Sublimation Printing - Products:
Sublimation printing enables any computer generated image to be reproduced into the surface of a range of materials. The computer image is printed using the special Sublimation Inks onto a release paper. The printed image is then placed in contact with a material in a Heat Press. In the Press the ink turns into a gas and reforms in the surface of the material it is in contact with. The materials must be PVC, Polyester or Polymer coated or ‘loaded’.
Sublimation Printing - Demonstration:
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AN INTRODUCTION TO DYE SUBLIMATION.
Sublimation printing is a relatively new but fast growing system being adopted in schools. In essence it allows students to reproduce four colour images in the surface of various different materials.
WHAT IS DYE SUBLIMATION PRINTING?
‘Sublimation’ is defined as turning a solid into a gas and back into a solid without any liquid stage. This allows the application of sublimation inks into a materials surface using a Heat Press to provide the required combination of heat, time and pressure. This combination causes the inks to be converted from a solid to a gaseous state enabling them to penetrate the surface so that a permanent, full colour image is formed. The colour penetrates the material giving a result which is long lasting, colourful and resistant to scratching. Dye Sublimation should not be confused with other dry laser processes that transfer the images to the surface of materials making them easy to scratch off. True Dye Sublimation uses wet ink technology.
WHAT ARE DYE SUBLIMATION INKS?
Dye Sublimation Inks are in essence a formulation of special coloured dyes suspended in liquids that can be passed through a digital ink jet printer.
WHAT MATERIALS CAN BE SUBLIMATION PRINTED?
Suitable materials are man made polymers such as Polyester and PVC. These can be ‘hard’ such as a polyester coated sheet of aluminium or ceramic tiles or ‘soft’ such as polycotton textiles. During the heat press stage the pores of these polymers open to allow sublimation ink (now in a gaseous state) to enter. As the temperature drops the pores close leaving the now solid ink image as part of the polymer.
In an education environment printable materials fall into three distinctive categories
SUBLIMATION SHEET MATERIALS
These are varied but include polymer coated aluminium; PVC sheets; coated plywood, plastic sheets, polymer coated magnetic materials, fibreglass and polycarbonates.
SUBLIMATION MATERIALS ALREADY ON-SITE AT SCHOOL
Foamex board, PVC and other plastics for vacuum forming, textiles containing polyester more than 50%
MINI ENTERPRISE PRODUCTS
Sublimation clocks and jigsaws, bags, ceramic tiles, ceramic mugs, business cards, coasters, place mats, id cards, mouse mats, tee and polo shirts, glass chopping boards and trophies.
All Sublimation materials tend to be white to enable true accurate colour reproduction. If you added an image to a coloured base the image would be distorted by the base sheet colour.
WHAT MATERIALS CANNOT BE SUBLIMATION PRINTED?
As dye Sublimation is always performed on a polyester, polymer or polymer coated item, materials such 100% cotton are not suitable as the natural fibres have no pores to open to accept the image. Cotton can be sublimated but the image will fade with a few washes making a 50% polyester 50% cotton weave a required minimum.
HOW DO YOU PRINT AN ITEM?
This is a digital printing system so you firstly select or create your colour image on a computer. Any picture from any software package will do - as long as it will print on a piece of paper it will be fine! Colour correction profile software is available but this is rarely necessary for sublimation printing in an education environment. Other simple adjustments can be made to the printer driver to ‘mirror print’ the image and to ensure the colours on the computer screen closely match the colours on the printed material.
The image is normally sized so that it is slightly larger than the selected material so it can ‘bleed’ over the edge leaving no white showing. The image is printed on sublimation paper ‘mirror image’ using the printer’s driver software. The printed image is then laid onto the sublimation material and secured with a little ‘heat tape’. The two are then placed in a Heat press for typically 1-2 minutes at a temperature between 160°- 200°c. The exact time and temperature depends on the material being used. At the end of the cycle the paper is removed to reveal a bright vibrant scratch resistant coloured image.
WHAT EQUIPMENT IS NEEDED FOR SUBLIMATION PRINTING?
Dye Sublimation Inks
Heat Press for flat material
Mug Press or domestic oven for mugs
Always Epson! Epson use ‘Piezo’ print head technology. This means they use a tiny crystal in the head that pulsates with a small electrical charge forcing droplets of ink onto the paper with virtually no heat being generated. ‘Bubble Jet’ printers from manufactures such as HP, Cannon and Lexmark heat the ink in the head to force droplets onto the paper. This means all these types of printers are unsuitable for use with sublimation inks that react to heat.
DYE SUBLIMATION INKS
Patents exist for European and US desk top (to A2) printing of Sublimation inks. These patented inks are available in slightly different forms and brands within Europe but are all offered at approximately the same market price. Pre-filled cartridges are available but 98% of customers use a Bulk Feed system. This consists of large (typically 100ml of each colour) reservoirs of ink connected by a tube system to continuous feed cartridges. Not only are Bulk Feeders convenient in that you do not have to keep replacing cartridges the ink delivered on the paper is much cheaper. An image printed with a Bulk Feeder can cost 25% of the cost of the same image printed with pre-filled cartridges. For this reason alone Bulk Feeders are the number one choice for sublimation printing.
If you used low cost photo copy paper too much of the ink would absorb into the paper itself and not enough would be ‘Sublimated’ into the material. Sublimation paper has a coating on the surface which effectively means the ink sits on the paper without ever thoroughly drying. Two types of paper are available, Economy Paper and Special Paper. The Special paper will work with all sublimation materials providing the best colour release and is essential with plastics as the thicker coating prevents sticking to warm sublimated plastic. The Economy grade is cheaper but still can be used on a wide range of materials.
HEAT PRESS, MUG PRESS AND OVEN
The constant even pressure and variable temperature control make a Sublimation Heat Press essential. Mugs will obviously not fit in a flat bed press so a special Mug Press can be purchased or alternatively the printed image adhered to the mug and the two placed in a domestic oven for 10 minutes.
Sublimation Printing can be used in conjunction with other manufacturing processes. For example; clear or white PVC sheet can be sublimated and then allowed to cool in the flat. The printed plastic can then be vacuum formed. A video resource is available from Mega which shows a vacuum forming tool being made on a laser cutter and the clear PVC being sublimated before it is vacuum formed to produce a colourful three dimensional light switch cover for a child’s room. Another example of sublimation printing and thermo-forming is with foam board. This can be printed and when it is still warm from the press formed into shapes using a simple press forming tool.