[gbl08ma]

Most printers do - at least that's what I found out after I realized both of my Epson printers wouldn't print in black without color cartridges. Color cartridges are still used when printing in black and white, because the black ink alone will look terrible. Granted, it would be better if printers offered an option to print with just the black ink and get the terrible result, for emergencies. However, I'm sure lots of people would just click the warnings/confirmations away and then complain about the bad quality of the results.

I should mention that if you do mostly black and white printing it may be more economical to get a laser printer, even just a grayscale one.

[kalleboo]

I thought it was due to the yellow tracking dots, but it turns out those are only on laser printers https://www.eff.org/issues/printers

[stephenr]

My canon inkjet has an option to use just the black (and i think just colour) cartridge.

[digi_owl]

I think you have to specifically pick a mode in the settings for each print job for the thing to use only black ink.

Just slapping a black and white document into the queue do not trigger this automatically.

[CaptSpify]

> Color cartridges are still used when printing in black and white, because the black ink alone will look terrible.

Source? Also, how do B&W printers solve this problem then?

[gbl08ma]

I know that when the color heads on my printers are obstructed, black text will often come washed out (as if you printed in economy mode, or worse). I have looked at black text, printed with my newer Epson, with a magnifying glass, and I can see a few color dots near the edges of the text (these are not photocopies, it's text documents printed in B&W mode). I suppose it works a bit like anti-aliasing in some font rendering systems.

I'm not sure how B&W inkjet printers solve it, but it's probably by spending more ink to avoid the wash-out. As other people pointed out, some color printers allow for printing with just the black cartridge in. I don't have one of these to compare, so it's possible the text doesn't look as crisp on these because of the lack of "anti-aliasing".

I suppose part of the reason for this limitation to apply to some printers but not others has to do with the business model (ink is expensive and for some brands/model lines it's the main source of revenue), and perhaps the technology used - some printers have disposable headers on the cartridges themselves, and others (like the printers I own) have non-disposable headers, which basically means the printer is ruined if ink dries up in the headers. This may be why some printers require the cartridges, even if empty, to be in, so the headers are not as exposed to the air.

Unfortunately manufacturers don't like to give extensive explanations (see my business model point above...), but on user forum threads like [0] and [1] there are some suggestions for why things are the way they are.

[0] http://www.tomshardware.co.uk/forum/224699-28-print-black-co... [1] http://superuser.com/questions/409473/how-to-print-in-black-...