Ink tank unit, an ink jet cartridge having said ink tank unit and an ink jet apparatus having said ink jet cartridge

An ink jet cartridge comprising:

• an ink jet head unit;
• and
• an ink accommodating container connected to said ink jet head unit, said ink accommodating container comprising:
• a partition for dividing said ink accommodating container into a first chamber and a second chamber, said first chamber having a supply portion for supplying the ink to said head and an atmosphere communicating section communicated with an atmospheric air, and said second chamber being communicated with said first chamber through a communication port and being substantially sealed except said communication port, said second chamber accommodating the ink to be supplied to said first chamber;
• a negative pressure generating member accommodated in said first chamber;
• and
• a rib contacting said negative pressure generating member to define a space, the space being provided on an upper surface of said first chamber in a state where said ink accommodating container is used,
• wherein, said atmosphere communicating section is disposed in said space without contacting said negative pressure generating member.

An ink jet apparatus comprising:

• an ink jet cartridge comprising an ink jet head unit and an ink accommodating container connected thereto;
• a carriage for detachably mounting said ink jet cartridge;
• and
• conveying means for conveying a recording medium which accepts ink discharged from said ink jet head unit;
• wherein said ink accommodating container comprises:
• a partition for dividing said ink accommodating container into a first chamber and a second chamber, said first chamber having a supply portion for supplying the ink to said head and an atmosphere communicating section communicated with an atmospheric air, and said second chamber being communicated with said first chamber through a communication port and being substantially sealed except said communication port, said second chamber accommodating the ink to be supplied to said first chamber;
• a negative pressure generating member accommodated in said first chamber;
• and
• a rib contacting said negative pressure generating member to define a space, the space being provided on an upper surface of said first chamber in a state where said ink accommodating container is used,
• wherein, said atmosphere communicating section is disposed in said space without contacting said negative pressure generating member.