GB2357262A

GB2357262A - Image bearing metal panels

Info

Publication number: GB2357262A
Application number: GB9929841A
Authority: GB
Inventors: Richard James Ernie Gardner; Nigel Jon Perry
Original assignee: GARDENERS DIGITAL Ltd
Current assignee: GARDENERS DIGITAL Ltd
Priority date: 1999-12-18
Filing date: 1999-12-18
Publication date: 2001-06-20
Anticipated expiration: 2019-12-18
Also published as: GB2357262A8; EP1108558A3; GB2357262B; EP1108558A2; GB9929841D0

Abstract

A method of forming image-bearing panel members comprises providing sheets 16 of metal coated on one side with a layer of plastics material, preferably a polymer. An image is printed on sheets 16 in a piece-wise manner by covering the plastic coating of sheets 16 with a transfer 15 carrying an image formed in sublimation ink and subjecting the transfer to temperatures, e.g. 200 deg C, and pressures, e.g. 1200 psi, sufficient to cause the ink to migrate to the plastics coating while the sheet 16 remains stationary. The reverse of the transfer may be coated in a permeable material, e.g. a foamed plastic. An apparatus for forming the panel member comprises first and second members 10, 11, between which the panel 16 and transfer 15 are placed. The first member 11 has heating means and the second member 10 has a layer of foamed material 12, e.g. silicone. At least one layer 13, 14 of woven polyester may cover the foamed material. Any excess gases from the sublimed ink may pass through the transfer 15, woven layers 13, 14 and foamed silicone 12 avoiding bleeding or blowing of colours into each other.

Description

2357262 PRINTED METAL PANELS This invention relates to a method of forming

printed metal panels and to an apparatus for forming the same.

It is well known to print paper signs, posters and advertisements etc. Such signs etc. are prone to degradation and discolouration. Furthermore such signs etc. are not waterproof and can sometimes present a fire hazard.

It has been proposed to solve the above-mentioned problems by providing a metal sign which is either painted or enameled with the relevant image.

A disadvantage of painted or enameled signs is that they are time consuming and expensive to produce and are limited in the amount of detail which they can carry.

We have now devised a method of forming printed metal panels which alleviates the above-mentioned problems.

In accordance with this invention, there is provided a method of forming image-bearing panel members comprising providing a plurality of sheets of metal coated on one side thereof with a plastics material and printing the sheets in a piece-wise manner by at least partially covering the plastics coating of the sheet to be printed with a printed transfer carrying the image and subjecting the transfer to conditions which cause the transfer material to migrate from the transfer to the plastics coating whilst the sheet remains stationary.

In this manner, an extremely detailed image can be applied to a metal panel. It will be appreciated that the metal panel is waterproof and is less pro ne to degradation and discolouration than conventional paper signs etc.

Preferably the image is transferred by heating the transfer to a high temperature in the order of 2000C.

Preferably the transfer is pressed onto the sheet during transfer. Preferably the force applied to the transfer is in the order of 1200 psi.

Preferably the transfer is printed with sublimation ink 2 which changes directly from the solid to the gaseous phase when it is heated: the resultant coloured gas cross-links with the plastics coating of the metal.

Preferably the sheets of metal are coated on one side thereof with a polymer material such as polyester.

A disadvantage of sublimation printing onto metal is that excess coloured gases cannot escape through the metal or through the press which is applying heat and pressure to the reverse side of the transfer. Hence, excess gases tend to flow laterally, thereby causing the adjacent colours to bleed or blow into each other.

We have overcome this problem by covering the reverse side of the transfer with a sheet of permeable material through which excess gases can dissipate.

is Preferably, the reverse side of the transfer is covered with a sheet of foamed plastics material.

Preferably, a laver of a woven material is disposed between the foamed plastics material and the transfer.

Also in accordance with this invention, there is provided an apparatus for forming an imagebearing panel member, the apparatus comprising first and second members having substantially flat opposed surfaces spaced apart from each other, a layer of foamed plastics material covering at least a portion of the surface of the first member, heating means in said second member, and means for urging the first and second members together, so as to press a sheet of metal coated on one side thereof with a plastics material against a printed transfer carrying the image, said transfer lying between the panel member and said foamed plastics material.

In use, the heat and pressure transfers the image from the transfer to the plastics coating of the metal.

Any excess gases generated permeate back through.the transfer and dissipate through the foamed plastics material.

3 The foamed plastics material also helps to provide resilient support as the panel and transfer are pressed together.

Preferably the foamed plastics material comprises silicone.

Preferably a layer of woven polyester material covers said foamed plastics material. We have found that this improves the dissipation of excess gases.

An embodiment of this invention will now be described by way of example only and with reference to the accompanying drawing, the single f igure of which is a sectional view through an apparatus in accordance with this invention for forming an image-bearing panel member.

The apparatus comprises a large flat metal bed 10, supported above the ground on legs (not shown). A press 11 is suspended above the bed 10, the bed and press 10,11 having opposed faces lying in parallel planes.

The upper surface of the bed 10 is covered by a layer 12 of foamed silicone plastics.

A heater (not shown) is provided in the press 11 for heating the under surface thereof and means (not shown) are provided for lowering the press 11 into face-to-face contact with the bed 10 and for subsequently exerting a substantial downwards force on the bed 10.

In use, in order to form an image-bearing panel member, at least part of the silicone layer 12 is covered by two layers 13,14 of a woven polyester material.

Next, a transfer sheet of paper 15 onto which the reverse of the image to be formed has been printed using inks carrying sublimation dyes, is placed on the. uppermost woven layer 14 with the printed side facing upwardly. Then, a sheet 16 of metal, coated on one side thereof with a plastics polymer material such as polyester, is placed on the transfer sheet 15 with its plastics coating facing downwardly i.e. towards the transfer sheet 15.

4 The press 11 is then lowered onto the bed 10 and pressure and heat applied for about 5 minutes. We have found that the heater should be set to about 2000C and that a pressure of 1200 psi should be applied.

The pressure and heat causes the inks in the transfer to sublime to gaseous phase, whereupon the resultant coloured gas cross-links with the polymer coating on the metal sheet 16, thereby forming a corresponding image on the coating.

Any excess gas that is generated has a tendency to flow laterally, thereby causing adjacent colours to bleed or blow into each other. However, in the present invention, any excess gas permeates back through the transfer 15 and through the woven polyester layers 13,14 and into the foamed silicone layer 12 which dissipated the gases, thereby avoiding the problem of colours bleeding or blowing into each other.

The printed metal Panel member which is produced can be extremely detailed and is yet waterproof and durable.

Claims

1. A method of forming image-bearing panel members comprising providing a plurality of sheets of metal coated on one side thereof with a plastics material and printing the sheets in a piece-wise manner by at least partially covering the plastics coating of the sheet to be printed with a printed transfer carrying the image, and subjecting the transfer to conditions which cause the transfer material to migrate from the transfer to the plastics coating whilst the sheet remains stationary.

2. A method as claimed in claim 1, in which the image is transferred by heating the transfer.

3. A method as claimed in claims 1 or 2, in which the transfer is pressed onto the sheet during transfer.

4. A method as claimed in claim 3, in which the force applied to the transfer is in the order of 1200 psi.

5. A method as claimed in claim 2, in which the transfer is printed with a sublimation ink which changes directly from the solid to the gaseous phase when it is heated.

6. A method as claimed in any preceding claim, in which the sheets of metal are coated on one side thereof with a polymer material.

7. A method as claimed in any preceding claim, in which the reverse side of the transfer is covered with a sheet of permeable material.

6

8. A method as claimed in claim 7, in which the reverse side of the transfer is covered with a sheet of foamed plastics material.

9. A method as claimed in claim 8, in which a layer of a woven material is disposed between the foamed plastics material and the transfer.

10. A method substantially as herein described with reference to the accompanying drawing.

11. An apparatus for forming an image-bearing panel member, the apparatus comprising first and second members having substantially flat opposed surfaces spaced apart from each other, a layer of foamed plastics material covering at least a portion of the surface of the first member, heating means in said second member, and means for urging the first and second members together, so as to press a sheet of metal coated on one side thereof with a plastics material against a printed transfer carrying the image, said transfer lying between the panel member and said foamed plastics material.

12. An apparatus as claimed in any claim 11, in which the foamed plastics material comprises silicone.

13. An apparatus as claimed in any claim 12, a layer of woven polyester material covers said foamed plastics material.

14. A apparatus substantially as herein described with reference to the accompanying drawing.