This invention concerns a method of making a decal, and particularly but not exclusively a decal for decorating a ceramic article; and also a decal made by such a method.

Decals are used for a variety of purposes. A common use of decals is for the decoration of ceramic articles. Such decals may be of the waterslide type where the decorative image is provided on a backing paper and is adhered thereto by a water soluble adhesive. The decal is generally placed into water prior to application such that the backing paper can be slid from the rest of the decal with some of the soluble adhesive remaining on the decal to provide adhesion onto an article.

Another type of decal is a heat release decal. In such a decal a heat actuable adhesive binds the decorative layer of the decal onto a backing paper and a further heat actuable adhesive is provided on the opposite side of the decorative layer. During application this further adhesive layer is heated to enable the decal to be mounted onto an article. The other adhesive layer is then actuated to permit the backing paper to be removed.

Decals for ceramic articles like other decals, are

generally provided with a covercoat in the form of a transparent layer which enables transportation and placement of the decal. Such decals are usually subsequently fired with the colours in the decorative layers being provided in most instances by pigments. The covercoat generally burns off during firing. Such decals are usually produced by traditional printing methods which require artwork to be filmed, the preparation of printing plates or silk screen plates and the setting up of presses by skilled people before a decal is produced. Other more flexible printing methods such as ink jet printing have been tried but difficulties are often encountered in using conventional inks for ceramics with such printing methods.

A thermal transfer printer is a machine presently used mainly in the production of rolls of labels. Such a printer creates an image by melting ink from a film ribbon and transferring it at selective locations onto a receiving material. Such a printer usually comprises a print head including a plurality of heating elements which may be arranged in a line. The heating elements can be operated selectively. A thermal ribbon comprising a relatively thin film with an ink coating on one side is located against the print head with the ink on the opposite side of the film to the print head. A substrate is made to pass beneath and substantially in

contact with the film, such that seletive heating of the print head causes ink on the film adjacent the actuated printing elements to be transferred to the substrate. The ink on the film is usually resin or wax based and a release agent may be provided between the ink and the film.

According to the present invention there is provided a method of making a decal, the method comprising printing a decoration onto a substrate using a thermal transfer printer.

The method preferably comprises printing a plurality of colours to form the decoration, and a separate print head is preferably provided for each colour. The print heads may be arranged such that the substrate passes the print heads sequentially.

Alternatively, the substrate may make a number of passes past one or more print heads.

A covercoat may be provided on the decal, and the covercoat is preferably printed by a thermal transfer printer, desirably with a separate print head for printing the covercoat. The covercoat is preferably printed only so as to cover the parts of the substrate upon which the decoration is provided.

Alternatively, the decoration may be printed onto a film, which film acts as a covercoat.

A carrier layer may be provided on the substrate prior to or subsequent to printing of the decoration, and the carrier layer is preferably printed by a thermal transfer printer. The decoration preferably comprises inks may be formed of coloured pigments, and which preferably include a heat actuable resin or wax.

The substrate may comprise transfer backing paper.

The decal may be of the waterslide type, and a water soluble adhesive may be provided on the backing paper.

Alternatively, the decal may be of the heat release type, and a first heat actuable adhesive may be provided on the backing paper, and a second heat actuable adhesive printed after the decoration, desirably by a thermal transfer printer.

The printer heads are preferably computer controlled. A plurality of decals may be printed sequentially onto a band of backing paper which is caused to move past the or each print head. A cutter may be provided to separate the printed decals from each

o t he r .

A registration mark may be printed on the substrate to ensure identical registration of the or each print head to the substrate.

The invention also provides a method of making a ceramic decal according to any of the preceding eleven paragraphs.

The invention still further provides a decal made by a method according to any of the preceding twelve paragraphs.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawing which is a diagrammatic side view showing a decal being made by a method according to the present invention.

The drawing shows a waterslide transfer according to the present invention being made. Three thermal transfer printer heads 10, 12, 14 are provided in line. The first head 10 is provided with a ribbon 16 of a first colour ceramic ink which extends from a first supply roller 18 to a take-up roller 20. The ribbon 16 comprises a thin film locatable adjacent the printer

head 10. On the film, on the opposite side thereof to the head 10, is provided a release layer upon which is provided a pigmented ink which includes a heat actuable wa .

The printer head 12 has a similar ribbon 22 again provided with a supply roller 18 and take-up roller 20. The ribbon 22 however is provided with a different colour pigmented ink. The head 14 is again similar, and is provided with a ribbon 24 extending between rollers 18 and 20. The ribbon 24 has mounted on it a material suitable for forming a covercoat for a ceramic decal. Each of the printer heads 10, 12, 14 comprises a plurality of selectively operable heating elements arranged in a line extending normally to the plane of the drawing.

Extending beneath the heads 10, 12, 14 so as to be substantially in contact with the respective ribbons 16, 22, 24 immediately beneath the heads 10, 12, 14, is a band 26 of ceramic decal backing paper. The band 26 comprises a paper with a layer of a water soluble adhesive such as dextrin provided thereon. The band 26 extends from a roll of paper (not shown) located to the left hand side relative to the drawing. The apparatus shown in the drawing is computer controlled.

In use, a decorative image required on a waterslide decal is entered or stored in the computer. The band of paper 26 is caused to move to the right as shown in the drawing. As the band 26 moves the heating elements in the respective heads 10, 12, 14 are selectively actuated so as to print a respective pattern of the ink or covercoat material located thereon, onto the band 26. The drawing shows the head 10 printing a first colour 28, with the head 12 printing a second colour 30 and the head 14 printing a covercoat 32 over the first and second colours 28, 30. The apparatus therefore produces a decal 34 which can be applied onto a ceramic article by conventional waterslide techniques for subsequent firing. Each decal 34 can obviously be cut from the band 26 as required.

There is thus described a method of producing a ceramic decal which provides for a considerable number of advantages relative to conventional techniques. This printing process is totally dry and trained operators are not required to operate the printers. No printing plates/printing screens are required to be made and this method is therefore economical with small runs. As the printing process is computer controlled, each decoration may be different and the artwork can be electronically stored. As the covercoat is printed using the transfer printer, this need only be printed directly over where

the decoration is provided.

Various modifications may be made without departing from the scope of the invention. For instance, the described example only discloses a two colour system and many further colours can obviously be printed to form a more complex decoration. A greater number of printer heads may be provided and/or different colours may be provided in subsequent runs beneath the same printer heads. Registration of the backing paper relative to the printer heads may be by virtue of electronic synchronisation or a registration mark could be printed on the substrate. A synchronised cutter may be provided downstream of the printer heads to separate the individual decals.

As an alternative to printing onto a backing paper, the decorative layer could be printed in reverse onto a film. This film could act as a covercoat being burnt off during firing, but allowing handling of the decal prior to application.

This method can be used to print other types of decals other than that described above. For instance, a carrier layer may be provided beneath or above the decorative layer. The method could be used to print heat release decals, and the heat actuable adhesive may

be printed using the transfer printer or by a different technique. The method may be used to print decals other than for use on ceramic articles. Spot colour where each colour is a separate image can be used as well as process colour where an image is split into its component parts.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.