JPS6221630B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an inkjet recording device that generates ink particles from a nozzle hole by applying a voltage required for particle generation to an electromechanical transducer during recording. Concerning prevention of clogging.

[Prior Art] There are many types of so-called inkjet recording devices that generate ink particles from nozzle holes to record and reproduce information on a recording medium.

Among these methods, a method (also called an on-demand method) in which a driving voltage is applied to an electromechanical transducer only during recording and ink particles are generated from a nozzle hole has the advantage that the device can be easily constructed.

However, since this type of inkjet device does not eject ink when not recording, there is a problem that if this state continues for a long time, the ink dries and the nozzle holes become clogged.

Techniques for preventing clogging of inkjet recording devices include a method of covering the nozzle hole surface with an ink evaporation prevention film as described in Japanese Patent Application Laid-Open No. 105534/1982, and a method attached to the application of Utility Model Application No. 101117/1983. A method is known in which the solvent is dripped from a solvent tank into a nozzle, as described in the microfilm photographed specification and drawings.

[Problems to be Solved by the Invention] However, all of these methods require means for supplying a clogging prevention liquid separate from ink, and therefore, the size and structure become large and complicated. There are drawbacks to it.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to prevent clogging of nozzle holes in a so-called on-demand type inkjet device without increasing its size or complicating its structure.

[Means for Solving the Problems] In order to achieve this object, the present invention provides a liquid film forming hole that opens at the end face of the nozzle head at the upper part of the nozzle hole for ejecting ink particles, an ink supply chamber, and the liquid film. The ink in the ink supply chamber is communicated with the forming hole and is supplied to the liquid film forming hole using capillary phenomenon, so that the ink constantly oozes out from the liquid film forming hole, thereby forming an ink film on the surface of the nozzle hole. The present invention is characterized in that the ink absorber is provided with a flow path formed to form an ink droplet, and an ink absorber that contacts the end surface of the nozzle head at a lower part of the nozzle hole for ejecting ink particles.

[Function] Ink always oozes out from the liquid film forming hole and forms an ink film on the surface of the nozzle hole, so the nozzle hole never gets clogged, and the ink flowing down the end face of the nozzle head is absorbed by the ink absorber at the bottom of the nozzle hole. Since the nozzle head is absorbed by the liquid, the nozzle head is not significantly contaminated, and the liquid film forming hole can be formed at the same time as the nozzle hole, so there is no need to increase the size of the liquid film and make the structure complicated. There's nothing to do.

[Example] Figures 1 and 2 show an on-demand type inkjet recording device, in which 1 is a nozzle head, 2 is a drive voltage source for an electromechanical transducer consisting of an electrostrictive vibrator, etc., and 3 is a generated voltage source. ink particle group,
4 is a recording medium. To explain the nozzle head 1 in more detail, 11 is a substrate, 12 is a side plate, 13 is an electromechanical transducer, and 14 is an ink supply pipe.

The illustrated nozzle head 1 has three nozzle holes, including ink chambers 15a, 15b, 15c,
Nozzle holes 16a, 16b, 16c, fluid diodes 17a, 17b, 17c, and common ink chamber 18
In addition, an ink supply hole 19 is formed.
is open. Side plates 12 are bonded to the substrate 11, and each side plate 12 has an ink chamber 15a.
Electromechanical transducer elements 13a-1 corresponding to ~15c
3c is glued.

Ink 20 is filled from an ink tank (not shown) through the ink supply pipe 14 and the ink supply hole 19 into the common ink chamber 18, fluid diodes 17a to 17c, ink chambers 15a to 15c, and nozzle holes 16a to 16c.

When a driving voltage signal of a polarity that reduces the internal volume of the ink chambers 15a to 15c is applied to the electromechanical transducers 13a to 13c, the ink chambers 15a to 1
The ink pressure in 5c increases, and the nozzle holes 16a~
Ink particles 13 are ejected from 16c.

The fluid diodes 17a to 17c are in the ink chamber 15.
The ink pressure generated in a to 15c is transferred to the common ink chamber 1.
Minimize the escape to nozzle hole 1 as much as possible.
6a to 16c.

In such an inkjet recording apparatus, images 30a to 30c are recorded as shown in FIG. (a) to (b) are accompanied by the passage of time. At the initial stage, the image 30a is well recorded, but as time passes, as shown in FIG. 3b, the image 30a becomes noticeably dotted by the nozzle hole 16a, and in FIG. 3c, the image 30a is no longer recorded.

In these cases, the wet state of the nozzle hole surface was observed as shown in FIG. 4. That is, the ink oozes out from the nozzle holes 16a to 16c, and the ink film 21 of the ink 20 is formed in the nozzle holes 16a to 16.
It covers the surface of c. In this state, the nozzle holes 16a to 16c are not clogged, and the third
It can be recorded as shown in Figure a. However, as time passes and the ink film 21 dries, the nozzle hole 16a
dries quickly, and as a result, the nozzle hole 16a becomes clogged. In this case, it was found that since the ink film 21 bleeds downward, the nozzles 16b and 16c located below the ink film 21 are hardly clogged.

In view of this, the inventors have developed a liquid film forming hole 22 which opens in the end surface of the nozzle head 1 above the nozzle holes 16a to 16c for ejecting ink for recording, as shown in FIGS. 5 and 6. The common ink chamber 18 and the liquid film forming hole 22 are connected to each other, and the ink in the common ink chamber 18 is supplied to the liquid film forming hole 22 using capillary phenomenon. It was considered to provide a flow path 23 that forms an ink film 21 on the surface of the nozzle hole by constantly causing ink to ooze out from the nozzle hole. No fluid diode is required between the flow path 23 and the common ink chamber 18. In this case, even if the ink 20 is not particularly pressurized, the ink 20 oozes out from the liquid film forming hole 22 due to capillary action in the flow path 23 . However, in this case, the end face of the nozzle head, especially its lower part, becomes dirty due to the accumulation of flowing ink. Therefore, the inventors proposed that the lowest nozzle hole 16 for ejecting ink particles
It was considered to provide an ink absorber 29 in contact with the end face of the nozzle head at the lower part of the nozzle head.

In this way, the liquid film forming hole 22 which opens at the end face of the nozzle head at the upper part of the uppermost nozzle hole 16a for ejecting ink particles communicates with the common ink chamber 18 and the liquid film forming hole 22. The ink in the ink chamber 18 is supplied to the liquid film forming hole 22 using capillary phenomenon, so that the ink constantly oozes out from the liquid film forming hole 22, thereby forming an ink film 21 on the surface of the nozzle hole. an ink absorber 29 that contacts the end surface of the nozzle head at the lower part of the lowest nozzle hole 16c for ejecting ink particles.
If the nozzle hole 16 is provided with a
It is possible to prevent clogging of a to 16c, and also prevent the end face of the nozzle head 1 from becoming abnormally dirty.

[Effects of the Invention] As described above, the present invention has a liquid film forming hole that opens at the end face of the nozzle head at the upper part of the nozzle hole for ejecting ink particles, and a liquid film forming hole that communicates with the ink supply chamber and the liquid film forming hole. A flow path configured to form an ink film on the surface of the nozzle hole by constantly oozing ink from the liquid film forming hole by supplying ink in the supply chamber to the liquid film forming hole using capillary phenomenon. By providing this, it is possible to prevent clogging of the nozzle hole without providing a special means for supplying the liquid, and the ink absorber that contacts the end surface of the nozzle head at the lower part of the nozzle hole for ejecting ink particles. By providing the body, it is possible to obtain the effect that the end face of the nozzle head is not contaminated abnormally.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIGS. 1 and 2 are schematic diagrams of an on-demand type inkjet recording device, FIG. 3 is an explanatory diagram showing an example of image recording, and FIG. 4 is a diagram of a nozzle hole. 5 and 7 are schematic diagrams of an on-demand type ink jet recording apparatus according to the present invention, and FIG. 6 is an explanatory diagram of the surface state of the nozzle holes. 1... Nozzle head, 3... Ink particle group, 1
3a to 13c...electromechanical conversion elements, 15a to 1
5c... Ink chamber, 16a to 16c... Nozzle hole, 18... Common ink chamber, 20... Ink, 2
1... Ink film, 22... Liquid film forming hole, 23...
...Flow path, 29...Ink absorber.

Claims (1)

[Claims] 1 The internal volume of the ink chamber is changed by an electromechanical conversion element provided corresponding to the ink chamber of the nozzle head, and the ink supplied from the ink supply chamber to the ink chamber is communicated with the ink chamber, and the end face of the nozzle head is In an inkjet recording device that records information by ejecting ink from a nozzle hole that is opened at The ink in the ink supply chamber is communicated with the forming hole and is supplied to the liquid film forming hole using capillary phenomenon, so that the ink constantly oozes out from the liquid film forming hole, thereby causing ink to reach the surface of the nozzle hole. An inkjet recording device comprising: a flow path for forming a film; and an ink absorber that contacts the end face of the nozzle head at a lower part of the nozzle hole for ejecting ink particles.