EP1957291A2

EP1957291A2 - Low-temperature decal

Info

Publication number: EP1957291A2
Application number: EP06813153A
Authority: EP
Inventors: Vasja Knapic
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-11-08
Filing date: 2006-11-08
Publication date: 2008-08-20
Also published as: WO2007055666A2; WO2007055666A3; SI22158A

Abstract

A low-temperature decal composed of a primary layer, a picture layer and a covering layer superimposing each other and arranged on a supporting material, wherein the picture layer located between the primary layer and the covering layer is prepared by a dry digital printing technique like per se known digital xerographic printing technique or per se known digital magnetographic printing technique or by a wet digital printing technique i.e. per se known ink-jet printing technique with pigment colour, which techniques make possible the preparation of a multicoloured print in one step, whereat the primary layer and the covering layer are both prepared by an optional application method with the condition that a uniform thickness of the layer is ensured within an allowance range that is equivalent to the allowance range of the uniformity of layer thickness at screen printing.

Description

Low-temperature decal

Subject of Invention

The subject of the invention relates to a low-temperature decal composed of a primary layer, a picture layer and a covering layer superimposing each other and arranged on a supporting material in the form of a sheet, which form is dictated by the individual production of the decal for usage e.g. on a ceramic base.

Tlie subject of the invention relates to a low-temperature decal composed of a primary layer, a picture layer and a covering layer superimposing each other and arranged on a supporting material in the form of an endless band, which form is dictated by the usage on an oblong base e.g. on skis.

Hereinbefore, there stand:

• the term low-temperature for a technological parameter of the operation of transferring a decal from a supporting material to the object to be marked, the temperature being between 160⁰C and 200⁰C, whereat the temperature does not influence the characteristics of any individual colour layer,

• the term primary layer for a material enabling, in the operation of transferring a decal from a supporting material to the object to be marked, the separation of the decal from said supporting material and the transfer thereof to the object to be marked as well as the fixation of the decal on the surface of the object to be marked with the surface originally attached to the supporting material, when the decal becomes an integral part of the object,

• the term picture layer for a coloured layer providing a decorative substance as such, and

• the term covering layer for a protective material that, as a rule, is transparent.

Research has shown that there exists a need for applying low-temperature decals on objects made of different materials e.g. metal, wood, plastics, thermoplastics. These materials can be sensitive to heat. Tlierefore the transfer operation of a low- temperature decal from the supporting material to the object to be marked also runs in the temperature range from T_ambient > 0⁰C to 250⁰C, whereby unchanged properties of the single layers of the low-temperature decal together with a good quality of the transfer and the fixing of the decal on the object to be marked are assured.

State of the Art

A known low-temperature decal provides one or more (depending on the number of printed colors) picture layers prepared by screen printing, which are located between a primary layer and a covering layer both also prepared by screen printing techniques.

The disadvantages of said known low-temperature decal are the disadvantages inherent in printings prepared by screen printing techniques, i.e. the relative coarseness of the printing raster on the one hand and, on the other hand, it is difficult to precisely superimpose the rasters of a two-colour or even multicolour printing. Therefore the use of a larger number of different colours and the production of more demanding colour printings are limited. The quality requirements of today's customers concerning images cannot be fulfilled. A great problem is the lengthiness of preparation of the picture layer because eveiy individual colour layer must be completely dry before the next colour layer is applied. To shorten the preparation time heating elements are often used, whereby, however, the economic reasons for the use of screen printing are not valid any more.

Contrary to analog printing techniques like screen printing, digital printing techniques make it possible to achieve very high quality standards of reproduction of any picture or graphic sign as required by today's customers. In fact, digital printing techniques are already used today for printing decals. Such decals and the corresponding methods are known from US 2004245126, US 2003200889, and EP1207050. However, for said digitally printed decals wet techniques of digital printing are used, especially those based on the principle of sublimation and with temperatures higher than 300⁰C. Yet such temperatures require heat resistant objects to be marked with decals. Many objects to be marked with decals, however, are made of materials sensitive to heat e.g. wood, plastic etc., which require low-temperature decals.

Since it is possible to produce decals for a known customer in advance, without the presence of the object to be marked, and the application and the fixing of the decals to the object is quick and easy without any additional devices required, there is still a need of decals.

Technical Problem

The technical problem to be solved by the present invention is how to conceive a low-temperature decal that will obviate the disadvantages of known low-temperature decals, especially regarding the low quality of reproduction of different graphical images, and at the same time it will be possible to provide the graphical image in one step and in a short time irrespective of the number of its colours, and the decal will still have all features of a low-temperature decal, all this by using per se known printing techniques and/or per se known printing devices.

Solution to the Technical Problem

According to the present invention, the object as set forth hereinbefore is achieved in a surprisingly simple manner in that said picture layer located between said primary layer and said covering layer both prepared by screen printing techniques is a layer prepared by per se known digital xerographic printing technique (which makes possible multicolour printing in one step).

The present invention also relates to a method of preparing low-temperature decals of the kind as set forth above, with said method so linked to said decal as to form a single general inventive concept. With known methods of preparing low-temperature decals of the kind as set forth above, said picture layer constituting a one- or multi-layer coloured image located between a primary layer and a covering layer both prepared by screen printing techniques is also prepared by screen printing technique.

The disadvantages of the known methods of preparing low-temperature decals of the kind as set forth above are stated hereinbefore and the object of the inventive method does not differ from the one of the decals as set forth above.

According to the present invention, the above object is achieved in a surprisingly simple manner in that said picture layer between said primary layer and said covering layer both prepared by screen printing techniques is prepared by per se known digital xerographic printing technique.

Finally, the present invention also relates to a novel use of per se known digital xerographic printing technique, with said use so linked to said decal and said method as to form a single general inventive concept.

The main advantage of the proposed novel use of said per se known digital xerographic printing technique for preparing the picture layer of the low-temperature decal of the kind as set forth above lies in the fact that the preparation of said picture layer by screen printing is given up and, by using digital xerographic printing technique, said picture layer - irrespective of the number of colours - is printed in a single manufacturing step and with a raster that is essentially denser than screen printing rasters.

Putting the invention into practice, especially by applying the invention onto objects made of different materials like ceramic, wood, metal, plastics and thermoplastics, and by trying to apply it onto objects where the marking by low-temperature decals could not be found in the past, has resulted in the development of new solutions described hereafter.

A new embodiment of the above invention is given by a low-temperature decal where the picture layer located between the primary layer and the covering layer both prepared by screen printing technique is prepared by per se known digital magnetographic printing technique, which is, like digital xerographic printing technique, a dry digital printing technique and makes possible the preparation of a multicoloured print in one step.

A further new embodiment of the above invention is given by a low-temperature decal where the picture layer located between the primary layer and the covering layer both prepared by screen printing technique is prepared by a wet digital printing technique, namely by per se known ink-jet printing technique with pigment colour.

At the economic exploitation of the invention there also arose a need for the application of the invention on objects in mass continuous production. For this reason the supporting material usually in sheet form can be replaced by supporting material in the form of an endless band. On such supporting material the primary layer is formed continuously by an optional applying method with the condition that a uniform thickness of the layer is ensured within an allowance range that is equivalent to the allowance range of the uniformity of layer thickness at screen printing, for example by rolls, jetting or the like. On the primary layer formed in such a way an optional coloured layer is formed by a dry digital printing technique e.g. by per se known digital xerographic printing technique or per se known digital magnetographic printing technique, or by a wet digital printing technique i.e. per se known ink-jet printing technique with pigment colour. The covering layer located above the picture layer is formed continuously like the primary layer by an optional application method with the condition that a uniform thickness of the layer is ensured within an allowance range that is equivalent to the allowance range of the uniformity of layer thickness at screen printing, for example by rolls, jetting or the like. After the removal from the supporting material the low-temperature decal formed as described above is placed onto an object with the surface of the primary layer originally attached to the supporting material, which step can be performed manually or by machine.

The application of the first embodiment especially onto objects of different purpose required a further reducing of costs of production of the low-temperature decal. Thus, when no high mechanical resistance and no very long life period of the low- temperature decal are required, the covering layer can be omitted. After the low-temperature decal has been placed on an object, the picture layer is with one of its surfaces in immediate contact with the primary layer and with the other surface in immediate contact with the surroundings.

The above-described embodiment leads to a new usage of the low-temperature decal. If the covering layer is omitted, an optional graphical image contained in the picture layer can be applied as a mirror image. The low-temperature decal is transferred onto an object in such a way that the surface of the picture layer that, after the production, is in immediate contact with the surroundings comes into immediate contact with the surface of the object. After the removal of the supporting material from the low-temperature decal, the surface of the primaiy layer that was originally attached to the supporting material becomes the outer surface of the low-temperature decal and in the same time acts as a covering layer. At the described usage of the low-temperature decal the primary layer is colourless. The fixing of the low- temperature decal onto the object is achieved either by an additional adhesive layer applied previously to the object or by a colourless transparent layer applied over the whole surface of the low-temperature decal as well as over the surface of the object with the low-temperature decal on it. Thereby the surfaces of the low-temperature decal as well as of the object are protected. Since the picture layer of the low-temperature decal according to the invention can be formed by per se known digital printing techniques and the devices for such printing are widespread and common on the market, it is possible to produce a semi-finished product consisting only of the supporting material and the primary layer. On such a semi-finished product a customer can apply an optional picture layer by known methods and devices and thus create a completely individual low-temperature decal that he then applies to an object. This enables small-series production or even individual production of low-temperature decals at a reasonable price. Such semifinished product should be in accordance with already known or new methods and materials forming the layers of the low-temperature decal. This represents a new market niche in the printing industry and a new semi-finished product is produced, which can be completed by the customer by printing with an optional personal computer and its attachments.

Claims

1. A low-temperature decal composed of a primary layer, a picture layer and a covering layer superimposing each other and arranged on a supporting material, characterized in that the picture layer located between the primary layer and the covering layer is prepared by a dry digital printing technique like per se known digital xerographic printing technique or per se hτown digital magnetographic printing technique or by a wet digital printing technique i.e. per se known ink-jet printing technique with pigment colour, which techniques make possible the preparation of a multicoloured print in one step, whereat the primaiy layer and the covering layer are both prepared by an optional application method with the condition that a uniform thickness of the layer is ensured within an allowance range that is equivalent to the allowance range of the uniformity of layer thickness at screen printing.

2. A low-temperature decal according to claim 1, characterized in that the primary layer and the covering layer both are prepared by screen printing technique.

3. A low-temperature decal according to claim 1, characterized in that the covering layer is omitted, so that the low-temperature decal consists of the primary layer and the picture layer with the condition that such a decal is allowed by the conditions of usage and the expected life period.

4. A low-temperature decal according to claim 1, characterized in that the covering layer is omitted, so that the low-temperature decal consists of the primary layer and the picture layer, whereat an graphical image contained in the picture layer is made as a mirror image and the picture layer is intended to be applied onto an object.

5. A low-temperature decal according to claim 1, characterized in that the covering layer and the picture layer are omitted, whereat the primary layer is chosen to subsequently receive any picture layer produced by known printing techniques with another producer or the customer of an object.