Cap, powder container, developer supply device, and image forming apparatus

A powder container for use with an image forming apparatus, comprising:

• a container body to contain powder;
• a discharge port, through which powder from the container body is to be discharged out of the container body, the discharge port disposed at a longitudinal end of the container body;
• a retainer that holds an information recording device that is rotatable relative to the container body, the information recording device including information to be communicated in at least one of a contact manner and a contactless manner;
• and
• a positioning member, rotatable relative to the container body, to engage with an image forming apparatus to position the powder container relative to the image forming apparatus, the positioning member disposed at a longitudinal end of the container body which is opposite to the discharge port.