JPH09164690A - Ink jet recording head, production thereof and ink jet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize an ink emitting direction by holding ink repelling capacity over a long period of time without generating the falling-off caused by the friction of wiping work and to simply and inexpensively produce an ink jet recording head. SOLUTION: This recording head is an ink jet recording head wherein at least the peripheries of ink emitting orifices are composed of metal and crosslinked matter of methylhydrogenpolysiloxane is provided to the peripheries of the ink emitting orifices. The recording head is produced by immersing at least the peripheries of the ink emitting orifices of the ink jet recording head wherein at least the peripheries of the ink jet emitting orifices are composed of metal in a methylhydrogenpolysiloxane soln. and pulling up the recording head to heat the same.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to an ink jet recording head. More specifically, the present invention relates to an inkjet recording head that maintains ink repellent performance for a long period of time and that has stable ink ejection directions.

[0002]

2. Description of the Related Art In a head of an ink jet recording apparatus, it is extremely important to strictly control the ink ejection direction. This is because, no matter how accurately the positions of the head and the recording medium are controlled during recording, the quality of the recorded image will be low if the ink ejection direction is not fixed. The cause is hydrophilicity around the ink ejection port when the ink is water-based. That is,
If the periphery of the ink ejection port is hydrophilic, the ink will wet it, and the ink ejected to the wet portion will be pulled, so to speak, and the ejection direction of the ink will be bent.

Therefore, in order to prevent the ink from getting wet around the ejection openings, there has been proposed a method of applying water repellent treatment or ink repellent treatment around the ejection openings. For example, when a wiping operation is performed by a method of applying silicone grease or the like as an ink repellent agent around the ink ejection port,
Even the silicone grease was wiped off, and there was a problem that the ink repellent performance could not be maintained for a long time.

Further, as a solution to such a problem, under the idea of increasing the binding force between the ink repellent agent and the periphery of the ink ejection port, a pretreatment is performed around the ink ejection port, and then an ink repellent treatment is performed. A method of doing so has been proposed (for example, Japanese Patent Laid-Open No. 6-210857). However, such a method has a problem that the manufacturing process becomes complicated.

[0005]

In view of the above problems, the present invention provides an ink jet recording head which retains ink repellency for a long period of time without falling off due to friction such as wiping work, and can be manufactured simply and at low cost. It is a thing.

[0006]

The present invention solves the above problems by the following gist.

That is, the ink jet recording head of the present invention is an ink jet recording head in which at least the periphery of the ink ejection port is made of metal, and has a crosslinked product of methylhydrogenpolysiloxane around the ink ejection port. It is an inkjet recording head.

Further, the ink jet recording head of the present invention is an ink jet recording head which is made of metal at least in the portion in contact with the ink discharge port and in the ink flow passage, and the portion in contact with the ink discharge port and the ink flow passage is methyl. An inkjet recording head having a cross-linked product of hydrogen polysiloxane. Furthermore, the method for manufacturing an inkjet recording head of the present invention has the following configuration in order to solve the above problems.

That is, a method of manufacturing an ink jet recording head characterized in that at least the ink jet recording head of which at least the ink ejection port periphery is made of metal is dipped in a methylhydrogenpolysiloxane solution, and is pulled up and then heated. Is.

[0010]

The present invention will be described in more detail below.

What is important in the present invention is that the periphery of the ink ejection port is made of metal. Generally, hydroxyl groups are present on the metal surface. Methyl hydrogen polysiloxane with ink repellency on its surface (hereinafter abbreviated as MHPS)
When the crosslinking reaction of MHPS is performed,
The crosslinked product of HPS and the hydroxyl group on the metal surface are bonded. As a result, the cross-linked product of MHPS is firmly fixed to the metal forming the periphery of the ink ejection port, and it is possible to impart durability and chemical resistance to friction (excluding extremely strong acid and strong alkali).

The cross-linking treatment of the MHPS may be performed not only on the periphery of the ink ejection port but also on the portion in contact with the ink flow path. In that case, impurities and the like in the ink are less likely to be deposited, and there is a secondary advantage that the ink is strong against clogging.

The metal used above is not particularly limited, and those generally used are used, but when leaving an exposed surface on which the MHPS crosslinked product is not laminated, remarkable rusting occurs. Things are not preferable. In this respect, for example, SUS303, S
Stainless steels such as US304, SUS316, SUS316J are preferably used. However, this is not the case when the MHPS crosslinked product is completely covered.

The layer thickness of the crosslinked product of MHPS is preferably preferably basically thin, but if it is too thin, problems may occur in strength, so 0.001 to 5 μm is preferable, and 0.
001 to 2 μm is more preferable, 0.01 to 1 μm is still more preferable, and 0.05 to 0.5 μm is still more preferable.

The ink jet recording head of the present invention can be used regardless of a system such as an on-demand system or a continuous system, but can be preferably used for the continuous system. In particular, in the continuous method, ink pressure is generally higher than in the on-demand method, and a robust head is desired. Therefore, it is suitable to use a metal for parts including the periphery of the ink ejection port, such as a nozzle plate. Because.

Next, a method of manufacturing the above ink jet recording head will be described.

While it has been described above that it is important that at least the periphery of the ink discharge port is made of metal among the parts constituting the ink jet recording head, at least that part is dipped in the MHPS solution, pulled up and then heated. , A three-dimensional crosslinked product of MHPS is formed. At that time, after pulling up from the MHPS solution and before heating,
It is preferable to blow a gas from the back side of the ink ejection port to blow off the MHPS solution in the ink ejection port. For example, so-called compressed air of 0.5 kg / cm 2 or more may be used. Further, it is not necessarily air, and may be gas such as nitrogen, but it is more preferable to use oxygen from the viewpoint of the crosslinking reaction of MHPS.

Further, instead of flowing the gas from the back side of the ink ejection port, the same effect can be obtained by conversely sucking the MHPS solution together with the gas of the atmosphere from the back side of the ink ejection port. The negative pressure to be sucked may be appropriately determined, but there is no particular problem as long as it is 10 mmHg or more.

Alternatively, a method in which the ink inlet on the opposite side of the ink outlet is closed by using, for example, a commercially available adhesive tape before the immersion and then the immersion is performed also prevents the ink outlet from being blocked by MHPS. It is preferably carried out for the purpose.

This is considered to be due to the following reason. That is, when the nozzle outlet is immersed in the MHPS solution, the MHPS solution tries to flow into the nozzle.
For that purpose, the air inside the nozzle must be expelled. Here, if the ink inflow port located opposite to the ink ejection port in the ink flow path communicates with the atmosphere, the MHP
The volume of air into which the S solution flows is easily expelled.
However, if the ink inlet is blocked with an adhesive tape or the like, the air that is removed because the MHPS solution flows in must exit through the MHPS solution side. The nozzle diameter is as small as several tens of μm, and MHPS
Since the solution also has a viscosity, the air inside the nozzle cannot substantially escape. Therefore, the MHPS solution almost never flows into the nozzle,
It is considered that the blockage due to

Further, it is also a preferable method to spin coat the MHPS solution at least around the ink ejection port, instead of dipping in the MHPS solution as described above.

In the case of spin coating, it is preferable that the nozzle portion is not located at the center of rotation of spin coating. Furthermore, if it is farther from the center of rotation, a strong centrifugal force acts and the MHPS solution is introduced into the nozzle. It is preferable from the viewpoint of acting in the direction of suppressing clogging.

In this case, a more uniform crosslinked film of MHPS can be obtained. In the case of spin coating, as in the case of the above-mentioned dipping method, it is preferable to spin the MHPS solution and then let the gas flow from the back side of the ink ejection port, or conversely suck the MHPS solution together with the gas. Further, these operations may be performed while spin coating. The program such as the number of rotations and the number of seconds of spin coating may be appropriately set so that the film thickness of the above-mentioned preferable crosslinked product of MHPS is obtained.

As in the dipping method, it is also preferable to block the ink inlet on the opposite side of the ink ejection port before spin coating, and then spin coat. In this case, the means for closing the ink inlet may be an adhesive tape or the like, and a mechanism for closing the ink inlet when the parts constituting the nozzle portion are installed on the base of the spin coater. It is also preferable to use a table of a spin coater equipped with. For example, such a mechanism refers to a mechanism in which a rubber is laid on a spin coater, and when a component forming a nozzle portion is installed on the spin coater, the rubber plays so as to block the ink inlet.

The MHPS used in the present invention is not particularly limited, but preferably has a viscosity of 5 to 1000 cp at 25 ° C., and 10 to 500 cp.
s is more preferable, 20-100 cp is more preferable, 20-40 cp is even more preferable. Further, it may be partially modified with epoxy, fluoroalkyl or the like.

The MHPS solution can be easily prepared by adding oily MHPS to a suitable solvent. The solvent is not limited, but very general hydrocarbons such as hexane, heptane, decane, toluene, benzene and the like, ketones such as acetone and methyl ethyl ketone may be used. The concentration of the MHPS solution is 0.1
10% is preferable, 0.3-5% is more preferable, and 0.
5 to 2% is more preferable. In the case of spin coating, MHPS stock solution can also be used.

In the case of the dipping method, at least the circumference of the ink ejection port is dipped in the MHPS solution for 1 second to
1 hour is preferable, 3 seconds to 30 minutes is more preferable, and 5 seconds to 20 minutes is further preferable.

The heating temperature is preferably 100 to 200 ° C, more preferably 120 to 180 ° C, and 140 to 16
0 ° C is still preferred. The heating time is preferably 10 minutes to 1 hour, more preferably 10 minutes to 30 minutes, and even more preferably 15 minutes to 25 minutes.

Further, for example, a catalyst such as zinc octanoate, iron octanoate, dibutyltin dilaurate, tin octanoate or the like may be added to the MHPS solution. The concentration may be appropriately determined, but it is 5 to 1 for MHPS.
5%, more preferably around 10% is suitable. In that case, although depending on the heating temperature, the heating time can be made shorter than that in the case where the catalyst is not added, and 1 minute to 10 minutes is sufficient.

The recording medium for ink jet recording in which the ink jet recording head of the present invention is used is not only paper, but synthetic fiber such as polyester or polyamide fiber, natural fiber such as cotton or silk, or semi-synthetic fiber. A woven fabric, a knitted fabric, a non-woven fabric, or various films made of, for example, can be used without any problem.

As for the ink to be used, various inks may be appropriately used corresponding to various non-recording materials.
A preferable example is a water-based ink having a viscosity of 3
It has a surface tension of 1 to 5 cp at 0 ° C. and a surface tension of 30 to 60 dyne / cm at 30 ° C. Further, for example, when it is used for so-called cloth such as woven fabric, knitted fabric and non-woven fabric, an inkjet dyeing method is particularly effective. In that case, when the cloth is made of polyester, use an ink containing a disperse dye or the like. When the cloth is made of polyamide, an ink containing an acid dye or the like can be used.

[0032]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. It should be noted that the validity and scope of the rights of the present invention are not limited or limited thereby.

[Example 1] As the ink jet device, a charge amount deflection type continuous ink jet printer was used. FIG. 1 shows a schematic view of a plate (hereinafter, referred to as a nozzle plate) having ink ejection ports used for this. In the figure, 1 is a nozzle plate, 2
Is an ink ejection port (nozzle). There are four nozzles in the nozzle plate at intervals of 10 mm, and each has a diameter of 5
0 μm.

This nozzle plate is ultrasonically cleaned with an organic solvent such as trichlene to degrease it, and then MHP.
S (made by Toray Dow Corning Silicone Co., Ltd. S
It was immersed in a hexane solution of H1107) (concentration 1%) for 10 minutes. Next, the nozzle plate was pulled up from the MHPS solution and immediately compressed air was blown from the back side of the nozzle plate to blow off the MHPS solution in the nozzle.

Then, the nozzle plate to which the MHPS solution (a part of hexane was volatilized and only MHPS was attached) was placed in an oven at 150 ° C. and heated for 20 minutes. The MHPS-treated nozzle plate taken out of the oven was cooled and then washed with hexane, but it was confirmed that the crosslinking reaction proceeded because MHPS did not elute. The contact angles of water before and after that are both about 100 °.
Met.

Next, the MHPS-treated nozzle plate was attached to the ink jet recording head portion of an ink jet printer so that the ink ejection direction faced downward, and the stability of the ink ejection direction was observed without applying a deflection voltage.

For observation, a one-dimensional line sensor type bar code reader (manufactured by Nippon System Development Co., Ltd.)
PDC-617E type) is installed so that four ink droplet streams can be read at a distance of about 7 cm below the ink ejection port (the ink droplet stream and the line sensor are separated from each other, but are in an orthogonal relationship), and a bar code reader. The scan signal and the trigger signal were taken out from the inside and connected to a digital oscilloscope (type 54510A manufactured by Hewlett Packard) so that the image read by the bar code reader could be displayed. The ink used (viscosity 3.5 cp, surface tension 40 dyne / cm) was a yellow disperse dye,
Consisting of water and polyhydric alcohol (concentration 20%), black drawing paper is placed on the opposite side of the barcode reader across the ink droplet stream, and it is strong against the ink droplet stream from above the barcode reader side. Shed light. By this method, the behavior of the ink droplet flow in the line sensor direction of the barcode reader can be grasped.

As a result of performing the above observation while continuously ejecting the ink droplet stream for 24 hours, the behavior of the ink ejection direction was within ± 50 μm for all nozzles.

Next, as a result of actually drawing a so-called solid picture every hour (one nozzle is deflected to 1
It was possible to obtain a uniform solid image without streaking even after 24 hours. Further, no ink adhesion was observed around the nozzles after 24 hours.

Further, the MHPS-treated nozzle plate tested for a total of 48 hours as described above was taken out, rubbed 200 times with a rubber blade while dropping ink with a dropper, and again mounted on an inkjet printer to continuously discharge ink for 24 hours. As a result of observing the direction, all the nozzles, which were exactly the same as those in the first 24 hours, behaved within ± 50 μm.

As described above, the ink jet recording head of the present invention maintains the ink repellent performance for a long period of time without dropping off due to friction such as wiping work, stabilizes the ink ejection direction, and is easily and inexpensively manufactured. It was shown that it was possible.

Example 2 The untreated nozzle plate used in Example 1 was ultrasonically washed with alkaline water (10% aqueous potassium hydroxide solution) and then placed on a spin coater.

0.1 cc of a hexane solution of MHPS (concentration: 10%) was dropped on the center of a nozzle plate installed on a spin coater, and spin coating was performed at 500 rpm for 5 seconds and subsequently at 2000 rpm for 5 seconds.

From the back side of the ink ejection port of the obtained nozzle plate, reconsider the pressure with a pump having an ability of 2000 Torr.
The HPS solution was blotted.

Thereafter, heating is performed in the same manner as in Example 1 to perform MHP.
An S-treated nozzle plate was obtained. This nozzle plate is
As in Example 1, the ink ejection direction was stabilized, and the crosslinked product of MHPS did not fall off due to friction such as wiping work.

[Third Embodiment] The untreated nozzle plate used in the first embodiment is degreased, and then the back side of the surface on which ink is ejected,
Adhesive tape was attached so that the ink inlet was blocked.

FIG. 2 is a schematic sectional view showing an example of one nozzle as a model.

Next, as shown in FIG. 3, the nozzle plate is mounted on a dedicated stand of the spin coater so that the ink ejection port faces upward and the nozzle is not located on the center of rotation.
One piece was installed on the object with respect to the center of rotation.

MHPS is placed on the installed nozzle plate.
Stock solution (manufactured by Toray Dow Corning Silicone Co., Ltd.
SH1107) hang 2cc, 30 minutes at 3000rpm
Spin coated for seconds.

The nozzle plate coated with MHPS was removed from the special stand of the spin coater, the adhesive tape was peeled off, and the same heat treatment as in Example 1 was performed.

The thus-obtained nozzle plate had good ink ejection stability, and the cross-linked product of MHPS did not fall off due to the wiping operation or the like.

[Comparative Example 1] MHPS in the above embodiment
The nozzle plate before the treatment was set in an inkjet printer, and the ink ejection direction was continuously observed for 24 hours. As a result, a behavior of about ± 200 μm was recognized. In addition, the ink adhered to the periphery of the nozzle after 24 hours as if it had spread. The contact angle of water with this plate was about 40 °.

Next, as a result of adjusting the deflection amount so as not to produce streaks on the first first sheet and drawing a solid picture every hour, streaks were produced from the first hour (second sheet).

[0054]

INDUSTRIAL APPLICABILITY As described above, the ink jet recording head of the present invention maintains ink repellent performance for a long period of time and stabilizes the ink ejection direction without dropping off due to friction such as wiping work, and is simple and inexpensive. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic view showing in model form an example of a nozzle plate that is a component of an inkjet recording head used in the present invention.

FIG. 2 is a schematic cross-sectional view schematically showing an example of a state in which an ink inlet of a nozzle plate, which is a component of an inkjet recording head used in the present invention, is closed.

FIG. 3 is a schematic view showing in model form an example of a state in which a nozzle plate, which is a component of the inkjet recording head used in the present invention, is installed on a dedicated stand of a spin coater.

[Explanation of symbols]

 1: Nozzle plate 2: Ink ejection port 3: Ink inlet 4. Adhesive tape 5. Spin coater stand

Claims (20)

[Claims] 1. An ink jet recording head comprising a metal at least around an ink ejection port, wherein the ink jet recording head has a crosslinked material of methylhydrogenpolysiloxane around the ink ejection port. 2. An inkjet recording head made of metal at least at a portion in contact with an ink ejection port and an ink flow path, wherein a cross-linked product of methylhydrogenpolysiloxane is provided at a portion in contact with the ink ejection port and the ink flow path. An inkjet recording head characterized by having. 3. The inkjet recording head according to claim 1, wherein the metal is stainless steel. 4. The ink jet recording head according to claim 1 or 2, wherein the layer thickness of methylhydrogenpolysiloxane is 0.001 to 5 μm. 5. The inkjet recording head according to claim 1 or 2, wherein the inkjet system is a continuous system. 6. An ink jet recording method comprising immersing at least the ink ejection port periphery of an ink jet recording head in which at least the ink ejection port periphery is made of metal, and immersing the immersed portion and then heating it. Head manufacturing method. 7. The method for manufacturing an ink jet recording head according to claim 6, wherein after the immersed portion is pulled up, gas is caused to flow from the back side of the ink ejection port to blow off the methylhydrogenpolysiloxane solution in the ink ejection port.
A method of manufacturing an ink jet recording head, which comprises heating after that. 8. A method for manufacturing an ink jet recording head according to claim 6, wherein after the immersed portion is pulled up, gas and methylhydrogenpolysiloxane solution are sucked from the back side of the ink ejection port and then heated. Method for manufacturing an inkjet recording head. 9. The method for manufacturing an ink jet recording head according to claim 6, wherein the immersion time in the methylhydrogenpolysiloxane solution is 1 minute to 1 hour. 10. A methylhydrogenpolysiloxane solution is applied by spin coating to at least the ink ejection port periphery of an ink jet recording head in which at least the ink ejection port periphery is made of metal, and then at least the coating portion is heated. And a method for manufacturing an inkjet recording head. 11. A method for manufacturing an ink jet recording head according to claim 10, wherein after applying by spin coating, a gas is caused to flow from the back side of the ink ejection port to blow off the methylhydrogenpolysiloxane solution in the ink ejection port, and thereafter. A method for manufacturing an ink jet recording head, which comprises heating. 12. A method for manufacturing an ink jet recording head according to claim 10, wherein after applying by a spin coating method, a gas and a methylhydrogenpolysiloxane solution are sucked from the back side of the ink ejection port and then heated. Method for manufacturing an inkjet recording head. 13. The method of manufacturing an ink jet recording head according to claim 10, wherein the methylhydrogenpolysiloxane solution is spin-coated while flowing gas from the back side of the ink ejection port. 14. The method of manufacturing an ink jet recording head according to claim 10, wherein the methylhydrogenpolysiloxane solution is spin-coated while sucking the gas and the methylhydrogenpolysiloxane solution from the back side of the ink ejection port. Inkjet recording head manufacturing method. 15. The method for manufacturing an ink jet recording head according to claim 6, wherein the heating temperature is 100 ° C.
To 200 ° C. A method for manufacturing an inkjet recording head, characterized in that: 16. The method for manufacturing an ink jet recording head according to claim 6, wherein the heating time is 10 minutes to 10 minutes.
A method for manufacturing an ink jet recording head, wherein the method is one hour. 17. The method for manufacturing an ink jet recording head according to claim 6 or 10, wherein the concentration of methylhydrogenpolysiloxane is 0.1% to 10%. 18. The method for manufacturing an ink jet recording head according to claim 6 or 10, wherein the ink inflow hole is blocked so that only the ink discharge port communicates with the atmosphere, and the methyl hydrogen polysiloxane is blocked so as to block the ink discharge port. A method for manufacturing an inkjet recording head, which comprises dipping a solution or a stock solution of methylhydrogenpolysiloxane and then dipping or spin coating. 19. The method of manufacturing an ink jet recording head according to claim 10, wherein at least the ink ejection port is installed off the center of rotation of the spin coat. 20. An ink jet recording method, wherein ink jet recording is performed using the ink jet recording head according to claim 1.