Ink tank, head cartridge and ink jet printing apparatus

摘要

A printing system having an ink tank for storing ink, the ink tank having a housing having an ink feeding port formed through a first surface for feeding ink therethrough, and a second surface opposite the first. An ink absorbing member is accommodated in the housing, is a porous member having a three-dimensional net-shaped structure molded of a composition comprising a condensate of (i) a compound having an amino group and (ii) formaldehyde, and has a first surface facing the ink feeding port. An alleviating member having more resilience than the ink absorbing member is disposed between the ink absorbing member and an ink outflow portion formed through the ink feeding port and alleviates pressure applied by the ink outflow portion against the ink absorbing member. Both the alleviating member and the ink absorbing member are deformed by compression against the ink outflow portion. A compensating member having more resilience than the ink absorbing member is disposed between the ink absorbing member and the ink outflow portion and applies a functional force to the ink absorbing member corresponding to deterioration of properties of the ink absorbing member. Another ink absorbing member having more resilience than the ink absorbing member is disposed between the ink absorbing member and the ink outflow portion.