Internal pressure-stabilizing apparatus, ink tank and ink-jet printer including the same

An ink tank for an ink-jet printer comprising:

• a main wall member which defines a main space which accommodates an ink and which has an ink discharge port to be communicated with nozzles which discharge the ink;
• and
• a subsidiary wall member which defines a subsidiary space communicated with the main space and which has an open hole which opens the subsidiary space to atmospheric air, wherein:
• a plurality of first areas and a plurality of second areas having liquid repellence higher than that of the first areas are formed alternately in an extending direction of the subsidiary space on an inner wall of the subsidiary wall member;
• and
• a difference in air pressure between both sides of a liquid, which is required for the liquid to enter a second area of the second areas when the liquid exists on a first area of the first areas disposed adjacently to the second area on a side far from the main space, is larger than a difference in air pressure between both sides of a liquid which is required for the liquid to enter the second area when the liquid exists on a first area disposed adjacently to the second area on a side near to the main space.

An ink-jet printer comprising:

• an ink-jet head which discharges an ink;
• and
• an ink tank which stores the ink to be supplied to the ink-jet head, the ink tank comprising:
• a main wall member which defines a main space which accommodates the ink and which has an ink discharge port to be communicated with nozzles which discharge the ink;
• and
• a subsidiary wall member which defines a subsidiary space communicated with the main space and which has an open hole which opens the subsidiary space to atmospheric air, wherein:
• a plurality of first areas and a plurality of second areas having liquid repellence higher than that of the first areas are formed alternately in an extending direction of the subsidiary space on an inner wall of the subsidiary wall member;
• and
• a difference in air pressure between both sides of a liquid, which is required for the liquid to enter a second area of the second areas when the liquid exists on a first area of the first areas disposed adjacently to the second area on a side far from the main space, is larger than a difference in air pressure between both sides of a liquid which is required for the liquid to enter the second area when the liquid exists on a first area disposed adjacently to the second area on a side near to the main space.