Patent ID: 8758705

Claim:
A dispenser comprising: a dispensing head including a cylinder body section having walls defining a cylindrical inner space, a dispensing cylinder section extending downward from the cylinder body section, and having a diameter smaller than that of the inner space of the cylinder body section, and a dripping port at an end of the dispensing cylinder section; a piston connected to be moved longitudinally through the inner space of the cylinder body section and into the dispensing cylinder section and moving up and down within the dispensing cylinder section, the piston having a diameter sufficiently smaller than a diameter of the inner space of the cylinder body section so as not to come into contact with the walls forming the inner space; an elevating mechanism connected to the piston to lift and lower the piston between an unsealing position extending out of the dispensing cylinder section and inside the cylinder body section, a dispensing start position located in an upper portion of the dispensing cylinder section and a dispensing end position located in a lower portion of the dispensing cylinder section, wherein a lifting stroke of the piston results in suction of a predetermined quantity of liquid into the dispensing cylinder section through the dripping port, and a lowering stroke of the piston results in dispensing of the liquid sucked into the dispensing cylinder section through the dripping port; and a sucking mechanism having a suction port connected to extend into and communicate with the cylinder body section to suck air into the cylinder body section and to thereby suck a liquid from the dispensing cylinder section up to a position above the dispensing start position inside the inner space of the cylinder body section when the piston is in said unsealing position extending out of dispensing cylinder section, and wherein the piston is lowered to the dispensing start position under a liquid surface of the liquid within the cylinder body section whenever the dispensing operation is started.