Printing-fluid cartridge including protrusion and interface

A printing fluid cartridge comprising:

• a storage chamber configured to store printing fluid;
• a supply portion including a supply hole through which the printing fluid is configured to flow out of the storage chamber in a frontward direction crossing a gravitational direction in an upright posture;
• a front surface at which the supply portion is provided;
• a rear surface away from the front surface in a rearward direction opposite to the frontward direction in the upright posture, the storage chamber being positioned between the front surface and the rear surface;
• an upper surface disposed upward relative to the storage chamber and facing upward opposite to the gravitational direction in the upright posture;
• a locking surface disposed at the upper surface and facing rearward;
• one protrusion positioned at the upper surface, wherein the one protrusion has one specific portion;
• an electrical interface disposed at the upper surface, the locking surface, the electrical interface, and the one protrusion being arranged in a recited order in the frontward direction in the upright posture, the one protrusion, the electrical interface, and the locking surface being arranged upward in a recited order in the upright posture;
• and
• another protrusion positioned at the upper surface and disposed rearward relative to the electrical interface, the another protrusion having another specific portion, the one protrusion and the another protrusion defining a plurality of imaginary planes each of which passes through the one protrusion and the another protrusion, each of the plurality of imaginary planes extending in a widthwise direction perpendicular to the gravitational direction and the frontward direction in the upright posture, the plurality of imaginary planes including a specific imaginary plane defined by the one specific portion and the another specific portion, the specific imaginary plane being positioned higher than any other imaginary plane between the one protrusion and the another protrusion, the electrical interface being positioned downward relative to the specific imaginary plane in the gravitational direction in the upright posture.

A printing fluid cartridge comprising:

• a storage chamber configured to store printing fluid;
• a supply portion including a supply hole through which the printing fluid is configured to flow out of the storage chamber in a frontward direction crossing a gravitational direction in an upright posture;
• a front surface at which the supply portion is provided;
• a rear surface away from the front surface in a rearward direction opposite to the frontward direction in the upright posture, the storage chamber being positioned between the front surface and the rear surface;
• an upper surface disposed upward relative to the storage chamber and facing upward opposite to the gravitational direction in the upright posture;
• a locking surface disposed at the upper surface and facing rearward;
• one protrusion positioned at the upper surface;
• and
• an electrical interface disposed at the upper surface, the locking surface, the electrical interface, and the one protrusion being arranged in a recited order in the frontward direction in the upright posture, the one protrusion, the electrical interface, and the locking surface being arranged upward in a recited order in the upright posture,
• wherein the one protrusion is closer to the front surface in the frontward direction than a center of gravity is to the front surface;
• and
• wherein the locking surface is closer to the rear surface in the rearward direction than the center of gravity is to the rear surface.