WO1991012145A1

WO1991012145A1 - Manufacture of signs

Info

Publication number: WO1991012145A1
Application number: PCT/GB1991/000196
Authority: WO
Inventors: Peter Mckie; Andre Ghilain Woodman Michael
Original assignee: Esselte Letraset Ltd
Current assignee: Esselte Letraset Ltd
Priority date: 1990-02-09
Filing date: 1991-02-08
Publication date: 1991-08-22
Anticipated expiration: 1992-08-09
Also published as: AU7253891A; GB9002918D0

Abstract

Coloured signs are produced by imaging a sign legend on to a temporary carrier sheet using xerographic toner, the temporary sheet being fed through the normal paper feed of a xerographic photocopying machine. The toner image is coloured using a heat transfer foil. The coloured toner image is then adhered to a thermoplastic coating on the rear surface of a transparent or translucent sign sheet and the carrier sheet stripped away. The legend may be provided with an appropriate background, e.g. by spray painting subsequently.

Description

MANUFACTURE OF SIGNS

This invention relates to the manufacture of signs.

There are many known methods for making signs. Many require substantial capital equipment to effect. Often, however, there is a need for simple manual techniques, particularly for the rapid production of individual signs by assembly of a legend, for example, wording, numerals or the like on an appropriate sign plate. In order to provide a sign which is relatively permanent, a particularly useful technique is to locate the sign legend on a piece of transparent or translucent material through which the legend is visible, the material serving to protect the legend.

UK Patent Specification No 2005596 discloses a method of making signs by assembling on an intermediate carrier a legend formed from individual transfer letters, which are then caused to adhere to the surface of a transparent or translucent sheet. While this method is valuable for many applications, it is restricted insofar as transferable letters are generally available in black, sometimes in white and a few other colours, but not in a wide range of colours.

European Patent Specification No 0191592 discloses a method for the production of a coloured legend on a carrier, for example a sheet of paper, which is effected by first forming the legend as a toner deposit on the sheet of paper, conventionally using a black thermoplastic toner such as is applied by a standard xerographic copying machine, and then colouring the surface of the toner areas by applying under heat and pressure a colouring foil thereto. With an appropriate selection of conditions, colouring material on the foil may be caused to adhere selectively to the toner image and not to the surrounding (paper) carrier so that when the colouring foil is stripped away, a coloured legend is left on the paper sheet. Toner image colouring systems working in this way have been commercialised under the trade mark OMNICROM. Coloured legends formed in this way can be adhered with their carrier to the rear of a transparent or translucent sheet, but.the results thereby obtained are generally unsatisfactory and in particular the presence of an adhesive between the transparent or translucent sheet and the carrier bearing the coloured legend is disadvantageous. Particularly if the sign is exposed to sunlight or other adverse conditions, the adhesive can fail leading to separation, or it can discolour or give rise to mottling or other uneven looking effects generating an uneven and unsatisfactory appearance.

According to the present invention, there is provided a method of making a sign which comprises the steps of:

1. forming a toner image upon a temporary carrier sheet;

2. applying from a colouring foil a colour layer to the toner image;

3. applying a layer of thermoplastic material to a transparent or translucent sign sheet or panel;

4. bringing the coloured image into contact with the thermoplastics layer on the sign sheet or panel under heat and pressure and

5. removing the temporary carrier sheet from the assembly,

the adhesion of the colour layer to the toner image and to the thermoplastics layer on the sign sheet being greater than the adhesion of the toner image to the temporary carrier sheet, whereby the temporary carrier sheet may be stripped away to leave the coloured legend adherent to the transparent or translucent sign sheet or panel and visible in colour when viewed through the transparent or translucent sign sheet or panel.

Working in this way, it is possible with simple, easily available equipment to produce sign legends in a wide range of colours. By selectively applying colouring foils to individual portions of the toner image while it is on the temporary carrier sheet, different parts of the legend may be coloured differently.

The application of a colouring foil preferably takes place under heat and pressure by passing the assembly of colouring foil and toner image bearing temporary carrier sheet through a heated nip, e.g. between a pair of heated silicone rubber coated rollers.

The nature of the sign sheet or panel and the temporary carrier sheet may vary widely, and simple experiment will determine appropriate combinations of materials which work adequately. The sign sheet or panel may be of any convenient transparent or translucent sheet material, for example of glass or of a transparent plastics such as clear polyvinyl chloride, polycarbonate resin, polyethylene terephthalate or polymethyl methacrylate. It may be of appropriate thickness to be used as such or, e.g. of thin material for subsequent use in an appropriately supported fashion, e.g. adhered to a door or wall.

The temporary carrier sheet is chosen to be one which may be handled by conventional xerographic copying machinery. It may be of paper provided with an appropriate surface or of a plastics film, where necessary having a surface treatment to provide a surface on to which the toner image may be adequately transferred within the xerographic copying apparatus but from which the toner image may be subsequently bodily removed. The temporary carrier sheet is preferably dimensionally heat stable. The material of choice is polyethylene terephthalate film.

The toner used to apply the toner image may be any conventional thermoplastics toner, i.e. the standard type of toner used in plain paper copying apparatus.

The colouring foil may be selected from a wide range of known such materials. The foils commercially available under the trade mark OMNICROM are suitable. The foils may bear a coating which is pigmented or they may bear, e.g. a metallic coating.

A wide variety of thermoplastic materials may be used to coat the sign sheet or panel. Thermoplastic acrylic polymers are particularly preferred as they are widely commercially available and can be evenly deposited from solution. Commercially available heated nip apparatus, for example that sold under the trade mark OMNICROM CT2000, can be used satisfactorily.

If desired, the sign may be improved in appearance by applying a colour layer over the legend which, when viewed, forms a background. This may be achieved by transfer from a colouring foil under heat and pressure or, e.g. by spray painting.

The present invention thus provides a simple and versatile sign making system enabling the production of coloured or multicoloured legends using easily available equipment and simple manipulative techniques. Attractive signs can be quickly produced on a one off basis even by relatively unskilled personnel. In addition to the photocopying apparatus and heated nip apparatus, all that is required is a supply of imageable sheets serving as temporary carrier sheets and a supply of transparent or translucent sign sheets or panels. These may be supplied pre-coated with the layer of thermoplastic polymer, packed in such a way as to indicate which side of the transparent sheet bears the coating.

The following examples will serve to illustrate the invention:

Example 1

Using a standard xerographic photocopying machine (Konica UBix 5502) a desired sign legend was imaged from a master on to a thin flexible A4 sized sheet of 75 micron polyethylene terephthalate film (Melinex '0' , ex ICI Limited) . The black toner image was then coloured metallic blue by placing over it a sheet of OMNICROM (Registered Trade Mark) foil of that colour and passing the assembly through a heated nip (OMNICROM CT2000, speed setting 3, temperature setting 4). The foil was stripped away to leave the toner image, now covered with a blue metallic reflective surface, on the polyethylene terephthalate sheet.

A sign sheet of optically clear polyethylene terephthalate (50 micron thick, Terphane P ex Hoechst) was taken and coated with a solution of butyl methacrylate resin (Plexigum P24 ex Rohm GmbH). The solution was made by dissolving the butyl methacrylate resin in an equal part by volume solvent blend of ethyl acetate and toluene to give a composition of viscosity appropriate for hand coating using a number 12 Meyer bar. The coating composition was applied in customary fashion and the coating allowed to dry in air for 30 seconds at 70°C. The dry coat weight was 5 to 6 gsm.

The polyethylene terephthalate sheet bearing the blue coloured toner image was then placed toner image side down, on top of the (coated side up) polyethylene terephthalate sign sheet and the assembly passed through the same heated nip (speed setting 3, temperature setting 4).

The flexible polyethylene terephthalate sheet was then pulled away from the polyethylene terephthalate sign sheet. The toner and previously applied blue coloration was firmly adherent to the coated sign sheet and the flexible polyethylene terephthalate sheet peeled away cleanly.

The sign so made could be used as such, the sign legend appearing against whatever background the sign sheet was placed against. Alternatively an improved appearance was obtained by applying to the coated side of the sign sheet an overall layer of a colour using a hot foil sheet as sold under the trade mark SIGNCOLOR (ex Esselte Letraset Limited) .

5 Example 2

A polyethylene terephthalate sheet bearing a toner image covered with a blue metallic reflective surface is made as . in Example 1.

10

A sheet of optically clear polyethylene terephthalate (50 micron thick, Terphane P ex Hoechst) was taken and coated with a solution of methyl methacrylate resin (Colacryl P1003, ex Cole Polymers Limited). The solution was made

15 by dissolving the methyl methacrylate resin in toluene to give a composition of viscosity appropriate for hand coating using a Meyer bar. The coating composition was applied in customary fashion and the coating allowed to dry in the air for 30 seconds at 70°C. The dry coat

20 weight was between 5 and 15 g.s.m.

The polyethylene terephthalate sheet was placed (coated side down) on to a thin acrylic sheet which was to constitute the sign sheet, and the assembly passed through 25 a heated nip (Letraset Sign Systems Heat Laminator, Roller 30) with the roller external temperature set to 150°C.

The polyethylene terephthalate sheet was peeled away, leaving the methyl methacrylate layer firmly adhered to ^• 30 the acrylic sign sheet.

The polyethylene terephthalate sheet bearing the blue coloured toner, was applied to the acrylic sign sheet placing the toner side down and again passing the assembly 35 through the same heated nip. The polyethylene terephthalate sheet was then pulled away from the acrylic sign sheet. The toner and previously applied blue colouration was firmly adherent to the coated sign sheet and the flexible polyethylene terephthalate sheet peeled away cleanly.

The sign so made could be used or further treated as in Example 1.

Example 3

A polyethylene terephthalate sheet bearing a toner image covered with a blue metallic reflective surface is made as in Example 1.

A solution of butyl methacrylate resin is made up of 30 percent by weight Plexigum P24 (ex Rohm GmbH) and 70 percent by weight ethoxy propyl acetate. This solution was screen printed directly on to an acrylic sign sheet. The screen printed layer was allowed to dry thoroughly. The polyethylene terephthalate sheet bearing the blue coloured toner image was placed (image side down) on the printed acrylic sheet and the assembly passed through the same heated nip as in Example 2.

The flexible polyethylene terephthalate sheet was then pulled away from the acrylic sign sheet. The toner and previously applied blue colouration was firmly adherent to the coated sign sheet.

The sign so made could be used or further treated as in Example 1.

Claims

CLAIMS1. A method of making a sign which comprises the steps of:

1. forming a toner image upon a temporary carrier sheet;

2. applying from a colouring foil a colour layer to the toner image;

3. applying a layer of thermoplastics material to a transparent or translucent sign sheet or panel;

5. removing the temporary carrier sheet from the assembly,

2. A method according to Claim 1 wherein different colouring foils are selectively applied to individual portions of the toner image while it is on the temporary carrier sheet, whereby different parts of the legend are coloured differently.

3. A method according to Claim 1 or 2, wherein the application of a colouring foil takes place under heat and pressure by passing the assembly of colouring foil and toner image bearing temporary carrier sheet through a heated nip.

4. A method according to any one of Claims 1 to 3 wherein the sign sheet or panel is of clear polyvinyl chloride, polycarbonate resin, polyethylene terephthalate or polymethyl methacrylate.

5. A method according to any one of Claims 1 to 4, wherein the temporary carrier sheet is of polyethylene terephthalate.

6. A method according to any one of Claims 1 to 5 wherein the thermoplastics material is a thermoplastic acrylic polymer.