JPH043306B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an inkjet recording device used in color printers, facsimile machines, and the like.

Conventional Structures and Problems Inkjet recording devices are a recording technology that has come to be widely used as computer output and in facsimiles, and has recently been in the spotlight as a color display hard copy device. However, one of the drawbacks of inkjet recording devices is that the nozzles become clogged due to ink drying. Various methods have been disclosed to overcome this drawback. The most basic method for preventing clogging is to use a cap that isolates the nozzle from the outside air and suppresses or prevents evaporation of the ink solvent.Furthermore, the inside of the cap can be constantly humidified with ink solvent vapor. A method of incorporating a humidifying member into a cap is known.

However, all methods have had problems with long-term reliability and stability.

FIG. 1 is a schematic diagram of a clogging prevention device disclosed in Japanese Utility Model Application Publication No. 56-27935, and the clogging prevention function will be briefly explained below.

In the figure, the head 1 is in its home position and the humidifying lid 2 is operated by an actuating mechanism (not shown).
is pressed against head 1. A humidifying member 3 is incorporated in the humidifying lid 2, and a humidifying liquid 6 is supplied through a humidifying container 4 and a humidifying liquid supply pipe 5.
The steam flows into the air chamber 9 from the air nozzle 8 of the head 1, and the air chamber 9 is humidified.

This suppresses evaporation of the ink solvent from the ink nozzle 10 and prevents clogging. However, even a humidifying lid having such a function cannot completely prevent the ink solvent from evaporating from the ink nozzle 10. One of the reasons for this is that the air chamber 9 of the head 1 communicates with an air supply passage 11, an air supply pump 12, a pressure regulating valve 13, and an ink reservoir 14, and the humidified steam in the air chamber 9 passes through these routes to the outside. This can lead to leakage. Note that 15 is ink and 16 is an ink supply pipe. For this reason, such clogging prevention devices require a nozzle diameter of approximately 40 μm.
The clogging life is approximately one month at 20℃ and 65%RH.

FIG. 2 is a schematic diagram of a clogging prevention device disclosed in Japanese Patent Publication No. 57-46476.

The same parts in the figure as in FIG. 1 are given the same reference numerals.

In the figure, when the equipment is stopped, air chamber 9 of head 1
The air supply passage 11 from the ink solvent tank 19 to the ink solvent tank 19 is isolated from the outside air by the ink solvent 20 accumulated in the air supply pipe 18 made of a permeable membrane, and is humidified by the vapor of the ink solvent 20. on the other hand,
The clogging caused by the evaporation of the ink solvent from the ink nozzle 10 adjacent to the air nozzle 8 is caused by the ink solvent accumulated in the permeable membrane air supply pipe 18 when the air supply pump 12 is activated at the start of recording. 2
0 is sent to the head air chamber 9 by air pressure, and the ink solvent is discharged from the air nozzle 8 while cleaning the ink nozzle 10.

However, with this method, if a nozzle is completely clogged, it may not be possible to eliminate the clog with one short passage of the ink solvent.

As described above, clogging caused by evaporation of ink solvent occurs when the ink solvent in the ink evaporates and the ink becomes a solid or highly viscous substance that sticks around the nozzle, causing the piezoelectric vibrator 17, etc. This occurs when the pressure waves generated are not pushed out, and the above method eliminates clogging by softening or reducing the viscosity of solids or highly viscous substances by humidifying or washing. However, none of them were sufficient.

Furthermore, it is well known that when an organic substance adheres to a metal, the adhesion force generally differs depending on the state of the metal surface. i.e. surface area, surface roughness,
Adhesive strength varies significantly depending on chemical properties, hardness, etc.

Incidentally, the nozzle of the ink jet head shown in FIGS. 1 and 2 uses a thin plate of austenitic stainless steel in which the nozzle is formed by drilling or electric discharge machining. However, although stainless steel is generally a nozzle material with excellent corrosion resistance, processability, and mechanical rigidity, some inks use chemicals that corrode stainless steel, such as dyes containing halogen elements. If used for a long period of time, the area around the ink nozzle may become slightly corroded.

In addition, during deburring work after nozzle processing,
This may cause scratches or drips on the nozzle opening. Such corrosion or scratches increase the adhesion of sticky or solid matter caused by evaporation of the ink solvent, causing clogging.

OBJECTS OF THE INVENTION The present invention provides an inkjet recording device that eliminates the problems such as clogging and corrosion as described above.

Structure of the Invention The present invention provides a highly hard film made of a carbide or nitride of a Group 3, Group 4, or Group 6 element on the surface of an ink nozzle, an air nozzle, etc. of an ink jet head using stainless steel as a nozzle material. This is an inkjet recording device with a

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 is an enlarged sectional view of the vicinity of the nozzle in one embodiment of the present invention.

In the figure, a thin stainless steel plate 26 constituting the ink ejection nozzle 10 has a surface containing group 3,
Highly hard substances 27 such as carbides or nitrides of Group 4 or Group 6 elements, such as boron carbide, boron nitride, silicon carbide, titanium carbide, silicon nitride, titanium nitride, or tungsten carbide, are deposited, sputtered, or plasma sprayed. Alternatively, it is formed by ion plating or the like. Reference numeral 8 denotes an air nozzle formed in the stainless steel plate material 30, through which an air flow from an air supply pump (not shown, but corresponds to FIG. 12) is injected through the air chamber 9. On the other hand, the ink in the ink pressure chamber 29 receives a pressure increase due to the vibration of a piezo diaphragm (not shown), and the pressure is propagated to the outer ink supply channel 15 via the ink coupling channel 28, and the ink is discharged. It is ejected from the nozzle 10 and is ejected onto the recording medium together with the air flow from the air nozzle 8.

In this configuration, the periphery of the ink ejection nozzle 10 and the nozzle wall surface become extremely hard due to the high hardness film 27, and are also chemically very stable (inert), so that they are prevented from being corroded by the ink. This prevents abrasion caused by passage, stabilizing the ejection of ink droplets over a long period of time, and furthermore, sticky or solid matter caused by ink drying can be easily peeled off simply by the ink ejection pressure of the piezo vibrator. Clogging life is significantly improved.

FIG. 4 is an enlarged sectional view of the vicinity of the nozzle in another embodiment of the present invention. The same parts in the figure as in FIG. 3 are given the same reference numerals. This embodiment is an example in which a highly hard material 37 similar to the highly hard material 27 is attached to the surface of a thin stainless steel plate 30 constituting the air discharge nozzle 8 in addition to the structure of the embodiment shown in FIG. . As a result, the abrasion resistance of the periphery of the air discharge nozzle 8 and the front surface thereof is greatly improved by the high hardness coating 37.
When the head cleaner made of an elastic material such as rubber disclosed in the above publication is used, scratches on the surface due to cleaning are eliminated, and the adhesion of ink mist and dust is also reduced, so that the cleaning effect is significantly improved.

FIG. 5 is an enlarged sectional view of the vicinity of the nozzles in a multi-nozzle head according to another embodiment of the present invention.

Generally, to assemble a multi-nozzle head,
As shown in the figure, a plate material 30 for forming air nozzles 8-a and 8-b, air supply distribution channels 9-a and 9
A plate material 31 for forming the ink discharge nozzles 10-a and 10-b, a plate material 2 for forming the ink discharge nozzles 10-a and 10-b
6. Plate material 32 for forming ink supply channels 15-a and 15-b, ink coupling channels 28-a and 2
A plate material 33 for forming the ink pressure chambers 8-b and a plate material 3 for forming the ink pressure chambers 29-a and 29-b.
4, etc., a plurality of plate materials are laminated using an adhesive such as epoxy resin or diffusion bonding.

However, when using an organic adhesive, there are many restrictions such as control of the adhesive layer and adhesive strength, and at present, diffusion bonding using a metal bonding material is the mainstream method of lamination. However, with dissipative bonding, stainless steel plates are heat-treated at a high temperature of 1000°C or higher, which removes the processing strain caused by rolling, resulting in a significant decrease in hardness, loss of mechanical rigidity, and the possibility of denting and damage. There are drawbacks to this. Furthermore, as described in FIGS. 2 and 3 above, it is technically difficult to use a plate material to which the above-mentioned highly hard coating is added as a nozzle material. Therefore, as shown in FIG.
After diffusion bonding 6, 32, 33, and 34, a highly hard coating 37 is applied to the surface of the plate material 30 by vapor deposition, sputtering, plasma spraying, ion plating, or the like. At this time, the highly hard material 37 passes through the openings of the air nozzles 8-a and 8-b and is also formed around the nozzles 10-a and 10-b as shown at 27-a and 27-b.

In the above embodiments, the type in which air is ejected from an air nozzle has been described, but the present invention can also be applied to an inkjet recording device in which only ink is ejected without using an air flow. . In this case, a highly hard coating may be formed on the surface of the ink nozzle.

Further, the highly hard coating may be formed at least on the nozzle surface, and may of course be formed on the nozzle wall surface, the back surface of the nozzle plate, etc.

Effects of the Invention As described above, the present invention provides an inkjet recording device in which the nozzle head itself of the inkjet head is made of stainless steel to ensure sufficient strength and rigidity, and a highly hard film is formed on the nozzle surface of the inkjet head. The device prevents corrosion and abrasion of the nozzle caused by ink, eliminates clogging caused by it, improves the cleaning effect by hardening the nozzle plate surface, and improves mechanical rigidity. This makes it possible to provide an inkjet recording device with high performance.

[Brief explanation of drawings]

1 and 2 are schematic configuration diagrams showing an example of a conventional inkjet recording device, and FIGS. 3, 4, and 5 are enlarged sectional views of the vicinity of the nozzles of an inkjet head in one embodiment of the present invention, respectively. It is. 1... Ink head, 2... Humidifying lid, 8... Air nozzle, 9... Air chamber, 10... Ink nozzle, 18... Permeable membrane air supply pipe, 20... Ink solvent, 27, 37... Highly hard film, 28... Ink coupling passage, 26, 30, 31, 32, 33,
34...Stainless steel plate material.

Claims (1)

[Claims] 1. A third ink discharge nozzle and/or air nozzle surface made of stainless steel.
The present invention is characterized by being equipped with an inkjet nozzle formed with a highly hard film made of a carbide of an element of Group 3, Group 4, or Group 6, or a nitride of an element of Group 3, Group 4, or Group 6. Inkjet recording device. 2. The inkjet recording device according to claim 1, wherein the stainless steel is austenitic stainless steel. 3. The inkjet recording device according to claim 1 or 2, wherein the highly hard film is formed by means such as vapor deposition, sputtering, plasma spraying, or ion plating.