JPS5830831B2 - Multi-nozzle head for inkjet - Google Patents

Description

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

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 and a diaphragm. The gasket 4 is interposed between the unit 2 and the unit 2, and there are 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 gasket 3, and a side wall 4 is also fixed to form a liquid chamber (not shown) communicating with each nozzle 1a and ink supply port 4a.

This liquid chamber is filled with printing ink that is pressurized and supplied from an ink reservoir (not shown) and injected through the ink supply port 4a, and pressurized from each nozzle 1a. The printing ink jets out to form an ink stream.

Furthermore, by vibrating a vibration plate 2a provided behind each nozzle 1a, printing ink is separated from the tip of the ink stream to form ink droplets.

However, in the conventional example configured in this way, since the ink supply port 4a is provided only on one side wall 4 of the liquid chamber, the ink supply pressure applied to the nozzle 1a increases as the distance from the ink supply port 4a increases. each nozzle 1a.
The ink droplets formed at the edges were not uniform in size, resulting in irregular printed characters and pictures.

Further, FIG. 2 shows another conventional example, in which the same reference numerals as in FIG. The pressure adjustment tubes 7 are a plurality of communication pipes that communicate the pressure adjustment tube 5 with a liquid chamber (not shown) formed in the inkjet multi-nozzle head.

In the conventional example configured in this way, the pressure of the printing ink passing through each communication pipe T is regulated by the pressure adjustment pipe 5 so that it becomes uniform, and the printing ink is supplied to the liquid chamber. Since the number of pipes 7 is large, printing ink is likely to leak due to packing defects, and maintenance work is time-consuming.

Furthermore, since the pressure adjustment tube 5 is used, the exclusive volume of the inkjet multi-nozzle head becomes large, and the ink supply path becomes long, increasing the amount of ink supplied, and the printing ink is used in a large amount of space. The disadvantage was that the printing ink deteriorated.

In order to eliminate the drawbacks of the conventional example, the present invention provides one or two pipes in which a plurality of ink outlet ports with different diameters are arranged in order from the ink inflow side in order of size in the liquid chamber. An object of the present invention is to provide a multi-nozzle head for inkjet in which pressure applied to nozzles is made uniform.

Embodiments will be described in detail below with reference to the drawings.

FIG. 3 shows an embodiment of the present invention, in which numeral 8 denotes 2 in which a plurality of ink outlet ports 8a having different diameters are arranged in a row.
The ink outlet 8a with a large diameter is provided at the tip side of the pipe 8, and the ink outlet 8a with a small diameter is provided at the inlet end of the pipe 8 for printing ink. The center line of the outlet 8a and the center line of each ink outlet 8a of the lower pipe 8 are aligned.
Figure 3 (see b).

Reference numeral 9 has a plurality of inkjet nozzles (not shown) arranged in a row on the front side, a cavity forming a liquid chamber 9a behind the nozzles, and a hole 9 through which the pipe 8 is inserted and supported.
It is a multi-nozzle unit consisting of both side walls provided with b, and two pipes 8 are installed in parallel above and below the liquid chamber 9a.

10 is an O-ring for shielding between the inserted pipe 8 and the hole 9b, 11 is a diaphragm unit provided with a diaphragm (not shown) on the front, and 12 is a multi-nozzle unit 9 and a diaphragm unit 11. 13 is an ink supply pipe whose one end is connected to an ink reservoir (not shown); 14 is a joint that connects the pipe 8 and the ink supply pipe 13 through a hole 14a; 14 is connected to the printing ink inflow end of the upper pipe 8, and the right joint 14 is connected to the printing ink inflow end of the lower pipe 8.

15 is the multi-nozzle unit 9, the joint 14 and the side wall 15
It is a patch that is interposed between the two.

Next, the operation of this embodiment will be explained.

First, the printing ink pressurized in the ink reservoir passes through the ink supply pipe 13 and the hole 14a of the joint 14, and is press-fitted into the upper pipe 8 from the left side, and into the lower pipe 8 from the right side. [see FIG. 3(b)], and is further press-fitted into the liquid chamber 9a from each ink outlet 8a of the pipe 8.

By the way, if the diameters of the ink liquid outlets 8a are all the same, the pressure of the printing ink ejected from the ink outlet 8a will be lower at the ink outlet 8a at the tip end of the pipe 8, and the pressure at which the printing ink flows into the pipe 8 will be lower. Although the ink outlet 8a on the end side is higher, in this embodiment, the diameter of the ink outlet 8a on the tip side of the pipe 8 is large, and the ink outlet 8a on the printing ink inflow end side of the pipe 8 is small. The pressure of printing ink ejected from each ink outlet 8a becomes uniform.

For this reason, the pressure applied to the printing ink in the liquid chamber 9a becomes uniform, and when the diaphragm vibrates, ink droplets of uniform size are ejected from each nozzle in accordance with the vibration of the diaphragm.

In this embodiment, an example has been described in which two pipes 8 are installed in parallel above and below the liquid chamber 9a, but it is also possible to install only either the upper pipe 8 or the lower pipe 8 in the liquid chamber 9a. Even in this case, the same effect as the embodiment shown in FIG. 3 can be obtained.

Further, FIG. 4 shows another embodiment of the present invention, in which the center line of each ink outlet 8a of the upper pipe 8 is shifted from the center line of each ink outlet 8a of the lower pipe 8. This is an example in which ink outlets 8a are provided in the upper and lower pipes 8 in this manner, and even if the number of ink outlets 8a provided in the pipe 8 is the same as that of the ink outlet 8 of the pipe 8 shown in the embodiment of FIG.
Even if it is less than the number a, the pressure of the printing ink ejected from each ink outlet 8a of one pipe 8 compensates for the decrease in the pressure of the printing ink ejected from each ink outlet 8a of the other pipe 8. Therefore, this ink pressure is adjusted in the liquid chamber 9a, and the pressure applied to the printing ink near the nozzles becomes uniform, and when the diaphragm vibrates, ink droplets of uniform size are released from each nozzle onto the diaphragm. It ejects in response to vibrations.

As explained above, according to the present invention, since the ink pressure near the ink outlet of the pipe and near the nozzle becomes uniform, the size of the ink droplet ejected from the nozzle becomes constant, and the ink supply Because the path is short and there are few connecting points, manufacturing, maintenance, and inspection work is easy, and the printing ink in the ink supply path is prevented from deteriorating, which has the advantage of reducing the occurrence of ink leakage. There is.

[Brief explanation of drawings]

1 and 2 are block diagrams of a conventional inkjet multi-nozzle head, and FIGS. 3 and 4 are block diagrams of an embodiment of the present invention. 1...Multi nozzle unit, 1a...
・Nozzle, 2... Vibration plate unit, 2a...
...Diaphragm, 3...-Putskin, 4...
・Side wall, 4a... Ink supply port, 5...
・Pressure adjustment pipe, 6...Ink supply pipe, 7.
...Communication pipe, 8...Pipe, 8a.
... Ink outlet, 9 ... Multi nozzle unit, 9a ... Liquid chamber, 9b ... Hole, 10 ... O ring, 11 ...Diaphragm unit, 12...Packskin, 13...
- Ink supply pipe, 14... Fitting, 14a... Hole, 5... Packing.

Claims (1)

[Claims] 1. In a multi-nozzle head consisting of a plurality of nozzles, a diaphragm unit with a diaphragm provided opposite the nozzles, and a liquid chamber, the ink outlet ports of the plurality of cylinders with different diameters are sequentially connected from the ink inflow side. An inkjet multiplier characterized in that one or two pipes arranged to increase in size are installed in the liquid chamber facing and parallel to the nozzles, so that the ink supply pressure applied to each nozzle is uniform. nozzle head.