Inkjet has a lot to offer the décor market, and there are indications its time may have finally come. John Corrall has some thoughts to share.
Inkjet is hardly new in the décor market. The ceramic tile
market changed over to inkjet almost overnight around the time of the 2008
financial crash. Tough times mean people have to look carefully at their
business. The market realised that the economics of inkjet made sense, and
suddenly no tile producer could afford to use any other technology. Rotary
screen died and inkjet quickly came to dominate. Now some 12 years later the tile
market is very mature, with all production lines long since converted to inkjet.
Machine sales into this market are all about replacements or upgrades. Ceramics
machine builders are now looking to move into other markets such as packaging,
textiles or “3D” ceramics such as tableware.
What about the rest of the décor market?
The key areas inkjet suppliers are targeting are: –
- wallpaper
- laminates (e.g. HPL)
- LVT
- edge band
- furniture direct-print
Wallpaper
This market has real potential. The vast majority of wallpaper is produced on large conventional presses. setup times are long, waste is high and a 600mm image repeat distance limits design possibilities. Digitally printed “mural” wallpaper exists, but it is a tiny fraction of the whole, largely limited by the very low speeds of the wide format machines used to print it (dominated by HP Latex printers). To capture this market the goal is digital print at full press speeds (60 to 70m/min). The problems lie in the ink. There are tough EU regulations to meet, a wide range of wallpaper stocks to print and low cost/m2 targets. Once these issues are solved there are 300 “analogue” wallpaper production lines to replace, and this might total 1000 including Asia.
Laminates
High Pressure laminate is used for furniture, flooring or
exterior cladding of buildings. It consists of a sheet of printed paper soaked
in resin (melamine) and bonded under heat and pressure to a board. The board
may be particle-board, MDF or itself made from multiple layers of resin-soaked
paper.
Inkjet is already used to print the paper sheets. Inks may
be UK or water-based. A key requirement is that they don’t fade when exposed to
heat (eg from a hot pan placed on the furniture). Board producers also expect
linear print speeds of 50m/minute minimum and print widths around 2.1metres (so
these are not small machines). Inkjet
machine builders in this market are Palis, KBA and Hymmen.
(LVT) Luxury Vinyl Tile
LVT can look like wood or ceramic tile flooring but is warm
underfoot and easier to fit. With any large area of print the human eye will
quickly pick out any repeated patterns, so inkjet has a big advantage in that
the printed images don’t need to repeat. From this point of view it can look
far more “natural” than conventional print. LVT normally consists of two or
more layers of PVC and for durability the print is on the inside – either on
the rear of the clear top layer or on the top surface of the second layer. The
main issue is to ensure that the inkjet print does not weaken the bond between
the PVC layers. Normally no adhesives are used – the layers are joined using
heat and pressure. But normal inkjet inks can act as a barrier and prevent good
adhesion between the layers.
Edge-band
While the top surface of say a table might have been printed by HPL, the edges also need decorating to match. Generally, this is done using “edge-band”. Edge-band is most commonly printed ABS that is then glued to the edge of the board. The edge-band is printed in widths of 300 to 500mm on a roll to roll system and slit to the required width. Inkjet inks are normally UV type.
While the top surface of say a table might have been printed by HPL, the edges also need decorating to match. Generally, this is done using “edge-band”. Edge-band is most commonly printed ABS that is then glued to theedge of the board. The edge-band is printed in widths of 300 to 500mm on a roll to roll system and slit to the required width. Inkjet inks are normally UV type.
Because after slitting the cut edge is visible it is normal to use pre-coloured plastic. For this reason, the inkjet may not be working very hard – typically it may be simply adding a wood-grain pattern on top of light-brown plastic. Colour matching of the edge-band to the rest of the board requires care. Even if the colour match is accurate, differences in gloss level between the top and sides of the board may be unacceptable. Metamerism issues also arise. So even if the board top and sides have an accurate colour match in daylight conditions, do they still match under LED or fluorescent lighting?
Agfa is very active in this market, The new Altamira Design PID (Printed Interior Decoration) ink set is tuned for printing a wide range of colours, including printing fashion colours (e.g. concrete, marble, stone…) and wood grain designs with low metamerism.
IIJ installed its first system for edge-band production back
in 2011.
Direct to Board
Use of digital print in laminates production opens up the
market to much wider design possibilities. But the true goal of any
just-in-time manufacturing system is always to leave the customisation until
the end. Printing onto laminate papers with inkjet doesn’t help much – since
the paper must be printed right at the start of the manufacturing process. The
decision about what image to print (which must also be matched by the edge
band) must be made before board production starts.
The ideal then would be to manufacture and stock plain,
unprinted boards and decorate them only as required. In other words, the
digital print system is printing directly onto an otherwise finished board. The
image to print can be chosen at the last moment and can vary continuously to
avoid “pattern-repetition”.
Again, this is not a new idea. Spanish machine builder
Barberan showed their first inkjet system for board printing in 2008. Cefla is
another recognised name in this market.
Ideally print systems need to print both the top and sides
of the board together and with the same inks – so avoiding any colour-match or
metamerism issues. When printing onto a large area such as a length of kitchen
worktop the accuracy of the board transport system becomes critical. Any errors
in the smoothness of the movement will result in visible “bands” in the print.
The next step after printing flat panels is then to print
onto 3D furniture e.g. chairs. While the same issues apply in terms of inks and
accuracy of motion, a further difficulty is the limited ink “throw” distance
available from the inkjet printheads. With complex 3D shapes – especially
concave shapes such as a chair backrest – it is difficult to get the inkjet
printheads close enough to the surface to be printed. Inevitably some
compromise is needed between using small ink drops for high print quality and
larger ink drops which will “fly” further.
Inkjet technology has already made inroads into the Décor
market, increasing design possibilities and reducing economic batch sizes. Arguably
late-stage customisation by direct-to-board printing will take this to another
level.