JPS59232872A - Ink jet recording head - Google Patents

Abstract

PURPOSE:To deaerate assuredly and secure a constant air layer in an ink liquid chamber, by a method wherein an opening part on the air layer side of a vent port communicated with an air layer provided in an ink liquid chamber is opened and closed by a solenoid valve. CONSTITUTION:The vent port 11 of a small diameter pipe communicated with the air layer 7 in the ink liquid chamber is provided in proximity to a nozzle orifice 10. The solenoid valve 9 is provided on the port 11. When the liquid surface of the ink 6 is lowered as recording proceeds, the ink is fed under pressure through a connecting pipe 14, and an electric current is passed to the valve 9, whereby an iron core 17 is moved upward against an energizing force of a spring 15 to open the opening part 11a, resulting in that air increased in amount is discharged to the exterior through the vent port 11. When the ink starts to leak through the port 11, the passage of the electric current to the valve 9 is stopped, and after causing the ink to leak also through the nozzle orifice 10, pressure feeding of the ink is stopped. When the diameter of the vent port 11 is set to be larger than that of the orifice, the liquid surface of the ink 6 can be easily raised, and can be set to a fixed level in a short time.

Description

Detailed Description of the Invention Technical Field The present invention relates to an inkjet recording head, and more particularly to an inkjet recording head that performs printing by ejecting ink supplied from an ink chamber provided with an air layer inside. be.

Prior Art Conventionally, such an inkjet head is provided with an ink chamber common to a plurality of nozzles, and this ink chamber moves together with the head as the carriage moves to perform printing. An air layer is provided in the ink liquid chamber to alleviate the impact force caused by the carriage direction change, etc. This air layer absorbs the instantaneous increase in ink pressure inside the nozzle when the carriage is compressed, and is applied to the nozzle. It provides a buffering effect that can minimize pressure. To perform this action, the amount of air layer is usually 0.3
It is set to about cc. In order to keep this air layer constant, conventionally, an air bleed means as shown in FIG. 1, 212 has been required.

That is, in FIG. 1, an ink chef T-head 1 having a plurality of nozzles arranged in a row is mounted on a carriage 2, and the carriage 2 is configured to reciprocate on a shaft 3''. In addition, an ink chamber is attached to the head 1 to supply ink to the nozzle.
Ink 6 is supplied to this ink liquid chamber from an ink supply pipe 4, and the above-mentioned air layer 7 is formed. In order to secure the liquid level of this air layer 7 and the ink 6, that is, to keep the volume of this air layer constant, an air bleed tube 5 is connected to an air bleed means and runs together with the carriage.
is provided. This tube is made of flexible plastic, and the ink tends to evaporate and move, making its arrangement complicated.

Another conventional example is shown in FIG. 2, in which the ink chamber is provided with a plug 8 having a screw structure.
A threaded plug 8 raises the ink level to ensure a constant air layer 7. However, even this structure has the disadvantage that the operation is very complicated.

Purpose Therefore, the present invention has been made in order to eliminate such conventional drawbacks, and is an inkjet recording method that secures a certain volume of air layer in the ink liquid chamber, performs reliable air removal, and performs good printing. The purpose is to provide the head.

Example Embodiments of the present invention will be described in detail below with reference to the drawings.

Embodiments of the present invention are illustrated in FIGS. 3 to 5,
Components that are the same as those shown in FIGS. 1 and 2 are given the same reference numerals, and their explanations will be omitted.

3 and 4, the inkjet head 1 is provided with a plurality of nozzle orifices 10 arranged in a line, and these orifices are arranged in an orifice spray 1-121 fixed to the head 1. Further, on this orifice plate 12, in the vicinity of the nozzle orifice 10, there is provided a vent hole 11 in the form of a thin tube made of glass, stainless steel, or the like and communicating with the air layer 7 of the ink liquid chamber. Further, a solenoid valve 9 is provided above the vent 11, and this solenoid valve 9 is fixed on the case of the inkjet head 1, and when the coil 9a is energized, the iron core 17
moves upward, and a sealing member 16 is attached to this iron core 17.
The shaft portion is sealed. As the iron core 17 moves up and down, the sealing member 17a moves up and down, thereby opening and closing the opening 11a of the vent. Normally, the seal member 17a
It is pushed downward by the spring 15, and the opening 11a is closed. In addition, the Infuji Elatra head 1 is the connecting pipe 1.
4 and a sealing member 13 communicate with an ink tank (not shown), and when the ink in the ink chamber decreases, ink is collected from the ink tank.

In such a configuration, when the liquid level of the ink 6 decreases during recording, the ink is pumped through the connecting pipe 14 and the solenoid valve 9 is energized. This causes the iron core 17 to spring 15
``against the old forces of'' and thereby opening 11
a opens. Therefore, the increased air is discharged to the outside through the vent 11.

On the other hand, when ink starts to leak from the vent 11, the power to the electromagnetic valve 9 is stopped, and after the ink has also leaked from the nozzle orifice, the ink pressure feeding via the connecting pipe 14 is stopped. The air in the air layer 7 may be slightly pressurized for a time immediately after the ink pressure feeding is stopped, but then it approaches atmospheric pressure and reaches an equilibrium state.

In the above example, the nozzle orifice lO1 vent 11
The leaked ink flows out into the capping part 18 as shown in FIG. 5, and is stored in a waste ink reservoir (not shown) through the discharge tube 19.

Effects As explained above, according to the present invention, a vent is provided that communicates with the air layer of the ink liquid chamber, and the opening on the air layer side of this vent can be opened and closed by a solenoid valve, so that air can be removed easily. Not only can this be done completely, but also a certain air layer can be ensured within the ink chamber to provide a good buffering effect. Furthermore, when the diameter of the vent port is made larger than the orifice diameter, the ink liquid level can be easily raised and the liquid level can be made constant in a short time.

[Brief explanation of the drawing]

FIGS. 1 and 2 are partially cutaway side views showing conventional structures, respectively, and FIGS. 3 to 5 show embodiments of the present invention.
FIG. 3 is a front view of the inkjet head, FIG. 4 is a side sectional view thereof, and FIG. 5 is a side view showing the configuration of the head when a capping portion is provided. ■... Ink sheet head 2... Carriage 6... Ink 7... Air layer 9... Solenoid valve 10... Nozzle orifice 1
1... Vent port 12... Orifice plate 17
a... Seal member 18... Capping part 19
...Exhaust tube

Claims (3)

[Claims] (1) Equipped with an ink chamber with an air layer inside and a nozzle for ejecting ink supplied from the ink chamber,
In an inkjet recording head that prints by moving the ink chamber and nozzle, a vent that communicates with the air layer of the ink chamber is provided near the nozzle, and the opening on the air layer side of this vent can be opened and closed by a solenoid valve. An inkjet recording head characterized by: (2) The inkjet recording head according to claim 1, wherein the diameter of the vent port is larger than the diameter of the nozzle. (3) The ink jet recording head according to claim 1 or 2, wherein the opening in the ink liquid chamber of the vent port is located at the interface between the ink liquid level and the air layer.