Method of making a metal container with relief decoration and related container

Abstract

A method of making a metal container comprises the steps of having at disposal a metal element, treating a surface of said metal element with a primer, subjecting said metal element to a first printing process with ink, and subjecting said metal element to a second digital printing process with at least one ink as to obtain a relief decoration.

Description

[0001] METHOD OF MAKING A METAL CONTAINER WITH RELIEF DECORATION

[0002] AND RELATED CONTAINER

[0003] Technical field

[0004] The present invention refers to a method of making a metal container with relief decoration, and to the related container.

[0005] Background art

[0006] Nowadays, several methods of printing on metal are known. One of the most common technologies is offset printing technology, which is widely effective in making prints on metal or tinplate sheets intended for the food market.

[0007] Offset printing is commonly referred to as an "indirect process": the image is transferred to the metal via ink that is processed by a roller system. This allows to obtain prints characterised by high definition, regardless of any irregularity of the support used.

[0008] Another existing technology is digital printing which, in contrast to offset printing, is a "direct process". In more detail, in this technology the shape to be printed is generated through electronic programs and it is imprinted through inks directly on the support, without any type of intermediate processing. This gives a high versatility to the machines that implement the aforementioned technology, since it is possible to easily make different types of prints simply by changing the program performed by the machinery itself.

[0009] Metal or tinplate sheets can be used to make food containers, such as jars and boxes of various shapes and sizes.

[0010] Due to the extensive use of food containers, there is a need to have available a printing method that can flexibly and completely customize the metal sheets. In fact, in addition to the compatibility of inks and paints with the food market, high print quality is required.

[0011] The containers on supermarket shelves are themselves communicators of the brand and extreme attention must be paid to the fidelity of the color, but also to the legibility of the label.

[0012] A problem of offset printing is related to the creation of relief decorations, increasingly requested by the market because they can give a high level of customization to the product, as well as increase its attractiveness to the customer. Currently, transparent paints are used, which allow the metal surface to be polished and protected from impacts and abrasions, but which are not able to give depth to the images represented.

[0013] A problem of digital printing on metal containers is related to the imperfect readability of texts with reduced character and to the precision of the print, even if it can be effectively used for relief prints.

[0014] In any case, the process of digital printing in relief involves a plurality of steps of the heads that dispense ink on a still metal sheet, which determines a limited efficiency, quantifiable in the realization of about 100 sheets per hour.

[0015] Disclosure of the invention

[0016] The aim of this invention is therefore to eliminate the above-mentioned disadvantages.

[0017] The invention, characterised as set out in the claims, achieves that aim by operating while the metal sheet is moving.

[0018] The main advantage obtained by means of this invention is the possibility to increase the efficiency up to make about 1500 sheets per hour of relief prints on metal, having a high precision and being, therefore, of high quality. In addition, the invention allows both the combined use of offset and digital printing technologies, and the use of digital technology alone for the entire printing process.

[0019] Finally, the present found allows wide freedom in customizing metal prints.

[0020] Brief description of the drawings

[0021] Further advantages and features of the invention will be more apparent in the detailed description which follows, with reference to the accompanying drawings, which show an example non-limiting embodiment, wherein: figure 1 shows the invention according to a transversal cross-sectional view.

[0022] Preferred embodiments of the invention

[0023] The invention refers to a method of making a metal container with relief decoration, and to the related container.

[0024] The method of making a metal container 1 comprises a first step consisting of having at disposal a metal element 2, preferably a steel sheet, called "black band", more preferably a tinplate sheet. A surface of this metal sheet 2 is treated with a primer to make it receptive to inks 3 and paints.

[0025] Subsequently, the metal sheet 2 is subjected to a first printing process with ink. This process can be offset or digital.

[0026] Once the first printing process is finished, the metal sheet 2 is subjected to a second digital printing process, wherein a thickness of colored or transparent ink is applied: in this way a relief decoration is made on the metal sheet with a single passage of the print heads on the sheet (single-pass).

[0027] In some cases, the first printing process and the second printing process are carried out in a single step by means of a digital printer. Preferably, the ink type 3 used in the first printing process comprises photoinitiators 3’ sensitive to UV and / or LED radiation, so as to facilitate drying. Another solution is that the ink 3 comprises solvents 3” which evaporate as a result of temperature increases.

[0028] The invention also concerns a metal container 1 comprising relief decorations, made by the method mentioned above. The container 1 comprises a metal element 2, preferably a sheet of tin-coated steel, often referred to as "tinplate", at least one layer 3 of ink and transparent or coloured ink relief decorations 4.

[0029] This container 1 can be made in various shapes, for example cylindrical or parallelepiped, and / or of various sizes. In addition, container 1 is configured to receive food, preferably liquids, such as milk or oil.

[0030] Therefore, this invention allows the realization of relief prints on metal, having a high precision and being, therefore, of high quality, conferred by the use of digital printers.

[0031] In addition, this invention allows to a user a wide freedom of choice in the customization of metal prints.

Claims

CLAIMS1. Method of making a metal container comprising the following steps:A. having at disposal a metal element (2);B. treating a surface of said metal element (2) with a primer;C. subjecting said metal element (2) to a first printing process with ink (3); characterised in that the method comprises the following step:D. subjecting said metal element (2) to a second digital printing process with inks as to obtain a relief decoration (4).

2. Method according to claim 1, characterised in that said metal element (2) consists of a metal sheet or of a tinplate.

3. Method according to claim 1 or 2, characterised in that in step C said first printing process is an offset or digital printing process.

4. Method according to any one of claims from 1 to 3, characterised in that steps C and D are performed simultaneously by a single digital printer.

5. Method according to any one of claims from 1 to 4, characterised in that said ink (3) used in said first printing process in step C comprises photoinitiators (3’) sensitive to UV and / or LED radiation, so as to facilitate drying.

6. Method according to any one of claims from 1 to 5, characterised in that said ink (3) used in said first printing process in step C comprises solvents (3”) which evaporate as a result of temperature increases.

7. Container made by the method according to any one of claims from 1 to 6, characterised by comprising a metal element (2), at least one ink layer (3) and ink relief decorations (4).

8. Container according to claim 7, configured to receive food.

Images