How is it that HP, king of printing, has zero presence in 3D printers?

Or Canon. Or Brother for that matter? These guys lead the leagues in printer sales to consumers and businesses. So why aren’t they diving into the booming 3D printer market?

By all accounts 3D printing is a huge growth area — In a research note Monday, Citigroup(s c) analyst Kenneth Wong said he expects the market — ranging from low-end consumer models to high-value production systems for making big-ticket items like automotive or airplane parts — to triple in size in five years. Now, as Quartz points out, that’s from a smallish current base —  the market is worth about $1.7 billion now but tripling that means a real opportunity and one, presumably, that printer kingpin HP and its rivals would love to capture.

IDC senior analyst Amy Machado conceded that traditional printer makers are not players here yet, but she said not to confuse lack of public action with a dearth of interest.  “Just because they’re not out promoting their work doesn’t mean they’re not doing it,” she cautioned.

And, to be fair, 3D printing is a different animal than its 2D cousin, although there is enough shared DNA that it makes sense to ask why traditional printing vendors are seemingly late to this party.

Big print boys laying in wait

One reason is  that its still early days in 3D printing and there are lots of factors to weigh, including the fact that some patents on laser sintering Fusion Deposition Modeling  — one type of 3D printing — are about to expire, she said.

Gartner(s it) Research Director Pete Basiliere said there are 7 broad categories of 3D printing, including the aforementioned FDM but also stereolithography and other techniques. But the gist of the process is that a machine (printer) deposits layer after layer of material in a pattern — think of an inkjet printer but one using a plastic or composite instead of ink — repeating its print design over and over to build up a component or structure according to a blueprint. GigaOM’s Signe Brewster has a great tutorial here.

3D printer leaders include Stratasys, which was an  HP partner for awhile  and 3D Systems. Stratasys  bought consumer 3D printer company Makerbot in June for $603 million. For the record, HP did sell a Designjet Color 3D printer — made by Stratasys — but that ended when the relationship did and it’ s not clear that many people bought one.

Sales model– sell the printer once, the supplies forever

From a vendor point of view, the appeal of 3D printing will seem familiar: You sell the machine but, more importantly, you sell the material that goes into the machine. Anyone who’s bought an $80 home printer then has to drop $30 per toner cartridge understands that lucrative business model.

And there’s money to be made in high-end, very finely manufactured components — printer heads, etc. — that go into these machines, said Basiliere.

While projections that every household will own a 3D printer soon are probably off the mark, there are huge opportunities in advanced manufacturing. “The biggest potential will be more on the high-end side — developing parts for aerospace for medical devices — short-run manufacturing stuff,” Machado said.

In an emailed statement, HP said it “continues to explore the many possibilities of 3D printing and is making efforts to wisely invest in the appropriate research and development to better harness the opportunity for the marketplace.”

It also said it “applauds the pioneers who challenge the current set of 3D print technologies in specialized and niche manufacturing.”

In other words: Give us a minute and we’ll be there.