the perforation line. In the case of the printing of sheets comprising a detachable useful surface and a narrow strip allowing their assembly, for example in the form of notebooks or bundles, the narrow strip of sheets tends to lift slightly relative to the detachable useful surface said sheets, Instead of staying flat. This defect is accentuated during printing, because the teeth or blades of the perforating threads act like punches and cut out particles of paper which they push into the slots or holes of the blanket. The accumulation of these particles progressively enlarges the marks formed in the blanket and in the sheets of paper, so that the perforation is less and less effective, the blistering of more and more important and the sheets of more and more. .

This state of affairs poses serious problems for the printer.

Indeed, at the end of the printing set. The printed and perforated sheets are very badly received and very badly "teased" or centered on the receiving board, due to the lack of rigidity of said sheets which are slightly folded and their blisters which cling to each other, so that the stack of sheets stacked on said receiving board is irregular and has one side higher than the other. The stacking height of the sheets is correspondingly reduced, which leads to frequent changes of the carriage. reception and, therefore, frequent machine stops. On the other hand, stacked sheets can be easily damaged and made useless, which results in significant loss of time when these sheets are numbered.

In addition. The printed and perforated sheets are generally beaded enough in an automatic binder which must receive sheets of sheets perfectly "jogged" or centered and flat above, so that it is necessary to resume, by hand, Another factor in wasting time is the "jogging" or centering of stacked maL sheets.

The object of the invention is in particular to remedy the abovementioned drawbacks of the perforation process according to which the teeth or cutting elements of the perforating threads are carried by the printing cylinder and applied against the blanket.

According to the invention, this object is achieved thanks to a bLanchet provided with at least one groove opening on its active external face or printing surface and in the bottom of the panel is accommodated a bar or blade made in a hard material, this bar comprising an upper face against lacquer are intended to come into pressure The perforating or cutting elements of the perforating threads fixed to the printing cylinder of the machine, during the printing process.

The blanket and the perforation process using it provide many advantages. They allow in particular: ~ a perfect perforation of the sheets, without blistering at the level of the perforations;

- to keep the initial planality of the sheets after leaving the main printing and pre-cutting line;

- a regular and perfect stacking of printed and perforated sheets, on the receiving board, of so it is possible to receive a maximum number of sheets over the stacking height available.

Thanks to these advantageous results, a significant time saving is obtained for the shaping and

Assembling of notebooks, bundles or other, printed and perforated sheets arriving perfectly cut and "teased" with the automatic collator.

On the other hand, it is possible to carry out, in a single pass and at the working speeds of the offset machines, the printing of one or more colors, the punching and numbering of the printed sheets, and, optionally, the impression of an accompanying color. The sharpness of the perforation means that when

THE SUBSEQUENT USE OF THE BUNDLES AND, ESPECIALLY, OF THE NOTEBOOKS, WE CAN VERY EASILY DETACH MULTIPLE SHEETS AT A TIME WITH A VERY BEAUTIFUL APPEARANCE RESULTING FROM THE PRE-CUTTING OF THESE SHEETS. The above aims, characteristics and advantages, and others still, will emerge more clearly from the following description and the attached drawings in which:

FIG. 1 represents, dried atically, a rotary printing machine, of the offset type, with which the advantage is advantageously the blanchet and the perforation process according to the invention.

Figure 2 is a plan view of a first embodiment of the bLanchet produced according to the invention.

Figure 3 is a plan view of a second embodiment of the blanket according to the invention.

Figure 4 is a perspective view of a bLanchet carrier cylinder provided with a blanket executed according to the invention.

Figure 5 is an exploded perspective view illustrating the method of fixing the bar or non-compressible blade in the bottom of the throat of the bLanchet. FIG. 6 is an exploded detail view, in section and on a larger scale, also showing the embodiment of the groove with a reinforced bottom of the Lanchet.

Figure 7 is a perspective view on a larger scale of a portion of perforating net intended to be fixed, removably, on the printing cylinder of the machine.

Figure 8 is a detail view, in section and on a larger scale, of a blanket mounted on a blanket cylinder.

Figure 9 is a detail view, in section and on a larger scale, of a perforating net installed on a printing cylinder, also called pressure or margin cylinder.

FIG. 10 is a partial view, in section and on a larger scale, illustrating the perforation of a sheet of paper by the use of the blanket and the perforation method according to the invention.

Reference is made to said drawings to describe an advantageous, although not limiting, example of execution of the blanket and implementation of the perforation process which are the object of the invention.

This is, more particularly interesting, applicable to rotary printing machines, such as offset machines of all kinds mainly comprising (Figure 1) a plate cylinder 1 which are associated inking rollers 2 and dampening rollers 3, a blanket cylinder 4 and a printing cylinder 5 also called a pressure cylinder or margin cylinder, a feeding station 6 receiving the stacks of blank sheets 7 to be printed, and a receiving tray 8 on which stack The printed sheets. numbered and perforated 9, after their passage in the printing and punching assembly. A jogging device (not shown) ensures the correct stacking of the printed sheets, on the receiving board.

The blanket cylinder 4 is intended for the removable mounting of the flexible blanket 10 made of rubber or elastomer with a very fine grain and perfectly regular and on which the pattern deposited on the plate is deposited on the plate installed on the plate cylinder 1, During the printing process, this pattern then transfers to the sheets of paper.

According to the invention, the bLanchet 10 is provided with at least one groove 11 opening on its printing face and in the bottom of which is housed a bar 12 made of a hard and non-compressible material.

The position of the groove or grooves 11 provided with a non-compressible bar 12 is a function of the location of the perforations to be executed on the award-winning sheets of paper.

In other words, the groove 11 or each groove 11 is provided at a location intended to come into contact with the cutting elements of a perforating thread bonded to the printing cylinder, during the printing process, as is best seen from the which follows.

Illustrated in Figure 2, by way of example, a blanket 10 provided with a groove 11 with a reinforced bottom which is arranged parallel to the axis of the cylinders 1, 4, 5 When Said blanket is installed on the blanket cylinder, while there is shown, in Figure 3, a blanket 10 provided with two parallel grooves 11 with reinforced bottom which are arranged in the direction ci con conferred when said blanket is mounted on the cylinder holder blanket.

We also understand that the blanket can also be equipped, at the same time, with one or more grooves with reinforced bottom oriented parallel to the axis of the cylinders, and with one or more grooves with reinforced bottom arranged in the opposite direction, as shown in FIG. 3.

More generally, it is emphasized that the or the grooves with a reinforced bottom 11-12 can be provided in any part of the external surface of the bLanchet, and according to any orientation or pattern, as required. It suffices, prior to the execution of the groove (s), to wear the usual and necessary marks on the blanket and to dig the said groove (s) at the locations of these marks.

The longitudinal walls 11a of the groove or of each groove 11 have a divergent orientation in the direction of the printing surface 10a of the blanket

10, as shown in particular in FIG. 6.

The groove or each groove 11 can be executed during the manufacture of the blanket or later, as required, before use thereof. In the latter case, a layer 13 of a sealant such as a polyurethane varnish is applied to the bottom and the sides of the groove after it has been dug to the desired size and height. , to ensure a permanent seal at this groove and thus avoid detergents used for frequent cleaning of the blanket, can not penetrate into the multi-layers of the latter.

Likewise, the non-compressible bar 12 constituting the reinforced bottom of the groove or of each groove

11, can be put in place during the manufacture of the blanket, or later, as required, before use thereof. In the latter case, the bar 12 can be glued in the bottom of the groove 11, removably, by means of an adhesive strip 14 provided with two opposite Lantes self-adhesive faces and having a width and a length identical to those of said strip. The double-sided adhesive strip 14 is fixed, via one of its self-adhesive Lantes faces, to the bottom of the groove, while the bar is glued to said adhesive strip by means of the second face. self-adhesive of the latter. The bar 12 forming the bottom of the groove 11 is formed by a strip of material which is not compressible or has a very low degree of malleability, but whose hardness is however less than that of the teeth or cutting elements of the perforating nets intended to be glued to the printing cylinder 5 of the machine. The bar 12 can advantageously consist of a small blade or tinsel of brass.

The upper face 12a of the non-compressible strip 12 housed in the groove 11 is set back relative to the active external surface or printing surface 10a of the bLanchet, so that a vacuum of height h is formed between said upper face 12a and the plane in which said printing surface 10a is located, so that the offset plate installed on the plate cylinder 1 can take place on said surface without encountering any relief.

For the implementation of the perforation method according to the invention, a perforating net 15 is removably fixed, for example by gluing, on the printing cylinder 5, at the desired location or locations, so that, during the rotation of the blanket cylinder 4 and of said printing cylinder, the teeth or cutting elements of said perforating net come to bear on the bar 12 reinforcing the bottom of the groove or grooves 11.

We illustrated, in Figure 7, at larger scale, an example of execution of a perforating net 15 capable of being advantageously used for the implementation of the method of the invention.

This perforating net, known per se, comprises a base 15a consisting of a steel nipple, the lower face of which is provided with a self-adhesive strip or layer 15b, the lower face of the latter being covered, before use. , by a removable protective film 15c. On its upper face, the base 15a is provided with teeth or cutting elements 15d aligned in the longitudinal direction of the said base.

The distance h between the upper face 12a of the non-compressible bar 12 and the plane in which it is included The active external face or printing surface 10a of the blanket 10 is barely less than or substantially equal to the height H of the perforating net 15 , so that sufficient pressure can be obtained from the end of the teeth or from the cutting edge of the cutting members 15d of said perforating thread on the upper face of said strip, making it possible to cut along the length of the teeth or a net perforation and perfect from the sheet of paper 16, without creating blisters or stain removal.

However, it is possible to raise the level of the upper face 12a of the bar 12 very slightly, relative to its normal location, by placing a shim of thin thickness between the bLanchet 10 and the bLanchet carrier cylinder 4, below from where the groove 11 is located. This wedge can be formed by a self-adhesive strip 17 glued, removably, on the underside of the bLanchet 10 (FIG. 8), or on the bLanchet carrier cylinder. 5, below the throat 11.

FIG. 10 illustrates the implementation of the method of the invention.

During the printing cycle or process, the sheet of paper 16 is pressed by the printing cylinder 5 provided with the perforating net 15, against the bLanchet 10 provided with a groove 11 equipped with a bar or lamella 12 non-compressible. When the locations where said perforating net and said groove are placed come into tengential contact, the ends of the teeth or the cutting edges of the cutting elements of said perforating net are pressed against the upper face of the bar or strip 12, which causes the sectioning according to the length of the teeth or the clean and perfect perforation of the sheet of paper.

Claims

1. - Blanket for rotary printing machine, for example for offset machine, equipped with a perforating device, characterized in that said blanket ⁽ 10) is provided with at least one groove (11) opening onto its printing face (10a) and in the bottom of which is housed a bar or lamella (12) made of a hard and non-compressible material, this bar comprising an upper face (12a) against which are intended to come into pressure The elements perforating or cutting (15d) perforating nets (15 ⁾ fixed on the printing cylinder (5) or pressure cylinder, or margin, of said machine, during the pressure process.

2. - Blanket for rotary printing machine, according to claim 1, characterized in that the bar

(12) constituting the bottom of the throat or of each throat

(11) is made of a non-compressible material whose hardness is lower than that of the teeth or cutting elements (15d ⁾ of the perforating threads (15) intended to be glued to the printing cylinder (5) of the machine.

3. - Blanket for rotary printing machine, according to claim 2, characterized in that the bar

⁽ 12) forming the bottom of the groove or of each groove ⁽ 11), is constituted by a brass foil.

4. - Blanket for rotary printing machine, according to any one of claims 1 to 3, characterized in that the bottom and the sides of the groove or of each groove (11) are covered with a layer

⁽ 13 ⁾ a sealant such as, for example, a polyurethane varnish.

5. - Blanket for rotary printing machine, according to any one of claims 1 to 3, characterized in that the non-compressible bar (12) is glued in the bottom of the groove (11), by means of a adhesive strip (14) with two opposite Lantes self-adhesive sides.

6. - Blanket for rotary printing machine, according to any one of claims 1 to 3, characterized in that the upper face (12a) of the bar or non-compressible strip (12) housed in the groove or in each groove (11), is set back relative to the printing surface (10a) of said bLanchet (10).

7. - Blanket for rotary printing machine, according to claim 6, characterized in that The distance (h) between the upper face (12a) of the bar or non-compressible strip (12) and the plane in which is located included the printing surface (10a) of said blanket (10) is barely less than or substantially equal to the height (H) of the perforating net (15) intended to be installed on the printing cylinder (5) of the machine .

8. - Process for perforating sheets during printing, for rotary printing machines, for example for offset machines comprising a blanket cylinder (4) and a printing cylinder (5), or pressure cylinder, or margin, according to which at least one perforating net (15) is removably fixed, on said printing cylinder, so as to ensure the perforation of the sheets (16) during their passage between the latter and said blanket, characterized in that the blanket ⁽¹⁰⁾ is provided at the location or intended location ^(s) to come into contact with The cutting elements (15d) of the perforating thread (s) (15), of one or more grooves (11) in the bottom of which which is housed a strip or strip (12) made of a hard and non-compressible material, so that, during the printing process, said cutting elements are pressed against said non-compressible bar, which ensures a clean and perfect perforation of the sheets of paper (16).

10 9. - Method according to claim 8, characterized in that the household, between the upper face (12a) of the non-compressible bar (12) and the plane in which is included the printing surface (10a) blanket (10), a vacuum whose height (h) is

- ₅ penalty less than or substantially equal to The height (H) of the perforating net (15) intended to be installed on the printing cylinder (5) of the machine.

10. - Method according to one of claims 8 or 9, characterized in that a shim (17) of small thickness 20 is disposed between the blanket (10) and the blanket cylinder (4), below The groove or each groove ⁽ 11 ⁾ provided with a non-compressible bar (12).