On Wednesday, March 11, 2015 at 1:04:41 AM UTC, Don Kelly wrote:
On 08/03/2015 1:22 AM, Charlie+ wrote:
On Fri, 6 Mar 2015 23:03:13 -0800, DaveC wrote as
underneath :

One source I found says that Canon uses light from an LED--bounced from a
prism at the bottom of the cartridge after ink is depleted--to trigger the
"Empty" signal. Epson apparently counts the spurts of ink and calculates the
arrival of "empty".

I couldn't find how HP do this. Anybody know?

Any inkjet that uses chipped cartridges guestimates the emptiness. Old
Canon printers certainly used the reflective prism, IP4000 was about the
last that had unchipped carts. and thus had an accurate end level
warning. I think most printers now would guestimate on the safe side
judging by the complaints of half full carts being classed as empty. I
dont know if Canon still uses the prisms on their modern chipped carts
but I would think probably not as the guestimate method gets you to buy
more ink earlier! Someone with one of the more modern Canons will know
Im sure! ... HP have had chips since very early days so levels will be
guestimated by software. C+
My old(?) Canon MP 620 uses chipped cartridges as far as I know and when
I get an empty signal -the cartridge is fully emptied.



--
Don Kelly

remove the 'cross' to reply directly



On my old Canon ip4300 printer the ink level can be seen through the
clear plastic of the cartridge,unlike my Epson BX525WD multifunction
printer.


Doug.