Powder pump and image forming apparatus having the powder pump and method therefor

摘要

A powder pump includes a case, a diaphragm, a working chamber which is partitioned with the case and the diaphragm, a powder inlet formed on the case for flowing the powder into the working chamber, a powder outlet formed on the case for flowing the powder in the working chamber out of the powder outlet, an inlet valve which opens the powder inlet when pressure in the working chamber is decreased by an operation of the diaphragm so that the powder flows into the working chamber from the powder inlet and shuts the powder inlet when the pressure in the working chamber is raised by the operation of the diaphragm, and an outlet valve which opens an outlet when the pressure in the working chamber is raised by the operation of the diaphragm, so as to let the powder flow through the powder outlet outside of the working chamber and shuts the powder outlet when the pressure in the working chamber is lowered by the operation of the diaphragm. The powder pump further includes a first space which is formed so as to communicate with the working chamber located at a place around a case wall part which partitions the powder inlet, and a second space which is formed so as to communicate with a powder flowing path located at the downstream side of a powder conveying direction from the outlet valve. The powder pump is utilized for conveying the toner in an image forming apparatus.