XPost: sci.electronics.design, sci.electronics.equipment, sci.el   
   ctronics.repair   
   From: charlie@xxx.net   
      
   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+   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)