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(11) | EP 0 945 265 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
Procedure for wet-process silk-screening curved-surface ceramic pieces of a constant cross-section Nassverfahren zum Siebdruck von keramischen Gegenständen mit gekrümmter Oberfläche und konstantem Querschnitt Procédé d'impression sérigraphique d'objects ceramiques à surface courbe et à section constante |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
OBJECT
[0001] The object to which the invention to be protected under this Patent refers consists of a new procedure for wet-process silk-screening curved-surface ceramic pieces of a constant cross-section.
[0002] This essentially entails a new process for decorating special ceramic pieces, particularly but not exclusively those in relief, that is, those known as lists (elongated, narrow fillets of molding), the formal features of which entail a curved surface and a constant cross-section along their full length.
BACKGROUND
[0003] The decoration of special ceramic pieces previously described hereinabove has been being performed by different methods other than silk-screening to date, given that the use thereof was not possible on having to work exclusively on flat screens were not possible to fit up to surfaces having curved relief.
[0004] Therefore, it has been necessary to previously resort to other procedures such as, for example, the manual method, in which the decoration is applied directly using a brush or sponge, which gives rise to color-related or formal irregularities and, as a result of the cost entailed therein in direct manual labor, which is prohibitive.
[0005] Another procedure proposed was that of decorating using transfers, which entailed the same added cost and has therefore used to a small extent.
[0006] A dry-process, powder-form color coating has also been employed using air brush techniques, this being a procedure by means of which an irregular, monotonous and not a very attractive decoration is achieved.
[0007] Finally, it has also been attempted to decorate these special ceramic pieces using a dabber machine with little success, given that the dabber mechanism carrying the motif to be applied on the curved surfaces exerts different pressures on the relief and the recessed areas, therefore giving rise to flawed printing.
DESCRIPTION OF THE INVENTION
[0008] The end purpose of the invention comprising the object of this Patent consists of overcoming the drawbacks inherent to the alternative procedures employed in decorating the aforesaid special ceramic components as previously described hereinabove.
[0009] For these purposes, a new procedure has been conceived, designed and tested in response to this priority objective which affords the possibility and facilitates the use of wet silk-screening for the decoration of curved-surface ceramic pieces, provided that they be of a constant cross-section along their full length, such as is the case of lists.
[0010] All of the practical advantages of silk-screening, such as those in following, are thus recovered:
- The fast operation inherent to mechanized, mass production.
- The formal, aesthetic richness resulting from the diversity of the motifs which can be applied.
- The decorative pattern being identical throughout as the result of the systematic repetition of the same motif.
- The economical cost of the process and the increase in the productivity thereof.
[0011] Prior to commencing the procedure, a flat silk screen is prepared in keeping with the known processing method which includes the operations of: stretching the silk screen (stretching lengthwise and crosswise); gluing to the frame; emulsionizing the fabric; developing the stencil on which the decorative motif is printed and drying the screen.
[0012] This new procedure employs the previously-prepared flat screen which is detached from its frame and is moved to another specific screen, on two opposite sides of which a replica of the profile of the uniform cross-section of the ceramic piece which is going to be decorated is located, on each of the sides of which rigid strips are attached which also reproduce the relief of the piece and are affixed to the frame by gripping the cloth which is stretched tight solely lengthwise of the piece so that it will adapt to its relief, after which it is then glued to the frame.
[0013] For applying the silk-screening inks, spatulas are used, the undersides of which are a negative replica of the relief of the piece for the purpose of achieving full contact with the same, forming a bath with two identical spatulas attached in parallel which affords the possibility of maintaining the optimum amount of ink inside the same and on the screen throughout the application process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] For the purpose of further expanding upon the description of the invention and to facilitate the interpretation of the formal structural and functional features thereof, drawings are attached on which different aspects of the preferred embodiments of the new procedures for wet-process silk-screening of curved-surface ceramic pieces of a constant cross-section which comprises the object of this Patent are shown in diagram form.
[0016] Fig. 1 is a perspective view of the conventional flat silk-screening screen holding the stencil with the decorative motif which is prepared separately as a preparation for the process.
[0017] Fig. 2 provides a perspective view of the specific frame employed in the procedure comprising the object of the Patent, with the grippers for securing the screen.
[0018] Fig. 3 is an A-A cross-section of the specific frame, showing the placement of one of the grippers for securing the screen in place.
[0019] Fig. 4 shows a perspective view of the bath formed by attaching two identical spatulas in parallel, the undersides of which comprise a negative of the relief of the piece which is going to be decorated.
DESCRIPTION OF A PREFERRED EMBODIMENT
[0020] To clearly illustrate the nature and the scope of advantageous application of the new procedure for wet-process silk-screening curved-surface ceramic pieces of a constant cross-section which comprises the object of this invention, a description is provided in following of the operating means and the functioning thereof, making reference to the drawings which, due to their representing a preferred embodiment of said object, of an informative nature, can be considered in the broadest and non-limiting sense of the application and the content of the invention.
[0021] This new procedure employs a flat screen (1) previously prepared with the stencil of the decorative motif (2), which is detached from its frame and is transferred to another specific frame (3), on two opposite sides of which the outline (4) of the uniform cross-section of the ceramic piece which is going to be decorated is reproduced.
[0022] On each one of the two opposite sides, rigid strips (5) are attached which also comprise a replica of the relief of the piece and are secured to the frame (3) by gripping the fabric of the screen (1), which is stretched tight in solely the lengthwise direction of the piece so that it will fit up to the relief thereof, after which it is then glued to the frame (3).
1. New procedure for wet-process silk-screening curved-surface ceramic pieces of a constant
cross-section,characterized essentially because a flat screen (1) is used which has been previously prepared
with the stencil of the decorative motif (2), which is detached from its frame and
is transferred to another specific frame (3), on two opposite sides of which the outline
(4) of the uniform cross-section of the ceramic piece which is going to be decorated
is reproduced, rigid strips (5) being secured tightly on each one of said sides, also
comprising a replica of the relief of the piece and being secured to the frame (3)
by gripping the fabric of the screen (1)), which is stretched tight in solely the
lengthwise direction of the piece so that it will fit up to the relief thereof, after
which it is then glued to the frame (3).
2. New procedure for wet-process silk-screening curved-surface ceramic pieces of a constant
cross-section as per Claim 1, characterized essentially due to the fact that for the application of the silk-screening inks,
spatulas are used the undersides (6) of which are a negative replica of the relief
of the piece for the purpose of achieving, with the shifting in position thereof lengthwise
along the piece, full contact therewith through the screen, forming with two identical
spatulas (7') - (7'') attached in parallel, a batch (8) which affords the possibility
of maintaining inside, on the screen, the optimum amount of ink throughout the process
of the application thereof.
1. Neue Vorgehensweise für Nassverfahren zum Siebdruck von keramischen Gegenständen mit
gekrümmter Oberfläche und konstantem Querschnitt, dadurch gekennzeichnet, daß ein
flaches Sieb (1) verwendet wird, das vorher mit der Schablone des Dekormotivs (2)
vorbereitet wurde, und das von seinem Rahmen abgenommen und auf einen anderen, speziellen
Rahmen (3) überführt wird, bei dem der Umriß (4) des einheitlichen Querschnitts der
keramischen Gegenstände die dekoriert werden sollen an zwei einander gegenüberliegenden
Seiten nachgebildet ist, starre Streifen (5), auf jeder der besagten Seiten fest gesichert
sind, die auch eine genaue Nachbildung des Reliefs des Gegenstandes umfassen und am
Rahmen (3) befestigt sind, mit denen das Gewebe des Siebes (1) eingespannt wird, das
allein in Längsrichtung des Gegenstandes festgezogen ist, so daß es mit dem Relief
ausgestattet ist, nachdem es an den Rahmen (3) geklebt ist.
2. Neue Vorgehensweise für Nassverfahren zum Siebdruck von keramischen Gegenständen mit
gekrümmter Oberfläche und konstantem Querschnitt nach Anspruch 1, im wesentlichen
durch den Umstand gekennzeichnet, daß für die Anwendung der Siebdruck-Farben Spatel
verwendet werden, deren Unterseiten (6) Negativkopien von dem Relief des Gegenstandes
sind, mit dem Ziel, beim Verschieben ihrer Position längs entlang des Gegenstandes
einen vollständigen Kontakt durch das Sieb zu erreichen, mit zwei identischen, parallel
angebrachten Spateln (7')-(7'') ein Bekken (8) bildend, welches die Möglichkeit gewährt,
innen, auf dem Sieb, die optimale Menge von Farbe während des Prozesses ihres Auftragens
aufrecht zu halten.
1. Nouveau procédé d'impression sérigraphique humide de pièces en céramique à surface
courbe et à section constante, caractérisé essentiellement par l'utilisation d'un
écran plat (1), que l'on a préparé au préalable avec le pochoir du motif décoratif
(2), qui est détaché de son cadre et est transféré à un autre cadre spécifique (3),
sur deux côtés opposés duquel est reproduit le contour (4) de la section uniforme
de la pièce en céramique qui va être décorée, des bandes rigides (5) étant fixées
de façon serrée sur chacun desdits côtés, comprenant également une réplique du relief
de la pièce et étant fixées au cadre (3) en serrant le tissu de l'écran (1), qui est
solidement étiré seulement selon la direction longitudinale de la pièce, de façon
à épouser le relief de celle-ci, après quoi on le colle au cadre (3).
2. Nouveau procédé d'impression sérigraphique humide de pièces en céramique à surface
courbe et à section constante selon la revendication 1, caractérisé essentiellement
par le fait que, pour l'application des encres sérigrahiques, on utilise des spatules
dont les surfaces inférieures (6) sont une réplique négative du relief de la pièce,
dans le but d'atteindre, leur position étant déplacée selon la direction longitudinale
de la pièce, un contact intégral avec celle-ci à travers l'écran, formant, à l'aide
de deux spatules identiques (7') - (7") fixées parallèlement, un bain (8) qui offre
la possibilité de maintenir à l'intérieur, sur l'écran, la quantité d'encre optimale
tout au long de son application.