HP has announced ten new Indigo presses, including a new series 5 sheetfed and series 6 label press that raise questions as to where the future of this technology now lies.
HP’s latest Indigo presses target a broad range of applications including packaging.
For this story I’m going to concentrate on the two most interesting of the new machines, and the only two which really bring something new to the party, the sheetfed Indigo 100K and the narrow web label press, the V12. I’ll deal with the other eight new Indigos in a separate story later this week.
The Indigo 100K is the first press to use Indigo’s new series 5 engines. This has basically been conceived of as a reasonably fast, high volume four-colour B2 printer. In a bizarre twist, the Indigo folks seem to have forgotten that digital presses are supposed to be about short run printing where fast turnaround and high print quality can make up for the higher cost per sheet. Instead, Indigo says that it is targeting offset printers though it very much looks as if Indigo is worried about the potential competition from sheetfed inkjet presses.
Naturally there’s no word as to what it costs, or what the click charge and the running costs might be, let alone the crossover point at which it could be compete against an inkjet or litho press. I think that the Indigo’s broad compatibility with a range of substrates and excellent image quality should be more than a match for many inkjets but it should be pointed out that inkjet generally has a significantly lower running cost than toner and that intelligent production planning linked to a modern imposition program should allow offset presses to produce a lot of reasonably short run jobs cost effectively.
It’s a B2 machine taking a 750 x 530mm sheet. It takes uncoated media from 70gsm to 400gsm and coated media from 90gsm to 400gsm. HP says that it can produce over one million B2 duplex sheets per month. It should be available commercially this summer.
The 100K can run at 6000 sph using Indigo’s CMY enhanced productivity mode, or EPM in simplex. For standard 4/4 colours this drops to 2250 sph or 4500 for 4/0. However, it only takes four colours for CMYK and not Indigo’s standard 7 colours. There doesn’t seem to be any option to upgrade the number of colours, and indeed, restricting the machine to four colours has contributed to the higher running speed, and will limit the click charge per sheet. HP says that it has improved the paper handling, adding offset-like gripper-to-gripper design for precision registration and that this has also helped to improve the overall running speed. It also boasts a five-input source feeder, colour automation, calibration and fast switchover between jobs and media.
The Indigo V12
This brings us to the Indigo V12, which is the first of a new line of series 6 machines and by far the most significant of the new Indigo machines announced though this is not due to be commercially available until 2022. The V12 is a narrow web label printer, so named because it can hold up to 12 colours. HP has updated the underlying architecture, called the Liquid Electrophotography Platform, or LEP to a new version named LEPx. Indigo’s standard LEP combines an offset process with liquid toner. The liquid toner uses very small (1-2 micron) toner particles complete with pigment and encapsulated in resin, which are then suspended in a carrier fluid. This allows for quite detailed images with strong colours and a relatively fast printing speed.
The offset process involves a laser unit writing each colour separation as a latent image to a Photo Imaging Plate, or PIP, which then attracts the charged toner particles from a Binary Ink Developer unit to the imaged areas to form one colour separated image. There is one BID per colour, with most Indigo presses having seven BIDs arranged one after the other around the drum.
This image is transferred to a blanket that’s heated, which helps to evaporate the carrier fluid and melts the toner particles to form a smooth film, which is then in turn transferred to the substrate that’s wrapped around the impression drum. Since the substrate is cooler, the sudden change in temperature helps to solidify the image film so that there’s no dot gain, and to bind it to the substrate, creating a very thin film layer that sits on top of the media surface, and is thin enough to mimic the texture of the media surface
The weakness in this system is that the entire process then has to be repeated for each colour, which slows down the process (and also counts as a separate click charge) so that users rarely use all seven colours. HP has tried to address this with its Enhanced Production Mode, or EPM, which prints just the CMY colours to save time, and actually does produce a reasonably good image quality, albeit with slightly muddy blacks, that will be acceptable for some jobs though not for all.
HP also developed a further workaround – Indigo One-Shot – where all the colour separations accumulate together on the heated blanket and are then transferred to the substrate in a single pass. This has allowed for faster production with the web presses and also means that the substrates have less exposure to the heated blanket so that the presses can handle more heat sensitive materials.
For the LEPx platform, HP has taken a more radical approach, using six imaging engines in a row so that it can create six colour separations, more or less in parallel rather than in sequence. This means that the transfer blanket has had to be replaced with a blanket belt, said to be several metres long, which moves between the imaging engines.
One thing that struck me whilst writing this story is the similarities between the Indigo and Landa processes, hardly surprising since Benny Landa is responsible for both. The Landa Nanography also relies on a heated blanket to evaporate the carrier fluid away, leaving behind the pigment as a thin film layer, and using the sudden drop in temperature from contact with the substrate to stop the pigments from melting further and to bind the film layer to the media surface. This is particularly noticeable with the V12 due to its use of a heated belt. Hopefully the patent lawyers have been through this and any arguments and licenses agreed.
It’s likely that Indigo will encounter some of the same problems that Landa has done in getting the image to come cleanly off the belt, and in cleaning the belt ready for the next image. In addition, the degree of heat involved in the process is likely to cause the belt to expand and contract and eventually break, making it into a rather expensive consumable item.
The other problem is that having six imaging systems means having six times the maintenance overhead and a much higher running cost.
The V12 uses the same electroinks and BID colour stations as the existing Indigo presses. The other key difference is that each imaging engine has two BIDs so that the press can be loaded with up to 12 colours. It looks as if only six of these can be used at any one time, ruling out the option to use a seven-colour extended colour gamut inkset or a six colour inkset with spot colours. However, this is unlikely to be a huge problem given the colour gamut that the Indigo process can achieve. Having 12 colours loaded does mean that operators can easily switch between colours as and when needed.
HP claims that the V12 is as fast as an analog press, which is only true if for some inexplicable reason you choose to run your flexo press at less than its rated speed. The V12 runs at 120mpm, for up to six colours, whereas many flexo presses can hit 200mpm, and some can run as fast as 240mpm.
The V12 does have a number of other features that will presumably also be applied to other series six engines. Thus the Photo Imaging Plate or PIP has been replaced with a Photo Imaging Drum, or PID, that’s said to last longer. In addition, HP has replaced the laser scanning unit writing head with a new array of high-resolution LEDs, which allows it to print at 1600 dpi resolution, up from the 812dpi of the rest of the Indigo line-up.
It supports substrates from 12 micron unsupported film to 450 micron, or 18pt, board, including pressure-sensitive, sleeves, flexible packaging, tubes and in-mould labels, using an integrated inline primer. HP claims that it can produce up to 130,000 linear meters per day with one operator.
You can find more details on both of these from hp.com. Watch this space as I’ll publish a follow-up story to cover the other new Indigo presses later this week.