	US 7,572,106 B2
	Ink pumping apparatus for printing press and ink leak preventing method
Nobuaki Nagao, Kawasaki (Japan); and Akira Ueda, Tokyo (Japan)
Assigned to Tokyo Kikai Seisakusho, Ltd., Tokyo (Japan)
Filed on Dec. 14, 2004, as Appl. No. 11/11,939.
Claims priority of application No. 2004-065209 (JP), filed on Mar. 09, 2004.
Prior Publication US 2005/0200665 A1, Sep. 15, 2005
Int. Cl. F04B 49/06 (2006.01); F04B 49/22 (2006.01); F04B 7/06 (2006.01)

U.S. Cl. 417—53 [417/289; 417/500; 101/366]

9 Claims

8. A method of preventing ink from leaking through a discharge hole in an ink pumping apparatus for a printing press, the method comprising:

providing a cylinder defining a main hole having an intake port for supplying ink and a discharge port for discharging ink, 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 discharge port has a different phase than a phase of said intake port;

providing 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 surface portion, said cut surface portion extending in the axial direction, wherein an outer circumference of said plunger blocks said intake port and said discharge port in one phase of rotation without said cut surface portion blocking said intake port and said discharge port, said outer circumference of said plunger blocking one of said intake port and said discharge port in another phase of rotation;

providing a stepping motor for reciprocating said plunger within the main hole of said cylinder in the axial direction while rotating said plunger;

providing a motor control means for determining a number of pulses to rotate said plunger to a blocked discharge port position and for controlling the rotation of said stepping motor;

providing a pump operating means for providing a stopping instruction as output;

receiving said stopping instruction with said motor control means;

determining a phase of rotation of said plunger via said motor control means when said stopping instruction is received by said motor control means;

controlling the rotation of said stepping motor based on said number of pulses with said motor control means such that said plunger rotates to said blocked discharge port position and said stepping motor is stopped via said motor control means when said plunger is in said blocked discharge port position, said outer circumference of said plunger engaging said inner surface of said cylinder in an area of said discharge port in said blocked discharge port position such that said outer circumference prevents ink from entering said discharge port.