Digital BW, The Print

Arthur Entlich did a long essay on the Epson Printers forum yesterday 
discussing the Epson cartridge chips and their low ink warnings.  
Essentially, all the printer can tell you is an estimate of the ink 
remaining based on its assumptions about how much ink was used.  It is a 
rough estimate at best.  For example, Art suggests that the printers can 
print dots of various sizes as called for by the driver, but the ink 
counter probably only uses an average dot size when figuring ink usage. 

Cleaning cycles are assumed to use all the ink that would flow through 
an unrestricted nozzle, but if you're cleaning to clear a blocked 
nozzle(s) and no ink is getting through, the printer still assumes 
you're flushing a "normal" amount from the cartridge each time.  It is 
possible, if you have a really clogged head, to put in a new cartridge 
and run cleaning cycles to the point where the printer calculates that 
your cartridge is empty, even though in fact NO ink has been removed 
from it because of the clog.  Still, the chip on the cartridge will be 
written as "empty" and the cartridge will no longer function in any 
printer unless you can reset it somehow.

This is not necessarily a criticism of Epson, given that the cost of an 
actual ink measurement system would probably be prohibitively expensive 
to install in the level of printers that Epson wants to sell by the 
million.  I believe Epson was hammered in their class action because 
their assumptions built into the ink usage calculations were designed so 
that even with perfectly "normal" usage the customer still was told to 
throw away the cartridge when there were /substantial/ amounts of ink left.

I do think the Canon system (in their BCI-6 cartridges - don't know if 
the newer printers still use it) was the far better way to go - the 
printer calculates usage, and displays estimated ink levels in each 
cartridge as you go, but the low ink warning is only triggered by an 
optical sensor which can tell when the ink reservoir is empty, meaning 
the only ink left is that in the sponge section.

Cheers,
Kip

Bob Frost wrote:
> Not sure what printer you are using, but my Epson R2400 gives me much more 
> useful info than you suggest.
>
> <snip>
>   


[Non-text portions of this message have been removed]