JP2010069853A - Liquid repelling film formation method, nozzle plate, ink-jet head, and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize discharge characteristics of ink, and to improve an abrasion resistance characteristic and an alkali resistance characteristic of a liquid repelling film. <P>SOLUTION: A liquid repelling film formation method is used for forming a liquid repelling film having a liquid repelling characteristic on the surface of a nozzle formation substrate having a nozzle hole. The liquid repelling film formation method includes: a first step of forming a first base layer composed of a plasma-polymerized film in a region on a first surface side of the nozzle formation substrate and other than a predetermined region including the nozzle hole; a second step of forming a second base layer composed of a plasma-polymerized film in a predetermined region including the first base layer and the nozzle hole; a third step of subjecting the surface of the second base layer to oxidation treatment in a gas atmosphere having a dew point of -40 to 20°C and introducing a hydroxyl group and/or absorption water; and a fourth step of forming the liquid repelling film on the second base layer which has been subjected to the oxidation treatment. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for forming a liquid repellent film, a nozzle plate, an ink jet head, and an electronic apparatus, and more particularly to a technique for forming a liquid repellent film having liquid repellency on the surface of a substrate having nozzle holes.

  In general, a recording head (inkjet head) of an inkjet recording apparatus includes a nozzle forming substrate (nozzle plate) in which a plurality of nozzle holes are formed, and uses, for example, an energy generating means such as a piezoelectric element or a heating element to form a pressure chamber. By pressurizing the ink, ink droplets are ejected from the nozzles communicating with the pressure chamber, and recording is performed on the recording medium.

  In an ink jet head, it is known that the shape and accuracy of nozzle holes affect the ejection characteristics of ink droplets, and the surface characteristics of the nozzle plate affect the ejection characteristics of ink droplets. For example, if ink adheres to the nozzle periphery of the nozzle plate surface, the ink droplet ejection direction may be bent, the ink droplet size may vary, or the ink droplet ejection speed may become unstable. Arise. In order to prevent these adverse effects, a liquid repellent film (liquid repellent film) is generally formed on the surface (ink discharge surface) of the nozzle plate to stabilize the discharge characteristics of ink droplets. .

  However, when the inkjet head runs with paper remaining in the vicinity of the discharge port due to paper jam or the like, the surface of the nozzle plate loses liquid repellency because the paper contacts the surface of the nozzle plate that has been subjected to liquid repellent treatment. There is a problem that it ends up.

In order to solve this problem, Patent Document 1 discloses that a step is provided on the outer peripheral portion of the nozzle hole of the ink jet head to protect the outer peripheral portion of the nozzle hole even when a paper jam occurs and the rub resistance of the liquid repellent film. Is disclosed. This step is performed by oxidizing the plasma polymerized film formed on the surface of the nozzle plate on the droplet discharge side in a processing gas atmosphere, so that the alkyl groups terminating on the surface of the plasma polymerized film are cut from the Si atoms. In order to disappear, the plasma polymerization film is generated by utilizing the decrease in the film thickness.
JP 2008-105231 A

  In the liquid repellent film forming method described in Patent Document 1, the degree of the step on the outer periphery of the nozzle hole, that is, the degree of reduction in the film thickness of the plasma polymerized film due to the oxidation treatment is determined by the energy intensity of ultraviolet rays or plasma during the oxidation treatment. Adjust according to the irradiation time. However, considering the intensity distribution of energy rays and the like, it is difficult to realize a reduction in film thickness uniformly over the entire surface. As described above, if the uniformity of the level difference at the outer peripheral portion of the nozzle hole is not sufficient, there arises a problem that the nozzle length changes and the ink ejection characteristics change.

  The present invention has been made in view of such circumstances. The nozzle hole is made uniform in level, the accuracy of the nozzle length is improved, the ink ejection characteristics are stabilized, and the rub resistance of the liquid repellent film is improved. It is an object of the present invention to provide a method for forming a liquid repellent film, a nozzle plate, an inkjet head, and an electronic device that improve alkali resistance.

  In order to achieve the above object, the liquid repellent film forming method according to the present invention (the invention according to claim 1) forms a liquid repellent film having liquid repellency on the surface of a nozzle forming substrate having nozzle holes. A liquid film forming method, wherein a first underlayer composed of a plasma polymerized film is formed in a region on one surface side of the nozzle forming substrate other than a predetermined region including the nozzle holes. A first step, a second step of forming a second underlayer composed of a plasma polymerized film in a predetermined region including the first underlayer and the nozzle hole, and a dew point of −40 to 20 ° C. In a gas atmosphere, the surface of the second underlayer is oxidized to introduce a hydroxyl group and / or adsorbed water, and the oxidation-treated second underlayer is applied to the second underlayer. And a fourth step of forming the liquid repellent film.

  According to the present invention, the first base layer is formed in a region other than the predetermined region including the nozzle hole, the second base layer is formed in the predetermined region including the first base layer and the nozzle hole, and the oxidation is performed. Since the liquid repellent film is formed on the treated second undercoat layer, a step can be formed uniformly in the liquid repellent film around the nozzle hole opening, stabilizing the ink ejection characteristics, and The abrasion resistance of the film can be improved.

  A second aspect of the present invention relates to an aspect of the liquid repellent film forming method according to the first aspect, wherein the first step includes a plasma polymerized film on one surface side of the nozzle forming substrate. A step of forming a first underlayer, a step of forming a resist layer in a region other than the predetermined region including the nozzle holes, a step of removing the first underlayer using the resist layer as a mask, And a step of removing the resist layer.

  A third aspect of the present invention relates to an aspect of the liquid repellent film forming method according to the first aspect, wherein the first step includes a predetermined hole including the nozzle hole on one surface side of the nozzle forming substrate. A step of forming a resist layer in the region, a step of forming a first underlayer composed of a plasma polymerization film on one side of the nozzle forming substrate, and the resist layer and the resist layer And a step of removing the first underlayer by lift-off.

  In order to achieve the above object, a nozzle plate according to the present invention (invention according to claim 4) is formed by the liquid repellent film forming method according to any one of claims 1 to 3. A liquid film is provided.

  In order to achieve the object, an ink jet head according to the present invention (invention according to claim 5) is provided with the nozzle plate according to claim 4.

  In order to achieve the object, an electronic apparatus according to the present invention (invention according to claim 6) is provided with the ink jet head according to claim 5.

  According to the present invention, the first base layer is formed in a region other than the predetermined region including the nozzle hole, the second base layer is formed in the predetermined region including the first base layer and the nozzle hole, and the oxidation is performed. Since the liquid repellent film is formed on the treated second underlayer, steps can be uniformly formed in the liquid repellent film around the nozzle hole opening, improving the nozzle length accuracy, and ink ejection characteristics. In addition, the rub resistance and alkali resistance of the liquid repellent film can be improved.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  First, an ink jet recording apparatus as an embodiment as an image forming apparatus according to the present invention will be described. FIG. 1 is an overall configuration diagram showing an outline of an ink jet recording apparatus. As shown in FIG. 1, the inkjet recording apparatus 10 includes a printing unit 12 having a plurality of recording heads 12K, 12C, 12M, and 12Y provided for each ink color, and each recording head 12K, 12C, 12M, and 12Y. An ink storage / loading unit 14 for storing ink to be supplied to the paper, a paper feeding unit 18 for supplying the recording paper 16, a decurling unit 20 for removing curling of the recording paper 16, and a nozzle surface of the printing unit 12 An adsorption belt conveyance unit 22 that is arranged opposite to the (ink ejection surface) and conveys the recording paper 16 while maintaining the flatness of the recording paper 16, a print detection unit 24 that reads a printing result by the printing unit 12, and a print And a paper discharge unit 26 for discharging the printed recording paper (printed matter) to the outside.

  In FIG. 1, a magazine for rolled paper (continuous paper) is shown as an example of the paper supply unit 18, but a plurality of magazines having different paper widths, paper quality, and the like may be provided side by side. Further, instead of the roll paper magazine or in combination therewith, the paper may be supplied by a cassette in which cut papers are stacked and loaded.

  In the case of an apparatus configuration using roll paper, a cutter 28 is provided as shown in FIG. 1, and the roll paper is cut into a desired size by the cutter 28. The cutter 28 includes a fixed blade 28A having a length equal to or greater than the conveyance path width of the recording paper 16, and a round blade 28B that moves along the fixed blade 28A. The fixed blade 28A is provided on the back side of the print. The round blade 28B is arranged on the print surface side with the conveyance path interposed therebetween. Note that the cutter 28 is not necessary when cut paper is used.

  When multiple types of recording paper are used, an information recording body such as a barcode or wireless tag that records paper type information is attached to the magazine, and the information on the information recording body is read by a predetermined reader. Therefore, it is preferable to automatically determine the type of paper to be used and perform ink ejection control so as to realize appropriate ink ejection according to the type of paper.

  The recording paper 16 delivered from the paper supply unit 18 retains curl due to having been loaded in the magazine. In order to remove this curl, heat is applied to the recording paper 16 by the heating drum 30 in the direction opposite to the curl direction of the magazine in the decurling unit 20. At this time, it is more preferable to control the heating temperature so that the printed surface is slightly curled outward.

  After the decurling process, the cut recording paper 16 is sent to the suction belt conveyance unit 22. The suction belt conveyance unit 22 has a structure in which an endless belt 33 is wound between rollers 31 and 32, and at least a portion facing the nozzle surface of the printing unit 12 and the sensor surface of the printing detection unit 24 is flat. It is configured to make.

  The belt 33 has a width that is greater than the width of the recording paper 16, and a plurality of suction holes (not shown) are formed on the belt surface. As shown in FIG. 1, an adsorption chamber 34 is provided at a position facing the nozzle surface of the print unit 12 and the sensor surface of the print detection unit 24 inside the belt 33 spanned between the rollers 31 and 32. Then, the suction chamber 34 is sucked by the fan 35 to be a negative pressure, whereby the recording paper 16 on the belt 33 is sucked and held.

  The power of a motor (not shown) is transmitted to at least one of the rollers 31 and 32 around which the belt 33 is wound, so that the belt 33 is driven in the clockwise direction in FIG. The recording paper 16 is conveyed from left to right in FIG.

  Since ink adheres to the belt 33 when a borderless print or the like is printed, the belt cleaning unit 36 is provided at a predetermined position outside the belt 33 (an appropriate position other than the print area). Although details of the configuration of the belt cleaning unit 36 are not shown, for example, there are a method of niping a brush roll, a water absorbing roll, etc., an air blowing method of spraying clean air, or a combination thereof. In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

It is possible to use a roller / nip conveyance mechanism instead of the suction belt conveyance unit 22, but if the roller / nip conveyance is performed in the printing area, the roller will come into contact with the printing surface of the paper immediately after printing, so that the image is blurred. There is a problem that it is easy. Therefore, as in this example, suction belt conveyance that does not contact the image surface in the printing region is preferable.

  A heating fan 40 is provided on the upstream side of the printing unit 12 on the paper conveyance path formed by the suction belt conveyance unit 22. The heating fan 40 heats the recording paper 16 by blowing heated air onto the recording paper 16 before printing. Heating the recording paper 16 immediately before printing makes it easier for the ink to dry after landing.

  The printing unit 12 is a so-called full-line type head in which line-type heads having a length corresponding to the maximum paper width are arranged in a direction (main scanning direction) orthogonal to the paper transport direction (sub-scanning direction). Each of the recording heads 12K, 12C, 12M, and 12Y constituting the printing unit 12 has a plurality of ink discharge ports (nozzles) arranged over a length exceeding at least one side of the maximum size recording paper 16 targeted by the inkjet recording apparatus 10. It is composed of a line type head.

  Recording corresponding to each color ink in the order of black (K), cyan (C), magenta (M), and yellow (Y) from the upstream side (left side in FIG. 1) along the conveyance direction (paper conveyance direction) of the recording paper 16. Heads 12K, 12C, 12M, and 12Y are arranged. A color image can be formed on the recording paper 16 by discharging the color inks from the recording heads 12K, 12C, 12M, and 12Y while conveying the recording paper 16.

  Thus, according to the printing unit 12 in which the full line head that covers the entire width of the paper is provided for each ink color, the recording paper 16 and the printing unit 12 are relatively moved in the paper transport direction (sub-scanning direction). It is possible to record an image on the entire surface of the recording paper 16 by performing this operation only once (that is, in one sub-scan). Thereby, high-speed printing is possible and productivity can be improved as compared with the shuttle type head in which the recording head reciprocates in the direction (main scanning direction) orthogonal to the paper transport direction.

  Note that the application range of the present invention is not limited to the printing method using the line-type head, and a short head that is less than the length in the width direction (main scanning direction) of the recording paper 16 is scanned in the width direction of the recording paper 16. Printing in the width direction is performed, and when printing in one width direction is completed, the recording paper 16 is moved by a predetermined amount in a direction perpendicular to the width direction (sub-scanning direction), and the recording paper 16 in the next printing area is moved. A serial method in which printing is performed in the width direction and printing is performed over the entire printing area of the recording paper 16 by repeating this operation may be applied.

  Further, in this example, the configuration of KCMY standard colors (four colors) is illustrated, but the combination of ink colors and the number of colors is not limited to this embodiment, and light ink and dark ink are added as necessary. May be. For example, it is possible to add a recording head that discharges light ink such as light cyan and light magenta.

  As shown in FIG. 1, the ink storage / loading unit 14 has tanks that store inks of colors corresponding to the recording heads 12K, 12C, 12M, and 12Y, and each tank has a pipeline that is not shown. Via the recording heads 12K, 12C, 12M, and 12Y. Further, the ink storage / loading unit 14 includes notifying means (display means, warning sound generating means, etc.) for notifying when the ink remaining amount is low, and has a mechanism for preventing erroneous loading between colors. is doing.

  The print detection unit 24 includes an image sensor (line sensor or the like) for imaging the droplet ejection result of the print unit 12, and means for checking nozzle clogging and other ejection defects from the droplet ejection image read by the image sensor. Function as.

The print detection unit 24 of this example is composed of a line sensor having a light receiving element array that is wider than at least the ink ejection width (image recording width) by the recording heads 12K, 12C, 12M, and 12Y. This line sensor is a photoelectric conversion element (pixel) provided with a red (R) color filter.
A color separation line CCD sensor comprising: an R sensor array in which G is arranged in a line, a G sensor array provided with a green (G) color filter, and a B sensor array provided with a blue (B) color filter It consists of Instead of the line sensor, an area sensor in which the light receiving elements are two-dimensionally arranged can be used.

  The print detection unit 24 reads the test pattern printed by the recording heads 12K, 12C, 12M, and 12Y for each color, and detects the ejection of each head. The ejection determination includes the presence / absence of ejection, measurement of dot size, measurement of dot landing position, and the like.

  A post-drying unit 42 is provided following the print detection unit 24. The post-drying unit 42 is means for drying the printed image surface, and for example, a heating fan is used. Since it is preferable to avoid contact with the printing surface until the ink after printing is dried, a method of blowing hot air is preferred.

  When printing on porous paper with dye-based ink, the weather resistance of the image is improved by preventing contact with ozone or other things that cause dye molecules to break by blocking the paper holes by pressurization. There is an effect to.

  A heating / pressurizing unit 44 is provided following the post-drying unit 42. The heating / pressurizing unit 44 is a means for controlling the glossiness of the image surface, and pressurizes with a pressure roller 45 having a predetermined uneven surface shape while heating the image surface to transfer the uneven shape to the image surface. To do.

  The printed matter generated in this manner is outputted from the paper output unit 26. It is preferable that the original image to be printed (printed target image) and the test print are discharged separately. The ink jet recording apparatus 10 is provided with sorting means (not shown) for switching the paper discharge path in order to select the print product of the main image and the print product of the test print and send them to the discharge units 26A and 26B. ing. Note that when the main image and the test print are simultaneously formed in parallel on a large sheet, the test print portion is separated by a cutter (second cutter) 48. The cutter 48 is provided immediately before the paper discharge unit 26, and cuts the main image and the test print unit when the test print is performed on the image margin. The structure of the cutter 48 is the same as that of the first cutter 28 described above, and includes a fixed blade 48A and a round blade 48B. Although not shown, the paper output unit 26A for the target prints is provided with a sorter for collecting prints according to print orders.

  Since the recording heads 12K, 12M, 12C, and 12Y provided for each ink color have the same structure, hereinafter, the recording head is represented by reference numeral 50.

  FIG. 2 is a perspective plan view showing a structural example of the recording head 50. As shown in FIG. 2, the recording head 50 includes a plurality of ink chamber units (recording elements corresponding to one nozzle) including nozzle holes 51 serving as ink droplet ejection openings, pressure chambers 52 corresponding to the nozzle holes 51, and the like. It has a structure in which unit droplet ejecting elements 53 are arranged in a staggered matrix (two-dimensional), thereby projecting so as to be aligned along the head longitudinal direction (direction perpendicular to the paper feed direction). High density of the substantial nozzle interval (projection nozzle pitch) is achieved.

  The pressure chamber 52 provided corresponding to each nozzle hole 51 has a substantially square planar shape, and the nozzle hole 51 and the supply port 54 are provided at both corners on the diagonal line. The shape of the pressure chamber 52 is not limited to this example, and the planar shape may have various forms such as a quadrangle (rhombus, rectangle, etc.), a pentagon, a hexagon, other polygons, a circle, and an ellipse. Further, the arrangement of the nozzle holes 51 and the supply ports 54 is not limited to the arrangement shown in FIG.

  FIG. 3 is a schematic cross-sectional view (a cross-sectional view corresponding to one ink chamber unit 53) showing a part of the recording head 50. As shown in FIG. 3, a nozzle plate 60 is joined to the front side (ink ejection side) of the recording head 50, and the nozzle surface 50 a of the recording head 50 is configured by the nozzle plate 60.

  A plurality of nozzles (nozzle holes) 51 are two-dimensionally formed in the nozzle plate 60, and each nozzle hole 51 communicates with a corresponding pressure chamber 52 as shown in the figure.

  A supply port 54 is formed at one end of each pressure chamber 52, and each pressure chamber 52 communicates with a common flow channel 55 via each supply port 54. The ink supplied from the ink storage / loading unit 14 shown in FIG. 1 is distributed and supplied to each pressure chamber 52 via the common flow channel 55.

  One wall surface of the pressure chamber 52 (upper wall surface in FIG. 3) is constituted by a diaphragm 56 and faces the pressure chamber 52 at a position corresponding to the pressure chamber 52 on the diaphragm 56 (that is, sandwiching the diaphragm 56). At the position), a piezoelectric element 58 having an individual electrode 57 is provided. The diaphragm 56 is made of a conductive material such as SUS, and also serves as a common electrode for the plurality of piezoelectric elements 58. In addition, a mode in which the diaphragm is formed of a non-conductive material such as resin is also possible. In this case, a common electrode layer made of a conductive material such as metal is formed on the surface of the diaphragm member. For the piezoelectric element 58, a piezoelectric body such as a piezo is preferably used.

  When a predetermined drive voltage is applied to the piezoelectric element 58 in a state where the pressure chamber 52 is filled with ink, the ink in the pressure chamber 52 is pressurized due to the deformation of the vibration plate 56 accompanying the displacement of the piezoelectric element 58. Ink droplets are ejected from the nozzle holes 51. When the piezoelectric element 58 returns to its original state after ink ejection, new ink is refilled into the pressure chamber 52 from the common channel 55 through the supply port 54.

  In the present embodiment, a piezoelectric method is employed in which ink is ejected using the displacement of the piezoelectric element. However, in the practice of the present invention, the ink ejection method is not limited. A thermal method in which bubbles are generated in the pressure chamber using thermal energy generated from the element and ink droplets are ejected with the pressure can also be employed.

  Next, the detailed structure of the nozzle plate 60 will be described. FIG. 4 is an enlarged cross-sectional view around the nozzle hole 51 of the nozzle plate 60. As shown in FIG. 4, three types of films are formed on the surface of the nozzle plate 60, a first plasma polymerization film 61, a second plasma polymerization film 62, and a liquid repellent film 63.

  Although the material which comprises the nozzle plate 60 is not specifically limited, It is preferable to comprise with a silicon-type material, a metal-type material, an oxide material, and a carbon-type material, and a silicon-type material is especially preferable among these.

  Further, the shape of the nozzle hole 51 in the nozzle plate 60 is not particularly limited, but is configured in a tapered shape or a funnel shape that tapers in the ink ejection direction (upward in FIG. 5). However, it is preferable from the viewpoint of achieving stable discharge. Furthermore, the inner diameter of the nozzle hole 51 is preferably 5 to 50 μm. In the present embodiment, a nozzle hole 51 having an inner diameter of 20 μm is used.

  The liquid repellent film 63 is formed to have a step at the opening end of the nozzle hole 51 on the ink discharge side. By forming in this way, it is possible to protect the nozzle hole 51 even when a paper jam occurs and to improve the rub resistance of the liquid repellent film.

  Next, an example of the liquid repellent film forming method according to the present invention will be described.

  FIG. 5 is a process diagram for explaining the liquid-repellent film forming method according to the present invention. Here, as shown in FIG. 5G, the case where the liquid repellent film 63 is formed on the surface 60a on the ink ejection side of the nozzle plate 60 will be described.

  First, as shown in FIG. 5A, the first plasma polymerization film 61 is formed on the surface 60 a on the ink ejection side of the nozzle plate 60.

  As the constituent material and the formation method (film formation method) of the first plasma polymerized film 61, the materials and methods described in JP 2008-105231 A can be preferably used.

  That is, examples of the constituent material of the first plasma polymerized film 61 include silicone materials such as organopolysiloxane and silane compounds such as alkoxysilane. Of these, silicone materials are preferred, and organopolysiloxanes are particularly preferred. By using organopolysiloxane for the first plasma polymerized film 61, it has a structure having a siloxane bond (Si-O) as a skeleton, and therefore, it can be easily combined with the constituent material (silicon-based material, etc.) of the nozzle plate 60 and easily. A plasma polymerized film can be formed.

  Of the organopolysiloxanes, it is preferable to use alkylpolysiloxanes. Since alkylpolysiloxane is a polymer compound, a polymer film can be formed on the nozzle plate 60. In addition, since the polymer has an alkyl group, the polymer structure has little steric hindrance, and a film in which molecules are regularly arranged can be formed. Of the alkylpolysiloxanes, dimethylpolysiloxane is particularly preferable. Since dimethylpolysiloxane is easy to produce, it can be easily obtained.

  Examples of the method for forming the first plasma polymerized film 61 include a plasma polymerization method, a vapor deposition method, a treatment with a silane coupling agent, a treatment with a liquid material containing polyorganosiloxane, and the like. Alternatively, two or more kinds can be used in combination.

  Among these methods, it is preferable to use a plasma polymerization method. Since the plasma of organopolysiloxane is generated by using the plasma polymerization method, the first plasma polymerization film 61 having a uniform and uniform film thickness can be formed.

  The average film thickness T1 of the first plasma polymerization film 61 is preferably about 10 to 1000 nm, and more preferably about 50 to 500 nm.

  Next, as shown in FIG. 5B, a resist 64 is applied on the first plasma polymerized film 61 and exposed using a mask corresponding to the pattern of the concentric region centered on the nozzle hole 51. By performing development, the resist 64 is patterned in a region other than the concentric region with the nozzle hole 51 as the center.

  Next, as shown in FIG. 5C, the portion of the first plasma polymerized film 61 where the resist 64 is not patterned is removed by etching, and further, as shown in FIG. 5D, the resist 64 is removed. .

  Next, as shown in FIG. 5E, the first plasma polymerized film 61 and the surface 60a on the ink discharge side of the nozzle plate 60 exposed by removing the first plasma polymerized film 61 are exposed to the second A plasma polymerization film 62 is formed. The constituent material and the formation method of the second plasma polymerization film 62 are the same as those of the first plasma polymerization film 61.

  In addition, when the above-mentioned dimethylpolysiloxane is used as a constituent material of the second plasma polymerized film 62, the reactivity is high. Therefore, when the second plasma polymerized film 62 is subjected to oxidation treatment as described later, methyl The group can be easily cleaved, which is preferable.

  The average film thickness T2 of the second plasma polymerization film 62 is preferably about 10 to 1000 nm, and more preferably about 50 to 500 nm. With such a thickness, an optimal amount of alkyl groups terminates on the surface of the second plasma polymerized film 62, so that a liquid repellent film having liquid repellency is obtained by an oxidation treatment and a reaction with a metal alkoxide described later. 63 can be formed.

  The film thickness ratio (T1 / T2) between the film thickness T1 of the first plasma polymerized film 61 and the film thickness T2 of the second plasma polymerized film 62 is preferably 0.5 to 1.5. With such a film thickness ratio, a step having an appropriate height can be formed.

  The second plasma polymerized film 62 is desirably made of the same material as that of the first plasma polymerized film 61, but may be made of a material different from that of the first plasma polymerized film 61.

  Next, as shown in FIG. 5F, the second plasma polymerization film 62 is subjected to an oxidation treatment in an atmosphere of moisture-containing gas (hereinafter referred to as “processing gas”). By oxidizing the second plasma polymerized film 62, hydroxylation and / or adsorbed water is introduced into the second plasma polymerized film 62 and the reaction with the liquid repellent film 63 is ensured. That is, by the oxidation treatment, the adhesion between the second plasma polymerization film 62 and the liquid repellent film 63 is increased, and the rub resistance of the liquid repellent film 63 can be improved.

  Regarding the conditions for the processing gas and the method for the oxidation treatment, the conditions and methods described in JP-A-2008-105231 can be preferably used.

  That is, the dew point of the processing gas is more preferably −40 to −20 ° C. With such a processing gas, it is possible to obtain the liquid repellent film 63 having a balance between abrasion resistance and alkali resistance.

Further, as an oxidation treatment method, a method of irradiating energy rays such as ultraviolet rays or plasma can be applied. According to this method, since the oxidation treatment can be performed only on the region irradiated with the energy rays, the SiO ₂ conversion can be efficiently performed.

  In particular, in the present embodiment, among the methods of irradiating energy rays, a method of performing oxidation treatment using plasma irradiation is preferable. In the case of using plasma irradiation as the oxidation treatment, examples of gas species that generate plasma include oxygen gas, nitrogen gas, hydrogen, inert gas (argon gas, helium gas, etc.), and one of these. Alternatively, two or more kinds can be used in combination.

  Finally, as shown in FIG. 5G, a liquid repellent film 63 is formed on the surface of the second plasma polymerized film 62 that has been subjected to the oxidation treatment.

  The liquid repellent film 63 is not particularly limited as long as it can form a siloxane bond with the second plasma polymerized film 62. For example, a metal alkoxide-based liquid repellent film, a fluorine-containing plasma polymerized film, or a silicone plasma. A polymerized liquid repellent film or the like can be applied.

  As a method for forming the metal alkoxide-based liquid repellent film, a method described in JP 2008-105231 A can be preferably used. That is, it can be performed using various processes such as a liquid phase process and a gas phase process, and among them, the liquid phase process is preferably used, and a liquid repellent film composed of a metal alkoxide is formed by a relatively simple process. Can be formed.

  As a method for forming a liquid repellent film composed of a plasma polymerized film, the method described in JP-A-2004-1006203 can be preferably used. That is, the plasma polymerized film (liquid repellent film) can be formed using a conventionally known plasma processing apparatus. As a raw material, a gasified liquid organopolysiloxane (silicone) is used as a raw material gas. If necessary, this raw material gas is mixed with a rare gas such as argon or helium, or a gas having an oxidizing power such as oxygen or carbon dioxide. Thereby, it can laminate | stack on the 2nd plasma polymerization film | membrane 62 in the state which superposed | polymerized the raw material.

  As described above, the liquid repellent film composed of a plasma polymerized film is formed by using a low molecular weight metal alkoxide as a raw material and subjecting it to plasma polymerization, and is excellent in resistance to a metal salt. Is suitable as a liquid repellent layer of a nozzle plate for an aqueous pretreatment liquid (metal salt solution) containing an ink flocculant.

  Further, it is preferable that the stepped portion region (recessed portion region) of the liquid repellent film 63 includes a region of 0.5 μm or more from the opening end on the ink ejection side of the nozzle hole 51 toward the outside. That is, the length L in FIG. 5 (g) is preferably 0.5 μm or more. With such a stepped region, the liquid repellency of the ink ejection portion can be appropriately protected.

  In addition, you may form the opening part of the 1st plasma polymerization film | membrane 61 using a different method.

  FIG. 6 is a process diagram for explaining a modification of the liquid repellent film forming method according to the present invention.

  First, as shown in FIG. 6A, a resist 65 is applied on the ink ejection side surface 60 a of the nozzle plate 60, and exposure is performed using a mask corresponding to a pattern of concentric regions around the nozzle holes 51. Thereafter, development is performed to pattern the resist 65 in a concentric region centered on the nozzle hole 51.

  Next, as shown in FIG. 6B, a first plasma polymerization film 61 is formed on the resist 65 in the region where the ink discharge side surface 60 a of the nozzle plate 60 is exposed. The constituent material, the forming method, and the average film thickness of the first plasma polymerization film 61 may be the same as those of the first plasma polymerization film 61 shown in FIG.

  Next, as shown in FIG. 6C, the first plasma polymerization film 61 in the circular region where the resist 65 is formed is removed together with the resist 65 by lift-off.

  The process after FIG.6 (c) is the same as the process after FIG.5 (e).

  As described above, the liquid repellent film 63 having a step on the ink discharge side surface of the nozzle plate 60 as shown in FIG. 4 can be formed. The height of the step is determined by the film thickness at the time of forming the first plasma polymerized film and the second plasma polymerized film, and the height of the step is adjusted by adjusting the amount of decrease in the film thickness of the plasma polymerized film. Compared with the technique described in Patent Document 1 to be determined, the step can be formed with high accuracy and uniformity.

  Thus, according to the present embodiment, the first plasma polymerization film 61 on the nozzle plate 60 is provided with a concentric opening centered on the nozzle hole 51, and the second polymerization film 62 is formed thereon. By forming the underlying plasma polymerized film in a two-stage film formation, and further forming the liquid repellent film 63 thereon, the uniformity of the step of the liquid repellent film 63 can be improved. The length becomes uniform, the ink ejection characteristics are stabilized, and at the same time, the rub and alkali resistance of the liquid repellent film can be improved.

  In the above-described embodiment, application to an inkjet recording apparatus for printing has been described as an example. However, the scope of application of the present invention is not limited to this example. For example, various shapes and patterns are obtained using liquid functional materials such as a wiring drawing device for drawing a wiring pattern of an electronic circuit and a fine structure forming device for forming a fine structure using a material for material deposition. It can be widely applied to devices.

Overall configuration diagram showing outline of inkjet recording apparatus Plane perspective view showing structure example of recording head Schematic sectional view showing a part of the recording head Enlarged sectional view around the nozzle hole 51 of the nozzle plate 60 Process drawing for demonstrating the liquid-repellent film formation method which concerns on this invention Process drawing for demonstrating the modification of the liquid repellent film formation method which concerns on this invention

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device, 50 ... Recording head, 51 ... Nozzle hole, 52 ... Pressure chamber, 54 ... Ink supply port, 55 ... Common flow path, 60 ... Nozzle plate, 60a ... Surface on the ink discharge side of nozzle plate 60, 61 ... 1st plasma polymerization film, 62 ... 2nd plasma polymerization film, 63 ... Liquid repellent film, 64, 65 ... Resist

Claims (6)

A liquid repellent film forming method for forming a liquid repellent film having liquid repellency on a surface of a nozzle forming substrate having nozzle holes,
A first step of forming a first underlayer composed of a plasma polymerized film in a region other than the predetermined region including the nozzle hole on one surface side of the nozzle forming substrate;
A second step of forming a second underlayer composed of a plasma polymerization film in a predetermined region including the first underlayer and the nozzle hole;
A third step of oxidizing the surface of the second underlayer under a gas atmosphere having a dew point of −40 to 20 ° C. to introduce hydroxyl groups and / or adsorbed water;
A fourth step of forming the liquid repellent film on the second underlayer subjected to the oxidation treatment;
A method for forming a liquid repellent film, comprising: The first step includes
Forming a first underlayer composed of a plasma polymerized film on one surface side of the nozzle forming substrate;
Forming a resist layer in a region other than the predetermined region including the nozzle hole;
Removing the first underlayer using the resist layer as a mask;
Removing the resist layer;
The liquid repellent film forming method according to claim 1, comprising: The first step includes
Forming a resist layer in a predetermined region including the nozzle holes on one side of the nozzle forming substrate;
Forming a first underlayer composed of a plasma polymerized film on one surface side of the nozzle forming substrate;
Removing the resist layer and the first underlayer formed on the resist layer by lift-off;
The liquid repellent film forming method according to claim 1, comprising:   A nozzle plate comprising a liquid repellent film formed by the method of forming a liquid repellent film according to claim 1.   An ink jet head comprising the nozzle plate according to claim 4.   An electronic apparatus comprising the inkjet head according to claim 5.

Images