JP2012213872A - Method of forming water-repellent film, nozzle plate, ink jet head and ink jet recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of forming a water-repellent film which can improve adhesion between a substrate and the water-repellent film and improve wear resistance.SOLUTION: The method of forming the water-repellent film 30 includes: an intermediate layer forming process of forming an intermediate layer 20 mainly constituted of Si-O bonds and having organic groups directly joined to Si on the substrate 10; an irradiation process of irradiating the intermediate layer 20 with excitation light to increase OH groups on the surface of the intermediate layer 20; a heating process of heating the substrate 10 and the intermediate layer 20; and an organic film forming process of forming an organic film on the surface of the intermediate layer 20 by a silane coupling agent 31. This invention also relates to a nozzle plate, an ink jet head and an ink jet recording device.

Description

  The present invention relates to a method for forming a water repellent film, a nozzle plate, an ink jet head, and an ink jet recording apparatus, and in particular, a method for forming a water repellent film using a coupling material, a nozzle plate, an ink jet head, and an ink jet recording apparatus. About.

  In an ink jet head used in an ink jet recording apparatus, if ink adheres to the surface of a nozzle plate, ink droplets ejected from the nozzles are affected, and the ink droplet ejection direction may vary. . If the ink adheres, it becomes difficult to land the ink droplet on a predetermined position on the recording medium, which causes the image quality to deteriorate.

  Therefore, various methods for forming a water-repellent film on the surface of the nozzle plate have been proposed in order to prevent ink from adhering to the surface of the nozzle plate to improve the discharge performance and to improve the maintenance performance.

  For example, Patent Document 1 below describes a member in which a plasma polymerized film is formed on a substrate, annealed to form a base film, and then a metal alkoxide liquid repellent film is formed on the surface of the base film. Has been. Patent Document 2 discloses an ink jet recording head manufacturing method in which after a nozzle plate surface is laser processed, residues adhered to the nozzle are removed by plasma, ion milling, and reverse sputtering, and then a water repellent layer is formed. Are listed.

Further, Non-Patent Document 1 describes a consideration regarding the adsorbed water of SiO ₂ .

Japanese Patent No. 4293035 JP-A-9-136421

Norio Hirashita et al., "Thermal Desorption and Infrared Studies of Plasma-Enhanced Chemical Vapor Deposited SiO Films with Tetraethyiorthosilicate" Japanese Journal of Applied Physics, Vol.32 (1993) pp.1787-1793

  In the member described in Patent Document 1, a plasma polymerized film is used as a base layer of the water repellent film, and the adhesion of the metal alkoxide water repellent material is enhanced by increasing the OH group of the substrate. However, increasing the number of OH groups by UV irradiation or plasma irradiation makes it easier for adsorbed water to adhere, so that there are fewer OH groups that bind to the water-repellent material, and conversely there is a problem in that adhesion is reduced. Further, in the method of Patent Document 2, removal is performed by plasma or the like in order to remove organic substances attached to the nozzle plate, and no consideration has been given to removing adsorbed water.

  The present invention has been made in view of such circumstances, and provides a method for forming a water-repellent film, a nozzle plate, an ink-jet head, and an ink-jet recording apparatus that can improve the adhesion between the substrate and the water-repellent film. The purpose is to do.

  In order to achieve the above object, the present invention provides an intermediate layer forming step of forming an intermediate layer in which an organic group is directly bonded to Si, mainly an Si-O bond, on the substrate, and the intermediate layer is irradiated with excitation light. And an irradiation step for increasing the OH groups on the surface of the intermediate layer, a heating step for heating the substrate and the intermediate layer, and an organic film forming step for forming an organic film on the surface of the intermediate layer with a silane coupling agent. A method for forming a water-repellent film is provided.

  When a water-repellent film is formed on the intermediate layer, the number of OH groups on the surface of the intermediate layer is increased by the irradiation process, so that the hydrogen-bonded water adsorption sites increase and the adsorbed water covers the OH groups. It is considered that the adhesion of the formed water repellent film is lowered. According to the present invention, since the heating process is performed after the irradiation process, the adsorbed water hydrogen-bonded to the OH group can be removed. Therefore, since the adhesiveness of the silane coupling agent bonded to the OH group can be improved, the durability of the water repellent film can be improved.

  In the present invention, after the heating step, the organic film forming step is preferably performed in a state where an environment in which water vapor does not adhere to the intermediate layer is maintained.

  According to the present invention, it is possible to prevent hydrogen-bonded water from adsorbing to OH groups by maintaining an environment in which water vapor does not adhere to the intermediate layer after the heating step. Therefore, the adhesiveness of the water repellent film formed by the organic film forming step can be improved.

  In the present invention, the heating step and the organic film forming step are preferably performed in the same vacuum chamber.

  In the present invention, the hydrogen bonding water can be prevented from adhering to the OH group of the intermediate layer by performing the heating step and the organic film forming step in the same vacuum chamber.

  In the present invention, the silane coupling agent is preferably a fluorine-containing silane coupling agent.

  By using a silane coupling agent containing fluorine as the silane coupling agent, water repellency can be effectively imparted.

  In the present invention, the heating step is preferably performed at 50 ° C. or higher and 350 ° C. or lower.

  In the present invention, the heating step is preferably performed at 200 ° C. or higher and 350 ° C. or lower.

  According to the present invention, by performing the heating step at 50 ° C. or higher and 350 ° C. or lower, more preferably 200 ° C. or higher and 350 ° C. or lower, free adsorbed water adsorbed on the intermediate layer and no OH group The hydrogen-bonded water that interacts with the water can be removed, and only the OH groups bonded in the intermediate layer can be left. Accordingly, in the next coating step, the OH group and the metal alkoxide coupling material can be easily bonded to each other, so that a water-repellent film having high adhesion can be manufactured.

  In order to achieve the above object, the present invention provides a nozzle plate comprising a water repellent film formed by the method for forming a water repellent film described above.

  In order to achieve the above object, the present invention provides an ink jet head comprising the nozzle plate described above.

  In order to achieve the above object, the present invention provides an ink jet recording apparatus comprising the ink jet head described above.

  The water repellent film formed by the water repellent film forming method described above can be suitably used for a nozzle plate, an ink jet head, and an ink jet recording apparatus.

  According to the method for forming a water-repellent film of the present invention, the water-repellent film can be formed while removing adsorbed water and free of OH groups on the intermediate layer. can do. In addition, since the wear resistance during maintenance can be improved, it can be suitably used as a nozzle plate, an inkjet head, and an inkjet recording apparatus.

It is a figure explaining the formation method of a water repellent film. It is the schematic of the chemical structure of the molecule | numerator which comprises an intermediate | middle layer. 1 is an overall configuration diagram showing an outline of an inkjet recording apparatus. It is a plane perspective view which shows the structural example of an inkjet head. It is sectional drawing which follows the IV-IV line in FIG. It is a table | surface figure which shows the result of a comparative example. It is a table | surface figure which shows the result of an Example.

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

  In the method for forming a water-repellent film according to the present embodiment, an intermediate layer forming step for forming an intermediate layer in which an organic group is directly bonded to Si, mainly an Si-O bond, and the intermediate layer is irradiated with excitation light. And an irradiation process in which the organic groups on the surface of the intermediate layer are changed to OH groups and the OH groups are increased, and heating to remove free adsorbed water and hydrogen-bonded water that has become easy to adhere by increasing the concentration of OH groups in the irradiation process. And an organic film forming step of applying a silane coupling agent to the OH group that has lost its bond with the removal of free adsorbed water and hydrogen-bonded water to form a water-repellent organic film.

  According to the above method for forming a water repellent film, it is possible to increase the concentration of OH groups. Further, after removing the adsorbed water that has been easily adhered by increasing the concentration of OH groups, Since the film is formed, it can be bonded to a high concentration of OH groups, so that the adhesion of the water-repellent film can be improved and the wear resistance can be improved.

  Hereinafter, each step will be described.

[Intermediate layer forming step]
FIG. 1A is a schematic view of a chemical structure in which an intermediate layer 20 is formed on a substrate 10.

  The material of the substrate 10 forming the intermediate layer is preferably any of silicon, glass, metal, ceramic, and polymer film. In the present invention, a strong water-repellent film can be formed from any of silicon, glass, metal, ceramic, and polymer film.

  A thin film in which an organic group (R) is directly bonded to Si (hereinafter also referred to as “Si—R bond”) is formed on the substrate 10 mainly with Si—O bonds. Examples of the organic group include aliphatic groups, aromatic groups, and heterocyclic groups. For example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, 2-methylbutyl, 1-methylbutyl, n-hexyl, isohexyl, 3-methylpentyl 2-methylpentyl, 1-methylpentyl, heptyl, octyl, isooctyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, cyclopentyl, cyclohexyl, adamantyl, vinyl, propenyl, butenyl, acrylic , Methacryl, octynyl, dodecenyl, undecenyl, cyclohexenyl, phenyl, tolyl, pyrenyl, phenanthrenyl, naphthyl, biphenylyl, terphenylyl, benzyl, phenethyl, na Other Chirumechiru, mention may be made of various heterocycles from heterocyclic groups mentioned above. From the viewpoint of production cost, a simpler structure such as a methyl group or an ethyl group can be preferably used.

A thin film in which an organic group is bonded directly to Si mainly with Si—O bonds is obtained by introducing a plasma of a mixed gas of silane-based gas and oxygen, such as monomethylsilane, dimethylsilane, trimethylsilane, and tetramethylsilane, and then a plasma CVD method. Alternatively, it can be formed by using a cat-CVD method. When forming by a cat-CVD method, a tungsten wire can be used as a catalyst. Thus, a film mainly composed of Si—O bonds in which CH ₃ groups are bonded as organic groups can be formed.

Further, a methylsiloxane material called an MSQ / organic SOG material, or a material having a similar structure to these materials and having a Si—CH ₃ bond and having a Si—O bond as a main component, for example, HSG made by Hitachi Chemical Co., Ltd. A polyorganosiloxane film can be produced by applying and baking a commercially available material such as HOSP / ULVAC ULKS Ver3 manufactured by Honeywell under the condition that Si-O is a skeleton and the organic group (R) remains in Si. .

[Irradiation process]
By irradiating the intermediate layer 20 obtained in the intermediate layer forming step with excitation light, the organic group is removed and the Si—R bond is converted to Si—OH.

  Regarding the conditions for the processing gas and the processing method, the conditions and methods described in Japanese Patent Application Laid-Open No. 2008-105231 can be preferably used.

  In the present invention, the excitation light can use energy rays such as ultraviolet rays or plasma. According to this method, since the energy ray can be oxidized only in the irradiation region, OH groups can be increased.

  In the case of performing plasma irradiation, oxygen plasma irradiation using a gas containing oxygen gas is preferably used as a gas species for generating plasma. According to the oxygen plasma irradiation, the oxygen plasma breaks the bond between the alkyl group and Si, and OH groups can be introduced onto the thin film.

  The atmosphere in which the irradiation process is performed is preferably performed under reduced pressure. By carrying out in a reduced pressure state, it is possible to prevent the thin film from adsorbing water vapor present in the atmosphere, and the adhesion of the silane coupling agent can be improved in the subsequent organic film forming step. Moreover, it is preferable to carry out on sealing conditions (for example, in a chamber). Thereby, since a thin film is oxidized in a state with a higher plasma density, more OH groups can be introduced onto the thin film. In addition, water vapor in the atmosphere can be prevented from adhering to the thin film as adsorbed water.

[Heating process]
The substrate 10 and the intermediate layer 20 are heated, and the adsorbed water attached to the intermediate layer 20 is removed.

  FIG. 2A is a schematic diagram of the chemical structure of the molecules constituting the intermediate layer 20 after the irradiation process, and FIG. 2B is a schematic diagram of the chemical structure of the molecules that constitute the intermediate layer 20 after the heating process. It is. FIG. 1B is a schematic view of the chemical structure after the irradiation step, and FIG. 1C is a schematic view of the chemical structure after the heating step. As shown in FIG. 2, when dehydrating by heating, there are three types of water.

  The free adsorbed water α is free adsorbed water that does not interact with other substances. Normally, water evaporates at 100 ° C., but FIG. 2 is a diagram showing minute pores. Since free adsorbed water is also contained in these pores, the vapor pressure is increased and vaporized. For this purpose, the temperature needs to be higher than usual. In order to desorb (evaporate) the free adsorbed water α, 200 ° C. is required.

  Hydrogen-bonded water β is adsorbed water that interacts with OH groups and is hydrogen-bonded to OH groups. Therefore, 200 to 350 ° C. is necessary to desorb the hydrogen-bonded water β.

  The OH group γ reacts with the metal alkoxide coupling material in the next organic film forming step to form a water repellent film. Therefore, by leaving the OH group γ without leaving, a film with higher density and higher adhesion can be formed. In addition, when removing OH group (gamma), the temperature of 350 degreeC or more is required.

  Therefore, in the heating step, it is preferable to heat in the range of 50 ° C. or higher and 350 ° C. or lower, more preferably in the range of 200 ° C. or higher and 350 ° C. or lower. By heating in this range, free adsorbed water α and hydrogen-bonded water β can be removed, and OH groups γ can be left, so that free OH groups γ can be increased.

  The method for heating the substrate and the thin film is not particularly limited, and the substrate and the thin film can be heated by an ordinary method such as heating in a heating furnace.

[Organic film process]
The organic film process is a process of forming an organic film by depositing a silane coupling agent on the intermediate layer 20 obtained in the heating process. FIG. 1 (d) is a schematic view of the chemical structure before bonding of the silane coupling agent and the intermediate layer, and FIG. 1 (e) is a schematic view of the chemical structure after bonding.

  As the silane coupling agent 31, a chlorine type, a methoxy type, an ethoxy type, an isocyanato type, or the like is preferably used. Since a large number of hydroxyl: OH groups serving as reaction sites for the silane coupling agent are formed on the surface of the intermediate layer 20, the silane coupling agent is bonded to the intermediate layer 20 at a high density by the coating process. A water film 30 can be formed.

  The water repellent film 30 can be formed by, for example, a physical vapor deposition method such as an evaporation method. The vapor deposition method is a method in which a film formation substrate is set in a vacuum chamber, and a material to be formed in the vacuum chamber is vaporized under a vaporizing condition (that is, a condition that vapor pressure is sufficient) to form a film. In the case of a silane coupling agent, a method of forming a film by heating and vaporizing the silane coupling agent is common.

The silane coupling agent is a silicon compound represented by Y _n SiX _4-n (n = 1, 2, 3). Y includes a relatively inactive group such as an alkyl group or a reactive group such as a vinyl group, an amino group, or an epoxy group. X is a group that can be bonded by condensation with a hydroxyl group on the substrate surface such as halogen, methoxy group, ethoxy group, or acetoxy group, or adsorbed water. Silane coupling agents are widely used as mediators of these bonds in the production of organic and inorganic composite materials such as glass fiber reinforced plastics, and Y is an inert group such as an alkyl group. In some cases, properties such as adhesion and friction prevention, gloss retention, water repellency, and lubrication are imparted on the modified surface. Moreover, when a reactive group is included, it is mainly used for the improvement of adhesiveness.

  Furthermore, the surface modified by using a fluorine-based silane coupling agent in which a linear fluorocarbon chain is introduced into Y has a low surface free energy like a PTFE (polytetrafluoroethylene) surface, and is water repellent. In addition, properties such as lubrication and mold release are improved, and oil repellency is also exhibited.

Examples of the linear fluoroalkylsilane include Y═CF ₃ CH ₂ CH ₂ , CF ₃ (CF ₂ ) ₃ CH ₂ CH ₂ , CF ₃ (CF ₂ ) ₇ CH ₂ CH _{2, and the} like.

For the Y portion, a material having a perfluoroether (PFPE) group (—CF ₂ —O—CF ₂ —) can be used.

As the silane coupling agent, a material X ₃ SiYSiX _{3 in} which silane coupling groups are bonded to both sides can be used as well as one side.

  Also, Daikin Industries, Ltd. OPTOOL, Harves Co., Ltd. Durasurf, Sumitomo 3M Co., Ltd. Novec EGC1720, Solvay Solexis Co., Ltd. Fluorolink S-10, T & K Nanos Co., Ltd., Shin-Etsu Commercially available silane coupling water repellent materials such as Seifel KY-100 and AGC Cytop M type manufactured by Chemical Industry Co., Ltd. can also be used.

  In addition, FIG.1 (d) shows the state by which the silane coupling agent 31 was hydrolyzed and X was substituted by the OH group. Thereafter, dehydration condensation occurs between OH groups on the intermediate layer 20 or adjacent silane coupling agents 31 to form a film having a structure as shown in FIG.

  Moreover, in this invention, it is preferable to perform from a heating process to an organic film formation process in the state which maintained the environment where water vapor | steam does not adhere to an intermediate | middle layer. Maintaining the state in which the adsorbed water adhering to the intermediate layer is removed by the heating process and preventing water vapor in the atmosphere from adhering to the intermediate layer between the heating process and the coating process, so that the adhesion is more A high film can be formed.

  As a method for suppressing the adhesion of water vapor, the organic film forming step can be carried out while maintaining the reduced pressure state of the heating step. For example, it can be performed by performing the organic film forming process from the heating process without leaking the vacuum state in the same apparatus. As the apparatus, a heating mechanism is provided in the water repellent film deposition apparatus, and the heating process and the organic film forming process are performed in the water repellent film deposition apparatus. The heating apparatus and the vapor deposition apparatus can be installed in the same vacuum chamber, and the heating process and the organic film forming process can be continuously performed.

  In addition, by carrying out the transfer from the heating process to the organic film forming process in an atmosphere of gas that does not contain water vapor, instead of making a vacuum, water vapor in the atmosphere is prevented from coming into contact with the substrate, Adsorption can be suppressed. As the gas, an inert gas such as nitrogen, argon, or helium can be preferably used. Moreover, when performing a heating process and an organic film formation process with the same apparatus, it can also carry out by putting between the processes in the atmosphere of the gas which does not contain the said water vapor | steam.

<Overall configuration of inkjet recording apparatus>
Next, as an example to which the water repellent film formed by the method of forming a water repellent film of the present invention is applied, a nozzle plate, an ink jet head having a nozzle plate, and an ink jet recording apparatus will be described. The water repellent film forming method of the present invention can be preferably used for a nozzle plate manufacturing method, an inkjet head manufacturing method, and an inkjet recording apparatus manufacturing method.

  FIG. 3 is a configuration diagram of the ink jet recording apparatus. In the inkjet recording apparatus 100, a recording medium 124 (sometimes referred to as “paper” for convenience) held on the impression cylinder (drawing drum 170) of the drawing unit 116 is provided with a plurality of colors from the inkjet heads 172M, 172K, 172C, 172Y. Is an impression cylinder direct drawing type ink jet recording apparatus that forms a desired color image by applying ink droplets of the ink. A treatment liquid (in this case, an aggregating treatment liquid) is applied onto the recording medium 124 before ink ejection. This is an on-demand type image forming apparatus to which a two-liquid reaction (aggregation) method for forming an image on a recording medium 124 by reacting a treatment liquid and an ink liquid is applied.

  As shown in the figure, the ink jet recording apparatus 100 mainly includes a paper feeding unit 112, a treatment liquid application unit 114, a drawing unit 116, a drying unit 118, a fixing unit 120, and a discharge unit 122.

(Paper Feeder)
The paper feeding unit 112 is a mechanism that supplies the recording medium 124 to the processing liquid application unit 114, and the recording medium 124 that is a sheet is stacked on the paper feeding unit 112. The paper feed unit 112 is provided with a paper feed tray 150, and the recording medium 124 is fed from the paper feed tray 150 to the processing liquid application unit 114 one by one.

(Processing liquid application part)
The processing liquid application unit 114 is a mechanism that applies the processing liquid to the recording surface of the recording medium 124. The treatment liquid contains a color material aggregating agent that agglomerates the color material (pigment in this example) in the ink applied by the drawing unit 116, and the ink comes into contact with the treatment liquid and the ink. And the solvent are promoted.

  As shown in FIG. 3, the treatment liquid application unit 114 includes a paper feed cylinder 152, a treatment liquid drum 154, and a treatment liquid application device 156. The treatment liquid drum 154 is a drum that holds and rotates the recording medium 124. The processing liquid drum 154 includes a claw-shaped holding means (gripper) 155 on the outer peripheral surface thereof, and the recording medium 124 is sandwiched between the claw of the holding means 155 and the peripheral surface of the processing liquid drum 154. The tip can be held.

  A processing liquid coating device 156 is provided outside the processing liquid drum 154 so as to face the peripheral surface thereof. The processing liquid coating device 156 includes a processing liquid container in which the processing liquid is stored, an anix roller partially immersed in the processing liquid in the processing liquid container, and the recording medium 124 on the anix roller and the processing liquid drum 154. And a rubber roller that transfers the measured processing liquid to the recording medium 124. According to the processing liquid coating apparatus 156, the processing liquid can be applied to the recording medium 124 while being measured.

  The recording medium 124 to which the processing liquid is applied by the processing liquid applying unit 114 is transferred from the processing liquid drum 154 to the drawing drum 170 of the drawing unit 116 via the intermediate transport unit 126.

(Drawing part)
The drawing unit 116 includes a drawing drum (second transport body) 170, a sheet pressing roller 174, and ink jet heads 172M, 172K, 172C, and 172Y. Similar to the treatment liquid drum 154, the drawing drum 170 includes a claw-shaped holding means (gripper) 171 on the outer peripheral surface thereof. The recording medium 124 fixed to the drawing drum 170 is conveyed with the recording surface facing outward, and ink is applied to the recording surface from the inkjet heads 172M, 172K, 172C, 172Y.

  The inkjet heads 172M, 172K, 172C, and 172Y are preferably full-line inkjet recording heads (inkjet heads) each having a length corresponding to the maximum width of the image forming area on the recording medium 124. On the ink ejection surface, a nozzle row in which a plurality of nozzles for ink ejection are arranged over the entire width of the image forming area is formed. Each inkjet head 172M, 172K, 172C, 172Y is installed so as to extend in a direction orthogonal to the conveyance direction of the recording medium 124 (the rotation direction of the drawing drum 170).

  The droplets of the corresponding color ink are ejected from the inkjet heads 172M, 172K, 172C, and 172Y toward the recording surface of the recording medium 124 held in close contact with the drawing drum 170, whereby the processing liquid application unit 114 performs the processing. The ink comes into contact with the treatment liquid previously applied to the recording surface, and the color material (pigment) dispersed in the ink is aggregated to form a color material aggregate. Thereby, the color material flow on the recording medium 124 is prevented, and an image is formed on the recording surface of the recording medium 124.

  The recording medium 124 on which an image is formed by the drawing unit 116 is transferred from the drawing drum 170 to the drying drum 176 of the drying unit 118 via the intermediate conveyance unit 128.

(Drying part)
The drying unit 118 is a mechanism for drying moisture contained in the solvent separated by the color material aggregation action, and includes a drying drum 176 and a solvent drying device 178 as shown in FIG.

  Similar to the processing liquid drum 154, the drying drum 176 includes a claw-shaped holding unit (gripper) 177 on the outer peripheral surface thereof, and the holding unit 177 can hold the leading end of the recording medium 124.

  The solvent drying device 178 is disposed at a position facing the outer peripheral surface of the drying drum 176, and includes a plurality of halogen heaters 180 and hot air ejection nozzles 182 disposed between the halogen heaters 180.

  The recording medium 124 that has been dried by the drying unit 118 is transferred from the drying drum 176 to the fixing drum 184 of the fixing unit 120 via the intermediate conveyance unit 130.

(Fixing part)
The fixing unit 120 includes a fixing drum 184, a halogen heater 186, a fixing roller 188, and an inline sensor 190. Like the processing liquid drum 154, the fixing drum 184 includes a claw-shaped holding unit (gripper) 185 on the outer peripheral surface, and the leading end of the recording medium 124 can be held by the holding unit 185.

  With the rotation of the fixing drum 184, the recording medium 124 is conveyed with the recording surface facing outward. The recording surface is preheated by the halogen heater 186, fixing processing by the fixing roller 188, and by the inline sensor 190. Inspection is performed.

  According to the fixing unit 120, the thermoplastic resin fine particles in the thin image layer formed by the drying unit 118 are heated and pressurized by the fixing roller 188 and are melted, and can be fixed and fixed to the recording medium 124. . Further, by setting the surface temperature of the fixing drum 184 to 50 ° C. or higher, drying is promoted by heating the recording medium 124 held on the outer peripheral surface of the fixing drum 184 from the back surface, thereby preventing image destruction during fixing. In addition, the image intensity can be increased by the effect of increasing the image temperature.

  In addition, when a UV curable monomer is contained in the ink, after the water is sufficiently volatilized in the drying unit, the image is irradiated with UV at the fixing unit equipped with a UV irradiation lamp. The monomer can be cured and polymerized to improve the image strength.

(Discharge part)
As shown in FIG. 3, a discharge unit 122 is provided following the fixing unit 120. The discharge unit 122 includes a discharge tray 192, and a transfer drum 194, a conveyance belt 196, and a stretching roller 198 are provided between the discharge tray 192 and the fixing drum 184 of the fixing unit 120 so as to be in contact therewith. It has been. The recording medium 124 is sent to the conveyor belt 196 by the transfer drum 194 and discharged to the discharge tray 192.

  Although not shown in the drawing, the ink jet recording apparatus 100 of the present example has an ink storage / loading unit for supplying ink to each of the ink jet heads 172M, 172K, 172C, and 172Y in addition to the above-described configuration, and application of processing liquid. A means for supplying a processing liquid to the unit 114, and a head maintenance unit for cleaning each ink jet head 172M, 172K, 172C, 172Y (wiping, purging, nozzle suction, etc. of the nozzle surface), A position detection sensor for detecting the position of the recording medium 124, a temperature sensor for detecting the temperature of each part of the apparatus, and the like are provided.

  Although the drum conveyance type inkjet recording apparatus has been described with reference to FIG. 3, the present invention is not limited to this, and the invention can also be used in a belt conveyance type inkjet recording apparatus.

[Inkjet head structure]
Next, the structure of the inkjet heads 172M, 172K, 172C, 172Y will be described. In addition, since the structure of each inkjet head 172M, 172K, 172C, 172Y is common, hereinafter, the head is represented by reference numeral 250 as a representative of these.

  4A is a plan perspective view showing an example of the structure of the inkjet head 250, and FIG. 4B is a plan perspective view showing another example of the structure of the inkjet head 250. FIG. 5 is a cross-sectional view (a cross-sectional view taken along line IV-IV in FIG. 4A) showing a three-dimensional configuration of the ink chamber unit.

  In order to increase the dot pitch formed on the recording paper surface, it is necessary to increase the nozzle pitch in the inkjet head 250. As shown in FIG. 4A, the ink jet head 250 of this example includes a plurality of ink chamber units 253 including nozzles 251 that are ink droplet ejection holes and pressure chambers 252 corresponding to the nozzles 251. It has a structure that is arranged in a matrix (two-dimensionally), and as a result, a substantial nozzle interval (projection) projected so as to be aligned along the head longitudinal direction (main scanning direction orthogonal to the paper transport direction). Nozzle pitch) is increased.

  The configuration in which one or more nozzle rows are configured over a length corresponding to the entire width of the recording medium 124 in a direction substantially orthogonal to the paper conveyance direction is not limited to this example. For example, instead of the configuration of FIG. 4A, as shown in FIG. 4B, short head blocks (head chips) 250 ′ in which a plurality of nozzles 251 are two-dimensionally arranged are arranged in a staggered manner. By connecting them together, a line head having a nozzle row having a length corresponding to the entire width of the recording medium 124 may be configured. Although not shown, a line head may be configured by arranging short heads in a line.

  As shown in FIG. 5, each nozzle 251 is formed on a nozzle plate 260 that forms the ink ejection surface 250 a of the inkjet head 250. The nozzle plate 260 is made of, for example, a silicon-based material such as Si, SiO2, SiN, or quartz glass, a metal-based material such as Al, Fe, Ni, Cu, or an alloy containing these, an oxide such as alumina or iron oxide. It is composed of a material, a carbon-based material such as carbon black and graphite, and a resin-based material such as polyimide.

  A water repellent film 262 having liquid repellency with respect to ink is formed on the surface of the nozzle plate 260 (the surface on the ink discharge side) to prevent ink adhesion.

  The pressure chamber 252 provided corresponding to each nozzle 251 has a substantially square planar shape, and the nozzle 251 and the supply port 254 are provided at both corners on the diagonal line. Each pressure chamber 252 is in communication with a common channel 255 through a supply port 254. The common channel 255 communicates with an ink supply tank (not shown) as an ink supply source, and the ink supplied from the ink supply tank is distributed and supplied to each pressure chamber 252 through the common channel 255.

  A piezoelectric element 258 having an individual electrode 257 is joined to a diaphragm 256 that constitutes the top surface of the pressure chamber 252 and also serves as a common electrode. By applying a driving voltage to the individual electrode 257, the piezoelectric element 258 is formed. Deformation causes ink to be ejected from the nozzle 251. When ink is ejected, new ink is supplied from the common flow channel 255 to the pressure chamber 252 through the supply port 254.

  The nozzle arrangement structure is not limited to the illustrated example, and various nozzle arrangement structures such as an arrangement structure having one nozzle row in the sub-scanning direction can be applied.

  Further, the printing method is not limited to a line type head, and printing is performed in the width direction by scanning a short head that is less than the length of the paper in the width direction (main scanning direction) in the width direction of the paper. When printing in the width direction is completed, the paper is moved by a predetermined amount in the direction perpendicular to the width direction (sub-scanning direction), printing is performed in the width direction of the paper in the next print area, and this operation is repeated to A serial method in which printing is performed over the entire printing area may be applied.

[Example]
On a silicon substrate having a thickness of 625 μm, a film in which an organic group was directly bonded to Si, mainly Si—O bonds, was formed by the following method. The film was formed by the cat-CVD method, and a mixed gas of monomethylsilane (CH ₃ SiH ₃ ) and oxygen was introduced into the chamber to form a film. A tungsten wire was used as the catalyst, and the temperature was set to 1400 ° C.

After the film formation, PM 1102-3 low-pressure mercury lamp (17 mW / cm ² ) manufactured by Sen Special Light Source Co., Ltd. was irradiated for a predetermined time. Then, after performing predetermined annealing (heat treatment), Daikin OPTOOL DSX was vapor-deposited to form a water repellent film. Irradiation conditions, annealing conditions, and results are shown in FIGS.

  The abrasion resistance test was evaluated by the following method. The microfiber cloth was wound around a rubber roller and set so that the pressure between the sample surface and the cloth was 45 kPa. After that, the microfiber was dipped in a solution obtained by diluting 3% by weight of black ink in pure water so that the acceleration condition was more than that of the cloth alone rubbing test. The sample surface was deteriorated by rotating the roller, and the measurement of the static contact angle with water was repeated every predetermined number of times. Prior to the test, all samples had a good contact angle of 110 to 120 °, and the point at which they reached 70 ° was defined as the wear resistance point. When 70 ° did not match the number of rotations, the wear point at 70 ° was obtained by proportionally calculating the number of rotations around 70 °. For example, when the contact angle is 80 ° at 2000 rotations and the contact angle is 60 ° at 3000 rotations, 2500 rotations are set as the wear resistance point.

The amount of dehydration corresponding to the amount of OH group γ and the amount of hydrogen-bonded water β is determined by using a predetermined 1 cm ² sample using a temperature-programmed desorption gas analyzer (TDS-MS) manufactured by Electronic Science The dehydration amount of hydrogen-bonded water β (200 to 350 ° C.) and OH group γ (350 ° C. or higher) was measured. In addition, the measurement of the amount of OH groups and the amount of bound water was carried out by preparing a sample separately, and in Example 3 using the internal heating mechanism of the water-repellent film deposition apparatus, the same heating was performed inside the TDS-MS apparatus. Evaluation was performed by cooling once while maintaining the vacuum state and performing TDS-MS measurement again. In Examples 1 and 2 using an external heating furnace, after heating with a TDS-MS apparatus, the atmosphere was once released to the atmosphere, left for a predetermined time, and then set in the TDS-MS apparatus again to create an equivalent environment. Evaluation was performed. In addition, since the amount of evaporated water is measured in TDS-MS, since 2≡Si—OH → —Si—O—Si— + H ₂ O ↑ by heating, the actual amount of OH groups is , Twice the figure.

  FIG. 6 shows an example in which the annealing process was not performed. An increase in the amount of OH was confirmed by UV irradiation, and until Comparative Example 2, the wear resistance was also improved. However, although the amount of OH in Comparative Example 3 and Comparative Example 4 increased, the wear resistance deteriorated. This is probably because the amount of adsorbed water increased due to the increase in OH groups, and the adhesion between the metal alkoxide coupling material and the intermediate layer deteriorated.

  FIG. 7 shows an example in which annealing treatment is performed after increasing OH groups on the intermediate layer by UV irradiation. The annealing treatment was performed in two types: an example using a heating furnace different from the water repellent film deposition apparatus and an example using a heating mechanism inside the water repellent film deposition apparatus. In the figure, they are described as “external heating furnace” and “internal heating mechanism”, respectively. In an example using an external heating furnace, after dehydration in the external heating furnace, a sample in which a substrate is set as quickly as possible (about 5 minutes) in a water-repellent film deposition apparatus, and after standing for about 30 minutes, water-repellent film deposition is performed. Samples set in the apparatus were manufactured.

  From FIG. 7, in Example 1 which was heated in an external heating furnace and performed quickly to the extent that adsorbed water did not adhere, a decrease in the amount of OH was observed compared to Comparative Example 3, but the amount of hydrogen-bonded water also decreased. The wear resistance was also improved. In Example 2, which was measured after being allowed to stand for 30 minutes, more hydrogen bonded water was observed than in Example 1, but the wear resistance was improved as compared with the comparative example.

  In Example 3 in which the water repellent film deposition apparatus is used and the hydrogen bonding water is reduced and removed in Example 3 that does not come into contact with the atmosphere even after annealing, the wear resistance of the water repellent material is improved. I was able to.

  DESCRIPTION OF SYMBOLS 10 ... Board | substrate, 20 ... Intermediate | middle layer, 30, 262 ... Water-repellent film, 31 ... Silane coupling agent, 100 ... Inkjet recording apparatus, 112 ... Paper feed part, 114 ... Treatment liquid provision part, 116 ... Drawing part, 118 ... Drying unit, 120 ... fixing unit, 122 ... discharge unit, 124 ... recording medium, 154 ... processing liquid drum, 156 ... processing liquid coating device, 170 ... drawing drum, 172M, 172K, 172C, 172Y ... inkjet head, 176 ... drying Drum, 180 ... warm air ejection nozzle, 182 ... IR heater, 184 ... fixing drum, 186 ... halogen heater, 188 ... fixing roller, 192 ... discharge tray, 196 ... conveying belt

Claims (9)

An intermediate layer forming step of forming an intermediate layer in which an organic group is directly bonded to Si mainly on Si-O bonds;
An irradiation step of irradiating the intermediate layer with excitation light to increase OH groups on the surface of the intermediate layer;
A heating step of heating the substrate and the intermediate layer;
An organic film forming step of forming an organic film on the surface of the intermediate layer with a silane coupling agent.   The method for forming a water repellent film according to claim 1, wherein the organic film forming step is performed after the heating step in a state where an environment in which water vapor does not adhere to the intermediate layer is maintained.   The method for forming a water repellent film according to claim 1 or 2, wherein the heating step and the organic film forming step are performed in the same vacuum chamber.   The method for forming a water-repellent film according to any one of claims 1 to 3, wherein the silane coupling agent is a silane coupling agent containing fluorine.   The method for forming a water-repellent film according to any one of claims 1 to 4, wherein the heating step is performed at 50 ° C or higher and 350 ° C or lower.   The method for forming a water repellent film according to claim 5, wherein the heating step is performed at 200 ° C. or higher and 350 ° C. or lower.   A nozzle plate comprising a water repellent film formed by the method of forming a water repellent film according to claim 1.   An ink jet head comprising the nozzle plate according to claim 7.   An ink jet recording apparatus comprising the ink jet head according to claim 8.

Images