A reservoir in a printer includes a body that includes a first inlet and a first outlet. The body defines an internal volume positioned between the first inlet and the first outlet. A valve is positioned within the body. Ink flows from the first inlet, through the valve, and into the internal volume when the valve is in an open position, and the ink is prevented from flowing through the valve and into the internal volume when the valve is in a closed position. The ink is configured to flow from the internal volume, through the first outlet, and into a printhead. A heater is positioned within the body, and the heater is configured to heat the ink.