Direct printing method for enamelling and decorating

Abstract

The invention relates to a direct printing method for enamelling and/or decorating on surfaces in general (ceramic, glass or metallic materials, inter alia), which are subjected to heat treatment following printing, consisting of transferring an enamel/ink, by means of the use of a device for emitting energy in the form of electromagnetic waves, preferably laser, from a carrier vehicle to the printing surface without any contact between said vehicle and the printing surface. The heat treatment, which is carried out at temperatures higher than 500 C., is used for the adherence of the enamel/ink to the substrate, producing the final ceramic and/or chromatic effect.

Claims

1. A direct printing method for enamelling and/or decorating on surfaces in general which are subjected to heat treatment following printing, comprising transferring an enamel/ink, by means of the use of a laser for emitting energy in the form of electromagnetic waves, from a carrier vehicle of the printing element to a printing surface, wherein: the distance between the printing element and the printing surface is greater than 500 micrometers and less than 2.5 millimeters; and the viscosity of the enamel/ink is comprised between 500 cPs and 10,000 cPs.

2. The printing method, according to claim 1, wherein the printing surfaces are smooth and/or raised.

3. The printing method, according to claim 1, wherein the surfaces are ceramic and/or glass materials.

4. The printing method, according to claim 1, wherein the enamel/ink is deposited in selected zones of the printing surface and/or throughout the entire printing surface.

5. The printing method, according to claim 1, wherein the deposited weight of the enamel/ink is up to 500 g/m.sup.2.

6. The printing method, according to claim 1, wherein the surfaces are fixed and the system comprising the energy-emitting device-carrier vehicle enamel/ink system moves in an XYZ coordinate system.

7. The printing method, according to claim 1, wherein the energy-emitting device-carrier vehicle enamel/ink system is fixed and the surfaces move by means of a transport system in a XYZ coordinate system.

8. The printing method, according to claim 1, wherein the energy-emitting device-carrier vehicle enamel/ink system moves along the Y-Z axes of an XYZ coordinate system and the surfaces are moved by means of a transport system on the X-axis of an XYZ coordinate system.

9. The printing method, according to claim 1, wherein the laser emits the laser light at a certain wavelength or in a wavelength interval.

10. The printing method, according to claim 1, wherein the enamel/ink comprises: at least one solid part at room temperature, responsible for conferring the corresponding ceramic and/or chromatic effect, which comprises at least one solid substance that absorbs the energy emitted by the energy-emitting device, which is selected from between simple oxides, mixed oxides, crystalline structures of any structure or chemical composition, carbon, carbides, nitrides or a combination thereof, to transform said energy into heat and bring about a change in volume and/or position of the enamel/ink, and at least one liquid part at room temperature in a percentage by weight of between 20% and 50% in the enamel/ink.

11. The printing method, according to claim 10, wherein the solid part is found in the enamel/ink in a percentage by weight between 50% and 80% and it has a particle size of D90 that can reach 40 micrometers.

12. The printing method, according to claim 10, wherein the absorbing substance is found in the enamel/ink in a percentage by weight of no more than 10%.

13. The printing method, according to claim 10, wherein the liquid part comprises at least one binding agent which is found in the enamel/ink in a percentage by weight of no more than 10%.

14. The printing method, according to claim 10, wherein the liquid part comprises at least one dispersing agent which is found in the enamel/ink in a percentage by weight of no more than 5%.

15. The printing method, according to claim 10, wherein the liquid part comprises at least one thixotropic anti-settling agent which is found in the enamel/ink in a percentage by weight of no more than 2%.

16. The printing method, according to claim 10, wherein the liquid part comprises at least one wetting agent which is found in the enamel/ink in a percentage by weight of no more than 2%.

17. The printing method, according to claim 10, wherein the liquid part comprises at least one levelling agent which is found in the enamel/ink in a percentage by weight of no more than 2%.

18. The printing method, according to claim 10, wherein the liquid part comprises at least one anti-foaming agent which is found in the enamel/ink in a percentage by weight of no more than 2%.

19. The printing method, according to claim 10, wherein the liquid part comprises at least one enamel/ink containing preservatives in a percentage by weight of no more than 2%.

Description

DESCRIPTION OF THE FIGURES

(1) As a complement to the description being made herein and for the purpose of helping make the characteristics of the invention more readily understandable, this specification is accompanied by a set of figures which, by way of illustration and not limitation, represent the following:

(2) FIG. 1 shows a general diagram of the direct printing method according to the present invention. The energy-emitting device (2) strikes the enamel/ink (4) through the carrier vehicle (3), giving rise to a change in volume and/or position of the enamel/ink (4) and causing it to be deposited on the printing surface (1).

(3) FIG. 2 shows a diagram of the direct printing method according to the present invention, wherein the change in volume and/or position of the enamel/ink (4) from the carrier vehicle (3) to the printing surface (1) is represented. The enamel/ink (4) may be deposited on certain zones of the printing surface (1), as represented in FIG. 2, or covering the entire printing surface (1).

(4) FIG. 3 shows a diagram of the direct printing method wherein the change in volume and/or position of the enamel/ink (4) from the carrier vehicle (3) to a raised printing surface (5) is represented. In accordance with the present invention, during this transfer process the distance between the enamel/ink (4) and the printing surface (5) is not less than 500 micrometers and not greater than 2.5 millimeters.

(5) FIG. 4 shows a diagram of the direct printing method according to the present invention, wherein the variation in height of the ceramic substrates (6 and 7) due to the differences in thickness arising between different parts within the production process is represented.

(6) FIG. 5 shows a diagram of the direct printing method according to the present invention wherein the printing surface is fixed and the movement occurs in an XYZ coordinate system of the laser-carrier vehicle-enamel/ink system.

(7) FIG. 6 shows a diagram of the direct printing method according to the present invention wherein the laser-carrier vehicle-enamel/ink system is fixed and the printing surface moves with movements in an XYZ coordinate system.

(8) TABLE-US-00001 List of references of the figures 1 Printing surface. 2 Energy-emitting device. 3 Enamel/ink carrier vehicle. 4 Enamel/ink. 5 Raised printing surface. 6 Ceramic substrate 1. 7 Ceramic substrate 2 of greater height than ceramic substrate 1. 8 Energy-emitting device-carrier vehicle-enamel/ink system with movement in an XYZ coordinate system. 9 Support or bench for fixing the surface to be enamelled/decorated. 10 Conventional transport system of the surface to be enamelled/ decorated.

PREFERRED EMBODIMENTS

(9) In order to complete the description being made herein and with the object of helping to better understand its characteristics, this specification is accompanied by various exemplary embodiments of enamel/ink to provide designs with ceramic and chromatic effects, according to the invention. In all cases, a laser beam has been used as an energy-emitting device.

(10) A preferred embodiment of the present invention is characterised in that it uses a laser beam as an energy-emitting device in the form of electromagnetic waves. In this way it is possible to focus a high amount of energy on a very small area of the enamel/ink, thereby producing drops to the order of picoliters and, therefore, a high quality in the printed image. In this regard, different types of lasers may be used, for example CO.sub.2, HeNe or Nd-YAG, among others. The different lasers are characterised, inter alia, by the wavelength or wavelength interval in which the energy beam is emitted, such as for example infrared, ultraviolet, green and red, among others, and by the energy emission mode, which may be continuous or pulsed. The selection of the type of laser according to the present invention shall be based on the composition of the enamel/ink to be applied.

(11) All the exemplary embodiments are indicated by way of illustration and not limitation.

(12) Compositions that Provide Ceramic Effects and their Properties

(13) Examples 1, 2 and 3 correspond to enamels which enable the ceramic effects of the glazing layer to be obtained according to the invention. Specifically, example 1 provides an enamel with a glossy opaque effect, example 2 provides an enamel with a satin matt effect and example 3 provides an enamel with a glossy coloured effect.

(14) The printing process of examples 1 to 3 has been carried out as follows. The printing surface moves in a conventional transport system while the laser-carrier vehicle-enamel system is fixed and in a transverse direction to that of the forward movement of said surface to be enamelled. In this regard, the system that transports the surfaces to be enamelled can reach speeds of up to 70 m/min. When the surface to be enamelled, which is moving, reaches the laser-carrier vehicle-enamel system, the laser emits an energy beam that penetrates the carrier vehicle and reaches the enamel. The incidence of said energy beam on the enamel is performed following a pattern or design so that, when the change in volume and/or position of the enamel in the form of bubbles occurs, these are deposited along the length and width of the surface to be enamelled in accordance with said pattern or design as the printing surface advances, without stopping at any time.

(15) TABLE-US-00002 Agent/function Component 1 2 3 Frit 1 Si, Al, Zn, K, 47%-70% 42%-55% Ca, Zr oxides Frit 2 Si, Zn, Ca 30%-45% oxides Raw material 1 SiO.sub.2 3%-10% 3%-10% Raw material 2 Na feldspar 15%-20% Raw material 3 Al.sub.2O.sub.3 5%-10% Absorber Graphite <10% <10% <10% Inorganic Blue - 5%-15% pigment Cobalt Spinel Structure Solvent 1 Glycol ether 20%-25% 5%-25% Solvent 2 Water 20%-35% Binding 1 Hydroxipropyl- <10% <10% <10% cellulose Binding 2 Carboxymethyl- <10% <10% cellulose- starch co-polymer Dispersing 1 Carboxylic acid <5% <5% <5% co-polymers Dispersing 2 Acrylic polymer <5% derivative Thixotropic Modified urea 2% <2% <2% anti-settling agent Wetting Polyether- 2% <2% <2% polysiloxane Preservative Isothiazolones 2% <2% <2% Viscosity (cPs) 3000 5200 4000 % solids >50% >50% >50% D90 40 20 20 (micrometers) D50 20 10 10 (micrometers) Type of laser Infrared Infrared Infrared
Compositions that Provide Chromatic Effects and their Properties

(16) Examples 4 to 7 correspond to inks which enable chromatic effects to be obtained according to the invention.

(17) The printing process of examples 4, 5 and 6 has been carried out in the following manner. The printing surface moves in a conventional transport system while the laser-carrier vehicle-ink system is fixed and in a transverse direction to that of the forward movement of said surface to be decorated. In this regard, the system for transporting the surfaces to be decorated can reach speeds of up to 70 m/min. When the surface to be decorated that is moving reaches the laser-carrier vehicle-ink system, the laser emits an energy beam that penetrates the carrier vehicle and reaches the ink. The incidence of said energy beam on the ink is performed following a pattern or design so that, when the change in volume and/or position of the ink in the form of bubbles occurs, they are deposited along the length and width the surface to be decorated in accordance with said pattern or design as the printing surface advances, without stopping at any time.

(18) The printing method of example 7 consists firstly of placing the surface to be decorated on a support or bench in order to immobilise it. Next, the laser-carrier vehicle-ink system is placed over the printing surface and the laser begins to emit an energy beam that penetrates the carrier vehicle and reaches the ink. The incidence of the energy beam on the ink is performed following a pattern or design so that, when the change in volume and/or position of the ink in the form of bubbles occurs, they are deposited on the surface to be decorated in accordance with said pattern or design. In order to deposit all the design or pattern on the printing surface, it remains immobile and the laser-carrier vehicle-ink system moves across the length and width of the printing surface along the XYZ coordinates, performing one or various passes over a same zone.

(19) TABLE-US-00003 Agent/function Component 4 5 6 7 Inorganic Yellow - 70%-80% pigment 1/ Praseodymium-doped Absorber Zr silicate structure Inorganic Black - Mixed 75%-80% pigment 2 FeCoNiCr oxide Inorganic Blue - Cobalt Spinel 50%-65% pigment 3 Structure Inorganic Pink - Cassiterite 50%-65% pigment 4 Structure Absorber 1 Graphite <10% <5% <10% Absorber 2 Pr.sub.6O.sub.11 <5% Solvent 1 Glycol ether 20%-45% 20%-45% Solvent 2 Water 25%-45% Solvent 3 Polyglycol 25%-50% 20%-25% Dispersing Carboxylic acid <5% <5% <5% agent 1 polymers Dispersing Acrylic polymer <5% agent 2 derivative Binding Hydroxipropyl- <10% <10% <10% agent 1 cellulose Binding Carboxymethyl- <10% agent 2 cellulose- starch co-polymer Wetting agent Polyether- <2% <2% <2% <2% polysiloxane Anti-foaming Polymethyl- <2% agent alcoxysilane Thixotropic Modified <2% <2% <2% anti-settling urea agent Viscosity (cPs) 4600 5100 5400 8000 % Solids >70% >75% >50% >50% D90 7 10 9 18 (micrometers) D50 4 6 5 10 (micrometers) Type of laser Ultraviolet Infrared Infrared Infrared

(20) The characteristics disclosed in the description, figures and claims may be significant both separately and in any combination thereof for implementing the invention in its different embodiments.