Canon iP4000 black ink cartridges?

[websnail]

I'm not sure of the answer, but maybe this will help: Remember, Canon uses the "ISO/JIS-SCID N5 pattern" image for testing ink coverage.

See it here: http://www.nifty-stuff.com/inkjet-printer-tco.php

Thanks for the thought but sadly it doesn't help much...

The problem I've got is that I too have a cost comparison sheet but it relies completely on knowing an accurate volume of ink that was available/used in the cartridge and of course the number of pages it printed.

Thankfully the output is using a standard 5% coverage but where things get confused is the actual volume of black ink that's provided in the BCI-3eBk carts.

I'm still having problems understanding how double the ink can result in two-thirds of the print output..

I think I'm going to have to phone Canon and get the info direct from the horses mouth...

 

[pebe]

I think the reason that the 6BK cart is so economical compared with the 3BK is that it's only used for color prints - and rarely at that. Have a look at a print through a powerful magnifier and you will be have great dificulty in finding any black dots. However, it is used exclusively when printing in grayscale.

 

[websnail]

*sigh*...

it just got even more confusing...

I found this:
http://www.superwarehouse.com/Canon_BCI-3eBk_Black_Ink_Tank/4479A003/p/118745
http://www.superwarehouse.com/Canon_BCI-6Bk_Black_Ink_Tank/4705A003/p/120052

Now, the figures on there show that the 3eBk will print: 420 @ 5%
.. while the 6Bk will print: 280 @ 5%


Ok... I couldn't leave this one alone so I phoned Canon and hopefully someone is going to explain exactly what's going on here Apparently I'll have a senior print tech' phoning me back later today... I'll keep you posted.

 

[websnail]

I think the reason that the 6BK cart is so economical compared with the 3BK is that it's only used for color prints - and rarely at that. Have a look at a print through a powerful magnifier and you will be have great dificulty in finding any black dots. However, it is used exclusively when printing in grayscale.

The only problem with that idea is that 5% coverage is still 5% coverage... whether it's 5% of one ink or 5% of another you would "think" that the ink used was at least partially comparable...

The only thing I can think of is that there's a difference in the amount of evaporation or volume lost between the two inks.. even so, the figures I've got at the moment seem to indicate that you'd need 27.5ml of 3Bk ink to get the same output as 13ml of 6Bk ink.. On a common sense level, that does seem just a little excessive