CA2035400A1 - Plant for manufacturing a mold in the form of a multi-impression plastic plate, in particular for reproducing intaglio printing plates, and method of actuating this plant - Google Patents
Plant for manufacturing a mold in the form of a multi-impression plastic plate, in particular for reproducing intaglio printing plates, and method of actuating this plantInfo
- Publication number
- CA2035400A1 CA2035400A1 CA002035400A CA2035400A CA2035400A1 CA 2035400 A1 CA2035400 A1 CA 2035400A1 CA 002035400 A CA002035400 A CA 002035400A CA 2035400 A CA2035400 A CA 2035400A CA 2035400 A1 CA2035400 A1 CA 2035400A1
- Authority
- CA
- Canada
- Prior art keywords
- plate
- electrode
- plant
- impression
- insulating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
- B41C3/00—Reproduction or duplicating of printing formes
- B41C3/06—Reproduction or duplicating of printing formes to produce printing blocks from plastics
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/02—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles
- B29C43/021—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of definite length, i.e. discrete articles characterised by the shape of the surface
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C59/00—Surface shaping of articles, e.g. embossing; Apparatus therefor
- B29C59/02—Surface shaping of articles, e.g. embossing; Apparatus therefor by mechanical means, e.g. pressing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
- B41D—APPARATUS FOR THE MECHANICAL REPRODUCTION OF PRINTING SURFACES FOR STEREOTYPE PRINTING; SHAPING ELASTIC OR DEFORMABLE MATERIAL TO FORM PRINTING SURFACES
- B41D7/00—Shaping elastic or deformable material, e.g. rubber, plastics material, to form printing surfaces
- B41D7/02—Shaping elastic or deformable material, e.g. rubber, plastics material, to form printing surfaces by impression
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B44—DECORATIVE ARTS
- B44B—MACHINES, APPARATUS OR TOOLS FOR ARTISTIC WORK, e.g. FOR SCULPTURING, GUILLOCHING, CARVING, BRANDING, INLAYING
- B44B5/00—Machines or apparatus for embossing decorations or marks, e.g. embossing coins
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B44—DECORATIVE ARTS
- B44B—MACHINES, APPARATUS OR TOOLS FOR ARTISTIC WORK, e.g. FOR SCULPTURING, GUILLOCHING, CARVING, BRANDING, INLAYING
- B44B5/00—Machines or apparatus for embossing decorations or marks, e.g. embossing coins
- B44B5/02—Dies; Accessories
- B44B5/028—Heated dies
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/0088—Multi-face stack moulds
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Manufacture Or Reproduction Of Printing Formes (AREA)
- Shaping Of Tube Ends By Bending Or Straightening (AREA)
- Photosensitive Polymer And Photoresist Processing (AREA)
- Lining Or Joining Of Plastics Or The Like (AREA)
- Printing Methods (AREA)
- Printing Plates And Materials Therefor (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
Abstract
DE LA RUE GIORI S.A. LAUSANNE/SWITZERLAND
PLANT FOR MANUFACTURING A MOLD IN THE FORM OF A MULTI-IMPRESSION PLASTIC PLATE, IN PARTICULAR FOR REPRODUCING
INTAGLIO PRINTING PLATES, AND METHOD OF ACTUATING THIS
PLANT
ABSTRACT
The plant comprises an electrode-carrying device for supporting a plate electrode (7), a plate-carrying device for supporting an original plate (19) having an engraved design, and sliding frames that carry a thermo-formable plastic plate (4) arranged between and movable relative to the original plate (19) and to said electrode (7). The original plate (19) forms a second electrode, both electrodes being connected to a high-frequency apparatus. The first plate electrode (7) has an outline (7a), which corresponds to an envelope of the design of the original plate (19) and therefore of the impression to be produced. The border of the first electrode is surrounded by an insulating border, the thickness of which is equal to that of said first electrode. By these measures it is pratically only the zone of impression that is heated during the compression molding using high-frequency heating.
Figure 2
PLANT FOR MANUFACTURING A MOLD IN THE FORM OF A MULTI-IMPRESSION PLASTIC PLATE, IN PARTICULAR FOR REPRODUCING
INTAGLIO PRINTING PLATES, AND METHOD OF ACTUATING THIS
PLANT
ABSTRACT
The plant comprises an electrode-carrying device for supporting a plate electrode (7), a plate-carrying device for supporting an original plate (19) having an engraved design, and sliding frames that carry a thermo-formable plastic plate (4) arranged between and movable relative to the original plate (19) and to said electrode (7). The original plate (19) forms a second electrode, both electrodes being connected to a high-frequency apparatus. The first plate electrode (7) has an outline (7a), which corresponds to an envelope of the design of the original plate (19) and therefore of the impression to be produced. The border of the first electrode is surrounded by an insulating border, the thickness of which is equal to that of said first electrode. By these measures it is pratically only the zone of impression that is heated during the compression molding using high-frequency heating.
Figure 2
Description
2~3~
J
F.ield of the invention The present invention relates to a plant for ~anufacturing a mold in the form of a thermo-formable, multiple-impression plastic plate, in particular for reproducing intaglio printing plates, using an original plate made of metal which bears an engraved or embossed design, and by means of compression molding with high-frequency heating of said plastic plat~, comprising a struture provided with an electrode-carrying device for supporting a plate electrode connected to a high-frequency apparatus, and with a plate-carrying device for supporting the original plate at a distance from and opposite to the said plate electrode; at least one sliding frame for supporting the plastic plate, said sliding frame being arranged between and movable with respect to said original plate and said plate electrode in two perpendicular horizontal directions; and comprising means for changing the distance between the said electrode-carrying and plate-carrying devices.
Said intaglio printing plates are intended for sheet-fed intaglio printing.
Prior art It is known to manufacture intaglio printing plates for sheet-fed printing using an original metal plate on which there has been carefully engraved the image to be reproduced consisting of engraved lines and zones of varying depths. Since the intaglio printing plate arranged on the plate cylinder has several identical impressions, in particular in the case where bank notes are printed, arranged in perpendicular rows, the impression must be multiplied and transferred onto the intaglio printing plate which is generally made of nickel. A plant for carrying out this multiplication on a thermo-formable plastic plate according to the preamble of claim 1 and as described in the introduction has already been proposed in the publication EP-A- 335 830.
In the case of a multiple-impression positive plastic plate, a known method to obtain the intaglio printing plate is as follows :
A layer of silver is applied onto the positive plate and a layer of copper is deposited on the silver-lined surface by means of electrolysis. By withdrawing the positive plastic plate, a negative copper plate, also called a female matrix or lower matrix, which comprises the engraved impressions, is obtained. The surface of this negative plate between the impressions must be machined so as to ensure that it is completely smooth and continuous. Using this negative copper plate, a positive nickel plate is reproduced, followed by a negative nickel plate, which i5 the actual intaglio printing plate which will be mounted on the plate cylinder. This plate must also undergo a finishing treatment so as to ensure, on the one hand, that the surface between the impressions is smooth and continuous and, on the other hand, that the rear of the plate in contact with the plate cylinder is also perfectly smooth and continuous. In order to increase the resistance to wear of the intaglio printing plate, ~3~
a layer of chrome is applied.
_ummary of the invention It is the object of the present invention to improve the plant for the manufacture of a mold having the form o~ a multiple-impression plastic plate in such a way that the impression have a perfect quality without the risk of deformation of the planeless of the surface of the plastic plate round about the impression. The mold in the form of a multiple-impression plate may be a positive mold or a negative mold and preferably serves as a base for manufacturing an intaglio printing plate having a given number of identical impressions.
The plant according to the invention is characterized in that the said original plate forms a second plate electrode connected to said high-frequency apparatus, in that the said first plate electrode has an outline which corresponds to an envelope of the design of the original plate and therefore of the impression to be produced, and in that the edge of the said first electrode is surrounded by an insulating border, with the inside edge adapted to the said outline and of a thickness equal to that of the said first plate electrode.
The advantages of this plant are as follows : By virtue of a plate electrode whose outline corresponds to the envelope of the design and by virtue of the insulating border surrounding this electrode, the use of high-frequency heating ensures not only more rapid and more uniform heating, but also affords that the heating is better confined to the region of the impression to be produced. In fact, during the heating of the plastic 2l~3~
plake, it has proved essential that, as far as possible, only this zone of the impression to be produced is heated and not the adjacent regions, in order to prevent the latter from being deformed during the molding operation. The plastic plate beyond the impression zones should remain absolutely plane so that this multiple-impression plastic plate can serve, without subsequent treatment of the surface, for reproducing the intaglio printing plates, as mentioned in the in~roduction.
If the plastic plate is heated by conventional means, for example electrically or by circulation of a hot fluid, it is virtually impossible to prevent this adjacent zone from being heated as well; for this reason, with the conventional methods, to prevent such heating of the adjacent zone, it is absolutely necessary to limit the temperature of final heating, which consequently makes it necessary to work with a greater pressure during the molding. In constrat, with the plant according to the invention, since the heated region is limited to the required zone, it is possible to work with higher temperatures, th~reby enabling a reduction in the pressure during the molding. Whereas, according to the conventional methods, a temperature of about 150 to 170 and a pressure of loo to 200 kg/cm2 are used, with the plant according to the invention it is possible to heat the plate up to a temperature of about 200C and apply a pressure of about 20 kg/cm2~
Preferably, at least one of the plate-carrying and electrode-carrying devices comprises heaking and cooling means, preferably by circulating a liquid, for a preheating of the electrodes before these electrodes are brought into contact with the plastic plate, and 2~3~
advantageous that the first electrode having said outline is carried by an insulating support and that said first electrode and its border are covered by a thin insulating layer o~ a rigid materi.al, preferably S mica.
Preferred embodiments of the plant are defined by the dependent claims.
The invention relates also to a method of actuating the plant according to the invention, which is characterized by the following steps :
a) a plastic plate made of thermo-formable material having essentially the dimensions of the mold required, is prepared;
b) a first plate electrode, the outline of which corresponds to the envelope of the design of the original plate and therefore of the impression to be pxoduced, is prepared;
c) the edge of the said first plate electrode is surrounded by an insulating border, the inside edge Of which is adapted to the said outline and the thickness of which is equal to the thickness of the said first plate electrode;
d) the said plastic plate is placed, in an adjusted position corresponding to the location of the first impression to be produced, between th~ first plate electrode and the original plate which is used as a second plate electrode;
e) the two electrodes are brought near to the said plastic plate and the latter is subjected to hiyh-frequency heating by producing, between the two electrodes, a high-frequency field for a given period of time until the plastic plate has reached a temperature suitable for molding;
f) the first impression is produced on the plastic plate by compressing the latter by applying the molding pressure;
g) the plastic plate is cooled, while the molding pressure is maintained;
h) the electrodes are separated and relative displacement is effected between, on the one hand, the plastic plate and, on the o~her hand, the electrodes, successively in the ~ther adjusted positions corresponding to the other impressions to be produced and, in each position, the steps e) to g) are repeated in order to reproduce th~ next impression.
A pre~erred variant of this method is characterized in that the electrodes are preheated before being brought into contact with the plastic plate.
Brief descri~tion of the drawin~s Two exempl~ry embodiments of the plant will be described with the aid of the accompanying drawing.
Figure 1 is a perspective view of a first form of e~bQdiment of the pLant for implementing the method.
Figure 2 is a partial and enlarged side view of 1;he plant.
Figure 3 is an enlarged side view of a variation of ~he pla~t.
25Figure 4 is a plan ~iew of an original plate ~howing a diagrammatic illustration o the design and the outline, or periphery, which surrounds the zone of design and thi~ outl~ne is of course imagina~y and h~s been ~hown only for the sake o th~ description.
30Figure S shows the plate elec~rode having an outline corr~sponding to that of the design.
~ Figure 6 is a view of the same electrode, but plac~d on an insulating support and surrounded by an insulating border.
35Figure 7 is a sectional ~iew along VII-VII of F~g~re 6.
Figure 8 shows a second form of embodiment of the plant~ illustrating only the ele~ents essential for the in~ention~
5~
Figure 9 is a diagra~matic view in the direc~-ion of the arrows IX-IX of Figure 8.
Fig~re 1~ is a sectional view of the electrode-car~ying device of Figures 8 and 9, along X-X of Figure 5 9, to an enlarged scale.
Figure 11 is a view similar to Figur~ 6 e~cept for the fact tha~ the shape of ~he electrode does not correspond exactly to the outline of the design, but ~o the rough envelope thereof and ~hat the border covers the entire insulating support and forms one piece with the latter.
Figure 12 is a sectional view along XII-XII of ~igure 11.
Description of the preferred_embodimen~s For the sake of greater clarity, first the plants for implementing the method and subsequently ~he method will be described.
The plant according to Figure 1 comprises a structure 1 serving as a base for the remainder of the plant. A first sliding frame 2 displaceable in a hori-zontal direction F2 is mounted on the structure 1. Asecond sliding frame 3 is mounted inside the sliding frame 2 and is displaceable inside the latter in a direction F3. A plastic plate 4, which is fixed by clamps 3a and will form the multiple-impression mold, is placed inside the second sliding frame 3. A few impressions 23 are indicated in Figure 1.
In the middle of the region in which the first sliding fr~m~ 2 moves, and below the sliding plane, is arranged the electrode~carrying device. As shown in Figure 2, this device comprises a support saddle 5 integral with the structure 1, on which there is arranged an insulati~g plate 6 supporting a heating and cooling device 8 consisting of a flat metal box in which a liquid can circulate and which is provided for this purpose with two pipes 8a and 8b for the inlet and outlet of the hot or cold liquid as required. ~n insulating,plate 26, on which there is arranged an insulating support 25 carrying ', - 8 -:
a first plate electrode 7, ~ests on this heatin~ a~d cooling de~ice ~ The arrangement and the configuration ~f this electro~e ~ will ~e describ~d in greater detail on the bas~s of Figures 4 ~o ~
Vertically in line withthe electrode thereis lo-catedaplate-carrying d~vice for fixing the orig-~nalplatel9 which, in the example under consideration, has an en-graved design on it. Thi~ original plate 19 is used as a second el~ctrode. The said plate-carrying device is installed by means of a framework 10 which, in the example illustrated in Figure 1, comprises four slanting legs and an llpper plate 9. A douhle-acting jack 11 is fixed onto this plate 9 and the rod 12 of the piston of the said jack passes through the plate 9 and carries, on its bo~tom end, the plate-carrying device. The latter consists of a support plate 13 provided with two guiding rods 14, 15 extending parallel to the rod 12 of the jac~
11 and passing through the upper plate 9. The actual plate carrisr carrying the original plate 19 is suspended via four thr~aded rods 16 provided with nuts 17 for adjusting the level. This plate carrier constitutes both a heating and cooling de~ice 18 consisting of a flat metal box provided with two pipes 18a and lBb serving as an inlet and outlet for the hot or cold liquid as re-quired.
A chamber 20, inside which a relative vacuwm maybe created, is ~rranged below the device 18. This chamber 20 consists of a bellows, the top end of which is in-tegral with the ~evice 18 and the ~ottom end ~f which is in close contact with the plastic plate 4.
Finally, on a console 21 there is arranged a high-frequency apparatus 22 as well as various controls enabling, for example, the sliding frames 2 and 3 to be displaced and the jack 11 to be controlled. In the example illustrated in Fiyures 1 and 2, the electrode 7 is connected to the live terminal of this high-frequency apparatus 22 whereas the original plate 19 is grounded, i.e. is in contact with the device 8 made o metal and the other elements of the metal structure l.
g 2~3~
Figure 4 shows the original plate 19 with an engra~ed design l9b which extends o~er an irregular zone marked by an ~utline forming the periphery 19a of this engraved zone. Of course, this outline does not exist in reality, it is indicated in Figure 4 in order to il-lustrate the boundary of the design clearly.
Figure S shows the electrode 7 cut in such a manner that its outline 7a corresponds to the envelope l9a. This electrode 7, which is preferably a sheet of copper about 0.5 m~ thick, is fixed, according to Figures 6 and 7, for example by bonding, onto an insulating support 25 about 1.5 to 2.0 mm thick, and is surrounded by an insulating border 24 which is bonded onto the insulating support 25 and the inner edge of which has the shape of the outline of the ~lectrode 7 and therefore fits around the edge of the latter. The border 24 has the same thickness as that of the alectrode 7 J their surfaces are therefore in the same plane (Figure 7).
The insulating support 25 and the border 24 are made of an electrically and thermally insulating mater-ial, preferably glass fibre-reinforced silicone, and cut ou~ of an elastic strip. In the example under cons~dera-tion, ~he border 24 is a part dïstinct from the insu-lating support 25 and only surrounds the region adjacent to the electrode 7 without covering the entire surface of th4 insulating suppor~ 25, the dimensio~ls of which correspond approximately to the original plate 19 or are slightly larger. The minimum width of the ~order 24 should be about 5 mm to ensure ~oth good support for the plastic plate 4 axound the Lmpression during the molding and gcod electrical and thermal insulation, so that the heating is concentrated exclusively on the zone defined by the outline 7a of the electrode 7. Under these condi-tions, any deformation of the surface of the plastic plate around the impression is pre~ented and perfect pl~neness beyond the impressions is guaranteed, this planeness being essential for the subsequent manufactur-ing of the intaglio printing plates.
Since the insulating support 25 is flexible and ~54~3~
relatively thin, pro~ision h~s been made, according to Figure 2, for a further insulating plate 26 made of rigid material, for example bakelite, 4 to 5 mm ~hick, which is therefore placed between the device 8 and the insulating support 25 to prevent dissipation of the high-frequency energy and to provide good support.
The electrode 7 can be connected to the high-frequency apparatus 22, not shown Ln the drawings, via the insulating support 25.
According to the variation of Figure 3, a rigid insulating thin plate 27, preferably made of mica, having a thickness of about 0.7 to 1.O mm, is placed on the said electrode and its border 24. This arrangement ensures a perfect impression and prevents the join between the edge of the electrode 7 and its border affecting the quality of the impression.
Figures 8 to 10 show a second form of embodiment of the plant, in which it is the original plate 19 which is connectsd via a copper strip 28 to the live outlet of the high-fre~uency apparatus 22. The jack 11 is installed on the framework 10 by means of plates 9, 9a, and the supporting plate 13, provided with the guiding rods 14, 15, is suspended from the end of the rod 12 of the piston of the said jac~ (Figure 9). Fixed to this supporting plate 13, by means of an electrically and thermally insulating plate 6', is the plate carrier consisting of the heating and cooling device 18 provided with the pipes 18a, 18b. The fixing of the original plate 19 is effected by means of a supporting frame 18c in metal contact with the device 18 in such a manner that the device 18/original plate 19 assembly form ~he high-poten~ial electrode in this case, the copper strip 28 being fixed to this frame 18c. The plant according to Figures 8 and 9 works without a vacuum chamber.
As far as the electrode carrier is concerned, it again comprises a heating and cooling device 8 consisting of a flat box which is provided with two pipes 8a, 8b for the circulation of the hot or cold liquid and is positioned, without any insulation, on the support saddle ~03$~
S by means of a ~hree-point support.
Figure lO shows the exact axrangement of this electrode carrier In this case, provision is made for a me~al pla~e 29 supporting the insulating plate 26 on which there is ar~anged the insulating support 25 carry-ing the electrode 7' surrounded by the insulating border 24 which forms one piece with the said support 25. The entire assembly is preassembled ~y means of s~rews 30 which pass through these elements and the bottom end of which emerges in a housing 29a of the metal plate 29 and is screwed into a nut ~Oa. The head of the ~crews 30 is embedded in conical holes ~b formed in the electrode 7~
so that these screws 30 are flush with the surface of the electrode. A mica plate 27 is also provided on top of the electrode 7~and its border 24. The metal plate 29 has inclined edges enabling it to be fixed to the device 8, together with all of the other elements, by means of winches 31 which likewise have inclined faces and clamp the said inclined edges of the ~etal plate 29. ~ith ~his arrangement, the electrode 7' is grounded ~y means of the screws 30, the device 8 and the structure.
The insulating part forming the support 25 and the border 24 is preferably a flexible plate made of silicone, with a thickness of 2 to 3 mm, on the surface of ~hich a recess with the shape of the outline of the electrode 7' has been made. The depth of this recess corresponds to the thickness of the electrode, na~ely about G.S mm. For this reason, the border 24 covers the entire insulating support 25(Figure 12).
As shown in Figure 11, the outline 7a of the elec~rode 7I does not exactly match in this case the de-tails oftheoutline ofthe engraved design,shown inFigure4 andrepresented.in dottedlines,butcorresponds toarougher envelope ~9a' Of course, these pl~nts are only exemplary em~odiments and, instead of only the plastic plate moving in the two direction F2, F3, the original plate 19 and the entire plate-carrying device together with the jack 11 and the electrode 7, 7' may, either move in a hori~ontal direction FZ or F3, and in this case the 2~3~
plastic plate 4 is displaceable in the other direction F3 or F2, or move in both directions, and thus the plastic plate 4 is fixed. Moreover, the heating and cooling devices 8, 18 may be of another type.
S The method will be described with the aid of the plant according to Figures 8 to 12.
A metal original plate 19 is prepared, this plate having on it engraved lines of varying depths constitut-ing the desi~n to be reproduced, and it is fixed to the plate carrier consisting of the heating and cooling device 18 by means of the insulating plate 6'.
A copper sheet forming the electrode 7' is prepared, this sheet being cut according to the envelope l9a' of the design, and it is fixed in the hollow of the lS insulating support 25 in such a way that it is surrounded by the border 24 (Figure 11).
A plas~ic plate 4 made of material being thermo-formable by means of molding and compression, for example COBE~ P.V.C., and having practicaLly the same dimensions as the intaglio printing plate required, is prepared.
This plastic plate 4 is arranged in the sliding frame 3 and held in position by adjustable clamps 3a enabling it to be kept uniformly tensioned inside the sliding frame 3 (Figure 1). By means of two sliding frames 2 and 3, the plastic plate 4 is brought into a ~irst adjusted position which corresponds to the position of the iirst Lmpression 23 (Figure 1). In this position, the zone to be deformed by molding is located between the electrode 7' and the original plate 19 which is located vertically above the elec~rode 7'.
The electrode 7~as well as the original plate 19 which itself forms an electrode are, in the raised position of the original plate 19, preheated by circulat-ing hot water thro-lgh ~he two devices 8, 18 until these electrodes reach a temperature of between 40 and 50C, in particular 45C, which generally takes about 2 minutes.
This preheating operation enables a better qualiSy impression to be obtained, since the problems of varying expansion of elements in contact are avoided, expansion -~ which could adversely affect ~he impression.
Once the preheating te~pera~ure is reached, ;the oxiginal plate lg i5 lowerèd, by means of the jack 11, until it is -in contact with the plastic plate 4 and, while applying a slight pressure o~ t~e order of 5 kg/em2, the high-frequency field is applied via the two elec-trodes until ~he plastic plate 4 reaches a temperature of about 200~C. To this end, a frequency of, for example, 27 MHz applied for 15 to 20 seconds is used. '~ests carried out have shown that the elec~rodes, the insulating support 25 and the insulating border 24 reach a temper-ature of only 40 to 50C. The temperature of 200aC of the plastic pla~e 4 is higher than that used with ~he methods known hitherto and enables a lower pressure to be sub-s~quently applied, thereby preventing deformation around the actual impression zone.
Once this temperature i5 obtained, the molding pressure to obtain the impression, for example of the order of 20 to 25 kglcm2, i.e. 5 to 10 ti~es less than for known methods, is exerted by means of the jack 11, the power supply of the electrodes is interrupted, and while maintainîng this molding pxessure, the original plate 19, the electrode 7' as we:ll as the plastic plate 4, are cooled by circulating cold water in the devices 8, 18~ When the original plate 19 has reached room temperature, i.e. about 20C, which takes roughly 2 to 2.5 minutes, the pressure is released and the original plate 19 is separated from the plastic plate 4 by raising the plate-carrying device. The operations to produce a single impression thus take about S minutes.
Then~ the plastic plate 4 is moved into a second adjusted position, displacement being effected either in the direction F2 or in the direction F3, and the same operations as above are restarted in order to obtain the second impression and so on, until as many impressions, lines and columns as req~ired have been applied onto the plate 4.
A mold in the form of a multiple-impression plate 4 (Figure 1) is thus obtained. Since an engraved ori~in-al plate was used, the mold obtained by the method is a ;~3546~
positive plastic mold. Nevertheless, a negative plastic mold would ~e obtained using the same method, if a positi~e original plate which, itself, would have been reproduced using an engraved prLmitive plate,were used.
S Furthermore, where appropriate, it is possible to leave out the preheating operation.
` If the plant according to Figures 1 ~o 3 is used for implementing the method, after the preheating phase, the plate-carrying device is lowered until the bottom end of the bellows of the chamber 20 comes into contact with the plastic plate 4 and an approxLmately 80% vacuum is created in this chamber with the aid of a device not shown. Molding under vacuum could have, under certain conditions, advantages, but is not necessary. Of course, lS after cooling and before mounting the original plate 19, the chamber 20 is connected to the external atmosphere.
Instead of the plate~carrying device being lowered in order to apply a compressive force on the plastic plate 4, it is possible to envisage that the plate carrier is fixed and that the electrode 7 with its support are raised in order to apply the pressure.
_ 15 -
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F.ield of the invention The present invention relates to a plant for ~anufacturing a mold in the form of a thermo-formable, multiple-impression plastic plate, in particular for reproducing intaglio printing plates, using an original plate made of metal which bears an engraved or embossed design, and by means of compression molding with high-frequency heating of said plastic plat~, comprising a struture provided with an electrode-carrying device for supporting a plate electrode connected to a high-frequency apparatus, and with a plate-carrying device for supporting the original plate at a distance from and opposite to the said plate electrode; at least one sliding frame for supporting the plastic plate, said sliding frame being arranged between and movable with respect to said original plate and said plate electrode in two perpendicular horizontal directions; and comprising means for changing the distance between the said electrode-carrying and plate-carrying devices.
Said intaglio printing plates are intended for sheet-fed intaglio printing.
Prior art It is known to manufacture intaglio printing plates for sheet-fed printing using an original metal plate on which there has been carefully engraved the image to be reproduced consisting of engraved lines and zones of varying depths. Since the intaglio printing plate arranged on the plate cylinder has several identical impressions, in particular in the case where bank notes are printed, arranged in perpendicular rows, the impression must be multiplied and transferred onto the intaglio printing plate which is generally made of nickel. A plant for carrying out this multiplication on a thermo-formable plastic plate according to the preamble of claim 1 and as described in the introduction has already been proposed in the publication EP-A- 335 830.
In the case of a multiple-impression positive plastic plate, a known method to obtain the intaglio printing plate is as follows :
A layer of silver is applied onto the positive plate and a layer of copper is deposited on the silver-lined surface by means of electrolysis. By withdrawing the positive plastic plate, a negative copper plate, also called a female matrix or lower matrix, which comprises the engraved impressions, is obtained. The surface of this negative plate between the impressions must be machined so as to ensure that it is completely smooth and continuous. Using this negative copper plate, a positive nickel plate is reproduced, followed by a negative nickel plate, which i5 the actual intaglio printing plate which will be mounted on the plate cylinder. This plate must also undergo a finishing treatment so as to ensure, on the one hand, that the surface between the impressions is smooth and continuous and, on the other hand, that the rear of the plate in contact with the plate cylinder is also perfectly smooth and continuous. In order to increase the resistance to wear of the intaglio printing plate, ~3~
a layer of chrome is applied.
_ummary of the invention It is the object of the present invention to improve the plant for the manufacture of a mold having the form o~ a multiple-impression plastic plate in such a way that the impression have a perfect quality without the risk of deformation of the planeless of the surface of the plastic plate round about the impression. The mold in the form of a multiple-impression plate may be a positive mold or a negative mold and preferably serves as a base for manufacturing an intaglio printing plate having a given number of identical impressions.
The plant according to the invention is characterized in that the said original plate forms a second plate electrode connected to said high-frequency apparatus, in that the said first plate electrode has an outline which corresponds to an envelope of the design of the original plate and therefore of the impression to be produced, and in that the edge of the said first electrode is surrounded by an insulating border, with the inside edge adapted to the said outline and of a thickness equal to that of the said first plate electrode.
The advantages of this plant are as follows : By virtue of a plate electrode whose outline corresponds to the envelope of the design and by virtue of the insulating border surrounding this electrode, the use of high-frequency heating ensures not only more rapid and more uniform heating, but also affords that the heating is better confined to the region of the impression to be produced. In fact, during the heating of the plastic 2l~3~
plake, it has proved essential that, as far as possible, only this zone of the impression to be produced is heated and not the adjacent regions, in order to prevent the latter from being deformed during the molding operation. The plastic plate beyond the impression zones should remain absolutely plane so that this multiple-impression plastic plate can serve, without subsequent treatment of the surface, for reproducing the intaglio printing plates, as mentioned in the in~roduction.
If the plastic plate is heated by conventional means, for example electrically or by circulation of a hot fluid, it is virtually impossible to prevent this adjacent zone from being heated as well; for this reason, with the conventional methods, to prevent such heating of the adjacent zone, it is absolutely necessary to limit the temperature of final heating, which consequently makes it necessary to work with a greater pressure during the molding. In constrat, with the plant according to the invention, since the heated region is limited to the required zone, it is possible to work with higher temperatures, th~reby enabling a reduction in the pressure during the molding. Whereas, according to the conventional methods, a temperature of about 150 to 170 and a pressure of loo to 200 kg/cm2 are used, with the plant according to the invention it is possible to heat the plate up to a temperature of about 200C and apply a pressure of about 20 kg/cm2~
Preferably, at least one of the plate-carrying and electrode-carrying devices comprises heaking and cooling means, preferably by circulating a liquid, for a preheating of the electrodes before these electrodes are brought into contact with the plastic plate, and 2~3~
advantageous that the first electrode having said outline is carried by an insulating support and that said first electrode and its border are covered by a thin insulating layer o~ a rigid materi.al, preferably S mica.
Preferred embodiments of the plant are defined by the dependent claims.
The invention relates also to a method of actuating the plant according to the invention, which is characterized by the following steps :
a) a plastic plate made of thermo-formable material having essentially the dimensions of the mold required, is prepared;
b) a first plate electrode, the outline of which corresponds to the envelope of the design of the original plate and therefore of the impression to be pxoduced, is prepared;
c) the edge of the said first plate electrode is surrounded by an insulating border, the inside edge Of which is adapted to the said outline and the thickness of which is equal to the thickness of the said first plate electrode;
d) the said plastic plate is placed, in an adjusted position corresponding to the location of the first impression to be produced, between th~ first plate electrode and the original plate which is used as a second plate electrode;
e) the two electrodes are brought near to the said plastic plate and the latter is subjected to hiyh-frequency heating by producing, between the two electrodes, a high-frequency field for a given period of time until the plastic plate has reached a temperature suitable for molding;
f) the first impression is produced on the plastic plate by compressing the latter by applying the molding pressure;
g) the plastic plate is cooled, while the molding pressure is maintained;
h) the electrodes are separated and relative displacement is effected between, on the one hand, the plastic plate and, on the o~her hand, the electrodes, successively in the ~ther adjusted positions corresponding to the other impressions to be produced and, in each position, the steps e) to g) are repeated in order to reproduce th~ next impression.
A pre~erred variant of this method is characterized in that the electrodes are preheated before being brought into contact with the plastic plate.
Brief descri~tion of the drawin~s Two exempl~ry embodiments of the plant will be described with the aid of the accompanying drawing.
Figure 1 is a perspective view of a first form of e~bQdiment of the pLant for implementing the method.
Figure 2 is a partial and enlarged side view of 1;he plant.
Figure 3 is an enlarged side view of a variation of ~he pla~t.
25Figure 4 is a plan ~iew of an original plate ~howing a diagrammatic illustration o the design and the outline, or periphery, which surrounds the zone of design and thi~ outl~ne is of course imagina~y and h~s been ~hown only for the sake o th~ description.
30Figure S shows the plate elec~rode having an outline corr~sponding to that of the design.
~ Figure 6 is a view of the same electrode, but plac~d on an insulating support and surrounded by an insulating border.
35Figure 7 is a sectional ~iew along VII-VII of F~g~re 6.
Figure 8 shows a second form of embodiment of the plant~ illustrating only the ele~ents essential for the in~ention~
5~
Figure 9 is a diagra~matic view in the direc~-ion of the arrows IX-IX of Figure 8.
Fig~re 1~ is a sectional view of the electrode-car~ying device of Figures 8 and 9, along X-X of Figure 5 9, to an enlarged scale.
Figure 11 is a view similar to Figur~ 6 e~cept for the fact tha~ the shape of ~he electrode does not correspond exactly to the outline of the design, but ~o the rough envelope thereof and ~hat the border covers the entire insulating support and forms one piece with the latter.
Figure 12 is a sectional view along XII-XII of ~igure 11.
Description of the preferred_embodimen~s For the sake of greater clarity, first the plants for implementing the method and subsequently ~he method will be described.
The plant according to Figure 1 comprises a structure 1 serving as a base for the remainder of the plant. A first sliding frame 2 displaceable in a hori-zontal direction F2 is mounted on the structure 1. Asecond sliding frame 3 is mounted inside the sliding frame 2 and is displaceable inside the latter in a direction F3. A plastic plate 4, which is fixed by clamps 3a and will form the multiple-impression mold, is placed inside the second sliding frame 3. A few impressions 23 are indicated in Figure 1.
In the middle of the region in which the first sliding fr~m~ 2 moves, and below the sliding plane, is arranged the electrode~carrying device. As shown in Figure 2, this device comprises a support saddle 5 integral with the structure 1, on which there is arranged an insulati~g plate 6 supporting a heating and cooling device 8 consisting of a flat metal box in which a liquid can circulate and which is provided for this purpose with two pipes 8a and 8b for the inlet and outlet of the hot or cold liquid as required. ~n insulating,plate 26, on which there is arranged an insulating support 25 carrying ', - 8 -:
a first plate electrode 7, ~ests on this heatin~ a~d cooling de~ice ~ The arrangement and the configuration ~f this electro~e ~ will ~e describ~d in greater detail on the bas~s of Figures 4 ~o ~
Vertically in line withthe electrode thereis lo-catedaplate-carrying d~vice for fixing the orig-~nalplatel9 which, in the example under consideration, has an en-graved design on it. Thi~ original plate 19 is used as a second el~ctrode. The said plate-carrying device is installed by means of a framework 10 which, in the example illustrated in Figure 1, comprises four slanting legs and an llpper plate 9. A douhle-acting jack 11 is fixed onto this plate 9 and the rod 12 of the piston of the said jack passes through the plate 9 and carries, on its bo~tom end, the plate-carrying device. The latter consists of a support plate 13 provided with two guiding rods 14, 15 extending parallel to the rod 12 of the jac~
11 and passing through the upper plate 9. The actual plate carrisr carrying the original plate 19 is suspended via four thr~aded rods 16 provided with nuts 17 for adjusting the level. This plate carrier constitutes both a heating and cooling de~ice 18 consisting of a flat metal box provided with two pipes 18a and lBb serving as an inlet and outlet for the hot or cold liquid as re-quired.
A chamber 20, inside which a relative vacuwm maybe created, is ~rranged below the device 18. This chamber 20 consists of a bellows, the top end of which is in-tegral with the ~evice 18 and the ~ottom end ~f which is in close contact with the plastic plate 4.
Finally, on a console 21 there is arranged a high-frequency apparatus 22 as well as various controls enabling, for example, the sliding frames 2 and 3 to be displaced and the jack 11 to be controlled. In the example illustrated in Fiyures 1 and 2, the electrode 7 is connected to the live terminal of this high-frequency apparatus 22 whereas the original plate 19 is grounded, i.e. is in contact with the device 8 made o metal and the other elements of the metal structure l.
g 2~3~
Figure 4 shows the original plate 19 with an engra~ed design l9b which extends o~er an irregular zone marked by an ~utline forming the periphery 19a of this engraved zone. Of course, this outline does not exist in reality, it is indicated in Figure 4 in order to il-lustrate the boundary of the design clearly.
Figure S shows the electrode 7 cut in such a manner that its outline 7a corresponds to the envelope l9a. This electrode 7, which is preferably a sheet of copper about 0.5 m~ thick, is fixed, according to Figures 6 and 7, for example by bonding, onto an insulating support 25 about 1.5 to 2.0 mm thick, and is surrounded by an insulating border 24 which is bonded onto the insulating support 25 and the inner edge of which has the shape of the outline of the ~lectrode 7 and therefore fits around the edge of the latter. The border 24 has the same thickness as that of the alectrode 7 J their surfaces are therefore in the same plane (Figure 7).
The insulating support 25 and the border 24 are made of an electrically and thermally insulating mater-ial, preferably glass fibre-reinforced silicone, and cut ou~ of an elastic strip. In the example under cons~dera-tion, ~he border 24 is a part dïstinct from the insu-lating support 25 and only surrounds the region adjacent to the electrode 7 without covering the entire surface of th4 insulating suppor~ 25, the dimensio~ls of which correspond approximately to the original plate 19 or are slightly larger. The minimum width of the ~order 24 should be about 5 mm to ensure ~oth good support for the plastic plate 4 axound the Lmpression during the molding and gcod electrical and thermal insulation, so that the heating is concentrated exclusively on the zone defined by the outline 7a of the electrode 7. Under these condi-tions, any deformation of the surface of the plastic plate around the impression is pre~ented and perfect pl~neness beyond the impressions is guaranteed, this planeness being essential for the subsequent manufactur-ing of the intaglio printing plates.
Since the insulating support 25 is flexible and ~54~3~
relatively thin, pro~ision h~s been made, according to Figure 2, for a further insulating plate 26 made of rigid material, for example bakelite, 4 to 5 mm ~hick, which is therefore placed between the device 8 and the insulating support 25 to prevent dissipation of the high-frequency energy and to provide good support.
The electrode 7 can be connected to the high-frequency apparatus 22, not shown Ln the drawings, via the insulating support 25.
According to the variation of Figure 3, a rigid insulating thin plate 27, preferably made of mica, having a thickness of about 0.7 to 1.O mm, is placed on the said electrode and its border 24. This arrangement ensures a perfect impression and prevents the join between the edge of the electrode 7 and its border affecting the quality of the impression.
Figures 8 to 10 show a second form of embodiment of the plant, in which it is the original plate 19 which is connectsd via a copper strip 28 to the live outlet of the high-fre~uency apparatus 22. The jack 11 is installed on the framework 10 by means of plates 9, 9a, and the supporting plate 13, provided with the guiding rods 14, 15, is suspended from the end of the rod 12 of the piston of the said jac~ (Figure 9). Fixed to this supporting plate 13, by means of an electrically and thermally insulating plate 6', is the plate carrier consisting of the heating and cooling device 18 provided with the pipes 18a, 18b. The fixing of the original plate 19 is effected by means of a supporting frame 18c in metal contact with the device 18 in such a manner that the device 18/original plate 19 assembly form ~he high-poten~ial electrode in this case, the copper strip 28 being fixed to this frame 18c. The plant according to Figures 8 and 9 works without a vacuum chamber.
As far as the electrode carrier is concerned, it again comprises a heating and cooling device 8 consisting of a flat box which is provided with two pipes 8a, 8b for the circulation of the hot or cold liquid and is positioned, without any insulation, on the support saddle ~03$~
S by means of a ~hree-point support.
Figure lO shows the exact axrangement of this electrode carrier In this case, provision is made for a me~al pla~e 29 supporting the insulating plate 26 on which there is ar~anged the insulating support 25 carry-ing the electrode 7' surrounded by the insulating border 24 which forms one piece with the said support 25. The entire assembly is preassembled ~y means of s~rews 30 which pass through these elements and the bottom end of which emerges in a housing 29a of the metal plate 29 and is screwed into a nut ~Oa. The head of the ~crews 30 is embedded in conical holes ~b formed in the electrode 7~
so that these screws 30 are flush with the surface of the electrode. A mica plate 27 is also provided on top of the electrode 7~and its border 24. The metal plate 29 has inclined edges enabling it to be fixed to the device 8, together with all of the other elements, by means of winches 31 which likewise have inclined faces and clamp the said inclined edges of the ~etal plate 29. ~ith ~his arrangement, the electrode 7' is grounded ~y means of the screws 30, the device 8 and the structure.
The insulating part forming the support 25 and the border 24 is preferably a flexible plate made of silicone, with a thickness of 2 to 3 mm, on the surface of ~hich a recess with the shape of the outline of the electrode 7' has been made. The depth of this recess corresponds to the thickness of the electrode, na~ely about G.S mm. For this reason, the border 24 covers the entire insulating support 25(Figure 12).
As shown in Figure 11, the outline 7a of the elec~rode 7I does not exactly match in this case the de-tails oftheoutline ofthe engraved design,shown inFigure4 andrepresented.in dottedlines,butcorresponds toarougher envelope ~9a' Of course, these pl~nts are only exemplary em~odiments and, instead of only the plastic plate moving in the two direction F2, F3, the original plate 19 and the entire plate-carrying device together with the jack 11 and the electrode 7, 7' may, either move in a hori~ontal direction FZ or F3, and in this case the 2~3~
plastic plate 4 is displaceable in the other direction F3 or F2, or move in both directions, and thus the plastic plate 4 is fixed. Moreover, the heating and cooling devices 8, 18 may be of another type.
S The method will be described with the aid of the plant according to Figures 8 to 12.
A metal original plate 19 is prepared, this plate having on it engraved lines of varying depths constitut-ing the desi~n to be reproduced, and it is fixed to the plate carrier consisting of the heating and cooling device 18 by means of the insulating plate 6'.
A copper sheet forming the electrode 7' is prepared, this sheet being cut according to the envelope l9a' of the design, and it is fixed in the hollow of the lS insulating support 25 in such a way that it is surrounded by the border 24 (Figure 11).
A plas~ic plate 4 made of material being thermo-formable by means of molding and compression, for example COBE~ P.V.C., and having practicaLly the same dimensions as the intaglio printing plate required, is prepared.
This plastic plate 4 is arranged in the sliding frame 3 and held in position by adjustable clamps 3a enabling it to be kept uniformly tensioned inside the sliding frame 3 (Figure 1). By means of two sliding frames 2 and 3, the plastic plate 4 is brought into a ~irst adjusted position which corresponds to the position of the iirst Lmpression 23 (Figure 1). In this position, the zone to be deformed by molding is located between the electrode 7' and the original plate 19 which is located vertically above the elec~rode 7'.
The electrode 7~as well as the original plate 19 which itself forms an electrode are, in the raised position of the original plate 19, preheated by circulat-ing hot water thro-lgh ~he two devices 8, 18 until these electrodes reach a temperature of between 40 and 50C, in particular 45C, which generally takes about 2 minutes.
This preheating operation enables a better qualiSy impression to be obtained, since the problems of varying expansion of elements in contact are avoided, expansion -~ which could adversely affect ~he impression.
Once the preheating te~pera~ure is reached, ;the oxiginal plate lg i5 lowerèd, by means of the jack 11, until it is -in contact with the plastic plate 4 and, while applying a slight pressure o~ t~e order of 5 kg/em2, the high-frequency field is applied via the two elec-trodes until ~he plastic plate 4 reaches a temperature of about 200~C. To this end, a frequency of, for example, 27 MHz applied for 15 to 20 seconds is used. '~ests carried out have shown that the elec~rodes, the insulating support 25 and the insulating border 24 reach a temper-ature of only 40 to 50C. The temperature of 200aC of the plastic pla~e 4 is higher than that used with ~he methods known hitherto and enables a lower pressure to be sub-s~quently applied, thereby preventing deformation around the actual impression zone.
Once this temperature i5 obtained, the molding pressure to obtain the impression, for example of the order of 20 to 25 kglcm2, i.e. 5 to 10 ti~es less than for known methods, is exerted by means of the jack 11, the power supply of the electrodes is interrupted, and while maintainîng this molding pxessure, the original plate 19, the electrode 7' as we:ll as the plastic plate 4, are cooled by circulating cold water in the devices 8, 18~ When the original plate 19 has reached room temperature, i.e. about 20C, which takes roughly 2 to 2.5 minutes, the pressure is released and the original plate 19 is separated from the plastic plate 4 by raising the plate-carrying device. The operations to produce a single impression thus take about S minutes.
Then~ the plastic plate 4 is moved into a second adjusted position, displacement being effected either in the direction F2 or in the direction F3, and the same operations as above are restarted in order to obtain the second impression and so on, until as many impressions, lines and columns as req~ired have been applied onto the plate 4.
A mold in the form of a multiple-impression plate 4 (Figure 1) is thus obtained. Since an engraved ori~in-al plate was used, the mold obtained by the method is a ;~3546~
positive plastic mold. Nevertheless, a negative plastic mold would ~e obtained using the same method, if a positi~e original plate which, itself, would have been reproduced using an engraved prLmitive plate,were used.
S Furthermore, where appropriate, it is possible to leave out the preheating operation.
` If the plant according to Figures 1 ~o 3 is used for implementing the method, after the preheating phase, the plate-carrying device is lowered until the bottom end of the bellows of the chamber 20 comes into contact with the plastic plate 4 and an approxLmately 80% vacuum is created in this chamber with the aid of a device not shown. Molding under vacuum could have, under certain conditions, advantages, but is not necessary. Of course, lS after cooling and before mounting the original plate 19, the chamber 20 is connected to the external atmosphere.
Instead of the plate~carrying device being lowered in order to apply a compressive force on the plastic plate 4, it is possible to envisage that the plate carrier is fixed and that the electrode 7 with its support are raised in order to apply the pressure.
_ 15 -
Claims (10)
1. A plant for manufacturing a mold in the form of a thermo-formable, multiple-impression plastic plate, in particular for reproducing intaglio printing plates, using an original plate (19) made of metal which bears an engraved or embossed design (19b), and by means of compression molding with high-frequency heating of said plastic plate (4), comprising a structure (1) provided with an electrode-carrying device (6, 8; 8, 26) for supporting a plate electrode (7) connected to a high-frequency apparatus (22), and with a plate-carrying device (13 to 18) for supporting the original plate (19) at a distance from and opposite to the said plate electrode (7); at least one sliding frame (3) for supporting the plastic plate (4), said sliding frame being arranged between and movable with respect to said original plate (19) and said plate electrode (7) in two perpendicular horizontal directions (F2 and F3); and comprising means (11, 12) for changing the distance between the said electrode-carrying and plate-carrying devices, characterized in that the said original plate (19) forms a second plate electrode connected to said high-frequency apparatus (22), in that the said first plate electrode (7, 7') has an outline (7a) which corresponds to an envelope (19, l9a') of the design (19b) of the original plate (19) and therefore of the impression to be produced, and in that the edge of the said first electrode (7, 7') is surrounded by an insulating border (24), with the inside edge adapted to the said outline and of a thickness equal to that of the said first plate electrode.
2. The plant as claimed in claim 1, characterized in that the said first plate electrode (7, 7') is carried by an insulating support (25)
3. The plant as claimed in claims 1 and 2, characterized in that the said insulating support (25) and the said insulating border (24) are one plastic piece, preferably consisting of an elastic material, on the surface of which a recess with the shape of the said outline has been made.
4. The plant as claimed in one of claims 1 to 3, characterized in that the said first electrode (7, 7') and its border (24) are covered by a thin insulating layer of a rigid material (27), preferably mica.
5. The plant as claimed in one of claims 1 to 4, characterized in that at least one of the plate-carrying and electrode-carrying devices comprises means (8, 8a, 8b; 18, 18a, 18b) for heating and cooling, preferably by circulating a liquid.
6. The plant as claimed in one of claims 1 to 5, characterized in that the plate-carrying device comprises heating and cooling means (18, 18a, 18b) consisting of a flat metal box which is in contact with the original plate (19) and which forms the second plate electrode with the latter, in that the said electrode-carrying device comprises a support saddle (5) on which heating and cooling means (8, 8a, 8b) consisting of a flat box supporting the first electrode (7 7'), are arranged and in that the plate-carrying device (13 to 18) is provided with means, preferably with a double-acting jack (11), for displacing said plate-carrying device vertically and applying a compressive force onto the plastic plate (4).
7. The plant as claimed in claim 6, characterized in that it is the assembly consisting of the said original plate (19) and the said box (18) which is connected by a conductor (28) to the live outlet of the high-frequency apparatus (22), and in that the said box (18) is mounted in an insulating manner by means of an insulating plate (6'), whereas the said first electrode (7, 7') is grounded.
8. The plant as claimed in one of claims 2 to 7, characterized in that the insulating support (25) carrying the said first electrode (7, 7') and its border (24) is positioned on an insulating plate (26) itself fixed onto a metal plate (29), the whole being preassembled by means of countersunk-head screws (30) which pass through all of the elements mentioned and are flush with the surface of the first electrode, all of these elements being fixed by fixing means onto a base of the electrode-carrying device, in particular on a box of a heating and cooling device (18).
9. A method of actuating the plant as claimed in claim 1, characterized by the following steps :
a) a plastic plate made of thermo-formable material having essentially the dimensions of the mold required, is prepared;
b) a first plate electrode, the outline of which corresponds to the envelope of the design of the original plate and therefore of the impression to be produced, is prepared;
c) the edge of the said first plate electrode is surrounded by an insulating border, the inside edge of which is adapted to the said outline and the thickness of which is equal to the thickness of the said first plate electrode;
d) the said plastic plate is placed, in an adjusted position corresponding to the location of the first impression to be produced, between the first plate electrode and the original plate which is used as a second plate electrode;
e) the two electrodes are brought near to the said plastic plate and the latter is subjected to high-frequency heating by producing, between the two electrodes, a high-frequency field for a given period of time until the plastic plate has reached a temperature suitable for molding;
f) the first impression is produced on the plastic plate by compressing the latter by applying the molding pressure;
g) the plastic plate is cooled, while the molding pressure is maintained;
h) the electrodes are separated and relative displacement is effected between, on the one hand, the plastic plate and, on the other hand, the electrodes, successively in the other adjusted positions corresponding to the other impressions to be produced and, in each position, the steps e) to g) are repeated in order to reproduce the next impression.
a) a plastic plate made of thermo-formable material having essentially the dimensions of the mold required, is prepared;
b) a first plate electrode, the outline of which corresponds to the envelope of the design of the original plate and therefore of the impression to be produced, is prepared;
c) the edge of the said first plate electrode is surrounded by an insulating border, the inside edge of which is adapted to the said outline and the thickness of which is equal to the thickness of the said first plate electrode;
d) the said plastic plate is placed, in an adjusted position corresponding to the location of the first impression to be produced, between the first plate electrode and the original plate which is used as a second plate electrode;
e) the two electrodes are brought near to the said plastic plate and the latter is subjected to high-frequency heating by producing, between the two electrodes, a high-frequency field for a given period of time until the plastic plate has reached a temperature suitable for molding;
f) the first impression is produced on the plastic plate by compressing the latter by applying the molding pressure;
g) the plastic plate is cooled, while the molding pressure is maintained;
h) the electrodes are separated and relative displacement is effected between, on the one hand, the plastic plate and, on the other hand, the electrodes, successively in the other adjusted positions corresponding to the other impressions to be produced and, in each position, the steps e) to g) are repeated in order to reproduce the next impression.
10. The method as claimed in claim 9, characterized in that the electrodes are preheated before being brought into contact with the plastic plate.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP90810117.3 | 1990-02-19 | ||
| EP90810117A EP0443292B1 (en) | 1990-02-19 | 1990-02-19 | Device and method for the manufacture of a multiple plastic mould for the reproduction of intaglio printing plates |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2035400A1 true CA2035400A1 (en) | 1991-08-20 |
Family
ID=8205905
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002035400A Abandoned CA2035400A1 (en) | 1990-02-19 | 1991-01-31 | Plant for manufacturing a mold in the form of a multi-impression plastic plate, in particular for reproducing intaglio printing plates, and method of actuating this plant |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0443292B1 (en) |
| JP (1) | JPH054322A (en) |
| KR (1) | KR910021303A (en) |
| CN (1) | CN1027527C (en) |
| AT (1) | ATE96087T1 (en) |
| AU (1) | AU631094B2 (en) |
| CA (1) | CA2035400A1 (en) |
| DE (1) | DE69004072T2 (en) |
| RU (1) | RU1828433C (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10328198A1 (en) | 2003-06-24 | 2005-01-20 | Bernd Hansen | embosser |
| FR2952578A1 (en) * | 2009-11-19 | 2011-05-20 | Itron France | Method for manufacturing e.g. distribution slide of deformable diaphragm gas meter, involves selecting set point temperature, application pressure and time to allow to be treated surface to have contact surface shape by creeping of material |
| CN101913164B (en) * | 2010-05-19 | 2012-08-22 | 广州毅昌科技股份有限公司 | Molding device for large-size flat-plate plastic product |
| FR2967605B1 (en) * | 2010-11-24 | 2013-09-13 | Oreal | METHOD FOR MODIFYING THE SURFACE CONDITION OF AN ARTICLE IN PLASTIC MATERIAL |
| FR2978948B1 (en) | 2011-08-09 | 2015-05-15 | Faurecia Interieur Ind | METHOD FOR PRODUCING A GARMENT COMPONENT COMPRISING A PARTICULAR APPEARANCE DECORATION ZONE |
| CN103879216B (en) * | 2012-12-20 | 2018-02-23 | 舍弗勒技术股份两合公司 | A kind of embossing device and its application method |
| CN107791735B (en) * | 2017-09-03 | 2023-08-01 | 深圳钜诚金匠银艺文化有限公司 | Mould and method for processing noble metal container |
| CN111976127A (en) * | 2019-10-10 | 2020-11-24 | 海盐县集佳建材有限公司 | A supplementary forming mechanism for decorating wallboard surface pattern |
| CN110843167A (en) * | 2019-11-08 | 2020-02-28 | 东莞市长好电子科技有限公司 | Production method based on double-sided concave-convex plate |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB843380A (en) * | 1957-07-29 | 1960-08-04 | Gen Tire & Rubber Co | Method of producing a polyurethane article |
| FR2223154A1 (en) * | 1973-03-26 | 1974-10-25 | Tisza Cipogyar | Template for high-frequency pressing - esp. of shoe uppers has increased conductivity |
| CH675097A5 (en) * | 1988-03-28 | 1990-08-31 | De La Rue Giori Sa |
-
1990
- 1990-02-19 EP EP90810117A patent/EP0443292B1/en not_active Expired - Lifetime
- 1990-02-19 AT AT90810117T patent/ATE96087T1/en not_active IP Right Cessation
- 1990-02-19 DE DE90810117T patent/DE69004072T2/en not_active Expired - Fee Related
-
1991
- 1991-01-31 CA CA002035400A patent/CA2035400A1/en not_active Abandoned
- 1991-01-31 AU AU70094/91A patent/AU631094B2/en not_active Ceased
- 1991-02-13 CN CN91100904A patent/CN1027527C/en not_active Expired - Fee Related
- 1991-02-18 RU SU914894511A patent/RU1828433C/en active
- 1991-02-19 JP JP3024660A patent/JPH054322A/en active Pending
- 1991-02-19 KR KR1019910002614A patent/KR910021303A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| AU631094B2 (en) | 1992-11-12 |
| DE69004072T2 (en) | 1994-04-28 |
| CN1027527C (en) | 1995-02-01 |
| CN1055704A (en) | 1991-10-30 |
| ATE96087T1 (en) | 1993-11-15 |
| RU1828433C (en) | 1993-07-15 |
| EP0443292B1 (en) | 1993-10-20 |
| DE69004072D1 (en) | 1993-11-25 |
| AU7009491A (en) | 1991-08-22 |
| JPH054322A (en) | 1993-01-14 |
| KR910021303A (en) | 1991-12-20 |
| EP0443292A1 (en) | 1991-08-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |