Refilled cartridge and method for manufacturing refilled cartridge

A method for manufacturing a refilled cartridge for performing refilling of printing material after use of a cartridge including

• a first case comprising a recess having a bottom surface and an opening, an open surface opposite to the bottom surface of the recess being open,
• a flexible portion attached to the opening of the recess,
• a second case that covers the open surface of the first case from the side opposite to the bottom surface of the recess,
• a pressure receiving portion opposite to the second case, the pressure receiving portion contacting the flexible portion,
• a chamber of variable capacity in which printing material is filled, the chamber constituted by the recess, the flexible portion, and the pressure receiving portion,
• a biasing member that generates negative pressure inside the chamber by applying force that expands the capacity of the chamber on the pressure receiving portion, and
• a detection portion including a prism and covering the opening to detect the printing material optically, wherein
• as the printing material inside the chamber is consumed, the capacity of the chamber becomes smaller and the pressure receiving portion moves toward the bottom surface of the recess,
• the method for manufacturing a refilled cartridge comprising:
• refilling the printing material such that two or more points across the biasing member on the pressure receiving portion do not contact the second case after refilling of the printing material is completed, and such that a prescribed volume of air exists inside the chamber after refilling of the printing material is completed, the prescribed volume of air being a volume for which the prism is in contact with the air when the cartridge is oriented such that the prism is on an upper side in a gravity direction.