JP2003191470A - Ink-jet recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a preferable image by preventing generation of a nozzle with ejection failure without deterioration of the printing speed or excessive ink consumption with regard to the maintenance technique of an ink-jet recording apparatus. <P>SOLUTION: Generation of a nozzle with ejection failure is prevented by forming an orifice plate with a porous material capable of being impregnated, and supplying a moisturizing liquid or an ink to the orifice plate so as to keep the nozzle meniscus surface in a moist state. Moreover, thickening of the ink in a meniscus derived from drying of the ink is prevented by regularly vacuuming the ink in the vicinity of the nozzle, that is, the meniscus by providing a negative pressure to the porous orifice plate so as to prevent generation of a nozzle with ejection failure by vacuuming the thickened ink in the meniscus surface via the orifice plate in addition to an ordinary ink supply path. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a maintenance technique in an ink jet recording apparatus that ejects ink droplets from nozzles to record on recording paper.

[0002]

2. Description of the Related Art FIG. 1 is a block diagram showing an example of the periphery of a head of an ink jet recording apparatus. At the end of printing operation, when printing is not performed, such as during standby, in order to prevent clogging due to ink evaporation from the nozzles, the head 1 is
A cap is applied by the capping means 2. The cap shields the head from the outside air, and the moisturizing effect of evaporation of the ink absorbed by the ink absorber 3 such as a sponge provided inside the cap suppresses the increase in the viscosity of the ink in the nozzle portion and also promotes clogging. Suppressed.

However, during printing, the cap is removed from the head and opened. Therefore, it tends to be in a dry state,
In order to prevent the nozzles that are rarely used from drying and sticking, ejection as a recovery operation for ejecting a predetermined number of ink droplets from all nozzle openings of each recording head, that is, a refresh operation, is performed at regular intervals. . This refresh operation is effective in preventing clogging and recovering from clogging, but extra ink is consumed in areas other than the recorded image.

FIG. 2 shows an example of a sectional view of an ink jet recording head in the prior art. 10 is an orifice plate, 20 is an ink chamber, 30 is a fixing member, 4
Reference numeral 0 is an ink supply tube, and 50 is an ink cartridge. Supply tube 40 from ink cartridge 50,
Ink 60 is stored in the common ink chamber 21 via the fixing member 30.
Is supplied. Ink 6 held in the common ink chamber 21
In the case of 0, an ink droplet is ejected from the nozzle opening 11 provided in the orifice plate 10 via the ink supply port 22, the pressure generating chamber 23, and the communication port 24 that communicates with the ink ejection port. .

In order to obtain a good image in an ink jet printer, it is important that a proper meniscus is obtained at the nozzle. Usually, when printing is not performed for a long period of time, the head is capped to prevent the viscosity of the meniscus from increasing due to evaporation of water and other volatile components in the ink. However, ink is not always ejected from the head during printing, and printing and non-printing are repeated. Particularly, in the case of heads arranged on a line in the width of the printing paper, there are areas where the printing load is relatively low. Therefore,
In the non-driving nozzle, the water content in the ink from the ink ejection port,
Evaporation of volatile components proceeds, and the viscosity of the meniscus increases. Further, as the drying progresses, the ink component becomes a film on the surface of the meniscus, which causes ejection failure and nozzle clogging when printing is restarted.

Therefore, in order to obtain good printing, the ink component is prevented from forming a film on the surface of the meniscus, or
For the purpose of destroying the formed film, shake the ink to the meniscus to the extent that ink is not ejected when not driving, or eject ink on the meniscus surface with high viscosity from the nozzle periodically. Get a normal meniscus,
So-called refreshing is performed.

However, frequent refreshing for head maintenance causes a decrease in printing speed. Further, the ink ejected by refreshing for head maintenance is not used for printing. In order to reduce the consumption of ink used for other than printing, it is sufficient to reduce the number of times of refreshing, but if the number of times of refreshing is insufficient, ejection failure and nozzle clogging will result.

The serial system, which has a relatively low speed and prints by moving the head, can also perform frequent refresh operations. However, in the line system, which is characterized by high-speed printing, refreshing which causes a decrease in printing speed is possible. Frequently performing the printing causes deterioration of printing performance.

With respect to the other maintenance operation, rocking, ink is not consumed because ink is not ejected. However, frequent rocking means a lot of time other than printing, and
This causes a decrease in printing speed.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to solve these problems and to obtain an ink jet recording apparatus which does not cause a printing speed decrease and excessive ink consumption for maintenance and does not cause ejection failure. To aim.

[0011]

In order to achieve the above object, in the present invention, a common ink chamber that stores ink, an ink supply port that communicates with the common ink chamber, and a pressure generation that communicates with the ink supply port. A recording head comprising a chamber and an orifice plate having a plurality of nozzle openings for ejecting ink to record on a recording material, the orifice plate comprising a porous member capable of impregnating ink,
In addition, the surface of the orifice plate on the ink ejection port side is subjected to an ink repellent treatment.

Further, the orifice plate seals one surface of a common ink chamber for supplying ink to each nozzle opening for ejecting ink.

A common ink chamber that stores ink, an ink supply port that communicates with the common ink chamber, a pressure generation chamber that communicates with the ink supply port, and a plurality of units that record ink by ejecting ink A recording head having an orifice plate having individual nozzle openings, wherein the orifice plate is made of a porous member capable of impregnating ink, and the surface of the orifice plate is subjected to surface treatment having no ink permeability. It is characterized by that.

Further, it is characterized in that it is provided with an ink supply path to the common ink chamber and a second supply path for supplying the moisturizing liquid or ink to the orifice plate.

Further, an orifice plate is connected to one end of the second communication port, and a suction pump is connected to the other end.

Further, the surface of the orifice plate on the ink chamber side is subjected to ink-philic treatment, and the surface on the ink ejection side is subjected to ink repellent treatment.

[0017]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings.

FIG. 3 is a sectional view showing the construction of a first example of the ink jet recording head according to the present invention. Also,
FIG. 4 is an enlarged view of the nozzle portion of the head of the first example of the present invention.

Here, the difference from the prior art is that the orifice plate 10 forming the nozzle opening 11 is made of a porous member capable of impregnating and holding a liquid, for example, a metal or ceramic material made by sintering or the like. It is being formed.

When a porous material is used for the orifice plate 10 and its property is utilized, when the ink is filled in the head, the orifice is introduced from the surface in contact with the common ink chamber and around the nozzle opening. In the plate 10,
The ink is permeated and held by the capillary phenomenon.

In other words, the surroundings of the meniscus 17 shown in FIG. 4 are always kept moist, and ink drying can be suppressed as much as possible even when the cap is opened.
Further, the surface of the orifice plate 10 on the ejection opening side is subjected to a surface treatment of the ink repellent film 18, so that the ink is prevented from seeping out to the surface of the orifice plate 10 other than around the nozzles.

Furthermore, since only the nozzle opening is slightly recessed and no ink repellent treatment is applied to that portion, the moisturizing property of the meniscus can be more effectively maintained.

FIG. 5 shows a second example of the present invention. The second communication port 41 provided in the fixed member 30 is directly connected to the orifice plate 10. The second communication port 41
Is a moisturizing liquid that can be mixed with ink (for example,
Glycerin or the like having a reduced viscosity is supplied to permeate and maintain the orifice plate 10.

Further, the surface of the orifice plate 10 (including the surface on the ink chamber side opposite to the surface on the ejection opening side) is subjected to a surface treatment that does not allow ink to permeate, and mixed with ink in the common ink chamber. It is supposed not to.

Here, the surface treatment that does not allow the ink to permeate is specifically a film formation on the surface of the multi-component member by a metal, a resin, or a combination thereof, and in particular, it is given a function as a water-repellent film. Shows the surface treatment. Examples of the treatment method include a plating treatment, a treatment by a vacuum deposition method or a sputtering method, and a coating treatment generally used for magnetic tapes and the like.

Further, it is preferable that the surface of the orifice plate 10 on the ink chamber side is subjected to ink-philic treatment and the surface treatment on the ejection opening side is subjected to ink repellent treatment. The reason is that the surface of the orifice plate 10 on the ink chamber side is subjected to ink-philic treatment to facilitate ink priming, and the surface treatment on the ejection opening side is subjected to ink repellent treatment. This is because there is an improvement in straightness and cleaning properties.

Due to the effect of the moisturizing liquid with which the orifice plate 10 is impregnated, the moisturizing property in the meniscus portion near the nozzle is maintained, and the ink is prevented from drying.

Further, as shown in FIG. 6, one end of the second communication port is connected to the orifice plate and the other end is connected to the suction pump. The negative pressure sucked by the suction pump gives a negative pressure to the porous material of the orifice plate, so that the ink in the vicinity of the nozzle opening can be sucked. Here, there are times when the printing apparatus does not always perform printing even when printing is being performed.

For example, if the sheet is a cut sheet, no printing is performed between pages, and if it is continuous paper, printing is not performed at the time of line feed such as a page break. At this time, the suction pump is operated to give a slight negative pressure. By this negative pressure, the ink near the nozzle, that is, the ink in the meniscus is sucked. By performing this suction regularly, it is possible to prevent the viscosity of the ink from increasing in the meniscus portion due to the drying of the ink as described above.

This makes it possible to obtain substantially the same effect as the regular refresh operation performed in the conventional example. In other words, it is possible to obtain the same effect as the conventional refresh operation without interrupting printing.
As a result, it is possible to prevent the execution printing speed of the printing apparatus from decreasing.

In the present invention, from the viewpoint of preventing foreign matter from adhering to the orifice plate 10, a capping means is required, but the capping frequency is lower than in the conventional case. Further, since it is sufficient to prevent foreign matter from adhering, a relatively simple capping means can be used.

[0032]

As described above, according to the present invention,
The area around the meniscus is always kept moist, and even when the capping means is opened, the drying of the ink can be suppressed as much as possible.

Further, by applying a negative pressure to the porous orifice plate and periodically sucking the ink in the vicinity of the nozzle, that is, in the meniscus, it is possible to prevent the ink from thickening in the meniscus portion due to the drying of the ink. Becomes

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating an example of a head periphery of an inkjet recording apparatus.

FIG. 2 is an example of a cross-sectional view of an ink jet recording head in the related art.

FIG. 3 is a cross-sectional view showing the configuration of a first example of an ink jet recording head according to the present invention.

FIG. 4 is an enlarged view of a nozzle portion in FIG.

FIG. 5 is a configuration diagram showing a second example of the ink jet recording head according to the present invention.

FIG. 6 is a schematic diagram showing an example of an inkjet recording apparatus according to the present invention.

[Explanation of symbols]

1 is a head, 2 is a capping means, 3 is an ink absorber, 4 and 5 are suction pumps, 6 is a waste ink tank, 10 is an orifice plate, 11 is a nozzle opening, 17 is a meniscus, 18 is an ink repellent film, 20 Is the ink chamber, 2
1 is a common ink chamber, 22 is an ink supply port, 23 is a pressure generating chamber, 24 is a communication port, 30 is a fixing member, 40 is an ink supply tube, 41 is a second communication port, 42 is an ink suction tube, and 50 is An ink cartridge, 60 is ink.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoru Tobita             Hitachiko, 1060 Takeda, Hitachinaka City, Ibaraki Prefecture             Machine Co., Ltd. F-term (reference) 2C056 EA14 EA17 EA25 EC08 EC21                       EC30 EC43 HA05 HA19 HA24                       JA13 JC13 KC02                 2C057 AF74 AG01 AG07 AM31 BA03

Claims (6)

[Claims] 1. A common ink chamber that stores ink, an ink supply port that communicates with the common ink chamber, a pressure generation chamber that communicates with the ink supply port, and a plurality of units that eject ink to record on a recording material. A recording head having an orifice plate having individual nozzle openings, wherein the orifice plate is made of a porous member capable of being impregnated with ink, and an ink repellent treatment is applied to a surface of the orifice plate on an ink ejection port side. An inkjet recording head characterized by being applied. 2. The ink jet recording head according to claim 1, wherein the orifice plate seals one surface of a common ink chamber that supplies ink to each nozzle opening for ejecting ink. 3. A common ink chamber that stores ink, an ink supply port that communicates with the common ink chamber, a pressure generation chamber that communicates with the ink supply port, and a plurality of units that eject ink to record on a recording material. A recording head having an orifice plate having individual nozzle openings, wherein the orifice plate is made of a porous member capable of impregnating ink, and the surface of the orifice plate is subjected to surface treatment having no ink permeability. An inkjet recording head characterized by the above. 4. An ink jet recording head according to claim 3, further comprising an ink supply path to a common ink chamber and a second supply path to supply a moisturizing liquid or ink to the orifice plate. 5. The ink jet recording head according to claim 4, wherein one end of the second communication port is connected to an orifice plate and the other end is connected to a suction pump. 6. The ink jet recording head according to claim 3, wherein a surface of the orifice plate on the ink chamber side is subjected to ink-philic treatment and a surface on the ink ejection side is subjected to ink repellent treatment.