The Linux kernel mostly supports any printer that you can plug into a serial or parallel port, but there are things to look out for, and printers that you won't be able to use, even though they can (electrically speaking) communicate with Linux. Primary among these incompatible printers are those referred to as "Windows" or "GDI" printers. They are called this because part or all of the printer control language and the design details of the printing mechanism are not documented. Typically the vendor will provide a Windows driver and happily sell only to Windows users; this is why they are called Winprinters. In some cases the vendor also provides drivers for NT, OS/2, or other operating systems.
Many of these printers do not work with Linux. A few of them do, and some of them only work a little bit (usually because someone has reverse engineered the details needed to write a driver). See the printer support list below for details on specific printers.
A few printers are in-between. Some of NEC's models, for example, implement a simple form of the standard printer language PCL that allows PCL-speaking software to print at up to 300dpi, but only NEC knows how to get the full 600dpi out of these printers.
Note that if you already have one of these Winprinters, there are roundabout ways to get Linux to print to one, but they're rather awkward and I've never tried it myself. See Section 12 of this document for more discussion of Windows-only printers.
As for what printers do work with Linux, the best choice is to buy a printer with native PostScript support. Nearly all Unix software that produces printable output produces it in PostScript, so obviously it'd be nice to get a printer that supports PostScript directly. Unfortunately, PostScript support is scarce outside the laser printer domain, and is sometimes a costly add-on.
Unix software, and the publishing industry in general, have standardized upon Postscript as the printer control language of choice. This happened for several reasons:
Postscript arrived as part of the Apple Laserwriter, a perfect companion to the Macintosh, the system largely responsible for the desktop publishing revolution of the 80s.
Postscript programs can be run to generate output on a pixel screen, a vector screen, a fax machine, or almost any sort of printer mechanism, without the original program needing to be changed. Postscript output will look the same on any Postscript device, at least within the limits of the device's capabilities. Before the creation of PDF, people exchanged complex documents online as Postscript files. The only reason this standard didn't "stick" was because Windows machines didn't usually include a Postscript previewer, so Adobe specified hyperlinks and compression for Postscript, called the result PDF, distributed previewers for it, and invented a market for their "distiller" tools (the functionality of which is also provided by ghostscript's ps2pdf and pdf2ps programs).
Postscript is a complete programming language; you can write software to do most anything in it. This is mostly useful for defining subroutines at the start of your program to reproduce complex things over and over throughout your document, like a logo or a big "DRAFT" in the background.
Postscript is fully specified in a publically available series of books (which you can find at any good bookstore). Although Adobe invented it and provides the dominant commercial implementation, other vendors like Aladdin produce independantly coded implementations as well.
Failing the (larger) budget necessary to buy a Postscript printer, you can use any printer supported by Ghostscript, the free Postscript interpreter used in lieu of actual printer Postscript support. The Ghostscript Home Page has a list of supported printers and information on the status of new and experimental drivers. Note that this page lists supported printers in the latest version of Ghostscript, while most Linux distributions can only ship a somewhat outdated version of Ghostscript due to the license. Fortunately, there is usually a prepackaged up to date Ghostscript made available in each distribution's contrib area. Please help improve the Ghostscript printer support page by reporting your successes and failures as it asks.
Adobe now has a new printer language called "PrintGear". I think it's a greatly simplified binary format language with some Postscript heritage but no Postscript compatibility. And I haven't heard of Ghostscript supporting it. But some PrintGear printers seem to support another language like PCL, and these printers will work with Linux (iff the PCL is implemented in the printer and not in a Windows driver).
If you want to buy a printer, you can look in several places to see if it will work. The cooperatively maintained Printing HOWTO printer database aims to be a comprehensive listing of the state of Linux printer support. A summary of it is below; be sure to check online for more details and information on what driver to use.
Ghostscript's printer compatibility page has a list of some working printers, as well as links to other pages. And Dejanews contains hundreds of "it works" and "it doesn't work" testimonials. Try all three, and when you're done, check that your printer is present and correct in the database, so that it will be listed properly in this document in the future.
This section is a summary of the online version. The online version includes basic specifications, notes, links to driver information, user-maintained documentation, manufacturer web pages, and so forth. The online version of this list is also interactive; people can and do add printers all the time, so be sure to check it as well. Finally, if your printer isn't listed, add it!
Printers here are categorized into three types:
Perfect printers work perfectly - you can print to the full ability of the printer, including color, full resolution, etc. In a few cases printers with undocumented "resolution enhancement" modes that don't work are listed as perfect; generally the difference in print quality is small enough that it isn't worth worrying about.
You can print fine, but there may be minor limitations or one sort or another in either printing or other features.
You can print, but maybe not in color, or only at a poor resolution. See the online listing's notes column for information on the limitation.
You can't print a darned thing; typically this will be due to lack of a driver and/or documentation on how to write one.
And without further ado, here is the printer compatability list:
HL-10V, HL-660, HL-720, HL-760.
HL-1050.
BJ-10e, BJ-20, BJ-200, BJC-210, BJC-240, BJC-250, BJC-610, BJC-620, BJC-70, BJC-800, LBP-8II, LIPS-III.
BJ-300, BJC-4000, BJC-4100, BJC-4200, BJC-4300, BJC-4400, BJC-7000, BJC-7004.
BJC-4550, MultiPASS C2500, MultiPASS C3500.
BJC-5000, LBP-460, LBP-660.
ActionLaser 1100, LP 8000, LQ 850, Stylus Color, Stylus Color 400, Stylus Color 500, Stylus Color 600, Stylus Color 640, Stylus Color 850, Stylus Color II, Stylus Color IIs, Stylus Pro XL.
Stylus Color 800, Stylus Photo 750.
Stylus Color 740.
2000Cse, 2500C, DesignJet 650C, DeskJet 1200C, DeskJet 1600C, DeskJet 1600Cm, DeskJet 400, DeskJet 420C, DeskJet 500, DeskJet 550C, DeskJet 600, DeskJet 660Cse, DeskJet 690C, DeskJet 850C, DeskJet 855C, DeskJet 870, DeskJet 870Cxi, DeskJet 890, LaserJet 1100, LaserJet 2100, LaserJet 2100M, LaserJet 4000N, LaserJet 4L, LaserJet 5, LaserJet 5L, LaserJet 5MP, LaserJet 6L, LaserJet 6MP, LaserJet 8000, LaserJet 8100, Laserjet 5000, Mopier 320, PaintJet XL300.
HP 660C.
DeskJet 1000C, DeskJet 670C, DeskJet 710, DeskJet 720C, DeskJet 722C, DeskJet 820C.
LaserJet 3100.
Jetprinter 3852.
Optra Color 1200, Optra Color 1275, Optra Color 40, Optra Color 45, Optra E, Optra E+, Optra Ep, Optra S 1250.
1020 Business, 3000, 5700, 7000.
1000, 1020, 1100, 2030, 2050, 2070, 5000, 7200, Winwriter 100, Winwriter 150c, Winwriter 200.
PagePro 6, PagePro 8.
P2X.
SuperScript 100C, SuperScript 1260, SuperScript 150C, SuperScript 650C, SuperScript 750C, SuperScript 860, SuperScript 870.
SuperScript 660i, SuperScript 660plus.
OL 410e, OL 610e/PS, OL 810e/PS, Okipage 6e, Okipage 6ex, Okipage 8c.
Okipage 4w.
Okipage 8w, okijet 2010.
JP350S.
KX-P1123, KX-P4440, KX-P5400, KX-P8420, KX-P8475.
KX-P6500.
KX-P6100, KX-P8410.
2425 Turbo EX.
4801, 6000.
DocuPrint C55, DocuPrint N17, DocuPrint N32.