GB2262913A

GB2262913A - Improvements in or relating to decoration of ceramic ware

Info

Publication number: GB2262913A
Application number: GB9223504A
Authority: GB
Inventors: Robin Graham Pavitt
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-01-03
Filing date: 1992-11-10
Publication date: 1993-07-07
Also published as: GB9223504D0; GB9200072D0

Abstract

A ceramic surface formation (10) and a method of applying substantially raised surface formations to ceramic ware by direct print applications. The surface formation (10) comprising either the same ceramic materials as the item of ware (12) to which it is to be attached or a mixture of feldspathic china material and zircon frit. The surface formation (10) further comprising other ingredients including glaze. The surface formation (10, 110, 210, 310, 410) is sequentially applied in a single or plurality of layers (14, 114, 118, 214, 218, 314, 340, 410) to provide the required raised characteristics. The ceramic surface formation (10, 110, 210, 310, 410) is attached to an item of ceramic ware (12, 112, 212, 312, 412) either raw unfired ware or to an item of prefired biscuit ware. The ceramic ware (12, 112, 213, 312, 412) may be raw glazed (316) or left unglazed prior to the application of the ceramic formation (10, 110, 210, 310, 410). Alternatively the ceramic formation (10, 110, 210, 310, 410) may be further provided with a conventional glaze coating (16, 116, 216) prior to firing. The ware (12, 112, 212, 312, 412) with the ceramic formation (10, 110, 210, 310, 410) are then once-fired. <IMAGE>

Description

I1?ROVEMENTS IN OR RELATING TO DECORATION OF CERAMIC WARE.

The present invention concerns improvements in or relating to decoration of ceramic ware and particularly but not exclusively to means for and a method of providing decorative surface formations on ceramic ware.

Conventionally surface formations. snd raised decorations are provided on ceramic ware during the forming of the ware, for example in a mould for the ware having a relief design engraved therein. The preperation and tooling required for such moulds makes them expensive to produce and often the moulds are only used for a limited period before the designs therein become worn and also dated. Further, a substantial percentage of such decorated ware is " lost " during the making processes prior to and including firing.

Raised decorations have been provided on ware by applying premoulded decorations to the ware or the original model. Such decorations have been moulded from a mould produced in a successive and complex procedure comprising making an initial, relatively large model of the decoration and from this model forming a plaster of paris, ceramic, metal, rubber or resin mould.

A further similar mould is made from this latest decoration and the process is repeated to create working moulds and or dies for production. During each repetition natural shrinkage or enlargement of the materials produces a relatively smaller or larger decoration. This procedure is very time consuming and expensive and is usually reserved for providing decorative formations on commercially expensive items of ware.

It is an object of the present invention to obviate or mitigate the aforementioned disadvantages.

The term " Ceramic " as used in the following specifications relates to fired and or unfired material and the term " Surface Formation " is to mean formations and decorations that are substantially raised from a surface of the ware when applied thereto.

According to the present invention there is provided a direct application of ceramic material onto preformed ceramic objects to provide surface formations.

Preferably but not exclusively the ceramic material of the decorative formation is the same material as the ceramic material of the item to which it is to be applied. Alternatively the ceramic material of the decorative formation may comprise a mixture of feldspathic china material and zircon frit, thereby providing a mixture that may be used on most or all white pottery bodies. The ceramic material may be in the raw unfired state or a ground prefired state. The formation preferably includes also glaze and optionally pigment.

The formation preferably comprises a number of superimposed layers.

The layers may have differing outlines such that a formation made up of a plurality of superimposed layers is profiled in cross-section perpendicular to the plane of the layers.

Preferably each layer is applied to the ceramic ware or a preceding layer by a screen printing technique.

Alternatively the formation may comprise a single layer formed by placing ceramic body material into a relief mould of the formation.

One or more layers comprising substantially glaze may be applied between the item of ware and the formation.

One or more layers comprising further ceramic material of a preselected colour or other property maybe provided as an uppermost layer. The further ceramic material may comprise, porcelain material, frit and zirconium silicate.

A layer of printed glaze may comprise the uppermost layer of a formation.

Still further according to the present invention there is provided a method of forming substantialy raised decorative formations directly onto a ceramic item by way of a silicon / gelatine or polymer bomb printing application.

Further according to the present invention there is provided a method of applying surface formations to ceramic ware comprising directly applying a formation of the type described in any of the preceding eight paragraphs, applying the formation to the ware and glazing the formation and ware conventionally and then firing the ware and formation without the need for a hard en ing-on firing.

The ware maybe initially fired prior to the application of the formation.

Preferably the formation is applied to the item of ceramic ware directly.

The ware maybe raw unfired prior to the application of the formation.

The item of ware maybe a tile, plate, mug or any moulded or hand formed ceramic item.

A specific embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1, shows a perspective view of an application of ceramic material according to the present invention, Figure 2, shows a section through II - II of an application of Fig 1, the.

ceramic material according to the first embodiment of the present invention on an enlarged scale.

Figure 3, shows a diagrammatic section similar to section II -II through an application according to a second embodiment of the present invention.

Figure 4, shows a diagrammatic section similar to section II -II through the ceramic application according to the third embodiment of the present invention.

Figure 5, shows a diagrammatic section similar to section II - II throilgh the ceramic application according to the fourth embodiment of the present invention.

Figure 6, shows a diagrammatic section through a process of application according to one particular method, shown spaced above a relief mould used in the production of the raised ceramic materials application, Figure 7, shows a diagrammatic section through the application process according to the fifth embodiment according to the present invention.

Referring to the drawings, Figure 1, is a decorative formation in the form of a ceramic material mixture 10, applied on a ceramic item of ware 12.

In a first embodiment, the ceramic material mixture 10, comprises substantially the same material as the body of the ware 12, to which it is to be applied in either unfired state or a ground prefired state and a proportion of glaze. The proportion of material to glaze and the material types used is dependent upon the type of ceramic ware 12, to which the ceramic surface formation 10, is to be applied. For example, a suitable proportion of material to glaze for use on ceramic ware is found to be approximately 50 parts ware body material to 5 parts of glaze by weight.

However, these proportions can be varied according to the type of finish desired on the finished article. For example, as the proportion of gLaze is increased, the surface of the decoration becomes more rounded and fluxed.

Colours such as body stains and underglaze colours may be included in the ceramic material 10 . The formation of 10, is formed by screen printing as described below.

The formation of ceramic material may be built up of a plurality of layers 14, ( see Fig 2 ) either unfired or in a ground prefired state, and glaze. The constituents are initially in a dry powder form and are mixed together with the addition of water to provide a substantially homogeneous blend / mixture. The mix may be passed through a filter lawn to remove any large lumps and then dried to powder form. The powder mix may at this stage or at the earlier stage when it was mixed with water, have colourant added, for example, body stains, oxides, or underglaze colourant.

The powder mix is then added to a suitable ceramic screen printing medium, either water based or oil based. The printing screens are formed in the conventional way using stensils that are capable of heavy deposits of printed medium and the mix is screen printed directly onto the item of ware 1?.

The item of ware 12, may be in the unfired state or sinter fired, or biscuit fired. The design printed on the ware 10, by a single printing step is normally only slightly raised from the surface 12. Formations of greater height may be formed by sequentially forming layers, one on top of the other using repeated printing procedures 14. The outline shape printed in each or some of the various layers 14, may differ such that the vertical cross-section of the decorative formation 10, is non-uniform.

For example, referring to figure 2, each subsequent layer 14, is of reduced width thereby forming a decorative ceramic material surface formation 10, with curved edges.

It is to be appreciated that the design of each layer will be varied according to the contours of the formation desired. Between the successive layers 14, being applied to the ware durring formation of the decorative formation 10, each layer 14, is allowed to substantially dry. This may be achieved simply by printing onto a warmed item of ware 12. When the ceramic surface formation 10, has been formed to the desired contours and allowed to dry the surface formation 10, and the item of ware 12, may be glazed in the conventional manner if desired 16. When the entire combination of surface formation 10, and the item of ware 12, have dried it may be fired to the optimum temperature for the ceramic body and or glaze used. This facilitates a once-firing technique.

In a second embodiment of the invention ( see fig 3 ) the ceramic decorative formation 110, is formed as hereinbefore described, from a mixture of ground sinter or maximum prefired biscuit material and a proportion of glaze. When the material surface formation 110, has been formed in layers 114, a further layer of fritted glaze 118 is applied by screen printing on top of the formation thus far 110. One or more such glaze layers ll8, may be applied. The application of 118, enables the successful application of n conventional glaze coating without the need for a hardening - on firing.

This embodiment of the invention is suitable for applications to prefired bisque ware and glost ware items 112. This entire decorative formation 110, plus the overprinted glaze 118, plus the conventional glaze coating ill6, may now be fired to the relevant glost temperature desired.

In a third embodiment of the invention shown in figure 4, a layer of glaze 220, is provided between the layers 214, and the item of ware 212.

This layer 220, facilitates retention of the decorative formation 210, onto the ware 212, Also provided in the surface formation of fig 4, is a layer 230, applied on top of the body layers 214, which comprises a mixture of ceramic body material and glaze. This layer 230, comprises body material and glaze in a different colour or shade of colour to the ceramic material in layers 214, and is chosen to give the surface formation 210, the desired colour or shade to compliment the ware to which it is applied 212. One particular composition of ceramic material of the layer 230, is sixty parts porcelain body material to fifty parts zircon frit and ten parts zirconium silicate. It is to be appreciated that the or each layer 230, may be applied to any embodiment of the invention.This layer 230, is also capable, upon firing, of fluxing enough so as to disguise the screen print texture otherwise apparent on a formation 210, that is designed to produce a crisp outline to the raised formation.

Further provided in the surface formation of fig 4, is a layer of fritted glaze 218, applied by screen printing on top of layer 230. One or more such glaze layers may be applied. The purpose of this layer 218, is as aforementioned when referring to fig 3.

in a fourth embodiment of the present invention shown in figure 5, a.

layer 340, of prefired feldspathic china material and a proportion of zircon frit is provided above a conventional coating of unfired glaze 316, applied to an item of raw unfired ware or prefired biscuit ware 312. The layer 340, visualy obscures the underlying glaze coating 316, which may be coloured by pigment or glaze stains. On to the layer 340, is applied n printed layer of transparent glaze 314, which is of a contrasting colour or shade to that of glaze-coating 316. A plurality of layers 314, and 340, may be applied. The glaze coating 316, and the printed layers 314, are to become bright and shiny glazes after firing. The maturing point of the glaze layers 316, and 314 are identical.The purpose of the opaque layer 340, is to provide a raft which seperates the glaze layers 316, and 31d, thus preventing their intermixing during the glaze melt, thereby enabling the creation of the raised ceramic formation 310. The glaze layers 314, and 316, retain their true characteristics and colour identity. The layers 314, and 340, provide a raised ceramic surface formation 310, over the conventional glaze coating 316, when the item of ceramic ware 312, with surface formation 310, attached are fired in a once-fire operation.

lt is to be appreciated that one or more features of one or more of the aforementioned embodiments may be inter-combined to produce various other surface formations within the scope of the invention, to give either a.- crisp outline or soft contours or texture to the decoration as desired.

The fifth embodiment of the invention is an alternative method of forming surface formations, comprising forming a. relief mould 440, of the required decorative formation 410, in a suitable medium, for example, metal, plastic, linoleum etc. ( see fig 6, ). The desired ceramic mixture 410, for the ceramic item 412, according to the aforementioned embodiments is prepared and mixed with a suitable carrier medium, such as used in screen printing.

The viscosity of this material is preferably sufficient to require heating to become fluid. The mixture is then heated and poured or rubbed into the relief mould 440, until the mould is full.

A rubber, gelatine, silicon, or polymer printing bomb 450, as used conventionally for bomb printed patterns is then pressed over the mould and into contact with the ceramic mixture which will form the ceramic formation 410. The mixture beiiig in contact with the bomb is removed from the mould when the bomb is raised from the moulds surface, this is indicated by the dotted lines in fig 6. 'urge bomb 450, plus the ceramic mixture 410, attached thereto is now lowered over and pressed onto an item of ceramic ware 412, ( see fig 7 ), thus locating the decorative formation onto an item of ware 412.When the bomb is once again raised as indicated by the dotted line, it is withdrawn from the ceramic material formation dlO, which has now cooled suf ficiently and become attached to the item of ware 412. The formation 410, and the item of ware 412, may then be allowed to dry and subsequently be fired or further decorated using this process and then fired.

It is to be appreciated that a plurality of surface formations 10, 110, 210, 310, 410, may be formed on a single item of ware 12, 112,212, 312, 412, so as for example, to provide a repetitive pattern of decorative formations to build up a pictorial device or the like.

It is to be appreciated that the surface formations 10, 110, 210, 310 410, may be applied in any fired or unfired state, for example, the ware 12, 112, 212, 312, 412, may be in the unfired dry clay state, sintered, biscuit, or glazed state.

The above described means of applying raised contoured surface formations created by applying direct printing of ceramic materials onto items of ceramic ware to provide decorations and patterns, provides a relatively easy, convenient and efficient technique. Such a combination of techniques does not require extensive tooling for patterned and relief moulds, since the decoration / formations are applicable to basic items of ware with no existing surface formations. Therefor, the advantages offered by the present invention include mainly the ability to limit the type of ware in the initial forming and or firing methods to plain, relatively inexpensive to produce ware having little or no surface formations.Consequently, the inevitable loss of a certain proportion of ware during the initial making procedures and firing6 results in less financial loss than would be incurred if the ware already comprised its decorative formation, as is conventional. The ware that survives the initial Inanufacturing may then be decorated with the surface formations according to the present invention. There is no apparent shrinkage of the ceramic surface formation upon firing when applied to biscuit or glost wares, the decoration remaining generally the same size as printed, with as much fine detail as required.

Further advantages of the invention include the ability to create many different designs of decoration with detail not achieved by conventional techniques, on ware using different combinations of surface formations and the ability to produce small numbers of any particular design relatively inexpensively.

Various modifications may be made without departing from the scope of the present invention, for example, any suitable ceramic item may he used, The proportions of ceramic materials may be varied according to the application.

Further additional materials may be added to the application, to or on top of, or underneath the formation mix according to requirements.

Claims

1. A ceramic surface formation ( 10, 110, 210, 310, /lilo ) chaxacterised in that the formation comprises a substantially raised decorative formation including a ceramic material and applied to ceramic ware ( 12, 112, 212, 312, 412 ) by direct printing.

2. A ceramic surface formation ( 10, 110, 210, 310, 410 ) according to claim 1, characterised in that the ceramic material of the raised decorative formation is the same material as the ceramic material of the item of ware ( 12, 112, 212, 312, 412 ) to which it is to be applied.

3. A ceramic surface formation ( 10, 110, 210, 310, 410 ) according to claim 1, characterised in that the çeranic material of the raised decorative formation comprises a mixture of feldspathic china material and zircon frit.

4. A ceramic surface formation ( 10, lilo, 210, 310, 410 ! according to any claims 1 to 3, characterised in that the ceramic material is in the raw unfired state.

5. A ceramic surface formation ( 10, 110, 210, 310, 410 ) accordion to any clairns 1 to 3, characterised in that the ceramic material is in a ground prefired state.

6. A ceramic surface formation ( 10, 110, 210, 310, 410 ) according to any preceding claim, characterised in that the formation includes glaze.

7. A ceramic surface formation ( 10, 110, 210, 310, 410 ) according to any preceding claim, characterised in that the formation includes pigment.

8. A ceramic surface formation ( 10, 110, 210, 310, 410 ) according to any preceding claim, in that the formation comprises a number of superimposed layers ( 14, 114, 118, 214, 218, 314, 340, 410 ).

9. A ceramic surface formation according to claim 8, characterised in that the layers ( 14, 114, 118, 214, 218, 340, 314 410) have differing outlines such that a formation ( 10, 110, 210, 310, 410 ) made up of R plurality of superimposed layers ( 14, 114 118, 214, 218, 314 340, 410 ) is profiled in cross-section perpendicular to the plane of the layers.

10. A ceramic surface formation ( 10, 110, 210, 310, 410 ) according to claims 8, and 9, characterised in that each layer ( 14, 114, 118, 214, 218, 314, 340 ) is applied to the item of ware ( 12, 112, 212, 312 ) or a preceding layer ( 14, 114, 118, 214, 218, 314, 340 ) by a screen printing technique.

11. A ceramic surface formation ( 410 ) characterised in that the formation (410 ) comprises a single layer formed by placing ceramic material as described in claims 1 to 7, into a relief mould ( 440 ) of the decorative formation. Applying a. silicon, gelatine or polymer printing bomb ( 450 ) to the surface of the relief mould ( 440 ) and the ceramic material ( 410 ) and printing the cerac material ( 410 ) onto the surface of the ware item ( 412 ).

12. A ceramic surface formation ( 410 ) according to claim 11, characterised in that the ceramic material is heated prior to or during location in the relief mould ( 440 ).

13. A ceramic surface formation ( 10, 110, 210, 310, 410 ) according to any preceding claim, cha.racterised in that the raised formation ( 10, 110, 210, 310, 410 ) is further provided with one or more layers of glaze( 118 ).

14. A ceramic surface formation ( 10, 110, 210, 310, 410 ) according to any preceding claim, characterised in that one or more layers of unfired glaze ( 220, 316 ) are provided between the raised formation ( 10, 110, 210, 310, 410 ) and the item of ware ( 12, 112, 212, 312, 412 ).

15. A ceramic surface formation ( 10, 110,210, 310, 410 ) according to claims 1 to 14, characterised in that the raised formation ( 10, 110, 210, 310, 410 ) is applied to a.n item of unfired conventionally glazed ware ( 12, 112, 212, 312, 412 ).

16. A ceramic surface formation ( 10, 110, 210, 310, 410, ) according to claims 1 to 14, characterised in that the raised formation ( 10, 110, 210, 310, 410 ) is applied to an item of prefired glazed ware ( 12, 112, 212, 312, 412 ).

17. A ceramic surface formation ( 10, 110, 210, 310, 410 ) according to any preceding claim, characterised in that the raised formation ( 10, 110, 210, 310, 410 ) is further glazed by a conventional technique ( 16, 11S, 216, 316 ) and firing the ware ( 12, 112, 212, 312, 412 ) and applied formation in a once-firing operation.

18. A ceramic surface formation ( 10, 110, 21(), 310, 410 ) according to any preceding claim, characterised in that the raised formation ( '1O, 110, 210, 310, 410 ) is applied to an item of raw unfired ware ( 12, 11S, 212, 312, 412 ).

19. A ceramic surface formation ( 10, 110, 210, 310, 410 ) according to any preceding claim , characterised in that the raised formation ( 10, 110, 210, 310, 410 ) is applied. to an item of prefired biscuit ware ( 12, 112, 212, 312, 412 )

20. A ceramic surface formation ( 10, 110, 210, 310) according to any claim relating to screen print applications, characterised in that the uppermost layer ( 230 ) of the formation is capable of fluxing enough so as to disguise the screen print texture.

21. A ceramic surface formation ( 10, 110, 210, 310 410 ) according to any preceding claim, characterised in that the first layer ( 340 ) of the formation is applied over a conventionally applied glaze in order to create an opaque raft, on to which further printed layers of glaze( 314 ) may be applied.