To prevent powder from naturally dropping with bridging effects without causing deterioration in powder characteristics such as aggregation and to control a filled amount to be constant by providing a discharging port sea having a plurality of annular ribs concentric with a radial rib on a lower part of a nozzle of a hopper for reserving powder equipped with a mechanism for feeding out the powder.
A discharging port seat 14 provided at a lower end of a nozzle 12 of a hopper 11 comprises annular ribs 16, 17 concentric with an outer rim annular rib 15 and a radial rib 18 integrally formed with the outer rim annular rib 15. The annular ribs 16, 17 are provided with such density that dropping of powder is stopped by bridging effects when a screw 2 stops. A cross sectional shape of the annular ribs 16, 17 and the radial rib 18 except the outer rim annular rib 15 is such that an upper part from at least its middle is reduced in a rib width as coming upper. Therefore, occurrence of aggregation of the powder based on passing resistance caused when a rib with a rectangular cross section is used can be prevented. As a result, a filling amount can be highly accurately controlled to be constant.
TAWARA EIJI
TAKAHASHI TORU
