Cartridge, printing apparatus, and method including a channel forming unit having a channel to supply liquid from a storage unit to a print element board

A printing apparatus that is equipped with a cartridge, the cartridge comprising:

• a box unit configured to store a liquid;
• a print element board capable of ejecting the liquid from ejection ports arrayed;
• a channel forming unit in which a channel configured to supply the liquid from the box unit to the print element board is formed, wherein the channel forming unit has a first surface configured to support the print element board and a second surface that is closer to the box unit than is the first surface;
• and
• a joint unit that is formed of a first resin filled in a space formed between the box unit and the channel forming unit and which joins the box unit and the channel forming unit together, wherein the first resin is injected from a gate section provided in the channel forming unit,
• wherein, in the space formed between the box unit and the channel forming unit, a buffer section configured to store the first resin excessively filled in a finally-filled portion of the first resin is arranged, the buffer section being formed at one end of the channel forming unit, and the gate section being formed at another end of the channel forming unit, and
• wherein, in the channel forming unit, a first cavity is formed between the first surface and the buffer section.

A method of producing a cartridge including a box unit configured to store a liquid, a print element board capable of ejecting the liquid from ejection ports that are arranged in an array, and a channel forming unit in which a channel configured to supply the liquid from the box unit to the print element board is formed, the method comprising:

• a first forming step of filling a resin into a first mold and a second mold that are clamped at first relative positions to form the box unit inside the first mold and to form the channel forming unit inside the second mold;
• a second forming step of filling a resin into the first mold and the second mold that are clamped at second relative positions that are different from the first relative positions to join the box unit and the channel forming unit together, wherein the channel forming unit has a first surface configured to support the print element board and a second surface that is closer to the box unit than is the first surface;
• and
• providing a joint unit that is formed of a first resin filled in a space formed between the box unit and the channel forming unit and that joins the box unit and the channel forming unit together, wherein the first resin is injected from a gate section provided in the channel forming unit,
• wherein, in the space formed between the box unit and the channel forming unit, a buffer section configured to store the first resin excessively filled in a finally-filled portion of the first resin is arranged, the buffer section being formed at one end of the channel forming unit, and the gate section being formed at another end of the channel forming unit, and
• wherein, in the channel forming unit, a first cavity is formed between the first surface and the buffer section.