JPH07290698A - Ink jet head - Google Patents

Abstract

PURPOSE:To displace a diaphragm and to discharge ink by impacting a hammer to the diaphragm by an attraction force, a repulsion force by an electromagnet and a spring. CONSTITUTION:An ink discharge unit and an ink discharge driver are mounted on a head base 9 in a direction in which a board (diaphragm) 3 is opposed to a hammer 12. A current flows to an assembled electromagnet, and when the current is interrupted after a permanent magnet 11 is attracted to the electromagnet, the hammer 12 is collided with the board 3. A pressure of an ink layer 5 is changed by the impact at that time, and ink droplet is discharged from an ink discharge port 2. Again, in order to optimize the ink discharge amount, a position of the driver is regulated, and fixed to discharge the droplet of an optimum amount from the discharge port.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an ink jet head which ejects ink drops to form an image on a recording medium.

[0002]

2. Description of the Related Art The structure of an ink jet head which has been put into practical use in the past is of the ink jet head in which a heat generating element is formed in the ink jet head, and when the heat generating element is energized, ink is evaporated to generate bubbles. The pressure inside the inkjet head is changed by changing the internal pressure and ejecting it from the ink ejection hole, and by attaching a piezoelectric element such as a piezo in the inkjet head and applying a voltage to the piezoelectric element to bend the piezoelectric element. Let
A method of ejecting from an ink ejection hole has been known.

[0003]

However, the above-mentioned heating element type and piezoelectric element type have the advantage that they are excellent in high density and high responsiveness of the driving element, but they are superior to the IC process. Since a large amount of equipment for processing is required, there is a drawback that the cost is high.

Further, the heating element type and the piezoelectric element type have a drawback that ink cannot be ejected unless a very high voltage is applied.

Therefore, the present invention has been made to solve such a drawback, and an object of the present invention is to provide an inkjet head which can be driven at a low cost and a low voltage.

[0006]

The ink jet head of the present invention uses a mechanism in which the substrate in contact with the ink has a diaphragm structure and the pressure in the ink jet head is changed by displacing the diaphragm to eject the ink. In the conventional inkjet head, the diaphragm is displaced by ejecting ink by impacting a hammer on the diaphragm portion with an attractive force and a repulsive force of an electromagnet and a spring.

Further, an iron piece is attached to the diaphragm portion, and the diaphragm is displaced by the attractive force and repulsive force of the electromagnet and the iron piece, and ink is ejected.

[0008]

According to the above configuration of the present invention, a current is passed through the electromagnet, the hammer on the spring is attracted by the magnetic force of the electromagnet, and then the current of the electromagnet is interrupted to cause a repulsive force to collide the hammer with the diaphragm. Let The impact at that time changes the pressure of the ink layer to eject ink droplets from the ink ejection port.

Further, an iron piece is attached to the diaphragm, an electric current is passed through the electromagnet, the diaphragm is attracted by the magnetic force of the electromagnet, the electric current of the electromagnet is interrupted, a repulsive force is generated, and the diaphragm is displaced to change the pressure of the ink layer. , Ejecting ink droplets from the ink ejection port.

[0010]

【Example】

(Embodiment 1) FIGS. 1 and 2 are views showing a structure in an embodiment of the present invention. After attaching the ink supply tube 6 to the substrate (diaphragm) 3, the nozzle plate 1 is adhered to form an ink ejection portion. The ink ejection drive unit is the yoke 8
A coil 7 is wound around the coil 7 to form a magnetic circuit by an electromagnet, and a leaf spring 10 having an iron piece or a permanent magnet 11 and a hammer 12 is attached to a yoke 8. In this embodiment, the permanent magnet 11 is attached to the leaf spring 10. Next, the ink ejection unit and the ink ejection drive unit are attached to the head base 9 in a direction in which the substrate (diaphragm) 3 and the hammer 12 face each other. When a current is passed through the electromagnet assembled in this way, and the current is interrupted after the permanent magnet 11 has attracted the electromagnet, the hammer 12 collides with the substrate (diaphragm) 3 by the force of the leaf spring 10. Ink layer 5 due to impact at that time
It was possible to eject the ink droplets from the ink ejection port 2 by changing the pressure. Again, by adjusting and fixing the position of the ink ejection drive unit in order to optimize the ink ejection amount, the optimum amount of ink droplets could be ejected from the ink ejection port.

Further, the minimum voltage applied to the electromagnet was about 3 V, and ink droplets could be ejected from the ink ejection port 2.

(Embodiment 2) The ink discharge drive portion of Embodiment 1 was changed from the leaf spring 10 to the coil spring 14 to manufacture a smaller size.

3 and 4 are views showing a modified structure of the first embodiment of the present invention. The ink discharge part was manufactured by the same process as in Example 1. The ink ejection drive unit winds the coil 7 around the pole piece 15 to form a magnetic circuit by an electromagnet, and attaches it to the yoke 8. The coil spring 14 is passed through the plunger 13 and inserted into the pole piece 15. Next, connect the ink ejection unit and the ink ejection drive unit to the substrate (diaphragm).
3 is attached to the head base 9 in a direction in which the tip of the plunger 13 faces each other. When a current is passed through the electromagnet thus assembled, and the current is cut off after the plunger 13 has attracted the electromagnet, the force of the coil spring 14 causes the tip of the plunger 13 to collide with the substrate 3. Due to the impact at that time, the pressure of the ink layer 5 was changed, and the ink droplets could be ejected from the ink ejection port 2. Again, by adjusting and fixing the position of the ink ejection drive unit in order to optimize the ink ejection amount, the optimum amount of ink droplets could be ejected from the ink ejection port.

Further, the minimum voltage applied to the electromagnet was about 4 V, and ink droplets could be ejected from the ink ejection port.

(Embodiment 3) An iron piece 16 was attached to the substrate (diaphragm) 3 of Embodiment 1 to make it smaller than that of Embodiment 2.

5 and 6 are views showing the structure of the third embodiment of the present invention. The ink discharge part is manufactured by the same process as in the first embodiment, and the iron piece 16 is attached to the substrate (diaphragm) 3. The ink ejection drive unit winds the coil 7 around the yoke 8 to form a magnetic circuit by an electromagnet. Next, the ink discharge unit and the ink discharge drive unit are connected to the substrate (diaphragm) 3
And the magnetic gap 17 face each other. A current is passed through the electromagnet assembled in this way, and the current is interrupted after the iron piece 16 is drawn to the electromagnet, whereby the repulsive force of the substrate (diaphragm) 3 causes a pressure change in the ink layer, and an ink droplet is ejected from the ink ejection port 2. Could be discharged. Again, by adjusting and fixing the position of the ink ejection drive unit in order to optimize the ink ejection amount, the optimum amount of ink droplets could be ejected from the ink ejection port.

Further, the minimum voltage applied to the electromagnet was about 4 V, and ink droplets could be ejected from the ink ejection port.

[0018]

As described above, according to the present invention, since a heating element or a piezoelectric element is not used for driving, the structure is simple, and a low-cost ink jet head that does not require sophisticated processing equipment is possible. Moreover, it is possible to drive the heating element and the piezoelectric element at a low voltage by an electromagnet instead of driving at a high voltage.

That is, according to the present invention, an inexpensive ink jet head driven at a low voltage is possible.

[Brief description of drawings]

FIG. 1 is an upper sectional view showing a first embodiment of the present invention.

FIG. 2 is a front view showing the first embodiment of the present invention.

FIG. 3 is an upper sectional view showing the second embodiment of the present invention.

FIG. 4 is a front view showing a second embodiment of the present invention.

FIG. 5 is an upper sectional view showing a third embodiment of the present invention.

FIG. 6 is a front view showing a third embodiment of the present invention.

[Explanation of symbols]

 1 Nozzle Plate 2 Nozzle (Ink Discharge Port) 3 Substrate (Diaphragm) 4 Adhesive Layer 5 Ink Layer 6 Ink Supply Tube 7 Coil 8 Yoke 9 Head Base 10 Leaf Spring 11 Permanent Magnet 12 Hammer 13 Plunger 14 Coil Spring 15 Pole Piece 16 Iron Piece 17 Magnetic gap

Claims (2)

[Claims] 1. A substrate in contact with ink has a diaphragm structure, and by displacing this diaphragm, the pressure in the inkjet head is changed, and in the inkjet head using a mechanism for ejecting ink, a diaphragm is formed by an electromagnet and a spring. An ink jet head characterized in that the diaphragm is displaced by ejecting ink by impacting a hammer with an attractive force and a repulsive force. 2. The ink jet head according to claim 1, wherein an iron piece is attached to the diaphragm portion, and the diaphragm is displaced by an attractive force and a repulsive force generated by the electromagnet and the iron piece to eject ink.