Liquid injection method, liquid injection device, and liquid cartridge in which a liquid is injected from a liquid injector to a liquid cartridge

A liquid cartridge into which a liquid is injected from a liquid injector, the liquid cartridge comprising:

• a liquid ejection head that ejects the liquid;
• a channel that is connected to the liquid ejection head and is capable of supplying the liquid to the liquid ejection head;
• and
• an opening portion that is connected to the channel and is provided to be wider than the channel,
• wherein the liquid injector includes a liquid injection unit including a tip and having an outer shape inclined and gradually tapered toward the tip,
• wherein the channel is provided to allow the liquid to be directly injected into the channel and is larger in width than the tip,
• wherein the channel is provided to allow the tip of the liquid injection unit to be inserted into the channel, and
• wherein the liquid is injected with the tip inserted into the channel of the liquid cartridge while keeping a state where the tip is out of contact with the liquid ejection head by contacting an inclined surface of the liquid injection unit with a part of the channel.