By Will Goodbody, Science & Technology Correspondent

In many ways mobile devices have made the need for printers and printing redundant.

But they aren’t dead yet and there’s still money to be made.

According to a recent report by Smithers Pira, the overall value of the printing market is set to top $980 billion by 2018.

Following its split from the other part of the company, HP Inc remains a leading player in printing.

In an effort to bolster its growth, the company has decided to change its model around personal printer ink supplies.

Instant Ink is a service based system that intends to tap into the growing subscription based mentality.

The concept is simple enough.

You subscribe to a monthly plan with different tiers depending on your level of ink use.

When your printer cartridges start to get low, the printer automatically sends an order to HP, which then sends you back an extra-large refill – in theory in plenty of time before the ink well runs dry.

The model has been in use in the UK for two years and also in the US.

According to Gary Tierney, HP Ireland’s Managing Director, the retention rate among those who’ve tried it is 90 per cent.

The plans are priced at €2.99 a month for up to 50 pages per month, €4.99 a month for Moderate 100 pages per month and €9.99 a month for 300 pages per month.

Unused pages roll over from month to month, although they can never exceed the total pages of the current plan to which a customer is subscribed.

If the user wants to change their plan, or indeed cancel it, they can do so at any time.

If additional pages are required they can automatically be purchased in blocks of 15, 20 or 25 pages for just €1 depending on the plan.

And if they are running close to their maximum number of pages for a month, HP automatically alerts them.

20 existing HP printers that have already been for sale for some time are compatible as are any new HP printers.

The system is reasonable straightforward to set up, although I did experience some issues registering for an account in Ireland, with an Irish postal address.

I kept ending up back on the HP UK page, which obviously wouldn’t recognise my address.

HP could perhaps do more to streamline the process for Irish users.

Once registered, however, the first cartridge for my demo printer was automatically ordered by the system, to ensure there was one in reserve.

It arrived quickly – HP guarantees two-day delivery.

I haven’t used the ink in it and the pre-installed cartridge up yet so I cannot yet judge how the system works for re-orders.

But the concept seems to be a smart one.

From the consumer point of view there is no longer any need to worry about running out of ink.

It also means the cost is spread out over a year and the price is the same for both colour and black and white.

Each cartridge also comes with an envelope for returning the old one back to HP for recycling.

From HP’s point of view, the model means a steady reliable and predictable stream of income.

It is already looking at developing it as a service in the business sector.

The company claims that an average user can save up to 70 per cent or €564 on their annual ink costs, based on a subscription to the 300 page plan where all pages are used each month.

In reality though, for most average home users who print a few documents and photos each month, the savings are likely to be considerably less, it any.

The real win is on convenience, which it is much harder to put a price on.

Comments welcome via Twitter to @willgoodbody