Ink-jet apparatus and method of the same

#This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2006-123927, filed Apr. 27, 2006, the entire contents of which are incorporated herein by reference.

#1. Field of the Invention

#The present invention relates to an ink jet apparatus that circulates ink through an ink jet head and ejects ink from nozzles of the ink jet head, and a control method thereof.

#The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention.

#FIG. 1 is a section view showing the internal structure of an ink jet head of first to seventh embodiments.

#FIG. 2 is a view showing the configuration of the first embodiment.

#In the following, a first embodiment of the present invention will be described with reference to the drawings.

#FIG. 1 shows a cross section of an ink jet head 11 of an ink circulating type. That is, a pressure chamber 3 is formed on a top surface side of an orifice plate 2 having a nozzle 1 for ejecting ink. Formed as a middle part of a channel 5 in the head which ink 4 runs through is narrowed, the pressure chamber 3 not only has the above-mentioned nozzle 1, but also has an actuator 6 on the surface side opposed to the nozzle 1. The ink 4 runs from right to left as shown in the figure, through the pressure chamber 3, in the channel 5 within the head.

#As the actuator 6 is driven, the ink 4 within the pressure chamber 3 forms an ink droplet 4a and is ejected from the nozzle 1. As the actuator 6, those directly or indirectly transforming the pressure chamber 3 by use of a piezoelectric device such as a PZT are known. Furthermore, as the ink jet head, any of those driving a diaphragm by static electricity, those heating ink by a heater and producing air bubbles to generate pressure, those directly moving ink 4 by static electricity, and like may be used. The position where the actuator 6 is to be provided is not limited to the surface side opposed to the nozzle 1, but may be a surface located in the depth direction of the figure, for example. In addition, the ink 4 in the pressure chamber 3 is not necessarily to be ejected from the nozzle 1 directly, and the pressure chamber 3 may be communicated with the nozzle 1 so that the ink 4 is ejected from the nozzle 1 when the actuator 6 is driven for generating pressure in the pressure chamber 3.