Patent ID: 7690906

Claim:
A rotary powder compression molding machine, comprising: a turret which is rotatably mounted in a frame via a vertical shaft; dies, each having a die bore, which are mounted on the turret; an upper punch and a lower punch which are vertically slidably held above and below each of the dies, tips of the upper and lower punches being insertable in the die bore, the upper and lower punches being pressable and movable toward each other to compression-mold powder filled in the die bore between a lower end face of the upper punch and an upper end face of the lower punch, and powder lubricant jet means for jetting powder lubricant against the end faces of respective of the upper and lower punches and against the die bore prior to filling of the powder into the die bore, the powder lubricant jet means including a first jet nozzle configured to jet the powder lubricant placed at a powder lubricant jet position substantially toward the end face of the upper punch; a second jet nozzle configured to jet the powder lubricant placed at a powder lubricant jet position substantially toward the end face of the lower punch; and a charger device including first and second electrodes for producing first and second electric fields, respectively, through which the powder lubricant to be jetted from the first jet nozzle and the powder lubricant to be jetted from the second jet nozzle pass respectively, the charger device being capable of rendering the powder lubricant to be jetted against each of the lower punch and the die different from the powder lubricant to be jetted against the upper punch in electrostatically charged condition, wherein the charger device comprises first voltage application means for applying a first voltage to the first electrode, and second voltage application means for applying a second voltage to the second electrode, the second voltage being higher than the first voltage.