JPS6112785B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording device used in a printer or the like that performs recording by jetting ink in accordance with an input signal.

Several types of ink jet recording devices have already been proposed, but one uses the deformation of the piezo element that occurs when a piezo element is placed in the head that ejects ink and a voltage is applied to the piezo element as a recording signal. Recently, the method of ejecting ink has been attracting attention because it can be realized with a simple configuration.

However, this type of inkjet recording device still lacks long-term stability, so there are few practical applications.In particular, when air bubbles form in the head that ejects ink, the piezo element deforms to apply ink pressure. When this occurs, the pressure is absorbed by the air bubbles, causing ink jetting to malfunction. Therefore, the entire ink flow path from the nozzle tip of the head to the ink tank must be kept free of air bubbles. Must be. However, maintaining this state requires extremely complicated procedures when replenishing or replacing ink, and if bubbles occur, it is difficult to repair them, which is a major drawback in terms of the long-term life of the device. It was hot.

The present invention aims to improve the above-mentioned drawbacks of inkjet recording devices, especially in integrated heads having a plurality of nozzles in one head, by eliminating air bubbles that may occur in the ink tank when replenishing ink or replacing the ink tank. This has been improved to prevent ink from penetrating into the jet head, and a conventional example and an embodiment of the present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a plan view a and a cross-sectional view b showing an example of a conventional head for an inkjet recording device. The head 1 is made by gluing together a lower substrate 2 and an upper substrate 3, and the lower substrate 3 is etched with a plurality of nozzles 4 and an ink chamber 5 connected to the nozzles 4, as well as an ink chamber for supplying ink to the ink chamber. The ink preparation chamber and the like are configured as grooves. Furthermore, piezo elements are provided on the outer surface of the upper substrate 3 corresponding to the ink chambers 5, and when a voltage is applied to these piezo elements 7, the piezo elements 7 deform, compressing the ink chambers, and ink is ejected from the tips of the nozzles. do. The configured head 1 receives ink from an ink introduction section 8 from an external ink tank via a pipe or the like, but if air bubbles enter the ink tank or pipe during ink replenishment, the air bubbles will cause the ink to become ink. The ink enters the ink preparation chamber 6 from the introduction section 8 and further enters any ink chamber 5. When air bubbles enter the ink chamber 5, the pressure on the ink is absorbed by the air bubbles as described above, and it becomes impossible to normally eject ink from the nozzle 4 corresponding to the ink chamber 5 into which the air bubble has entered. The present invention solves this type of conventional drawback, and one embodiment thereof is shown in FIG.

FIG. 2 shows a plan view of an ink ejecting head used in the inkjet recording apparatus of the present invention. The ink ejecting head shown in FIG. 2 is installed in an inkjet recording apparatus with the upper part facing upward and the lower part facing downward. Forming an ink preparation chamber and the like between a pair of substrates is the same as in the conventional example shown in FIG. 1, and a cross-sectional view is omitted. The ink ejecting head includes an ink preparation chamber 12 between a pair of substrates 9, and an ink chamber 1 connected to the ink preparation chamber 12.
1. A nozzle 10 connected to an ink chamber is provided, an ink introduction section 14 is provided at the bottom of the ink preparation chamber 12, and a bubble outlet path 2 is connected to an open hole 15 to the atmosphere at the top.
2 is formed. Note that a piezo element 13 is bonded on the substrate corresponding to the ink chamber.
The ink preparation chamber 12 and the ink chamber 11 are connected to each other by an ink supply path.

To explain in detail, the inkjet recording device of the present invention has an ink preparation chamber 12, a plurality of ink chambers 11, and an ink chamber between the substrates by forming a groove in at least one of the pair of substrates 9 and bonding it to the other substrate. By forming 10 groups of nozzles corresponding to the ink ejection head, an ink ejection head is constructed. The ink preparation chamber 12 is vertically long, and the ink preparation chamber 1 is vertically long.
A plurality of ink supply passages 21 connected to each of the ink chambers 11 and a group of nozzles 10 connected to the ink supply passages are formed in order from the side in the vertical direction of 2.
(The nozzle groups 10 are formed in the vertical direction on the side surface of the head.) An ink introducing section 14 is provided at the lower part of the ink preparation chamber 12, and a bubble outlet passage 22 for discharging air bubbles in the ink is connected to the upper part. Air bubble outflow path 22
is formed along with the ink preparation chamber 12, the ink supply path 21, etc. at the joint of a pair of substrates constituting the head. The bubble outflow path 22 is formed between the pair of substrates so as to extend from the top of the ink preparation chamber 12 to the atmosphere opening hole 15 formed above the nozzle group 10 .

Ink is supplied from the ink introduction section 14 to the ink preparation chamber 1.
The ink is supplied into the ink tank 2 and is ejected from the nozzle 10 from the ink chamber 13 via the ink supply path 21. The air bubbles mixed in the ink move upward in the ink preparation chamber 12 and are discharged to the outside from the atmosphere opening hole 15 via the air bubble outlet path 22 provided above the ink preparation chamber 12. At this time, pressure may be applied from the ink introducing portion 14 to discharge the ink from the atmosphere opening hole, or the nozzle surface and the atmosphere opening hole may be covered with a cap to discharge air bubbles.

Since the ink ejecting head used in the inkjet recording apparatus of the present invention is constructed as described above, even if air bubbles are mixed in the ink supplied from the ink introduction section 14 into the ink preparation chamber 12, Since the bubbles are vertically elongated, the bubbles can go up therein, pass through the bubble outlet path 22 provided at the upper part of the ink preparation chamber 12, and be discharged to the outside from the atmosphere opening hole 15. In addition, since the mixed air bubbles always stay in the upper part of the ink preparation chamber 12, they go to the nozzle part and
It never becomes impossible to spray. Such an ink ejecting head can be formed at the same time as an ink preparation chamber by joining a pair of substrates, and is easy to configure and manufacture.The ink preparation chamber is formed in a thin container sandwiched between the pair of substrates. This prevents the generation of bubbles in the ink preparation chamber due to vibrations caused by head movement, and also reduces the amount of ink in the preparation chamber when refilling the ink when recording resumes after a certain period of time after ink ejection has stopped. It's easy. Also,
An air vent hole is provided on the nozzle side, and when pressure is applied from the ink introduction part to discharge air bubbles and the ink is discharged, it is easy to dispose of the ink that flows out from the air vent hole. Air bubbles can also be discharged from the atmosphere opening by lowering the air pressure inside the cap by covering the air opening with a clogging prevention cap, and the air bubbles can be easily discharged.

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and may be applied to a head provided with a plurality of nozzles, corresponding ink chambers, and an ink preparation chamber. It can be applied if

As described above, the present invention can provide a head for an inkjet recording device that prevents the intrusion of air bubbles, and is highly stable, that is, highly practical.

[Brief explanation of the drawing]

FIG. 1 shows a conventional jetting head for an inkjet recording apparatus, and FIG. 2 shows an embodiment of the present invention. Injection head shown.

Claims (1)

[Claims] 1. An inkjet recording device comprising an ink ejecting head in which a groove is formed in at least one of a pair of substrates, and an ink preparation chamber, a plurality of ink chambers, and nozzle groups corresponding to the ink chambers are formed at the joint with the other substrate. In the apparatus, the ink preparation chamber is vertically elongated, and a plurality of ink supply paths connected to the respective ink chambers of the ink and the nozzle group connected to the ink supply paths are arranged sideways in order in the vertical direction of the vertically elongated ink preparation chamber. The pair of substrates have an ink introduction section in the lower part of the ink preparation chamber, and an air vent hole formed in the upper part of the ink preparation chamber on the side of the nozzle opening side above the nozzle group. An inkjet recording device characterized in that air bubble outflow paths formed between the inkjet recording devices are connected.