JPS6139906B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-nozzle head for an inkjet.

Conventionally, this type of apparatus has been constructed as shown in FIG. In Fig. 1, a plurality of inkjet multi-nozzles 1a are provided in one row on the front, and a space for forming a liquid chamber 1b behind the nozzles 1a and a space for supplying printing ink to the liquid chamber 1b. The multi-nozzle unit 2 has a diaphragm 2a on the front, and an air chamber 2 on the back of the diaphragm 2a.
An electrostrictor 2c is fixed to the back of the diaphragm 2a, and a terminal plate 2d is fixed to the rear wall of the diaphragm 2a. It is connected to the plate 2d by a lead wire 2e. 3 is an ink supply pipe whose one end is connected to the ink supply port 1c, 4 is an accumulator whose lower part is connected to the ink supply pipe 3, and 5 is a pump for applying pressure to the printing ink in the accumulator 4. Accumulator 4 by
The printing ink in the liquid chamber 1b communicating with the
A pressure of Kg/cm ² is applied. however,
In the conventional example configured in this way, since the pressure inside the air chamber 2b is approximately equal to atmospheric pressure, the diaphragm 2a
is curved toward the air chamber 2b, making it impossible to accurately transmit the vibrations of the electrostrictor 2c to the diaphragm 2a, making it impossible to maintain a constant size of the ink droplet 6 ejected from the nozzle 1a in response to the vibration of the diaphragm 2a. There was a drawback that I couldn't do it. Further, if a thick diaphragm 2a is used to compensate for this drawback, there is a drawback that the driving voltage of the electrostrictor 2c must be increased.

In addition, Fig. 2 shows another conventional example.
Items with the same reference numerals as in the figure indicate the same thing.
Further, 7 is a support for supporting the diaphragm 2a in the liquid chamber 1b, and the diaphragm 2a is immersed in the printing ink filled in the liquid chamber 1b to equalize the pressure applied to both sides of the diaphragm 2a. There is. However, in the conventional example configured as described above, since the electrostrictor 2c and the lead wire 2e are also immersed in the printing ink together with the diaphragm 2a, the electrostrictor 2c and the lead wire 2e are required to be insulated. This has the disadvantage of making manufacturing, maintenance, and inspection work difficult, as well as increasing manufacturing costs, maintenance, and inspection costs.

Moreover, FIG. 3 shows still another embodiment,
Components with the same reference numerals as those in FIG. By increasing the internal pressure, the ink supply pressure applied to the front side of the diaphragm 2a and the back pressure applied to the back side of the diaphragm 2a are equalized.
However, in the conventional example configured in this way, two pumps 5 and 8, a control device for controlling these two pumps 5 and 8, and a pressure difference between the ink supply pressure and the back pressure are detected. Since a detection device is required for this purpose, manufacturing, maintenance, and inspection operations are difficult, and manufacturing costs and maintenance and inspection costs are high.

In order to eliminate the drawbacks of the above-mentioned conventional example, the present invention provides an inkjet multi-function inkjet multifunction device in which the ink supply pressure applied to the front side of the diaphragm and the back pressure applied to the back side of the diaphragm are equalized by one pump and one accumulator. It provides a nozzle head. below,
Examples will be explained in detail with reference to the drawings.

FIG. 4 shows an embodiment of the present invention.
Components with the same reference numerals as in FIG. Yotsute Accumulator 4
When pressure is applied to the printing ink inside, a pressure equal to the ink supply pressure is simultaneously applied to the air in the air section 4a above the accumulator 4, and even if the pressure applied to the printing ink from the pump 5 changes, the ink supply pressure remains constant. and air pressure always change equally. Therefore, the ink supply pressure in the liquid chamber 1b and the air pressure in the air chamber 2b are always equal, and no pressure difference occurs between the ink supply pressure applied to the front surface of the diaphragm 2a and the back pressure applied to the rear surface of the diaphragm 2a. .

As described above, according to the present invention, since a thin diaphragm can be used, the size of the ink droplet ejected from the nozzle can be made constant without increasing the driving voltage of the electrostrictor. In addition, there is no need for special insulation treatment, and since only one pump is required, there is no need for a pump control device or a pressure difference detection device, so manufacturing, maintenance, and inspection work are easy, and the product price and maintenance are low. This has the advantage of reducing inspection costs.

[Brief explanation of the drawing]

1 to 3 are block diagrams of a conventional multi-nozzle head for an inkjet, and FIG. 4 is a block diagram of an embodiment of the present invention. 1... Multi-nozzle unit, 1a... Nozzle, 1b... Liquid chamber, 1c... Ink supply port, 2...
...Diaphragm unit, 2a...Diaphragm, 2b...Air chamber, 2c...Electrostrictor, 2d...Terminal plate, 2e...
...Lead wire, 3...Ink supply pipe, 4...Accumulator, 4a...Air section, 5...Pump, 6...
...Ink drop, 7... Strut, 8... Air pump,
9,10...Air pipe.

Claims (1)

[Claims] 1. A diaphragm unit including a plurality of nozzles, a diaphragm provided opposite the nozzles, a liquid chamber formed between the nozzles and the front surface of the diaphragm, and an air chamber formed on the back surface of the diaphragm. In the multi-nozzle head, the lower part of one accumulator is communicated with the liquid chamber, and the air part of the upper part of the accumulator is communicated with the air part, so that the ink supply pressure and back pressure applied to the diaphragm are made equal. Features a multi-nozzle head for inkjet.