Refilling technique for inkjet print cartridge having two ink inlet ports for initial filling and recharging

A method for using a refillable print cartridge comprising the steps of:

• providing said print cartridge having a print cartridge body containing a first ink reservoir having been initially filled with a quantity of ink supplied through an ink fill port in said print cartridge body, said ink fill port being sealed with a first seal;
• removably mounting said print cartridge on a carriage in a printer;
• providing an external second ink reservoir containing ink, separate from said print cartridge;
• operating said printer incorporating said print cartridge so as to print ink on a medium from said quantity of ink in said first ink reservoir;
• recharging said first reservoir, when said quantity of ink in said first ink reservoir is at least partially depleted, by:
• a) coupling said external ink reservoir to a recharge port on said body, said recharge port being separate from said ink fill port and being sealed with a second seal having an opened state and a closed state, said closed state providing a fluid seal of said first ink reservoir, said opened state providing fluid communication between said external ink reservoir and said first ink reservoir when said external ink reservoir is connected to said recharge port, said second seal allowing no ambient air to enter said first ink reservoir when in fluid communication with said external ink reservoir;
• b) creating a negative pressure, relative to atmospheric pressure, in said first ink reservoir after said quantity of ink in said first ink reservoir has been at least partially depleted;
• and
• c) supplying said ink from said external ink reservoir to said first ink reservoir via a transfer tube connected between said external ink reservoir and said first ink reservoir.