JPS6135254A - Recording head for ink jet recorder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to inkjet recording, in which recording is performed by forming recording liquid t, generally called ink, into small droplets using one method and attaching the ink droplets to a recording surface. It relates to a recording head applied to an apparatus, and in particular, it is equipped with a thin slot forming a flow path for recording liquid and a relay liquid chamber to which a thin slot is connected. The present invention relates to a recording head that applies pressure waves to a recording liquid, thereby ejecting small droplets from an ejection port provided at one end of the slot.

[Background of the invention]

Among the various recording methods currently known, it is a non-innocent 4-act recording method that generates almost no noise during recording, is capable of high-speed recording, and does not require any special fixing treatment on plain paper. The so-called inkjet method, which can perform recording on images, is an extremely useful method for realizing printing devices such as various printers and word processors. Various methods have been proposed for this inkjet method, some have been improved and commercialized, and others are still being put into practical use.

An inkjet recording device uses various working principles to eject and fly small droplets of recording liquid (referred to as ink in the following explanation) from a narrow ejection opening (nozzle), and makes them adhere to a recording material such as paper. This is for recording.

The inkjet recording apparatus is roughly classified into several types based on the method of generating ink droplets and the control method for controlling the flying direction of the generated ink droplets.

One of the representative methods is USP359, for example.
6275, USP 3298030, etc., in which ink droplets with a controlled amount of charge are generated by a continuous vibration generation method, and a uniform electric field is applied to the ink droplets with a controlled amount of charge. This method controls the flight trajectory of ink droplets by flying them between deflection electrodes. This method is generally called a continuous method.

Another typical method compared to this is USP37471
In this method, an electrical recording signal is applied to a vieno vibration element attached to an ink ejection head having a nozzle for ejecting ink, and this electric recording signal is transmitted to the pieno vibration element. into mechanical vibration,
In this method, ink droplets are ejected from the nozzle whenever necessary according to the mechanical vibration. This is the so-called on-demand method. In addition, there is also an inkjet method, which differs in principle and concept from these methods, as disclosed in Japanese Patent Application Laid-Open No. 54-5993.
It is proposed in No. 6. This method applies a thermal pulse as a signal to the ink introduced into the liquid chamber.
In this method, the ink is made into small droplets and ejected through a discharge port (nozzle) attached to the liquid chamber according to the acting force generated when the state of the ink changes.

In any of the above-mentioned inkjet recording devices, in order to obtain commercial quality images, it is necessary to regularly and intermittently eject fine ink droplets of equal diameter. A stable ink supply is essential for smooth and stable ejection flight, and in particular, for the purpose of high-speed inkjet recording, the trend is toward multi-array recording heads and high-density integration. This is a big problem in the current situation.

One way to solve these problems is to use an ink supply pipe from an ink tank to supply ink to an ink ejection port. A structure in which a stable ink supply is obtained by providing an ink reservoir inside the ink tank and using it as an ink reservoir has come to be used. However, even with this structure, there is a problem in that air bubbles generated in the ink supply pipe or the recording head accumulate in the relay liquid chamber, making it impossible to fulfill its original role of supplying ink.

[Purpose of the invention]

An object of the present invention is to eliminate uneven ink supply due to the accumulation of air bubbles caused by the conventional ink supply path configuration in the recording of an inkjet recording device provided with a relay liquid chamber as described above, and to ensure stable ink supply. The objective is to provide a solution to inkjet recording that enables high-quality recording.

[Summary of the invention]

The recording head according to the present invention is characterized in that the recording head for an inkjet recording apparatus is equipped with a narrow slot that forms a recording liquid flow path and a relay liquid chamber to which the slot is connected. J (Ice%＠Bokutai★Nihiro Wo Ichiya) Place the ink supply port of the ink supply pipe that opens into the relay liquid chamber in the direction of gravity relative to the position of the bubble removal port of the bubble removal pipe that opens into the relay liquid chamber. By arranging it lower than the other hand, the above object can be achieved.

[Embodiments of the invention]

This will be explained below with reference to the drawings.

To record the present invention, first, before explaining the
A conventional recording head will be explained with reference to FIGS. 4 to 6. In FIGS. 4 to 6, 1 indicates line array type multi-orifice inkjet recording. this is,
Inside the recording head body 4, there are many thin slots 2 that form ink flow paths, and a relay liquid chamber 3 connected to these slots.
An ejection port is formed at the tip of the slot, and the ink is ejected as small droplets from the ejection port by pressure waves applied to the ink in the slot by a pressure wave driving device (not shown). It is configured to perform recording by making it fly and attaching it to a recording material.

An ink supply pipe 5 connected to an ink tank (not shown)
is connected to the head body 4 via the terminal 6 and opens into the relay liquid chamber 3. Further, a bubble vent v7 connected to ink (not shown) is connected to the head main body 4 via a terminal 8 and opens into the relay liquid chamber 3. Reference numeral 9 denotes a substrate, to which the main body 4 is joined.

In this recording head, there is a possibility that air bubbles 1o generated within the ink supply tube or within the recording head may accumulate in the relay liquid chamber 3, making it impossible to sufficiently fulfill the original purpose of supplying ink. In order to remove such air bubbles, a bubble removal pipe 7 is connected to the relay liquid chamber 3, but as shown in FIG. It is inappropriate to remove air bubbles 10b from the corners of the chamber 3 through the bubble removal tube 7. For this purpose, the ink supply pipe 5
Even if a method is used in which the ink is forcibly fed into the relay liquid chamber 3 using a screwdriver or the like, and the bubbles 10 are pushed away to the bubble removal pipe 7 side using hydraulic pressure, a sufficient effect cannot be obtained with the conventional shape and position. The air bubbles 10b at the corners of the relay liquid chamber 3 could not be removed. Furthermore, the remaining air bubbles gradually grew to the point where all of the air bubbles that were generated one after another collapsed, making the ink supply unstable.

The present invention makes it possible to completely remove such air bubbles, and examples thereof are shown in Fig. M1-Fig. 3.

In these figures, 20 is a line array type.

Shows a multi-orifice, inkjet recording head,
This is composed of a substrate 21 and a main body 22 bonded thereto. On one side of the substrate 21, the main body 22
230 rows of thin slots forming a large number of ink flow paths are arranged in parallel, an ink ejection port (nozzle) is formed at the tip of the slot, and a relay liquid connected to the slot 23 is provided in the main body 22. A chamber 24 is formed. O ink that performs recording by ejecting the ink as small droplets from the ejection port by a pressure wave applied to the ink in the groove hole by a pressure wave driving device (not shown) and adhering it to the recording material. Ink supply pipe 2 connected to a tank (not shown)
5 is connected to the main body 22 via a terminal 26 and opens into the relay liquid chamber 24. A bubble removal pipe 27 connected to a tube (not shown) is connected to the main body 22 via a terminal 28 and opens into the relay liquid chamber 24.

According to the present invention, the open ink supply pipe 25 is provided in the relay liquid chamber 24.
The ink supply port 29 is located lower than the bubble removal port 30 of the bubble removal pipe 27 that opens into the relay liquid chamber 24 by Δh with respect to the direction of gravity.

According to this arrangement according to the present invention, the air bubbles 31 in the relay liquid chamber 24 rise in the direction opposite to gravity within the filled ink, so that they naturally gather near the bubble removal port 300. When pressurized ink flows in from the ink supply tube 25 side using a pump (not shown), the air bubbles 31 pass through the bubble removal port 30 and the bubble removal pipe 27 together with the ink in the ink relay liquid chamber 24. The air bubbles inside the inkjet recording head are completely removed.

In addition, in order to remove air bubbles even more efficiently, as shown in FIG.
It is preferable to adopt a structure in which the ceiling of the relay liquid chamber 24 is sloped so that bubbles rising in the liquid chamber are guided to the bubble removal port 30.

〔Effect of the invention〕

As is clear from the above description, the present invention has a simple structure, can completely eliminate the bubbles in the six-ratio recording head, and achieves stable printing quality. It is possible to provide inkjet printing capable of recording.

[Brief explanation of drawings]

FIG. 1 is an external perspective view showing an embodiment of a recording head according to the present invention, FIG. 2 is a sectional view taken along chain line U-11 in FIG. 1, and FIG. 3 is a sectional view taken along chain line 111-1 in FIG. 1. , Fig. 4 is an external perspective view showing an example of inkjet recording with a conventional relay liquid chamber and bubble removal structure, and Fig. 5 is a dashed line v in Fig. 4.
6 is a sectional view taken along the dashed line M--■ in FIG. 4.
Main body 23...Slot hole 24...Relay liquid chamber
25... Ink supply tube 26... Terminal
27...Bubble removal tube 28...Terminal
29... Ink supply port 30... Bubble removal port, 11 [I Fig. 2

Claims (1)

[Claims] It has a thin slot forming a flow path for the recording liquid and a relay liquid chamber to which the slot is connected. In a recording head of an inkjet recording device that ejects and flies small droplets from an ejection port at one end, the ink supply port of the ink supply pipe that opens into the relay liquid chamber is connected to the ink supply port of the ink supply pipe that opens into the relay liquid chamber. A recording head for an inkjet recording device, characterized in that the recording head is disposed lower in the direction of gravity than the position of a bubble removal port.