Patent ID: 7364281

Claim:
A tiny air-pressure balance device between an ink cartridge and an ink bottle, comprising: an ink bottle having an outlet and a bottle mouth for refilling ink therein; a balance device mounted on a top of said ink bottle; said balance device including: a body portion closely mounted and sealed with said ink bottle; inside of said body portion furnished with a first cylinder body for receiving a spring and a second cylinder body for receiving a valve base; the spring having a tiny resilient force, and being mounted on the first cylinder body in said body portion; one end of said spring pushed against a ring-shaped recess in said first cylinder body, while other end thereof pushed against a round surface of a valve; the valve having the round surface at one end thereof to be in contact with a seal ring on a bottom of the valve base, while other end thereof having a flat surface with a valve rod having a suitable length; a short conic surface and a ring-shaped flat surface furnished between said valve rod and said valve flat surface; the valve base mounted in a cylindrical hole of said second cylinder body on said body portion, and center thereof having a through hole with a seal ring, and said seal ring being in close contact with a spherical surface of said valve; an outer lid having a round surface, and having a through hole in center thereof; said outer lid to be mounted over outer end of said body portion.