Depends on the model, some of them do have seperate print heads, mainly the bussnes jet series, the office jet and multi fuction don't generally.
HP do a couple of nice cheap multi fuction printers (Inkjet & a4 scanner all in one) not sure what they'll be like for drying out.
I've got an old mono HP laserjet 1100, it just keeps on going, doesn't get used for a month or so then will happly spits out a few pages. (only problem with it is the paper feed, but newer models tend to be far better on the feed)
One thing to be aware of is that currently printer prices are very low but toner/ink is expensive, I'm sure this is how they make there money.
Also every time they release a new model it needs differnt cartridges
Colour lasers are really bad for this as often buying a full set of toners actually costs more than the printer.
Another note, often when you get a new printer the ink/toner cartridges it comes with are only 1/4 cappasity and you'll often have to buy a USB lead as they very rarely come with them.