Pressure differential regulating valve unit, a liquid cartridge and a method for assembling a liquid cartridge

A valve unit accommodated within a liquid cartridge body which includes a liquid containing section for containing therein liquid and a liquid supplying section for supplying the liquid to the outside of the cartridge body, the valve unit comprising:

• a valve member which is elastically deformable to open in accordance with a pressure difference generated between the liquid containing section and the liquid supplying section, said valve member comprising a cylindrical peripheral edge;
• a valve lid comprising a substantially cylindrical valve member holding part inserting inside said peripheral edge of said valve member for fixing said peripheral edge;
• and
• an urging member provided between said valve member and said valve lid for urging said valve member in a direction away from said valve lid.

A method for manufacturing a liquid cartridge, which comprises a liquid containing section for containing a liquid, a cartridge body comprising a liquid supplying part for supplying said liquid in said liquid containing section outside and a valve unit comprising a valve member contained in said cartridge body to be opened when a pressure difference between said liquid containing section and said liquid supplying part occurs, comprising the steps of:

• preparing said cartridge body comprising said liquid containing section and a valve unit containing section, which is a concave part formed at said cartridge body, communicating with said liquid containing section;
• forming a valve unit by putting an urging member, which urges said valve member toward a direction being distanced from said valve lid, between said valve member comprising a peripheral edge part, of which a peripheral edge is cylindrical in shape, elastically deformable based on said pressure difference and a valve lid comprising a valve member holding part of a substantially cylindrical shape for fixing said peripheral edge part by being inserted into said peripheral edge part of said valve member;
• and
• attaching said valve unit to said valve unit containing section.