Ink ejection printing devices

Claim 2

In a device for applying a fluid in drop form to a surface, which device includes a fluid ejector head provided with at least one chamber having an outlet channel, connector means and an inlet channel arranged to be connected to a line for receiving fluid from a reservoir and for supplying such fluid to the inlet channel, and means for applying pressure pulses to the fluid in the chamber, the improvement comprising a valve disposed in said ejector head in the fluid flow path between said connector means and said inlet channel, said valve constituting means for reducing pressure surges in the fluid in the forward direction of fluid flow and those in the direction opposite the flow, and for closiNg the flow path between said connector means and said inlet channel when there is a drop in pressure in such line.

Claim 3

An arrangement as defined in claim 1 wherein said valve comprises: an antechamber formed in said ejector head and disposed in the fluid flow path between said connector means and said inlet channel; a diaphragm located in said antechamber to divide said antechamber into first and second pressure chambers, said diaphragm having a bore communicating with at least said first pressure chamber; and means defining an abutment surface in each said pressure chamber, each said abutment surface being in line with said bore, said abutment surfaces being opposite one another, and at least said abutment surface in said first chamber including a surrounding abutment portion facing the part of said diaphragm which surrounds said bore, said diaphragm being deflectable at least toward said abutment portion surrounding said abutment surface in said first chamber; said arrangement further comprising a capillary channel forming the fluid outlet from said second pressure chamber.

Claim 4

An arrangement as defined in claim 2 wherein said ejector head is further provided with a passage defining the inlet to said valve and communicating with said first pressure chamber, said passage having the form of a labyrinth and including means defining a further abutment surface located to be struck by fluid flowing into said valve.

Claim 5

An arrangement as defined in claim 3 wherein said abutment surfaces and said further abutment surface each have a concave curvature.

Claim 6

An arrangement as defined in claim 2 wherein said valve further comprises a sealing ring located in said first pressure chamber to surround said bore in said diaphragm, and wherein said first pressure chamber is provided with a sealing surface located to come into sealing engagement with said ring when said diaphragm is deflected toward said abutment surface in said first chamber, thereby closing said valve.

Claim 7

An arrangement as defined in claim 1 wherein said device is switchable into an inactive state, said valve comprises: an antechamber formed in said ejector head and disposed in the fluid flow path between said connector means and said inlet channel, said antechamber being located adjacent, and bounded by, an outer wall of said head; a diaphragm disposed in said antechamber and provided with a bore forming part of said fluid flow path; a ferromagnetic plate carried by said diaphragm and surrounding said bore; and a sealing member carried by said diaphragm and surrounding said bore; said sealing member facing the bounding surface of said antechamber defined by said outer wall of said head, and said diaphragm being deflectable in a direction to bring said sealing member into sealing engagement with said bounding surface so as to place said valve in its closed state; and said arrangement further comprises a magnet located outside said head and movable into a position adjacent said outer wall at which the magnetic field of said magnet exerts an attractive force on said ferromagnetic plate sufficient to deflect said diaphragm toward said outer wall to bring said sealing member into sealing engagement with said bounding surface.

Claim 8

An arrangement as defined in claim 1 wherein said device is switchable into an inactive state, said valve comprises an antechamber presenting a sealing surface, and a valve body displaceably arranged in said antechamber to come into sealing engagement with said sealing surface so as to place said valve in its closed state, and said arrangement further comprises control means operatively associated with said valve body and movable into a position for bringing said valve body into sealing engagement with said sealing means, and spring means connected to move said control means into such position when said device is switched into its inactive state.