Here's a simple solution to refilling the carts once the chip problem is solved.
get yourself a decent scale that will let you weigh in grams. (I have a PROSCALE LC-300 that I use to weigh scrap silver) before you put your new cartridge in the printer weigh it. Then when it runs out of ink weigh it again The difference between the numbers will tell you how many grams of ink you used. Using a small dixie cup set the TARE value to zero and then using a syringe fill the cup with the reqired amount of ink. refill the syringe with the ink from the cup and inject it into the cartridge
Geklingel Great idea I have usual domestic digital scale. This seems accurate enough, any parcels I send match exactly the ones at the Post Office. 1 further suggestion when you put your first batch of ink in your chosen container you do so 2ml at a time and using a cocktail or similar stick make yourself a dipstick of each colour at each 2ml increment.
Then when you come to refill you can either weigh as per your original post or with your dipstick check if any ink remains and only top up the difference.
To start with it may pay to only fill to 75/80% as suggested by The Hat . If no leaks occur you can then increase next time around. The only drawback I can see is that you are taking ink out of container putting it into another small container, then sucking it up with your syringe its exposed to the air for a while and a possible disaster with spilling it or knocking it over, which with my bifocals plus strong prisms could well happen.
Nevertheless it is an accurate way to determine the amount of ink required
barfl2 My OCP ink comes in 16 oz (500ml) bottles which I transfer into 2 oz squeeze bottles. In addition I placed a plastic check valve between the needle and bottle so I have no drips until I squeeze the bottle firmly. A second advantage occurs when I complete the refill and release my 'squeeze' on the bottle--no ink is sucked back into the bottle.
A major advantage of a squeeze bottle over the syringe is not just the ease of refilling but knocking over the open ink bottle because of the stiction of a syringe. To get the syringe to start moving one has to apply sufficient force to overcome the static friction--and then POW!! the syringe jerks forward or back. Better to knock over a 2 oz bottle than a 17 oz--YwifesMMV!!
I would appreciate you telling us where you got the check valves and what size are they?
Are you getting your bottles and needles from Howard Electronics?