EP0325535A1 - Method for mounting and positioning offset printing plates with a magnetic support, and the plates and offset printing machines used for realising the method - Google Patents

Method for mounting and positioning offset printing plates with a magnetic support, and the plates and offset printing machines used for realising the method Download PDF

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Publication number
EP0325535A1
EP0325535A1 EP89400151A EP89400151A EP0325535A1 EP 0325535 A1 EP0325535 A1 EP 0325535A1 EP 89400151 A EP89400151 A EP 89400151A EP 89400151 A EP89400151 A EP 89400151A EP 0325535 A1 EP0325535 A1 EP 0325535A1
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EP
European Patent Office
Prior art keywords
plate
cylinder
plates
offset printing
positioning
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EP89400151A
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German (de)
French (fr)
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EP0325535B1 (en
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Jean-Marie Nouel
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Individual
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Individual
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41F—PRINTING MACHINES OR PRESSES
    • B41F27/00—Devices for attaching printing elements or formes to supports
    • B41F27/02—Magnetic devices

Definitions

  • the present invention relates to a method and a device for the magnetic attachment of offset plates.
  • Offset plates are currently placed on printing machines using various mechanical devices among these devices, the most used are constituted by two jaws which tighten and tension the plates around the plate cylinder; these mechanical devices have various drawbacks, among which we can mention the existence of an unbalance (more or less significant depending on the nature of the jaws) on the plate cylinder, a positioning of the plate requiring precise and long adjustments and a certain weakening of the plate due to mechanical stress, which leads, for aluminum-based plates for example, to the risk of breakage during installation at start-up, or during rolling.
  • the printer part of the plate that is to say the part of the plate which includes the ink-absorbing and aquaphile zones. It is therefore first of all necessary, by known means, to ensure that this printing part of the plate is exactly positioned in relation to the plate itself, that is to say in relation to fixed marks (sides of the plate, lines drawn on the plate, hole lines made on one edge of the plate ...) integral with this plate (or forming part of the plate). As indicated above, the means for exactly positioning the printer part on the plate are known.
  • Magnetic snapping is also known; it consists in that the plate cylinder has, flush with its surface, a sufficient number of magnets so that the plate is securely attached to it.
  • These magnets can have the most diverse shapes, they are generally in the form of studs or benches arranged along the generatrices of the cylinders.
  • the following two means should be used: - a prior bending of the plate, a threading of the plate on nipples formed on the plate cylinder, in the vicinity of an edge thereof, in a plane perpendicular to the axis of the cylinder, this threading being made possible by the arrangement, the along one of the edges of the plate, openings suitably positioned to correspond to said pins.
  • prior “bending” is meant that the plate is subjected before its installation, on the plate cylinder, a permanent deformation such that said plate, initially planar, is in the form of a cylinder whose the diameter is of the order of magnitude of the diameter of the plate cylinder, and even preferably slightly smaller.
  • This bending operation obviously implies that the nature of the steel which constitutes the base of the plate is suitably chosen, this choice being within the reach of any specialist in this material.
  • this bending operation involves a certain elongation of the outer surface portion of the plate; avoid any excessive deformation and make sure, by bending under identical or similar conditions for the various plates, to always have an identical elongation of said surface portion.
  • This possibility thanks to the prior bending, to control and make reproducible from one plate to another this elongation phenomenon, is important because it allows the realization of a very precise positioning of the plate.
  • a plate is obviously used provided, along and in the vicinity of at least one of its lateral edges, with suitable openings.
  • the shape, dimensions (generally the diameter) and the relative position of these openings must correspond to the pins with which these openings must cooperate. Taking into account the high mechanical properties of the steel-supported plates and taking into account the prior bending under controlled conditions, it is possible to provide a very precise adaptation of said openings with said nipples.
  • the pins on which the plate openings are threaded are arranged on the plate cylinder, in the vicinity of an edge of said cylinder and in a plane perpendicular to the axis of the cylinder.
  • the offset plates most often have, on their edges, openings intended to ensure the positioning of the printing part of the plate with respect to said plate. It is obviously possible to use these openings to, in cooperation with pins arranged on the cylinder, position the plate, but experience proves that, in current machines, such pins would not be positioned beyond the neighboring cylinders and rollers. of the plate cylinder, which would require sometimes expensive arrangements of said cylinders and rollers. Thus, most often, it is preferred to use other openings, often in greater numbers, to ensure the positioning of the plates.
  • the present invention therefore relates to a method for hooking and positioning offset plates on the plate cylinders of offset machines by using a magnetic hook, characterized in that a plate is used in the vicinity of at at least one of its lateral edges of the openings suitably arranged, in that said plate-carrying cylinder comprises, in the vicinity of at least one of its edges, a series of pins arranged in a plane perpendicular to the axis of the cylinder, said pins being adapted to said openings and that a prior bending of the plate is carried out before positioning the latter on said cylinder by using said pins and said openings.
  • the present invention also relates to - offset plates usable for implementing the method of hooking and positioning according to the invention, said plates being characterized in that they have a steel base and a series of openings arranged in the vicinity of at least one of the longitudinal edges of said plates, - offset machines for implementing the method of hanging and positioning according to the invention, characterized in that their plate cylinder has a width slightly greater than that of the immediately neighboring cylinders and that said plate-carrying cylinder has on its projecting part with respect to the immediately neighboring cylinders and rollers a series of pins.
  • the plates are maintained and positioned by pins located in the vicinity of the edge of the plate cylinder and no longer by means (jaws for example) arranged along a generator of said cylinder. It follows that the sides of the plate which are arranged, after positioning, along a generator of said cylinder are free, that is to say are only held by means of the magnets arranged on the cylinder. In general, this arrangement does not cause any difficulties (all the more so as a person skilled in the art will properly dispose the magnets on said cylinder), but it may be that during the handling of the plate the edges thereof (edges positioned along the generators) are slightly deformed; this deformation could cause the plate to tear off during rolling.
  • the plate cylinder could comprise, on a portion of said cylinder corresponding to the ends of the plate, a slight depression in which at least one magnet is disposed. . It is understood that thanks to this depression the ends of the plates will always be slightly reentrant (that is to say will be maintained within the theoretical circle formed by the plate cylinder) and cannot, therefore, undergo damage, even in the event of accidental deformation of the ends of the plate.
  • the plate cylinder of this machine is 1045 mm wide.
  • this plate cylinder is of sufficient width to be able to use there in the vicinity of the edges of the fixing studs according to the invention, said cylinder has been replaced by a plate cylinder (of perfectly cylindrical shape) of 1,100 mm in width comprising, flush with its surface, magnets arranged along generatrices of said cylinder.
  • FIGS. 1 and 2 This transformation of the machine is shown diagrammatically in FIGS. 1 and 2.
  • the plate cylinder 1 has, with respect to the plate cylinder of a corresponding current offset machine, the following characteristics: - Magnets 4 which are flush with the surface of said cylinder have been arranged along generatrices of the cylinder - there are disposed in the vicinity of the edges of said cylinder pins 5 (which will cooperate with the openings formed along the edges of the plates) and, so as not to have to modify the rollers 2 and 3, the plate cylinder is enlarged by so as to reject said nipples outside the grip of rollers 2 and 3.
  • FIG. 3 there is shown, in section along II-II, an improvement of the invention consisting in providing on a cer taine width of the cylinder a slight depression 6.
  • this depression we have arranged, for example and preferably, a magnet 4.
  • the offset plate When the offset plate is placed around the cylinder at least one of the ends of said plate (the likely end to be torn off during rolling) will be attracted by the magnet 4.
  • the two ends of said plate can be attracted by the magnet 4 (or by other magnets mounted in said depression 6.
  • a plate will be used comprising a black iron support whose mechanical qualities are those of European standard T 61 and whose thickness is 25/100.
  • This black iron support was covered with a layer of hydrophilic matt chromium and a positive photosensitive encrophilic layer.
  • This plate has the distinction of having, on its two sides, openings which correspond exactly to the pins 5 present on the plate cylinder.
  • the plate is then placed around the plate cylinder by inserting the plate through the pressure end side and then placing this plate so as to thread the pins into the holes in the plate.
  • This process provides rapid and precise positioning of the plate.
  • the width of the plate is the same as that of the plate cylinder and that said plate has openings on its two lateral sides.
  • This arrangement is not essential since it is possible to use for a plate cylinder with a width L two plates each having a width a little less than L / 2; each of these plates will have active openings only on one of its lateral sides.

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  • Supply, Installation And Extraction Of Printed Sheets Or Plates (AREA)
  • Printing Plates And Materials Therefor (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
  • Screen Printers (AREA)

Abstract

The present invention relates to a method for mounting and positioning printing plates with a magnetic support on an offset printing machine, characterised in that the plate, after being insulated, laid out and, where appropriate, baked, is bent in such a way as to have a permanent deformation causing said plate to have the form of an open cylinder, and is then slipped onto studs (5) formed on the plate cylinder (1) in the vicinity of at least one edge of said cylinder and in a plane perpendicular to the axis of the cylinder, this slipping on being made possible by the provision, along at least one lateral edge of the plate, of orifices suitably positioned to correspond to said studs, and is then laid against the plate cylinder by means of magnets flush with the surface of said cylinder. <IMAGE>

Description

La présente invention concerne un procédé et un dispo­sitif pour l'accrochage magnétique des plaques offset.The present invention relates to a method and a device for the magnetic attachment of offset plates.

Les plaques offset sont actuellement mises en place sur les machines d'impression à l'aide de dispositifs mécaniques divers parmi ces dispositifs, les plus utilisés sont constitués par deux mâchoires qui serrent et tendent les plaques autour du cylindre porte-plaque ; ces dispositifs mécaniques présentent divers inconvénients parmi lesquels on peut mentionner l'existence d'un balourd (plus ou moins important selon la nature des mâchoires) sur le cylindre porte-plaque, un positionnement de la plaque nécessitant des ajustements précis et longs et une certaine fragilisation de la plaque du fait de contrainte mécanique, qui entraîne, pour les plaques à base d'aluminium par exemple, des risques de casse lors de la mise en place au démarrage, ou pendant le roulage.Offset plates are currently placed on printing machines using various mechanical devices among these devices, the most used are constituted by two jaws which tighten and tension the plates around the plate cylinder; these mechanical devices have various drawbacks, among which we can mention the existence of an unbalance (more or less significant depending on the nature of the jaws) on the plate cylinder, a positioning of the plate requiring precise and long adjustments and a certain weakening of the plate due to mechanical stress, which leads, for aluminum-based plates for example, to the risk of breakage during installation at start-up, or during rolling.

Ces dispositifs mécaniques d'accrochage semblent, malgré leurs inconvénients signalés ci-dessus, pleinement justifiés car au moins 99 % des plaques offset utilisées aujourd'hui sont à base d'aluminium.These mechanical fastening devices seem, despite their drawbacks mentioned above, fully justified since at least 99% of the offset plates used today are based on aluminum.

Or il semble depuis quelques années qu'une nouvelle ten­dance se dessine dans l'industrie de l'offset consistant à utiliser à nouveau, comme base des plaques, de l'acier. Les propriétés magnétiques de ce matériau sont connues ; aussi il peut être souhaitable d'utiliser cette propriété pour accrocher, sur les machines offset, les plaques offset à support acier (à support magnétique).However it seems for a few years that a new tendency is emerging in the industry of offset consisting in using again, as base of the plates, steel. The magnetic properties of this material are known; also it may be desirable to use this property to hang, on offset machines, offset plates with steel support (with magnetic support).

Le principe de fixer une plaque typo au flexo à support acier sur le cylindre porte-plaque d'une machine d'impression est connu et a été préconisé depuis longtemps. Malheureusement pour diverses raisons, ce mode d'accrochage n'a jamais été mis en oeuvre dans le procédé offset.The principle of fixing a typo plate to the flexo with steel support on the plate cylinder of a printing machine is known and has been advocated for a long time. Unfortunately for various reasons, this method of attachment has never been used in the offset process.

De plus, la fixation magnétique des plaques offset ne se révèle intéressante que dans la mesure où on met en oeuvre, grâce à cette fixation, des moyens qui permettent non seulement un accro­ chage rapide des plaques mais encore un positionnement précis des­dites plaques afin de diminuer la durée des réglages. Ce sont ces moyens qui constituent l'invention.In addition, the magnetic fixing of offset plates proves interesting only insofar as one implements, thanks to this fixing, means which allow not only an addict quick loading of the plates but also precise positioning of the said plates in order to reduce the duration of the adjustments. These are the means which constitute the invention.

En réalité, ce qu'il convient de positionner, c'est la partie imprimante de la plaque, c'est-à-dire la partie de la plaque qui comporte les zones encrophiles et aquaphiles. Il convient donc tout d'abord par des moyens connus de s'assurer que cette partie imprimante de la plaque est exactement positionnée par rapport à la plaque elle-même, c'est-à-dire par rapport à des repères fixes (côtés de la plaque, lignes tracées sur la plaque, lignes de trous ménagés sur un bord de la plaque...) solidaires de cette plaque (ou faisant partie de la plaque). Comme indiqué ci-dessus, les moyens pour positionner exactement la partie imprimante sur la plaque sont connus.In reality, what should be positioned is the printer part of the plate, that is to say the part of the plate which includes the ink-absorbing and aquaphile zones. It is therefore first of all necessary, by known means, to ensure that this printing part of the plate is exactly positioned in relation to the plate itself, that is to say in relation to fixed marks (sides of the plate, lines drawn on the plate, hole lines made on one edge of the plate ...) integral with this plate (or forming part of the plate). As indicated above, the means for exactly positioning the printer part on the plate are known.

L'accrochage magnétique est également connu ; il consiste en ce que le cylindre porte-plaque comporte, affleurant à sa sur­face, un nombre suffisant d'aimants pour que la plaque y soit soli­dement fixée. Ces aimants peuvent avoir des formes les plus diverses, ils se présentent généralement sous forme de plots ou de bancs disposés le long des génératrices des cylindres. Il est souhaitable de tenir compte du caractère spécifique de l'impression offset qui se caractérise par la présence d'eau sur la plaque, cette eau de mouillage pouvant, dans une certaine mesure, s'infil­trer sous la plaque ; pour tenir compte de cette eau, il pourra être utile de protéger les surfaces des aimants disposés sur le cylindre, cette protection pouvant se faire, par exemple, grâce à l'utilisation d'un film mince imperméable ou grâce au dépôt, sur les surfaces à protéger, d'une mince couche protectrice d'un maté­riau imperméable quelconque.Magnetic snapping is also known; it consists in that the plate cylinder has, flush with its surface, a sufficient number of magnets so that the plate is securely attached to it. These magnets can have the most diverse shapes, they are generally in the form of studs or benches arranged along the generatrices of the cylinders. It is desirable to take into account the specific nature of offset printing which is characterized by the presence of water on the plate, this wetting water being able, to a certain extent, to infiltrate under the plate; to take this water into account, it may be useful to protect the surfaces of the magnets placed on the cylinder, this protection being able to be done, for example, by the use of an impermeable thin film or by deposit, on the surfaces to protect, with a thin protective layer of any waterproof material.

Pour réaliser le positionnement précis de la plaque, il convient de mettre en oeuvre les deux moyens suivants:
- un cintrage préalable de la plaque,
- un enfilage de la plaque sur des tétons ménagés sur le cylindre porte-plaque, au voisinage d'un bord de celui-ci, dans un plan perpendiculaire à l'axe du cylindre, cet enfilage étant rendu possible par l'aménagement, le long d'un des bords de la plaque, d'ouvertures convenablement positionnées pour correspondre auxdits tétons.To achieve the precise positioning of the plate, the following two means should be used:
- a prior bending of the plate,
a threading of the plate on nipples formed on the plate cylinder, in the vicinity of an edge thereof, in a plane perpendicular to the axis of the cylinder, this threading being made possible by the arrangement, the along one of the edges of the plate, openings suitably positioned to correspond to said pins.

Par "cintrage" préalable on entend que l'on fait subir à la plaque avant sa mise en place, sur le cylindre porte-plaque, une déformation permanente telle que ladite plaque, initialement plane, se trouve sous la forme d'un cylindre dont le diamètre est de l'ordre de grandeur du diamètre du cylindre porte-plaque, et même de préférence légèrement inférieur. Cette opération de cintrage implique bien évidemment que la nature de l'acier qui constitue la base de la plaque soit convenablement choisie, ce choix étant à la portée de tout spécialiste de ce matériau. On signalera de plus que cette opération de cintrage implique un certain allongement de la portion superficielle extérieure de la plaque ; on évitera toute déformation trop importante et on fera en sorte, en réalisant le cintrage dans des conditions identiques ou voisines pour les diverses plaques, d'avoir toujours un allongement identique de ladite portion superficielle. Cette possibilité, grâce au cintrage préalable, de contrôler et de rendre reproductible d'une plaque à l'autre ce phénomène d'allongement, est importante car elle permet la réalisation d'un positionnement très précis de la plaque.By prior "bending" is meant that the plate is subjected before its installation, on the plate cylinder, a permanent deformation such that said plate, initially planar, is in the form of a cylinder whose the diameter is of the order of magnitude of the diameter of the plate cylinder, and even preferably slightly smaller. This bending operation obviously implies that the nature of the steel which constitutes the base of the plate is suitably chosen, this choice being within the reach of any specialist in this material. It will also be noted that this bending operation involves a certain elongation of the outer surface portion of the plate; avoid any excessive deformation and make sure, by bending under identical or similar conditions for the various plates, to always have an identical elongation of said surface portion. This possibility, thanks to the prior bending, to control and make reproducible from one plate to another this elongation phenomenon, is important because it allows the realization of a very precise positioning of the plate.

Pour réaliser l'enfilage de la plaque sur les tétons, on utilisera bien évidemment une plaque munie, le long et au voisinage d'un de ses bords latéraux au moins, d'ouvertures convenables. La forme, les dimensions (généralement le diamètre) et la position relative de ces ouvertures devront correspondre aux tétons avec lesquels ces ouvertures devront coopérer. Compte tenu des pro­priétés mécaniques élevées des plaques à support acier et compte tenu de la réalisation d'un cintrage préalable dans des conditions contrôlées, il est possible de prévoir une adaptation très précise desdites ouvertures avec lesdits tétons. Les tétons sur lesquels les ouvertures de la plaque sont enfilées sont disposés sur le cylindre porte-plaque, au voisinage d'un bord dudit cylindre et dans un plan perpendiculaire à l'axe du cylindre. Pour qu'il n'y ait pas de difficultés particulières du fait de la présence de ces tétons et de cylindres et de rouleaux voisins (cylindre porte-­ blanchet et rouleaux d'encrage et de mouillage) il suffira, et cela constitue un aspect secondaire de l'invention, de prévoir que le cylindre porte-plaque sera légèrement plus large que les cylindres et rouleaux voisins.To thread the plate onto the nipples, a plate is obviously used provided, along and in the vicinity of at least one of its lateral edges, with suitable openings. The shape, dimensions (generally the diameter) and the relative position of these openings must correspond to the pins with which these openings must cooperate. Taking into account the high mechanical properties of the steel-supported plates and taking into account the prior bending under controlled conditions, it is possible to provide a very precise adaptation of said openings with said nipples. The pins on which the plate openings are threaded are arranged on the plate cylinder, in the vicinity of an edge of said cylinder and in a plane perpendicular to the axis of the cylinder. So that there are no particular difficulties due to the presence of these pins and of neighboring cylinders and rollers ( blanket and inking and wetting rollers) it will suffice, and this constitutes a secondary aspect of the invention, to provide that the plate-carrying cylinder will be slightly wider than the neighboring cylinders and rollers.

Les plaques offset comportent le plus souvent, sur leurs bords, des ouvertures destinées à assurer le positionnement de la partie imprimante de la plaque par rapport à ladite plaque. On peut bien évidemment utiliser ces ouvertures pour, en coopération avec des tétons aménagés sur le cylindre, positionner la plaque, mais l'expérience prouve que, dans les machines actuelles, de tels tétons ne seraient pas positionnés au-delà des cylindres et rou­leaux voisins du cylindre porte-plaque, ce qui nécessiterait des aménagements parfois onéreux desdits cylindres et rouleaux. Ainsi, le plus souvent, on préfère utiliser d'autres ouvertures, souvent en nombre plus grand, pour assurer le positionnement des plaques.The offset plates most often have, on their edges, openings intended to ensure the positioning of the printing part of the plate with respect to said plate. It is obviously possible to use these openings to, in cooperation with pins arranged on the cylinder, position the plate, but experience proves that, in current machines, such pins would not be positioned beyond the neighboring cylinders and rollers. of the plate cylinder, which would require sometimes expensive arrangements of said cylinders and rollers. Thus, most often, it is preferred to use other openings, often in greater numbers, to ensure the positioning of the plates.

La présente invention concerne donc un procédé permettant l'accrochage et le positionnement des plaques offset sur les cylindres porte-plaque des machines offset par utilisation d'un accrochage magnétique, caractérisé en ce que l'on utilise une plaque portant au voisinage d'au moins un de ses bords latéraux des ouvertures convenablement aménagées, en ce que ledit cylindre porte-plaque comporte au voisinage d'au moins un de ses bords une série de tétons disposés dans un plan perpendiculaire à l'axe du cylindre, lesdits tétons étant adaptés auxdites ouvertures et que l'on réalise un cintrage préalable de la plaque avant de posi­tionner celle-ci sur ledit cylindre par utilisation desdits tétons et desdites ouvertures.The present invention therefore relates to a method for hooking and positioning offset plates on the plate cylinders of offset machines by using a magnetic hook, characterized in that a plate is used in the vicinity of at at least one of its lateral edges of the openings suitably arranged, in that said plate-carrying cylinder comprises, in the vicinity of at least one of its edges, a series of pins arranged in a plane perpendicular to the axis of the cylinder, said pins being adapted to said openings and that a prior bending of the plate is carried out before positioning the latter on said cylinder by using said pins and said openings.

La présente invention concerne également
- des plaques offset utilisables pour la mise en oeuvre du pro­cédé d'accrochage et de positionnement selon l'invention, lesdites plaques étant caractérisées en ce qu'elles ont une base en acier et une série d'ouvertures aménagées au voisi­nage d'au moins un des bords longitudinaux desdites plaques,
- des machines offset pour la mise en oeuvre du procédé d'ac­crochage et de positionnement selon l'invention,
caractérisées en ce que leur cylindre porte-plaque a une largeur légèrement supérieure à celle des cylindres immédiatement voisins et que ledit cylindre porte-plaque comporte sur sa partie débordant par rapport aux cylindres et rouleaux immédiatement voisins une série de tétons.The present invention also relates to
- offset plates usable for implementing the method of hooking and positioning according to the invention, said plates being characterized in that they have a steel base and a series of openings arranged in the vicinity of at least one of the longitudinal edges of said plates,
- offset machines for implementing the method of hanging and positioning according to the invention,
characterized in that their plate cylinder has a width slightly greater than that of the immediately neighboring cylinders and that said plate-carrying cylinder has on its projecting part with respect to the immediately neighboring cylinders and rollers a series of pins.

On notera que, selon l'invention, les plaques sont main­tenues et positionnées par des tétons situés au voisinage du bord du cylindre porte-plaque et non plus par des moyens (mâchoires par exemple) disposés selon une génératrice dudit cylindre. Il s'en­suit que les côtés de la plaque qui sont disposés, après position­nement, le long d'une génératrice dudit cylindre sont libres, c'est-à-dire ne sont maintenus qu'au moyen des aimants disposés sur le cylindre. En général, cette disposition n'entraîne pas de diffi­cultés (d'autant plus que l'homme de l'art disposera convenablement les aimants sur ledit cylindre) mais il peut se faire que lors des manipulations de la plaque les bords de celle-ci (bords positionnés le long des génératrices) soient légèrement déformés ; cette défor­mation pourrait entraîner lors du roulage un arrachement de la plaque. Pour surmonter cette difficulté il a été prévu, selon un des aspects de l'invention, que le cylindre porte-plaque pourrait comporter, sur une portion dudit cylindre correspondant aux extré­mités de la plaque, une dépression légère dans laquelle au moins un aimant est disposé. On conçoit que grâce à cette dépression les extrémités des plaques seront toujours légèrement rentrantes (c'est-à-dire seront maintenues à l'intérieur du cercle théorique formé par le cylindre porte-plaque) et ne pourront, de ce fait, subir de dommages, même en cas de déformations accidentelles des extrémités de la plaque.It will be noted that, according to the invention, the plates are maintained and positioned by pins located in the vicinity of the edge of the plate cylinder and no longer by means (jaws for example) arranged along a generator of said cylinder. It follows that the sides of the plate which are arranged, after positioning, along a generator of said cylinder are free, that is to say are only held by means of the magnets arranged on the cylinder. In general, this arrangement does not cause any difficulties (all the more so as a person skilled in the art will properly dispose the magnets on said cylinder), but it may be that during the handling of the plate the edges thereof (edges positioned along the generators) are slightly deformed; this deformation could cause the plate to tear off during rolling. To overcome this difficulty, it has been provided, according to one aspect of the invention, that the plate cylinder could comprise, on a portion of said cylinder corresponding to the ends of the plate, a slight depression in which at least one magnet is disposed. . It is understood that thanks to this depression the ends of the plates will always be slightly reentrant (that is to say will be maintained within the theoretical circle formed by the plate cylinder) and cannot, therefore, undergo damage, even in the event of accidental deformation of the ends of the plate.

L'exemple non limitatif suivant illustre l'invention ; cet exemple sera lui-même illustré par les figures 1 à 3 :

  • - la figure 1 représente une vue longitudinale schéma­tique d'un rouleau porte-plaque selon l'invention ;
  • - la figure 2 est une section selon II-II de la figure 1;
  • - la figure 3 est une section selon II-II d'un cylindre du porte-plaque comportant une dépression selon l'invention.
The following nonlimiting example illustrates the invention; this example will itself be illustrated by FIGS. 1 to 3:
  • - Figure 1 shows a schematic longitudinal view of a plate roller according to the invention;
  • - Figure 2 is a section along II-II of Figure 1;
  • - Figure 3 is a section along II-II of a cylinder of the plate holder having a depression according to the invention.

ExempleExample

Considérons une machine offset 4 couleurs à feuilles de la firme OCMSA référence Aurélia 700 utilisant des plaques 775 x 1 035 mm et pouvant imprimer une surface de papier maximum de 710 x 1 020 mm.Consider a 4-color sheetfed offset machine from OCMSA, reference Aurélia 700, using 775 x 1,035 mm plates and capable of printing a maximum paper area of 710 x 1,020 mm.

Le cylindre porte-plaque de cette machine a une largeur de 1 045 mm.The plate cylinder of this machine is 1045 mm wide.

Bien que ce cylindre porte-plaque soit d'une largeur suf­fisante pour pouvoir y utiliser au voisinage des bords des tétons de fixation selon l'invention, on a remplacé ledit cylindre par un cylindre porte-plaque (de forme parfaitement cylindrique) de 1 100 mm de largeur comportant, affleurant à sa surface, des aimants disposés selon des génératrices dudit cylindre.Although this plate cylinder is of sufficient width to be able to use there in the vicinity of the edges of the fixing studs according to the invention, said cylinder has been replaced by a plate cylinder (of perfectly cylindrical shape) of 1,100 mm in width comprising, flush with its surface, magnets arranged along generatrices of said cylinder.

A environ 15 mm de chacun des bords dudit cylindre, on a disposé des tétons régulièrement répartis. La machine offset, ainsi transformée, est prête pour réaliser des impressions en utilisant le procédé selon l'invention.About 15 mm from each of the edges of said cylinder, regularly distributed pins were placed. The offset machine, thus transformed, is ready to make prints using the method according to the invention.

On a schématisé cette transformation de la machine sur les figures 1 et 2.This transformation of the machine is shown diagrammatically in FIGS. 1 and 2.

Sur la figure 1 on voit

  • - en 1 le cylindre porte-plaque
  • - en 2 un rouleau encreur
  • - en 3 un rouleau de mouillage.
In Figure 1 we see
  • - in 1 the plate cylinder
  • - in 2 an ink roller
  • - in 3 a dampening roller.

Le cylindre porte-plaque 1 présente, par rapport au cylindre porte-plaque d'une machine offset correspondante actuelle, les caractéristiques suivantes :
- on a disposé selon des génératrices du cylindre des aimants 4 qui affleurent à la surface dudit cylindre
- on a disposé au voisinage des bords dudit cylindre des tétons 5 (qui coopéreront avec les ouvertures ménagées le long des bords des plaques) et, pour ne pas avoir à modifier les rou­leaux 2 et 3, on a élargi le cylindre porte-plaque de façon à rejeter lesdits tétons à l'extérieur de l'emprise des rou­leaux 2 et 3.The plate cylinder 1 has, with respect to the plate cylinder of a corresponding current offset machine, the following characteristics:
- Magnets 4 which are flush with the surface of said cylinder have been arranged along generatrices of the cylinder
- there are disposed in the vicinity of the edges of said cylinder pins 5 (which will cooperate with the openings formed along the edges of the plates) and, so as not to have to modify the rollers 2 and 3, the plate cylinder is enlarged by so as to reject said nipples outside the grip of rollers 2 and 3.

Sur la figure 3 on a représenté, en coupe selon II-II, un perfectionnement de l'invention consistant à ménager sur une cer­ taine largeur du cylindre une légère dépression 6. Dans cette dépression on a disposé, par exemple et de préférence, un aimant 4. Lorsque la plaque offset sera mise en place autour du cylindre au moins une des extrémités de ladite plaque (l'extrémité susceptible d'être arrachée lors du roulage) sera attirée par l'aimant 4. Bien évidemment les deux extrémités de ladite plaque peuvent être attirées par l'aimant 4 (ou par d'autres aimants montés dans ladite dépression 6.In Figure 3 there is shown, in section along II-II, an improvement of the invention consisting in providing on a cer taine width of the cylinder a slight depression 6. In this depression we have arranged, for example and preferably, a magnet 4. When the offset plate is placed around the cylinder at least one of the ends of said plate (the likely end to be torn off during rolling) will be attracted by the magnet 4. Obviously the two ends of said plate can be attracted by the magnet 4 (or by other magnets mounted in said depression 6.

Comme plaque offset à support magnétique (acier) on uti­lisera, par exemple, dans l'invention une plaque comportant un sup­port en fer noir dont les qualités mécaniques sont celles de la norme européenne T 61 et dont l'épaisseur est 25/100. Ce support en fer noir a été recouvert d'une couche de chrome mat hydrophile et d'une couche photosensible positive encrophile.As offset plate with magnetic support (steel), for example, a plate will be used comprising a black iron support whose mechanical qualities are those of European standard T 61 and whose thickness is 25/100. This black iron support was covered with a layer of hydrophilic matt chromium and a positive photosensitive encrophilic layer.

Cette plaque a la particularité de comporter, sur ses deux côtés, des ouvertures qui correspondent exactement aux tétons 5 présents sur le cylindre porte-plaque.This plate has the distinction of having, on its two sides, openings which correspond exactly to the pins 5 present on the plate cylinder.

Cette plaque après insolation, développement et cuisson, est passée dans une rouleuse qui lui fait subir une déformation permanente telle qu'à l'état de repos ladite plaque se présente sous la forme d'un cylindre ouvert dont le diamètre est de l'ordre de grandeur (et même de préférence légèrement inférieur) du diamètre du cylindre porte-plaque.This plate after exposure, development and cooking, is passed through a rolling machine which makes it undergo a permanent deformation such that in the state of rest said plate is in the form of an open cylinder whose diameter is of the order of size (and even preferably slightly smaller) of the diameter of the plate cylinder.

La plaque est alors placée autour du cylindre porte-­plaque en introduisant la plaque par le côté fin de pression puis on dispose cette plaque de manière à enfiler les tétons dans les trous de la plaque.The plate is then placed around the plate cylinder by inserting the plate through the pressure end side and then placing this plate so as to thread the pins into the holes in the plate.

On obtient par ce procédé un positionnement rapide et précis de la plaque.This process provides rapid and precise positioning of the plate.

On notera que dans l'exemple ci-dessus la largeur de la plaque est la même que celle du cylindre porte-plaque et que ladite plaque comporte des ouvertures sur ses deux côtés latéraux. Cette disposition n'est pas indispensable car il est possible d'utiliser pour un cylindre porte-plaque d'une largeur L deux plaques présen­tant chacune une largeur un peu inférieure à L/2 ; chacune de ces plaques ne comportera d'ouvertures actives que sur un de ses côtés latéraux.Note that in the example above the width of the plate is the same as that of the plate cylinder and that said plate has openings on its two lateral sides. This arrangement is not essential since it is possible to use for a plate cylinder with a width L two plates each having a width a little less than L / 2; each of these plates will have active openings only on one of its lateral sides.

Claims (3)

1. Procédé d'accrochage et de positionnement de plaques d'imprimerie à support magnétique sur une machine d'impression offset, caractérisé en ce que la plaque après insolation, développement et éventuellement cuisson est
- cintrée de façon à présenter une déformation permanente amenant ladite plaque à avoir la forme d'un cylindre ouvert puis
- enfilée sur des tétons (5) ménagés sur le cylindre (1) porte-plaque, au voisinage d'au moins un bord dudit cylindre et dans un plan perpendiculaire à l'axe du cylindre, cet enfilage étant rendu possible par l'aménagement, le long d'au moins un bord latéral de la plaque, d'ouvertures convenablement positionnées pour correspondre avec lesdits tétons, puis
- appliquée contre le cylindre porte-plaque grâce aux aimants affleurant à la surface dudit cylindre.1. Method for hanging and positioning printing plates with magnetic support on an offset printing machine, characterized in that the plate after exposure, development and possibly baking is
- curved so as to present a permanent deformation causing said plate to have the shape of an open cylinder then
- threaded on pins (5) formed on the cylinder (1) plate holder, in the vicinity of at least one edge of said cylinder and in a plane perpendicular to the axis of the cylinder, this threading being made possible by the arrangement , along at least one lateral edge of the plate, openings suitably positioned to correspond with said pins, then
- applied against the plate cylinder thanks to the magnets flush with the surface of said cylinder. 2. Plaques d'impression offset utilisables pour la mise en oeuvre du procédé d'accrochage et de positionnement selon la revendication 1, caractérisées en ce que :
- elles comportent un support magnétique
- elles comportent le long d'au moins un de leurs bords latéraux des ouvertures convenablement aménagées.2. Offset printing plates usable for implementing the hanging and positioning method according to claim 1, characterized in that:
- they have a magnetic support
- They include along at least one of their lateral edges of the openings suitably arranged. 3. Machines d'impression offset utilisables pour la mise en oeuvre du procédé d'accrochage et de positionnement de plaques d'impression précintrées à suypport magnétique selon la revendication 1, caractérisées en ce que leur cylindre porte-plaque comporte des aimants et que ledit cylindre présente une largeur légèrement supérieure à la largeur des cylindres et rouleaux immédiatement voisins et comporte sur au moins une partie ainsi débordante une série de tétons de fixation.3. Offset printing machines which can be used for implementing the method of hanging and positioning pre-bent printing plates with magnetic support according to claim 1, characterized in that their plate cylinder comprises magnets and that said cylinder has a width slightly greater than the width of the immediately neighboring cylinders and rollers and comprises on at least one part thus projecting a series of fixing studs.
EP89400151A 1988-01-21 1989-01-19 Method for mounting and positioning offset printing plates with a magnetic support, and the plates and offset printing machines used for realising the method Expired - Lifetime EP0325535B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89400151T ATE88670T1 (en) 1988-01-21 1989-01-19 METHOD OF FIXING AND POSITIONING OFFSET PRINTING PLATES WITH MAGNETIC ASSISTANCE AND PRINTING PLATE AND OFFSET PRINTING MACHINE FOR CARRYING OUT THE PROCESS.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8800664A FR2626214B1 (en) 1988-01-21 1988-01-21 METHOD FOR HANGING AND POSITIONING OFFSET PRINTING PLATES WITH MAGNETIC SUPPORT, AS WELL AS OFFSET PRINTING PLATES AND MACHINES FOR USE THEREOF
FR8800664 1988-01-21

Publications (2)

Publication Number Publication Date
EP0325535A1 true EP0325535A1 (en) 1989-07-26
EP0325535B1 EP0325535B1 (en) 1993-04-28

Family

ID=9362499

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89400151A Expired - Lifetime EP0325535B1 (en) 1988-01-21 1989-01-19 Method for mounting and positioning offset printing plates with a magnetic support, and the plates and offset printing machines used for realising the method

Country Status (4)

Country Link
EP (1) EP0325535B1 (en)
AT (1) ATE88670T1 (en)
DE (1) DE68906168T2 (en)
FR (1) FR2626214B1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5354148A (en) * 1991-10-01 1994-10-11 Colas Apparatus for spreading a bonding emulsion, or similar fluids, and road-building machine
EP0775577A1 (en) * 1995-11-21 1997-05-28 BIELOMATIK LEUZE GmbH + Co. Device for processing layer material

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10112761A1 (en) 2000-04-13 2001-10-18 Heidelberger Druckmasch Ag Method for using a printing plate for illustrating and flexographic printing involves securing printing plate by magnetic cylinder in illustrating machine and then undertaking printing using illustrated plate

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1629376A (en) * 1926-11-13 1927-05-17 Howard T Buck Attaching means for multigraph signature plates
CH323933A (en) * 1954-08-30 1957-08-31 Herzer Alfred Emil Magnetizable, flat and flexible printing form carrier for doctor blade gravure
GB1505548A (en) * 1976-12-09 1978-03-30 Plastotype Ltd Printing apparatus

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1286536C (en) * 1986-02-07 1991-07-23 Donnelley (R.R.) & Sons Company Printing cylinder with retractable plate register pin and method of assembly

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1629376A (en) * 1926-11-13 1927-05-17 Howard T Buck Attaching means for multigraph signature plates
CH323933A (en) * 1954-08-30 1957-08-31 Herzer Alfred Emil Magnetizable, flat and flexible printing form carrier for doctor blade gravure
GB1505548A (en) * 1976-12-09 1978-03-30 Plastotype Ltd Printing apparatus

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5354148A (en) * 1991-10-01 1994-10-11 Colas Apparatus for spreading a bonding emulsion, or similar fluids, and road-building machine
EP0775577A1 (en) * 1995-11-21 1997-05-28 BIELOMATIK LEUZE GmbH + Co. Device for processing layer material
US5792262A (en) * 1995-11-21 1998-08-11 Bielomatik Leuze Gmbh & Co. Processing tool for processing ply material or the like

Also Published As

Publication number Publication date
FR2626214A1 (en) 1989-07-28
DE68906168T2 (en) 1993-11-18
FR2626214B1 (en) 1995-05-12
DE68906168D1 (en) 1993-06-03
ATE88670T1 (en) 1993-05-15
EP0325535B1 (en) 1993-04-28

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