Image forming device, powder supply device, and powder storing unit including a gas supplying unit

In an image forming device including an image support object which supports an electrostatic latent image, and a developing device which turns the electrostatic latent image formed on the surface of the image support object, into a visible image with toner, a powder storing unit stores powder for image formation which is either a developing agent containing a toner and a carrier or a toner. A powder supplying unit supplies the powder stored in the powder storing unit, to the developing device. The powder storing unit includes a gas supplying unit which blows off a gas from an exhaust outlet of the gas supplying unit into the powder storing unit, and a powder passage which allows the powder storing unit to communicate with the developing device.