JPS6160772B2 - - Google Patents

Description

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

Conventionally, this type of apparatus has been constructed as shown in FIG. In FIG. 1, 1 is a multi-nozzle unit provided with a plurality of inkjet nozzles 1a, 2 is a diaphragm unit provided with an arc-shaped diaphragm 2a that vibrates in response to an input signal, and 3 is a multi-nozzle unit 1. The packing 4 interposed between the diaphragm unit 2 and the diaphragm unit 2 is two side walls, one of which has an ink supply port 4a. The multi-nozzle unit 1 and the diaphragm unit 2 are fixed together through a packing 3.
Furthermore, the side wall 4 is fixed to each nozzle 1a and the diaphragm 2.
An ink chamber (not shown) is formed between the ink chamber and the ink chamber a, and an ink supply port 4a is provided to communicate with the ink chamber.

In the conventional example configured in this way, the printing ink that is pressurized by an ink reservoir (not shown) and supplied to the ink chamber from the ink supply port 4a is transferred to the diaphragm 2a provided behind each nozzle 1a. By applying an excitation voltage to vibrate the diaphragm 2a, ink droplets are ejected from the nozzle 1a. However, since the ink supply port 4a is provided in the side wall 4, the printing ink ejected from the ink supply port 4a into the ink chamber flows along the nozzle 1a between the nozzle 1a and the diaphragm 2a, and the ink In the vicinity of the ink supply port 4a, the ink does not diffuse and forms a strong and fast flow, and in the distance from the ink supply port 4a, it diffuses to form a weak and slow flow. For this reason, in the vicinity of the ink supply port 4a, the flow of printing ink causes disturbance in the printing ink staying near the nozzle 1a, which obstructs the supply of printing ink to the nozzle 1a and prevents the diaphragm 2a.
This causes unevenness in the vibration intensity transmitted to the printing ink near the nozzle 1a.
The size of the ink droplets ejected from the ink droplets is not uniform, resulting in irregular images printed on recording paper (not shown). Furthermore, the printing ink that has strayed from the flow of printing ink stagnates along the diaphragm 2a, and the printing ink that has remained in this stagnation for a long time deteriorates, accelerating the deterioration of the printing ink in the ink chamber.
There is a drawback that solid substances in the printing ink adhere to and accumulate on the diaphragm 2a, changing the vibration characteristics of the diaphragm 2a.

In addition, Fig. 2 shows another conventional example.
Items with the same reference numerals as in the figure indicate the same items.
Further, 5 is a pressure regulating pipe that communicates with an ink reservoir (not shown) via an ink supply pipe 6, and 7 is an ink chamber (not shown) formed in the multi-nozzle head for inkjet and the pressure regulating pipe 5. It is a plurality of communicating pipes.

In the conventional example configured as described above, the pressure of the printing ink is regulated by the pressure regulating tube 5 so that the pressure of the printing ink passing through each communication pipe 7 is uniform, and the printing ink is supplied to the ink chamber. However, nozzle 1a
and the outlet of the communication pipe 7 are close to each other, pressure fluctuations in the ink reservoir are directly applied to the printing ink near each nozzle 1a, and the diaphragm 2
This causes unevenness in the vibration intensity transmitted from a to the printing ink near the nozzle 1a.
There was a drawback that the size of the ink droplets ejected from a was not uniform, resulting in irregular images printed on recording paper (not shown). Furthermore, the printing ink that has strayed from the flow of printing ink stagnates in the upper part of the ink chamber and along the diaphragm 2a, and the printing ink that has remained in this stagnation for a long time deteriorates, causing deterioration of the printing ink in the ink chamber. However, solid substances in the printing ink may adhere to and accumulate on the diaphragm 2a, changing the vibration characteristics of the diaphragm 2a.

In order to eliminate the drawbacks of the conventional example described above, the present invention provides a multi-nozzle comprising a plurality of nozzles, a diaphragm provided facing the nozzles, and an ink chamber provided between the nozzles and the diaphragm. At the head,
1 to 1 or 2 pipes installed in the ink chamber.
A direction that does not intersect the vibration transmission area between the diaphragm and the nozzle (the spatial area obtained by connecting the outer periphery of the electrostrictor and the nozzle corresponding to the electrostrictor) in which the multiple ink outlets opened in a row do not intersect with the vibration transmission area between the diaphragm and the nozzle. The pipe is surrounded by a resistive plate with countless holes, and the printing ink ejected from the ink outlet is diffused throughout the ink chamber by the resistive plate, and the printing ink flowing inside the ink chamber is To provide a multi-nozzle head for an inkjet printing device, the purpose of which is to weaken and slow down the flow of printing ink and eliminate stagnation of printing ink in an ink chamber. Hereinafter, embodiments will be described in detail with reference to the drawings.

3 and 4 show an embodiment of the present invention, in which 8 is a pipe provided with a plurality of ink outlets 8a in a row, 9 is a resistance plate provided with numerous holes 9a, Reference numeral 10 includes a plurality of ink jet nozzles 10a arranged in a row on the front, a cavity for forming an ink chamber 10b provided behind the nozzles 10a, and a hole 10c for inserting and supporting the pipe 8. The two pipes 8 are installed in parallel above and below the ink chamber 10b, and the ink outlet 8a of the upper pipe 8 faces upward, and the ink outlet 8a of the lower pipe 8 faces upward. The ink outlet 8a is installed facing downward, and the resistance plate 9 is installed so as to cover the periphery of each pipe 8 to the ink chamber 10b.
(See Figure 4). 11 is an O-ring that shields between the inserted pipe 8 and the hole 10c, 12 is a diaphragm unit having a diaphragm 12a on the front and a connector 12b on the back. An electrostrictor 12d connected to the connector 12b by 12c is fixed. 13 is a packing interposed between the multi-nozzle unit 10 and the diaphragm unit 12; 14;
15 is an ink supply pipe whose one end is connected to an ink reservoir (not shown); 15 is a joint that communicates the pipe 8 with the ink supply pipe 14 through a hole 15a; the left joint 15 is connected to the upper pipe 8; It is connected to one end and closes one end of the lower pipe 8.
The right joint 15 is connected to the other end of the lower pipe 8 and closes the other end of the upper pipe 8. 16
is a gasket interposed between the multi-nozzle unit 10 and the joint 15.

Next, the operation of this embodiment will be explained. First, the printing ink pressurized by the ink reservoir is press-fitted into the upper and lower pipes 8 through the ink supply pipe 14 and the hole 15a of the joint 15, and is further jetted upward from the ink outlet 8a of the upper pipe 8. The printing ink hits the top wall of the ink chamber 10b and spreads, one flow of printing ink flows from the top wall of the ink chamber 10b to the front wall, and the other flow of printing ink flows from the top wall of the ink chamber 10b to the front wall. The flow flows from the upper wall to the diaphragm 12a, and the resistance plate 9
The nozzle 1 hits the hole 9a and is further diffused.
Flows into 0a. Similarly, the printing ink ejected downward from the ink outlet 8a of the lower pipe 8 hits the bottom wall of the ink chamber 10b and spreads, while the printing ink flows from the bottom wall of the ink chamber 10b. The other printing ink flows from the lower wall of the ink chamber 10b to the diaphragm 12a, and the other printing ink flows from the lower wall of the ink chamber 10b to the diaphragm 12a.
The nozzle 1 hits the hole 9a and is further diffused.
Flows into 0a. That is, if the aperture ratio of the ink outlet 8a and the hole 9a of the resistor plate 9 is (2:11), and the total area ratio of the ink outlet 8a and the hole 9a of the resistor plate 9 is (1:10), then the upper and lower The printing ink ejected from the ink outlet 8a of the pipe 8 at a speed of 20 mm per second hits the upper and lower walls of the ink chamber 10b and is diffused, and is further diffused throughout the ink chamber 10b by the resistor plate 9. In addition, the flow of the printing ink flowing into the nozzle 10a becomes a weak and slow flow of 2 mm per second, so that the printing ink staying near the nozzle 10a is no longer disturbed, and the printing ink is smoothly replenished into the nozzle 10a. And from the diaphragm 12a to the nozzle 10
The vibration intensity transmitted to the printing ink near a becomes constant. Further, even if pressure fluctuation occurs in the ink reservoir, the pressure is also diffused, so that the fluctuating pressure applied to the printing ink near the nozzle 10a is reduced. Furthermore, the printing ink ejected from the ink outlet 8a is diffused throughout the ink chamber 10b and reaches the nozzle 1.
Since the printing ink flows into the ink chamber 10b, no stagnation of printing ink is formed in the ink chamber 10b.

As explained above, according to the present invention, printing ink is smoothly replenished into the nozzle, the vibration intensity transmitted to the printing ink near the nozzle is made constant, and pressure fluctuations in the ink reservoir are further reduced. This has the advantage that the size of the ink droplets ejected from the nozzle becomes uniform, and the image printed on the recording paper becomes regular. Also, by eliminating stagnation of printing ink in the ink chamber, deterioration of the printing ink can be prevented, and solid substances in the printing ink can be prevented from adhering to and accumulating on the diaphragm, thereby changing the vibration characteristics of the diaphragm. It has the advantage of being able to prevent

[Brief explanation of the drawing]

1 and 2 are block diagrams of a conventional multi-nozzle head for an inkjet printing device, FIG. 3 is a block diagram of an embodiment of the present invention, and FIG. 4 is a sectional view of FIG. 3. 1, 10...Multi nozzle unit, 1a, 1
0a... Nozzle, 2, 12... Vibration plate unit,
2a, 12a... diaphragm, 3, 13, 16... packing, 4... side wall, 4a... ink supply port, 5
...Pressure adjustment pipe, 6, 14...Ink supply pipe, 7...Communication pipe, 8...Pipe, 8a...
Ink outlet, 9... Resistance plate, 9a... Hole, 10
b... Ink chamber, 10c... Hole, 11... O ring, 12b... Connector, 12c... Lead wire,
12d...Electrostrictor, 15...Joint, 15a...
hole.

Claims (1)

[Claims] 1 Consists of a plurality of nozzles, a diaphragm provided opposite the nozzles, an ink chamber provided between the nozzles and the diaphragm, and an electrostrictor fixed behind the diaphragm. In the multi-nozzle head, at least one pipe is disposed outside the vibration transmission area from the electrostrictor to the nozzle in the ink chamber, and a plurality of ink outlet ports opened in a row in the pipe are provided. The pipe is oriented in a direction that does not intersect the vibration transmission area between the electrostrictor and the nozzle, and the pipe is covered with a resistor plate having numerous holes, so that the printing ink ejected from the ink outlet is directed toward the resistor. 1. A multi-nozzle head for an inkjet printing device, characterized in that the ink is diffused and flows throughout the ink chamber by a plate.