JP2009056752A - Hydrophilizing treatment method, hydrophilizing treatment device, and fluid jetting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrophilizing treatment method where hydrophilic properties are surely imparted to the inside of the flow passage of a fluid jetting head, thus the adsorption of bubbles on the wall face of the flow passage can be suppressed, to provide a hydrophilizing treatment device, and to provide a fluid jetting device. <P>SOLUTION: Disclosed is a hydrophilizing treatment method where hydrophilizing treatment is performed to the inside of the flow passage R of a fluid in a jetting head 24 provided with a nozzle forming face 11A in which a plurality of nozzle openings 211 are formed and jetting a fluid from the nozzle openings 211. While applying pressure from the upstream side of the flow passage R, the inside of the flow passage R is packed with a hydrophilic liquid material. Then, the hydrophilic liquid material is discharged from the inside of the flow passage R. After the discharge of the hydrophilic liquid material, the flow passage R is subjected to drying treatment. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydrophilic treatment method, a hydrophilic treatment device, and a fluid ejection device.

The fluid ejecting apparatus is an apparatus that includes a fluid ejecting head capable of ejecting liquid as droplets and ejects various liquids from the fluid ejecting head. As a typical fluid ejecting apparatus, for example, an ink jet recording head (hereinafter simply referred to as a recording head) as a fluid ejecting head.
An image recording apparatus such as an ink jet printer that performs recording by forming dots by ejecting and landing liquid ink as ink droplets from a nozzle opening of the recording head toward an ejection target such as recording paper (For example, see Patent Documents 1 to 3).
Japanese Patent Laid-Open No. 6-40030 JP-A-9-39243 JP-A-4-146153

In the recording heads disclosed in Patent Documents 1 and 2, a flow path forming substrate on which a flow path is formed and a nozzle plate on which nozzle openings are formed are bonded together with an adhesive. For this reason, there is a possibility that bubbles will be retained due to the uneven portions formed in the bonding region of the adhesive in the flow path.
However, it is difficult to strictly control the amount of adhesive applied, the amount of adhesive protruding into the flow path, and the amount of sink marks in order to prevent such bubble retention.
In addition, as disclosed in Patent Document 3, when the flow path forming substrate is made of a plastic resin having low hydrophilicity, the hydrophilicity of the ink in the flow path is lowered, which is generated on the flow wall surface. It becomes difficult to discharge the air bubbles. Therefore, it may be possible to prevent bubbles from adsorbing on the wall surface of the flow path using a plastic material having hydrophilicity. However, the acrylic / nylon resin conventionally used as the above-mentioned hydrophilic plastic has sufficient hydrophilicity. It was hard to say. Therefore, it is conceivable to use hydrophilic ink, but in this case, there is a problem that the degree of freedom in design is narrowed by the limited ink that can be used.
Alternatively, it is also conceivable that the inside of the flow path is hydrophilized by passing and discharging a hydrophilic liquid into the flow path to prevent the bubble adsorption. In such a case, since the hydrophilic liquid is diluted with pure water or a solvent to ensure fluidity in the flow path, it is difficult to sufficiently obtain the effect of the hydrophilic treatment.

The present invention has been made in view of such circumstances, and a hydrophilic treatment method capable of suppressing the adsorption of bubbles to the wall surface of the flow path by reliably imparting hydrophilicity to the flow path of the fluid ejection head, An object of the present invention is to provide a hydrophilization treatment device and a fluid ejection device.

In order to solve the above-described problem, the hydrophilization method of the present invention includes a nozzle forming surface in which a plurality of nozzle openings are formed, and is hydrophilic in the fluid flow path in the ejection head that ejects fluid from the nozzle openings. A hydrophilic treatment method for performing a treatment, the step of filling the flow path with a hydrophilic liquid material while applying pressure from the upstream side of the flow path, and the step of discharging the hydrophilic liquid material from the flow path And a step of drying the flow path after discharging the hydrophilic liquid material.

According to the hydrophilization method of the present invention, for example, even a hydrophilic liquid material having a high concentration and a high viscosity, which can obtain a high hydrophilic property, can be satisfactorily passed in a pressurized state and can be passed into the flow path. Can be filled reliably. Even after the discharge, the hydrophilic liquid material adheres to minute uneven portions in the flow path, and forms a hydrophilic film after drying. Therefore, the uneven part in the flow path is coated with the hydrophilic film, so that a smooth flow can be obtained in the flow path, and the bubble retention in the uneven part can be reduced. Therefore, according to the present invention, it is particularly effective in an ejection head that has a bonding structure using an adhesive and has an uneven portion of an adhesive portion formed in a flow path.

In the hydrophilic treatment method, the hydrophilic liquid material is preferably discharged from the upstream side of the flow path while being pressurized.
When the hydrophilic liquid material is discharged, if a suction operation is performed from the nozzle forming surface side downstream of the flow path, many hydrophilic liquid materials adhere to the nozzle forming surface. On the other hand, in the present invention, the amount of the hydrophilic liquid material adhering to the nozzle forming surface can be reduced by discharging the hydrophilic liquid material from each nozzle opening while applying pressure from the upstream side.

Moreover, in the said hydrophilic treatment method, it is preferable to apply pressure by applying a gradual pressure in the step of filling the hydrophilic liquid material into the flow path.
According to this configuration, it is possible to satisfactorily fill the flow path with the hydrophilic liquid material by applying a gradual pressure to the pressure during pressurization.
At this time, it is more preferable to apply pressure from the upstream side of the flow path so as to alternately repeat the positive pressure state and the negative pressure state.
According to this configuration, it is possible to satisfactorily fill the flow path with a hydrophilic liquid material having a high concentration and a high viscosity.
Moreover, it is preferable to change the magnitude of the pressure applied in the positive pressure state and the negative pressure state.
According to this configuration, it is possible to satisfactorily fill the flow path with a hydrophilic liquid material having a high concentration and a high viscosity.

Moreover, in the said hydrophilization processing method, it is preferable to apply a pressure so that a positive pressure state and a state which does not apply a pressure may be repeated for every predetermined space | interval at the time of the said pressurization.
According to this configuration, it is possible to satisfactorily fill the flow path with a hydrophilic liquid material having a high concentration and a high viscosity.

The hydrophilic treatment method preferably includes a step of cleaning the nozzle forming surface after discharging the hydrophilic liquid material and before drying the flow path.
According to this configuration, it is possible to prevent the occurrence of a problem that the ejection characteristics of the head are changed by the hydrophilic film formed on the nozzle forming surface after the hydrophilic liquid material is dried.

The hydrophilization processing apparatus of the present invention is a hydrophilization processing apparatus that includes a nozzle forming surface in which a plurality of nozzle openings are formed, and performs a hydrophilization treatment in a fluid flow path in an ejection head that ejects fluid from the nozzle openings. A tank containing a hydrophilic liquid material, a pressure mechanism for pressurizing from the upstream side of the flow path and filling the hydrophilic liquid material in the flow path, and after discharging the hydrophilic liquid material, And a drying mechanism for performing a drying process in the flow path.

According to the hydrophilization treatment apparatus of the present invention, for example, even a highly concentrated and high viscosity material that can obtain high hydrophilicity, the hydrophilic liquid material can be satisfactorily passed through the flow path by the pressurization mechanism. Can be filled reliably. Even after the discharge, the hydrophilic liquid material adheres to minute uneven portions in the flow path, and forms a hydrophilic film after drying. Therefore, the uneven part in the flow path is coated with the hydrophilic film, so that a smooth flow can be obtained in the flow path, and bubble retention due to the uneven part can be reduced. Therefore, according to the present invention, it is particularly effective in an ejection head that has a bonding structure using an adhesive and has an uneven portion of an adhesive portion formed in a flow path.

In the hydrophilic treatment apparatus, the pressurization mechanism includes a pressurization control unit that controls a pressurization state, and the pressurization control unit applies a gradual pressure to the lyophilic liquid material. It is preferable to perform a filling process.
According to this configuration, it is possible to satisfactorily fill the flow path with the hydrophilic liquid material by applying a gradual pressure to the pressure during pressurization.

Moreover, in the said hydrophilic treatment apparatus, it is preferable that the said pressurization control part controls the said pressurization mechanism so that a positive pressure state and a negative pressure state may be repeated alternately.
According to this configuration, it is possible to satisfactorily fill the flow path with a hydrophilic liquid material having a high concentration and a high viscosity.

Moreover, in the said hydrophilic treatment apparatus, it is preferable that the said pressurization control part can adjust the magnitude | size of the pressure applied at the time of the said positive pressure and negative pressure.
According to this configuration, it is possible to satisfactorily fill the flow path with a hydrophilic liquid material having a high concentration and a high viscosity.

Moreover, in the said hydrophilic treatment apparatus, it is preferable that the said pressurization control part controls the said pressurization mechanism so that a positive pressure state and a state which does not apply a pressure may be repeated for every predetermined interval.
According to this configuration, it is possible to satisfactorily fill the flow path with a hydrophilic liquid material having a high concentration and a high viscosity.

The hydrophilic treatment apparatus preferably includes a cleaning mechanism that cleans the nozzle forming surface after the discharge of the hydrophilic liquid material and prior to the drying process of the ejection head.
According to this configuration, since the nozzle forming surface is cleaned by the cleaning mechanism, it is possible to prevent the occurrence of problems such as a change in the jetting characteristics of the head due to the hydrophilic film formed on the nozzle forming surface by drying the hydrophilic liquid material. it can.

The fluid ejecting apparatus of the present invention is a fluid ejecting apparatus including an ejecting head that ejects fluid from a plurality of nozzle openings formed on a nozzle forming surface, and a hydrophilic film is formed on an inner surface of the fluid flow path in the ejecting head. And the hydrophilic film covers the uneven portion of the inner wall surface.
According to the fluid ejecting apparatus of the present invention, since the concave portion of the inner wall surface of the flow path is covered with the hydrophilic film, a smooth flow can be obtained in the flow path, and the bubble retention due to the concave portion is reduced. Become. Therefore, according to the present invention, it is particularly effective in an ejection head that has a bonding structure using an adhesive and has an uneven portion of an adhesive portion formed in a flow path.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the technical scope of the present invention is not limited to the following embodiments. In the drawings used for the following description, the scale of each member is appropriately changed in order to make each member a recognizable size.

First, an embodiment of a hydrophilization apparatus according to the present invention will be described with reference to the drawings.
The hydrophilization processing apparatus includes a nozzle forming surface in which a plurality of nozzle openings are formed, and an apparatus for performing a hydrophilic treatment on the wall surface of the flow path of an ink jet recording head (jet head) described later that ejects fluid from these nozzle openings. It is.

FIG. 1 is a diagram showing a schematic configuration of a hydrophilic treatment apparatus of the present invention.
As shown in FIG. 1, the hydrophilization treatment apparatus 1 adds a tank 3 containing a hydrophilic liquid material 2 that imparts hydrophilicity to the flow path wall surface, and a hydrophilic liquid material supplied from the upstream side of the flow path. Pressurizing mechanism 4 that pressurizes and fills the inside of the flow path, and after discharging the hydrophilic liquid material filled in the flow path, the inkjet recording head 24 (hereinafter referred to as the recording head 24) is subjected to a drying process, After discharge of the hydrophilic liquid material, a management unit (drying mechanism, cleaning mechanism) 8 is provided for cleaning the nozzle forming surface prior to the drying process of the recording head 24.

The pressurizing mechanism 4 includes a pressurizing pump 6 and a pressurizing control device (pressurizing control unit) 7. The pressurization control device 7 is configured by a computer or the like, for example, and can control the pressurization pump 6. A tank 3 is connected to one end of the pressure pump 6 via a tube T1.
The tube T1 is provided with a valve B1 for adjusting the ink flow rate from the tank 3 into the pressurizing pump 6, and the valve B1 is adjusted by a valve control device (not shown).

In addition, the management unit 8 includes a drying mechanism such as a heater that satisfactorily dries the channel wall surface to which the hydrophilic liquid material is adhered. Further, the management unit 8 supplies a cleaning liquid (for example, pure water) that can clean the hydrophilic liquid material to the nozzle forming surface 211A (not shown).
And a cleaning liquid scraping part such as a spatula for scraping the cleaning liquid supplied to the nozzle forming surface 211A.

The other end of the pressurizing pump 6 is connected to the ink jet recording head 24 via a tube T2. The head side of the tube T2 is branched into four, and each is connected to an ink introduction port that supplies ink of the same color. Thereby, it is possible to individually pass the hydrophilic liquid material through the flow path through which the same color ink flows. Further, a valve B2 for adjusting the ink flow rate to the ink jet recording head 24 and selecting the nozzle processing row is provided at a branch portion of the tube T2.

In this embodiment, a hydrophilic resin such as a polymer, specifically, polyvinyl alcohol (PVA) is used in this embodiment as the hydrophilic liquid material. In addition, as a hydrophilic liquid material, it is not limited to this, For example, you may use a hydrophilic emulsion etc.

Here, prior to the description of the hydrophilic treatment method using the hydrophilic treatment apparatus 1, the inkjet recording head 24 subjected to the lyophilic treatment by the hydrophilic treatment apparatus 1 of the present invention, and the inkjet recording head 24 are described below. A configuration of an ink jet printer (fluid ejecting apparatus) provided will be described with reference to the drawings. 2 is a perspective view showing an outline of the internal structure of the ink jet printer IJ1 according to the embodiment of the present invention, FIG. 3 is a front view thereof, and FIG. 4 is a sectional side view thereof.

As shown in FIGS. 2 to 4, the ink jet printer IJ1 includes a paper feeding unit 10 that feeds the printing paper P, a carriage unit 20 that includes the ink jet recording head 24 and the carriage 22, a transport unit 60 that transports the printing paper P, An ink system unit 50 that performs maintenance of the ink jet recording head 24 is provided.
The carriage unit 20 is connected to the upper side of the transport unit 60, the ink system unit 50 is connected to the side, and the paper feeding unit 10 is connected to the rear side of the carriage unit 20, so that the four units are combined. ing.

The paper feed unit 10 includes a paper feed unit frame 12, a paper feed roller 13, a movable guide 14,
A fixed guide 15 and a hopper 16 are provided. Then, the rotation shaft 13 a of the paper feed roller 13, the hopper 16, and the like are attached to the paper feed unit frame 12.

The carriage unit 20 includes a carriage guide shaft 25, a carriage motor 27, a driven pulley 29, a paper detector 36, and the like. A discharge frame 30 is attached to the carriage unit 20.
A driving pulley 28 is attached to the carriage motor 27, and the carriage belt 26 is suspended between the driving pulley 28 and the driven pulley 29. A carriage 22 is fixed to the carriage belt 26, and the carriage 22 reciprocates in the main scanning direction along the carriage guide shaft 25 by the rotation of the carriage motor 27.

The transport unit 60 includes a transport unit frame 61, a transport drive roller 62, a transport driven roller 63, a transport driven roller holder 64, a paper discharge drive roller shaft 65a, a paper guide 67, and the like. A transport drive roller 62, a transport driven roller holder 64, a paper discharge drive roller shaft 65a, a paper guide 67, and the like are attached to the transport unit frame 61. A platen 66 is formed on the transport unit frame 61.

Further, the transport unit 60 includes a drive motor 69, by which the paper feed roller 13, the transport drive roller 62, the paper discharge drive roller 65, and the ink system unit 50.
Is to be driven.

The ink system unit 50 includes an ink receiving member and a blade unit (both not shown), and is connected to the side of the transport unit frame 61.
The ink receiving member receives ink that is continuously ejected from the inkjet recording head 24 during the flushing process performed to prevent the ink from drying. And
The ink receiving member is connected to a waste ink tank via a discharge tube, and the ink accumulated in the ink receiving member is sent to the waste ink tank.
The blade unit is configured to be movable between a position crossing the reciprocation area of the carriage 22 and a position retracting from the reciprocation area. For example, when the carriage 22 moves from the print area to the home position, the blade unit Cleaning is performed by wiping the nozzle surface.

On the hopper 16 disposed on the upstream side of the ink jet printer IJ1 (the rear side of the ink jet printer IJ1), for example, printing paper P of A4 size or the like is deposited and stored in an inclined posture. The hopper 16 is configured to be rotatable around a rotation fulcrum (not shown) located at the upper portion, and the lower portion presses against or separates from the paper feed roller 13 by rotating. It is like. Further, the side edge of the printing paper P on the hopper 16 is guided by a movable guide 14 and a fixed guide 15 that can slide in the width direction of the hopper 16. When the hopper 16 comes into pressure contact with the paper feed roller 13, the uppermost one of the printing papers P
As the paper feeding roller 13 rotates, the downstream side (the front side of the ink jet printer IJ1).
It comes to be drawn out.

The paper feed roller 13 has a substantially D shape when viewed from the side, and rotates when the rotation shaft 13a is driven to rotate. The paper feed roller 13 is controlled so that the flat portion thereof faces the print paper P during the printing operation, thereby preventing the generation of the transport load of the print paper P.

The paper guide 67 is disposed substantially horizontally below and downstream of the paper feed roller 13, and the leading edge of the printing paper P fed out by the paper feed roller 13 is in contact with the paper guide 67 obliquely and smoothly downstream. Guided to the side. Further on the downstream side, the conveyance drive roller 6 that is rotationally driven.
2 and a transport driven roller 63 pressed against the transport drive roller 62, and the printing paper P is nipped between the transport drive roller 62 and the transport driven roller 63 and transported downstream at a constant pitch. .
The transport driven roller 63 is urged so as to always come into pressure contact with the transport drive roller 62 by a transport driven roller holder (not shown).

A platen 66 and the inkjet recording head 24 are arranged in the vertical direction downstream of the conveyance driving roller 62, and the printing paper P is conveyed below the inkjet recording head 24 by the rotation of the conveyance driving roller 62. Further, the platen 66 is supported from below.

The ink jet recording head 24 includes a carriage 22 on which the ink cartridge 23 is mounted.
At the bottom. When the carriage 22 reciprocates in the main scanning direction while being guided by the carriage guide shaft 25 extending in the main scanning direction, the inkjet recording head 2
4 ejects black, yellow, cyan, magenta and the like toward the printing paper P.
The ink cartridge 23 is, for example, four cartridges (that is, containers in which four colors of ink (black, yellow, cyan, magenta) are separately filled)
Each can be exchanged independently.

A paper discharge driving roller 65, a paper discharge driven roller 31, and a paper discharge auxiliary roller 32 are disposed downstream of the ink jet recording head 24. A plurality of paper discharge driving rollers 65 are attached to a paper discharge driving roller shaft 65a extending in the main scanning direction. The paper discharge driven roller 31 is provided so as to be driven and rotated by lightly contacting the paper discharge driving roller 65. Accordingly, the printing paper P printed by the inkjet recording head 24 is discharged downstream by the rotation of the paper discharge driving roller 65 while being nipped by the paper discharge driving roller 65 and the paper discharge driven roller 31. Is done.
The paper discharge auxiliary roller 32 is provided slightly upstream of the paper discharge driven roller 31 and presses the print paper P slightly downward to prevent the print paper P from lifting from the platen 66. Thereby, the distance between the printing paper P and the inkjet recording head 24 is regulated.

FIG. 5 is a diagram showing an outline of a cross-sectional configuration of the recording head 24. The recording head 24 discharges ink from the nozzle openings in the form of droplets. As shown in FIG. 5, the recording head 2
4 is a flow path forming substrate 220 constituting a pressure generating chamber 221 communicating with a nozzle (nozzle opening) 211 from which ink is discharged, and a pressure generating chamber 221 disposed on the upper surface of the pressure generating chamber 221.
Are provided with a piezoelectric element 300 that causes a pressure change, and a housing 310 that covers the piezoelectric element 300.

The flow path forming substrate 220 includes a substrate body 410 and the diaphragm 4 bonded on the substrate body 410.
00. The substrate body 410 is configured by bonding a plate-like member made of a plastic resin with an adhesive 250 such as polypropylene or PET. A plurality of nozzles 2 are provided on the lower surface side of the flow path forming substrate 220 (on the side opposite to the piezoelectric element 300).
A nozzle substrate 210 having a nozzle forming surface 211 </ b> A on which 11 is formed is bonded through an adhesive 250.

Each pressure generating chamber 2 is attached to the nozzle substrate 210 when bonded to the flow path forming substrate 220.
Nozzle 211 is formed at a position corresponding to 21. The pressure generation chambers 221 are separated by side walls (not shown) and connected to a reservoir 223 that is a common flow path via a supply port 224. In addition, an ink introduction port 225 for supplying ink to the reservoir 223 is formed in the housing 310, and an introduction path 226 that connects the ink introduction port 225 and the reservoir 223 is provided in the flow path forming substrate 220. It has been. As many ink inlets 225 as the number of inks supplied from the ink cartridge 23 (four in this embodiment) are provided.

As described above, since the wall surface of the flow path R in the recording head 24 is configured by a bonding structure using the adhesive 250, a sink is formed on the flow path wall surface when the adhesive 250 sinks at the bonded portion. Here, the flow path R corresponds to a region where ink introduced into the recording head 24 through the ink inlet 225 flows until reaching the nozzle 211.

Incidentally, as shown in FIG. 6, the conventional recording head that has not been subjected to the hydrophilization treatment by the hydrophilization treatment apparatus 1 causes the ink flow at the uneven portions (area surrounded by a circle in the figure) formed on the flow path wall surface. A problem arises in which stagnation occurs and the generated bubbles P are adsorbed.

On the other hand, in the recording head 24 according to the present embodiment as shown in FIG. 5, the hydrophilic film M is formed on the inner wall surface of the flow path R by the hydrophilic treatment apparatus 1 described above. This hydrophilic membrane M is a flow path R.
It is in the state which covered the recessed part in the inner wall surface. Since the inner wall surface of the flow path R is thus covered with the hydrophilic film M, a smooth flow can be obtained in the flow path R.

(Hydrophilic treatment method)
Subsequently, an embodiment of the hydrophilic treatment method of the present invention will be described by describing the operation method of the hydrophilic treatment apparatus 1.
First, the tube T2 is connected to the recording head 24 as shown in FIG. Specifically, the tube T <b> 2 is connected to the ink introduction port 225 of the recording head 24. A container 9 for collecting the hydrophilic liquid material discharged from the flow path R is disposed at a position facing the nozzle formation surface 211A of the recording head 24.

Subsequently, the hydrophilization treatment device 1 opens the valve B1 by the valve control device, and the tube T1.
The lyophilic liquid material stored in the tank 3 is caused to flow into the pressurizing pump 6. Specifically, in the present embodiment, polyvinyl alcohol (PVA) is stored in the tank 3 in a stock solution state without being diluted. Since the polyvir alcohol stock solution has a high concentration, it has a very high hydrophilicity but also has a high viscosity. In the hydrophilization treatment apparatus 1 according to the present embodiment, the lyophilic liquid material is fed into the tube T2 while the pressurization control device 7 drives the inside of the pressure pump 6 to pressurize the lyophilic liquid material. At this time, the lyophilic liquid material can be fed into the recording head 24 (flow path R) from the ink introduction port 225 by opening the valve B2 provided in the tube T2.

In the present embodiment, the pressurization control device 7 performs the filling process of the lyophilic liquid material by applying a gradual pressure. In this way, by adjusting the pressure at the time of pressurization, a highly viscous lyophilic liquid material (
In this embodiment, polyvinyl alcohol (PVA) can be satisfactorily filled in the flow path R.

Here, the variation of the pressurization method of the pressurization pump 6 by the pressurization control apparatus 7 is demonstrated. FIG. 7 shows a signal input from the pressurization control device 7 to the pressurization pump 6. In the figure, the horizontal axis indicates time, and the vertical axis indicates pressure intensity.
FIG. 7A shows a case where a signal that repeats a positive pressure (compression) state and a state where no pressure is applied is sent to the pressurizing pump 6 at predetermined intervals. That is, the pressurizing pump 6 applies a compressive force to the lyophilic liquid material in a pulse manner. Here, the predetermined interval is appropriately set according to the length, width, and the like of the flow path R through which the lyophilic liquid material can be satisfactorily poured into the flow path R.
FIG. 7B shows a case in which a signal is sent to the pressurizing pump 6 so that a positive pressure state and a negative pressure (suction) state are alternately repeated.
FIG. 7C shows a case where the positive pressure state and the negative pressure state shown in FIG. 7B are alternately repeated and a signal for changing the magnitude of the applied pressure is sent to the pressurizing pump 6. Is shown.
As shown in FIGS. 7A to 7C, a hydrophilic liquid material (polyvinyl chloride) is formed in the flow path R (reservoir 223, pressure generation chamber 221 and the like) by driving the pressurization pump 6 with the pressure gradually increased and decreased. Alcohol) can be satisfactorily passed to fill every corner of the recording head 24.

In the recording head 24 according to the present embodiment, the flow path forming substrate 220 constituting the flow path R is the adhesive 2.
Since a plurality of members are bonded to each other via 50, the flow path wall surface has minute uneven portions. As described above, the hydrophilic liquid material (polyvinyl alcohol) filled in the entire region of the flow path R while being pressurized adheres to the uneven portions and coats the uneven portions.

A hydrophilic liquid material (polyvinyl alcohol) is filled in the recording head 24 and then left for a predetermined time. Thereby, the hydrophilic treatment material can be adhered to the wall surface of the flow path R. Thereafter, the hydrophilic liquid material is discharged by applying pressure from the upstream side of the flow path R. In particular,
The hydrophilic liquid material is discharged from the nozzle 211 by sending air pressure into the flow path R by operating the pressure pump.

By the way, when the hydrophilic liquid material is discharged by sucking from the nozzle forming surface 211A side, which is the downstream side of the flow path R, many hydrophilic liquid materials adhere to the nozzle forming surface 211A.
On the other hand, in this embodiment, since the hydrophilic liquid material is discharged from each nozzle 211 by applying pressure from the upstream side of the flow path R, the amount of the hydrophilic liquid material adhering to the nozzle forming surface 211A can be reduced. Therefore, it is possible to simplify the cleaning process of the nozzle forming surface 211A described later.

After discharging the lyophilic liquid material, the inside of the flow path R is dried by the management unit 8. As a result, the lyophilic liquid material is dried and fixed, and a hydrophilic film M composed of polyvinyl alcohol is formed on the channel wall surface. This hydrophilic film M is a film that coats the irregularities formed in the flow path R.
As shown in FIG. 5, it forms in the state which the recessed part resulting from the sink of the adhesive agent 250 in a junction part was embedded. Therefore, the uneven portion on the inner wall surface of the flow path is smoothed by the hydrophilic film M.

As described above, according to the present embodiment, a polyvinyl alcohol stock solution that is highly hydrophilic by pressurization is allowed to pass through the flow path R as a hydrophilic liquid material, thereby adhering in the flow path R. The uneven part resulting from the bonding structure by the agent 250 can be coated with the hydrophilic film M. Therefore, a smooth flow can be obtained in the flow path R, and the bubbles can be easily discharged by reducing bubble retention in the concavo-convex portion. Therefore, it is possible to reduce bubble retention due to stagnation of the ink flow.

(Experimental result)
Here, experimental results showing the effect of the hydrophilic film M formed by the method according to the embodiment will be described.
FIG. 8 shows the presence or absence of bubble adsorption in the flow path R subjected to the hydrophilic treatment according to the present invention described above.
FIG. 8A shows a case where pure water is allowed to flow in the flow path R, and FIG. 8B shows ink in the flow path R. FIG. It shows the case of flowing. In addition,
In the figure, the static contact angle means a value relative to pure water on the channel wall surface. Further, in the table, polypropylene is an adhesive 250 used for the joint portion of the flow path R.

As shown in FIG. 8A, when the treated surface is polypropylene (that is, when the hydrophilic treatment is not performed), the static contact angle is increased to 95 to 100 °. Thus, if the hydrophilicity in the flow path R is low, bubble adsorption will occur at the joint in the flow path R (uneven portions due to the adhesive 250). Then, even if a strong suction process such as chalk cleaning was performed as the bubble discharge process, the bubbles could not be completely removed.
Therefore, it can be confirmed that it is important to improve the hydrophilicity in the flow path R in order to prevent bubble adsorption in the flow path R or to discharge the bubbles.

Moreover, in order to improve the fluidity | liquidity of the polyvinyl alcohol in the flow path R, it diluted 100 times and set the viscosity to about 5 cp. Note that 5 cp is a value equivalent to the viscosity of general ink flowing in the flow path R.
In this case, since sufficient hydrophilicity was not obtained (static contact angle 60 °), it was confirmed that bubble adsorption still occurred in the flow path R. Further, in order to discharge the bubbles, a strong suction operation such as chalk cleaning is required.

On the other hand, in the present invention, the inside of the flow path R is coated with the hydrophilic film M by allowing the polyvinyl alcohol stock solution having a high viscosity of 30 cp to flow through the flow path R satisfactorily. The treated surface on which the hydrophilic film M is formed has a static contact angle as small as 45 to 50 ° and is imparted with high hydrophilicity. Therefore, bubbles are not adsorbed in the flow path R, and it was confirmed that the bubbles can be reliably discharged out of the flow path R by performing a weak suction operation such as low-speed cleaning as the bubble discharge processing.

In addition, when ink is allowed to flow in the flow path R shown in FIG. 8B, as in the case of pure water, if the hydrophilic treatment is not performed (when the present invention is not applied), bubbles are adsorbed in the flow path R. Even when chalk cleaning is performed, bubbles cannot be completely removed.

On the other hand, if the present invention is adopted, the inner surface of the flow path R is coated with a hydrophilic film M composed of a polyvinyl alcohol stock solution, and high hydrophilicity is imparted.
Therefore, even when pure water is flowed into the flow path R, bubbles are not adsorbed in the flow path R, and bubbles are removed from the flow path R by performing a weak suction operation such as low-speed cleaning as a bubble discharge process.
It was confirmed that it can be reliably discharged outside.

The present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the invention.
For example, in the above embodiment, the same hydrophilic liquid material is allowed to flow into the ink flow path R to form the same hydrophilic film M. For example, the ink flowing in the flow path R for each flow path R Alternatively, a lyophilic liquid material that imparts good hydrophilicity may be introduced to form a different hydrophilic film for each flow path R.

It is a figure which shows schematic structure of a hydrophilization processing apparatus. It is a perspective view which shows the outline of the internal structure of an inkjet printer. It is a front view which shows the outline of an inkjet printer. It is a sectional side view which shows the outline of an inkjet printer. 2 is a cross-sectional view illustrating a schematic configuration of a recording head 24. FIG. It is a figure which shows the cross-sectional structure of the recording head when not performing a hydrophilic treatment. It is a figure which shows the input signal from a pressurization control apparatus to a pressurization pump. It is the table | surface which showed the experimental result which confirmed the effect by a hydrophilic film | membrane.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hydrophilization processing apparatus, 2 ... Hydrophilic liquid material, 3 ... Tank, 4 ... Pressure mechanism, 6 ... Pressure pump, 7 ... Pressure control apparatus (pressure control part), 8 ... Management mechanism (drying mechanism) , Cleaning mechanism), 24... Recording head (jetting head), 211... Nozzle (nozzle opening), 211 A.
Hydrophilic membrane, R ... channel

Claims (14)

A hydrophilization method comprising a nozzle forming surface in which a plurality of nozzle openings are formed, and performing a hydrophilic treatment in the fluid flow path in an ejection head that ejects fluid from the nozzle openings,
Filling the flow path with a hydrophilic liquid material while applying pressure from the upstream side of the flow path;
Discharging the hydrophilic liquid material from the flow path;
And a step of performing a drying process on the flow channel after discharging the hydrophilic liquid material. The hydrophilic treatment method according to claim 1, wherein the hydrophilic liquid material is discharged while being pressurized from the upstream side of the flow path. The hydrophilic treatment method according to claim 1 or 2, wherein, in the step of filling the hydrophilic liquid material into the flow path, pressurization is performed while applying a gradual pressure. The hydrophilic treatment method according to claim 3, wherein pressure is applied from the upstream side of the flow path so as to alternately repeat a positive pressure state and a negative pressure state during the pressurization. The hydrophilic treatment method according to claim 4, wherein the magnitude of pressure applied in the positive pressure state and the negative pressure state is changed. The hydrophilization method according to claim 3, wherein pressure is applied so as to repeat a positive pressure state and a state in which no pressure is applied at predetermined intervals during the pressurization. The hydrophilization treatment according to any one of claims 1 to 6, further comprising a step of cleaning the nozzle forming surface after discharging the hydrophilic liquid material and before the drying treatment of the flow path. Method. A hydrophilization treatment apparatus comprising a nozzle forming surface in which a plurality of nozzle openings are formed, and performing a hydrophilic treatment in the fluid flow path in an ejection head that ejects fluid from the nozzle openings,
A tank containing a hydrophilic liquid material;
A pressurizing mechanism for pressurizing from the upstream side of the flow path and filling the hydrophilic liquid material in the flow path;
And a drying mechanism that performs a drying process in the flow channel after discharging the hydrophilic liquid material. The pressurization mechanism has a pressurization control unit that controls the pressurization state,
9. The hydrophilization apparatus according to claim 8, wherein the pressurizing control unit performs the filling process of the lyophilic liquid material by applying a gradual pressure. The hydrophilic treatment apparatus according to claim 9, wherein the pressurization control unit controls the pressurization mechanism to alternately repeat a positive pressure state and a negative pressure state. The hydrophilization processing apparatus according to claim 10, wherein the pressurization control unit can adjust the magnitude of the pressure applied during the positive pressure and the negative pressure. The hydrophilic treatment apparatus according to claim 9, wherein the pressurization control unit controls the pressurization mechanism to repeat a positive pressure state and a state where no pressure is applied at predetermined intervals. The hydrophilization treatment according to claim 7, further comprising a cleaning mechanism for cleaning the nozzle formation surface after the discharge of the hydrophilic liquid material and prior to the drying processing of the ejection head. apparatus. A fluid ejecting apparatus including an ejecting head that ejects fluid from a plurality of nozzle openings formed on a nozzle forming surface,
A fluid ejecting apparatus, wherein a hydrophilic film is formed on an inner surface of the fluid flow path in the ejecting head, and the hydrophilic film covers an uneven portion of the inner wall surface.

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