Patent ID: 7572106
Filing Date: 2009-08-11
Classification: B41F,B41P

Abstract:
1. An ink pumping apparatus for a printing press that receives and discharges ink supplied under pressure, the apparatus comprising: a cylinder defining a main hole having an intake port for sucking ink and a discharge port for discharging ink supplied from said intake port, said cylinder being closed at one end, said intake port and said discharge port being located along an inner surface of the cylinder such that said intake port and said discharge port differ in phase; a plunger, said main hole of said cylinder receiving said plunger such that said plunger is rotatable and movable in an axial direction, said plunger having a portion chipped off in a radial direction from one end thereof to define a cut portion extending in an axial direction, said plunger having an outer circumference portion located opposite said cut portion at said one end, said outer circumference portion of said plunger blocking said intake port and said discharge port in one phase of rotation, said cut portion of said plunger not blocking said intake port or said discharge port in said one phase of rotation, said outer circumference portion blocking one of said intake port and said discharge port in another phase of rotation; a stepping motor for reciprocating said plunger within the main hole of said cylinder in the axial direction while rotating said plunger; and a motor control means for determining a number of pulses to rotate said plunger to a phase of rotation in which said outer circumference portion blocks said discharge port and for controlling the rotation of said stepping motor based on said number of pulses such that the outer circumference portion of the plunger blocks said discharge port when said motor control means stops said stepping motor, whereby said cut portion does not block said discharge port when said stepping motor is stopped, said outer circumference portion of said plunger pressing against said inner surface of said cylinder at said discharge port when said motor control means stops said stepping motor such that said outer circumference portion seals said discharge port, whereby ink cannot leak out of said discharge port.