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Comment by radicalbyte | Hacker News Reader

I'd stay away from their InkJet printers. Mine has a chip which forces you to replace coloured ink when it's empty.

I've not printed one color page, yet I recently had to install a new yellow ink cartridge in order to print in black/white.

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I think all new inkjet printers do this. I have an Epson Workforce and after my wife printed a small color job, I had to buy new color cartridges to print a black and white document.

From what I've read, even when you are printing just in black, the printer uses a small amount of color ink to stop the cartridge heads from clogging. Still, I would appreciate not having to run out and buy a blue cartridge just to print 3 pages of a text document.

My guess is its printing micro dots to identify your printer.

Actually this could be true. I had an assignment in our security class to investigate this[0] and it turned out three out of three printer tested used this! Made a little processing program to facilitate the detection[1]. Quite shocked to see how common it was..

[0]https://www.eff.org/fr/issues/printers

[1]https://github.com/BenjaminPoilve/DotPrinter

Something I didn't realize at first, but read about online is that when you buy a new printer that comes with cartridges, those cartridges almost empty. You will have to get replacements for them after just a few print jobs, the next cartridge you install will last a lot longer.

That's true. If they bundled a full cartridge with the printer, it would often be cheaper to just buy another printer than to buy ink/toner. My color laser printer was $200. A full set of toner replacements from HP would be $357 - third party it's about $120 for all four colors.

I've had an MFP refuse to scan because they needed a new color cartridge.

They lay down some yellow ink under the black to make it look better (I used to work for HP).

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.

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

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

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.

> 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?

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-...

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