Inkjet printer with low nozzle to chamber cross-section ratio

1. A nozzle arrangement for an inkjet printhead, said nozzle arrangement comprising:

a substrate defining an ink chamber with an ink ejection port and ink holes for receiving ink from an ink reservoir;

a magnetic actuation device arranged in the chamber and actuatable via an external pulsed magnetic field to eject ink via the ink ejection port; and

a blocking mechanism arranged in the chamber and configured to operatively block movement of the actuation device to prevent ejection of ink from the chamber.

2. The nozzle arrangement of claim 1 , wherein the magnetic actuation device includes a magnetic soft core surrounded by a nitride coating so that the device includes an end protuberance.

3. The nozzle arrangement of claim 2 , wherein the blocking mechanism includes a thermal actuator having a copper resistive circuit with two arms through which a current is operatively passed thereby causing said arms to be heated.

4. The nozzle arrangement of claim 3 , wherein one arm is of a serpentine nature and is encased in polytetrafluoroethylene (PTFE) which has a high coefficient of thermal expansion, thereby increasing the degree of expansion upon heating, said serpentine arm configured to expand with the PTFE portions by means of a concertain-like movement.

5. The nozzle arrangement of claim 4 , wherein the blocking mechanism is located in a cavity in a side wall of the chamber so that the serpentine arm of the blocking mechanism receives ink flow for cooling purposes.

6. The nozzle arrangement of claim 1 , wherein the chamber includes a nozzle plate manufactured from a boron doped epitaxial layer on a silicon wafer which has been back etched to the point of the epitaxial layer, said epitaxial layer etched utilizing a mask so as to form the nozzle rim and the ejection port.

7. The nozzle arrangement of claim 1 , which is manufactured according to micro-electromechanical manufacturing system (MEMS) techniques.