JP2005059255A - Inkjet head and inkjet recording apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet head which is equipped with a nozzle plate without variant holes by improving the durability against wiping of a fluorine type water repellent film formed at a nozzle forming member surface, and securing a workability of nozzles by an excimer laser. <P>SOLUTION: A resin member 121 with a plurality of the nozzles 44 and a plurality of ink liquid chambers communicating with the nozzles 44 are set. Ink droplets are discharged from the nozzles 44 by driving an energy generating means corresponding to each nozzle 44 and changing the volume in the ink liquid chamber. An SiO<SB>2</SB>film 122 is formed at a surface of the resin member 121, and a fluorine system water repellent agent layer 128 is laminate coated on the SiO<SB>2</SB>film 122. The fluorine type water repellent agent layer 128 has a film thickness of over 30 Å and not larger than 100 Å, and therefore is good in the durability against wiping. A process for forming the fluorine type water repellent film does not require a long time, and inexpensive production is made possible. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ink jet head and an ink jet recording apparatus. More specifically, the present invention improves the durability of a water repellent film formed on the surface of a nozzle forming member in an image forming apparatus such as an ink jet printer and a copying apparatus for a long period of time. The present invention relates to an inkjet head capable of obtaining good image quality without deterioration of water repellency, and an inkjet recording apparatus using the inkjet head.

  In an ink jet head used in an ink jet recording apparatus, recording is performed by ejecting ink droplets from nozzles, so the shape and accuracy of the nozzles have a great influence on the ink droplet ejection characteristics. Further, it is known that the characteristics of the surface of the nozzle forming member forming the nozzle also affect the ejection characteristics of the ink droplets. For example, if ink adheres to the nozzle periphery on the surface of the nozzle forming member and a non-uniform ink pool occurs, the ink droplet ejection direction may be bent or the ink droplet size may vary, resulting in ink droplets. It is known that inconveniences such as unstable flight speed occur.

  Therefore, in the ink jet head, a water repellent film is formed on the discharge side surface of the nozzle so as to have water repellency, thereby improving the uniformity of the surface of the nozzle forming member and stabilizing the flying characteristics of the ink droplets. In the past, the following has been proposed.

  Patent Document 1 proposes an ink jet print nozzle head provided with a nozzle having an organic resin layer containing a copolymer containing tetrafluoroethylene as a water repellent layer on one surface of a support substrate.

  Patent Document 2 proposes a nozzle forming method for an inkjet recording head in which a coating layer made of a fluoropolymer is provided on the surface of a nozzle forming member, and excimer laser is irradiated from the back side to perform nozzle hole processing. ing.

  Further, in Patent Document 3, an adhesive member is attached to one surface of a nozzle plate, a laser beam is irradiated from the opposite side surface, and after processing so that a part of the plate remains, the adhesive member is peeled off and remains. A nozzle forming method for removing a part has been proposed.

  Furthermore, an inorganic oxide island-shaped thin layer is formed between the nozzle forming member and the water repellent layer, and the material and film thickness of the thin layer are specified to achieve both water repellency and excimer laser processability. Although a head has been proposed, the wiping durability has been improved to some extent, but in order to achieve a sufficient level, it is necessary to increase the film thickness to some extent, and compatibility with workability by an excimer laser is not sufficient.

  In addition, the material of the wear-resistant fine powder made of an organic material is a material (polyimide) having good workability by excimer laser, and the fine powder layer having the fine powder is provided between the nozzle forming member and the water repellent layer. Thus, an ink jet head that solves the problem of insufficient wiping resistance has been proposed.

In addition, the nozzle forming member is a polyimide film, an SiO ₂ film is formed on the surface, and a fluorine water-repellent film is coated on the surface of the SiO ₂ film for 1 to 30 mm to form a nozzle hole for an inkjet head. It has been proposed to form a nozzle.
Japanese Patent Laid-Open No. 10-305582 JP-A-6-87216 Japanese Patent No. 2914146

  As described above, in the ink jet head, a water repellent film is formed on the discharge side surface of the nozzle to provide water repellency, thereby improving the uniformity of the surface of the nozzle forming member and stabilizing the flying characteristics of the ink droplets. However, when a resin material is used as a nozzle forming member, a water repellent film is formed on the surface of the resin material. However, since the adhesion between the resin material and the water repellent is not so good, it is very difficult to apply directly.

  For this reason, the surface of the resin material is roughened to form fine irregularities, and a water repellent is applied on the surface to improve the adhesion, but sufficient adhesion can be secured. Not in. In other words, water repellency is obtained in the initial stage after application, but the surface is rubbed by a wiping operation performed to remove ink droplets and dust adhering to the nozzle plate surface and nozzle openings, so that adhesion is improved. Since the water repellent layer peels off gradually, the water repellency deteriorates.

In addition, when a fluorine-based water repellent is used, adhesion is improved by forming a SiO ₂ film on the surface of a resin material or the like that is a nozzle forming member and applying a fluorine-based water repellent thereon. It has also been tried. In this case, unless the SiO ₂ film thickness is increased to a certain extent (for example, 200 mm or more), a sufficient adhesion improving effect cannot be obtained. However, for example, when performing a nozzle hole processing with an excimer laser processing, but the nozzle forming member can be ensured excimer laser processability be formed of polyimide or the like, since the SiO ₂ film is poor excimer laser processability, clean the nozzle hole formation Will not be possible, and irregular shaped nozzle holes will be generated.
Further, since the nozzle plate is always in contact with the ink, the liquid contact resistance against the alkaline ink is required.

  The present invention improves the durability of the water-repellent film formed on the surface of the nozzle forming member with respect to the wiping operation, maintains the water-repellent performance for a long period of time, and has the ink contact resistance and at the same time, improves the excimer laser processability of the nozzle. An object of the present invention is to provide an ink jet head having good image quality and no deterioration with time, and an ink jet recording apparatus using the ink jet head by providing a nozzle plate that is secured and has no irregular holes.

  In addition, when the film thickness of the fluorine-based water repellent film is thin and the ink is in contact with the surface of the nozzle forming member, the water repellency performance deteriorates over time. It is an object to provide an ink jet head and an ink jet recording apparatus in which the water repellency performance does not deteriorate with time even when the ink comes into contact with the liquid, and the image quality does not deteriorate due to long-term use. And

  Although it is possible to increase the film thickness of the fluorine-based water repellent film, the thicker the film is, the larger the amount of material used and the longer the processing time and the higher the component manufacturing cost. An object of the present invention is to provide a low-cost inkjet head and inkjet recording apparatus by optimizing the film thickness of the fluorine-based water-repellent film so that the treatment for forming the fluorine-based water-repellent film does not require a long time. And

  Ink used for inkjet recording has various compositions, but inks that are said to have good color development cannot be used because conventional water-repellent films do not provide sufficient water-repellent performance. However, the present invention is low in cost, has high water repellency, is not deteriorated by alkaline ink, has sufficient water repellency for high color inks, and can form high quality images. An object of the present invention is to provide an ink jet head and an ink jet recording apparatus that can be used.

The inkjet head according to claim 1 includes a nozzle forming member having a plurality of nozzles for discharging ink droplets, and a plurality of ink liquid chambers in communication with the nozzles, and drives energy generating means corresponding to the nozzles. In the ink jet head that changes the volume of the ink liquid chamber and ejects ink droplets from the nozzle, a SiO ₂ film is formed on the surface of the nozzle forming member, and a fluorine-based water repellent film is formed on the SiO ₂ film. The agent layer is laminated, and the film thickness of the fluorine-based water repellent layer is more than 30 mm.

  The ink-jet head according to claim 2 is the ink-jet head according to claim 1, wherein the film thickness of the fluorine-based water repellent layer is 100 mm or less.

  An ink jet head according to a third aspect is the ink jet head according to the first or second aspect, wherein the fluorine-based water repellent layer is made of a modified perfluoropolyoxetane.

  According to a fourth aspect of the present invention, there is provided an ink jet recording apparatus that records an image on a recording medium by ejecting ink droplets from a nozzle by driving energy generated by a driving element driven in accordance with a recording signal. The inkjet head according to any one of 1 to 3 is used.

(Function and effect of claim 1)
By interposing the SiO ₂ film between the nozzle forming member and the fluorine-based water repellent, the fluorine-based water repellent is in close contact with the SiO ₂ film by chemical bonding, so the adhesion with the nozzle forming member is increased, A water-repellent film having strong resistance to rubbing such as wiping can be obtained. Furthermore, it is possible to provide a highly reliable inkjet head that does not deteriorate the water repellency even when it is in contact with ink for a long period of time.

(Function and effect of claim 2)
A necessary and sufficient range is obtained as the film thickness for ensuring the characteristics of the ink jet head of claim 1. That is, when the film thickness of the fluorine-based water repellent exceeds 30 mm, the ink contact performance can be ensured. On the other hand, if the film thickness exceeds 100 mm, the function is not improved and the cost is increased. Therefore, this range which is more than 30 mm and not more than 100 mm is an appropriate range of film thickness.

(Function and effect of claim 3)
By using modified perfluoropolyoxetane (manufactured by Daikin Industries, trade name: OPTOOL DSX) as a fluorine-based water repellent, both wiping durability and excimer laser processability can be achieved, and ink wet reliability can be secured.

(Function and effect of claim 4)
A highly reliable ink jet recording apparatus having high image quality over a long period of time and having stable performance can be provided at low cost.

The present invention includes a nozzle forming member having a plurality of nozzles for discharging ink droplets, and a plurality of ink liquid chambers in communication with the nozzles, and driving energy generation means corresponding to the nozzles to drive the energy generation means. In an inkjet head that changes the volume in the ink liquid chamber and ejects ink droplets from the nozzle, a SiO ₂ film is formed on the surface of the nozzle forming member, and a fluorine-based water repellent layer is laminated on the SiO ₂ film The film thickness of the fluorine-based water repellent layer is more than 30 mm, preferably 100 mm or less. By interposing a SiO ₂ film between the nozzle forming member and the fluorine-based water repellent, fluorine Since the water-based water repellent is in close contact with the SiO ₂ film by chemical bonding, the adhesion with the nozzle forming member is increased, and a water repellent film having a strong resistance to rubbing such as wiping can be obtained. Furthermore, it is possible to provide a highly reliable inkjet head that does not deteriorate the water repellency even when it is in contact with ink for a long period of time. Further, when the film thickness of the fluorine-based water repellent exceeds 30 mm, the ink contact performance can be secured, and when the film thickness does not exceed 100 mm, the processing time for forming the fluorine-based water repellent layer The manufacturing cost of parts can be reduced without requiring a long time.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a perspective view schematically showing a mechanism portion of an ink jet recording apparatus according to the present invention, and FIG. 2 is a side sectional view of the mechanism portion.

  The ink jet recording apparatus shown in FIG. 1 includes a carriage 13 that can move in the main scanning direction inside a recording apparatus main body 1, a recording head 14 that includes an ink jet head mounted on the carriage 13, and an ink cartridge that supplies ink to the recording head 14. The printing mechanism 2 composed of 15 etc. is accommodated, the paper 3 fed from the paper feed cassette 4 or the manual feed tray 5 is taken in, a required image is recorded by the printing mechanism 2 and then mounted on the rear side. The paper is discharged onto the discharged paper discharge tray 6.

  The printing mechanism unit 2 holds the carriage 13 slidably in the main scanning direction (vertical direction in FIG. 2) with a main guide rod 11 and a sub guide rod 12 which are guide members horizontally mounted on left and right side plates (not shown). The carriage 13 has a recording head 14 composed of an inkjet head for discharging ink droplets of yellow (Y), cyan (C), magenta (M), and black (Bk) with the ink droplet discharge direction directed downward. Each ink cartridge (ink tank) 15 for supplying ink of each color to the recording head 14 is replaceably mounted on the carriage 13.

  The ink cartridge 15 has an air port that communicates with the atmosphere upward, a supply port that supplies ink to the recording head 14 below, and a porous body filled with ink inside. The ink supplied to the recording head 14 by the force is maintained at a slight negative pressure. Ink is supplied from the ink cartridge 15 into the recording head 14.

  Here, the carriage 13 is slidably fitted to the main guide rod 11 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the secondary guide rod 12 on the front side (upstream side in the paper conveyance direction). doing. In order to move and scan the carriage 13 in the main scanning direction, a timing belt 20 is stretched between a driving pulley 18 and a driven pulley 19 that are rotationally driven by a main scanning motor 17. The carriage 13 is reciprocally driven by forward and reverse rotation of the main scanning motor 17.

  Further, although the recording heads 14 of the respective colors are used here as the recording heads, a single head having nozzles for ejecting ink droplets of the respective colors may be used. Further, as will be described later, the recording head 14 includes a vibration plate that forms at least a part of the wall surface of the ink flow path and an electrode opposite to the vibration plate, and deforms and displaces the vibration plate with an electrostatic force to apply ink. An electrostatic inkjet head that presses is used.

  On the other hand, in order to convey the paper 3 set in the paper feed cassette 4 to the lower side of the recording head 14, the paper feed roller 21 and the friction pad 22 for separating and feeding the paper 3 from the paper feed cassette 4 and the paper 3 are guided. The guide member 23 that performs the above operation, the transport roller 24 that transports the fed paper 3 in an inverted manner, the transport roller 25 that is pressed against the peripheral surface of the transport roller 24, and the feed angle of the paper 3 from the transport roller 24 are defined. A tip roller 26 is provided. The transport roller 24 is rotationally driven by a sub-scanning motor 27 through a gear train.

  A printing receiving member 29 is provided as a paper guide member for guiding the paper 3 fed from the transport roller 24 below the recording head 14 in accordance with the range of movement of the carriage 13 in the main scanning direction. A conveyance roller 31 and a spur 32 that are rotationally driven to send the paper 3 in the paper discharge direction are provided on the downstream side of the printing receiving member 29 in the paper conveyance direction, and the paper 3 is further delivered to the paper discharge tray 6. A roller 33 and a spur 34, and guide members 35 and 36 that form a paper discharge path are disposed.

  At the time of recording, the recording head 14 is driven according to the image signal while moving the carriage 13 to eject ink onto the stopped paper 3 to record one line, and after the paper 3 is conveyed by a predetermined amount, Record the line. Upon receiving a recording end signal or a signal that the trailing edge of the sheet 3 has reached the recording area, the recording operation is terminated and the sheet 3 is discharged.

  Further, a recovery device 37 for recovering defective ejection of the recording head 14 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 13. The recovery device 37 includes a cap unit, a suction unit, and a cleaning unit. While waiting for printing, the carriage 13 is moved to the recovery device 37 side, and the recording head 14 is capped by the capping means, and the ejection opening (nozzle) is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting (purging) ink not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.

  When a discharge failure occurs, the discharge port (nozzle) of the recording head 14 is sealed with a capping unit, and bubbles and the like are sucked out together with ink from the discharge port with a suction unit through a tube. Etc. are removed by the cleaning means, and the ejection failure is recovered. Further, the sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

Next, an ink jet head constituting the recording head 14 of the ink jet recording apparatus will be described with reference to FIGS.
3 is an exploded perspective view showing the inkjet head in an exploded manner, FIG. 4 is a cross-sectional view showing the inkjet head in the longitudinal direction of the diaphragm, and FIG. 5 is an enlarged view of the main portion in the longitudinal direction of the diaphragm of the inkjet head. FIG. 6 is an enlarged cross-sectional view showing a main part along the short side direction of the diaphragm of the inkjet head.

  The inkjet head 40 includes a flow path substrate 41 that is a first substrate using a silicon substrate such as a single crystal silicon substrate, a polycrystalline silicon substrate, or an SOI substrate, a silicon substrate provided below the flow path substrate 41, It includes an electrode substrate 42 that is a second substrate using a Pyrex (registered trademark) glass substrate, a ceramic substrate, and the like, and a nozzle plate 43 that is a third substrate provided on the upper side of the flow path substrate 41. A nozzle 44 for discharging, a pressure chamber 46 that is an ink flow path that communicates with each nozzle 44, a common liquid chamber flow path 48 that communicates with each pressure chamber 46 via a fluid resistance portion 47 that also serves as an ink supply path, and the like. Forming.

  The flow path substrate 41 is formed with a pressurizing chamber 46 and a recess that forms a diaphragm 50 that also serves as a first electrode that forms the bottom of the pressurizing chamber 46, and the nozzle plate 43 has a fluid resistance portion 47. A groove to be formed is formed, and a through-hole for forming a common liquid chamber channel 48 is formed in the channel substrate 41 and the electrode substrate 42.

  Here, for example, when a single crystal silicon substrate is used as the flow path substrate 41, boron is injected into the diaphragm thickness in advance to form a high-concentration boron layer serving as an etching stop layer, and bonded to the electrode substrate 42. Then, the concave portion that becomes the pressurizing chamber 46 is anisotropically etched using an etching solution such as a KOH aqueous solution, and at this time, the high-concentration boron layer becomes an etching stop layer, and the diaphragm 50 is formed with high accuracy. Further, when the diaphragm 50 is formed of a polycrystalline silicon substrate, a method of forming a polycrystalline silicon thin film to be a diaphragm on the liquid chamber substrate, or the electrode substrate 42 is previously planarized with a sacrificial material and formed thereon After the polycrystalline silicon thin film is formed, it can be formed by removing the sacrificial material.

Although an electrode film may be separately formed on the diaphragm 50, as described above, the diaphragm 50 also serves as an electrode by impurity diffusion or the like. An insulating film can also be formed on the surface of the diaphragm 50 on the electrode substrate 42 side. As this insulating film, an oxide insulating film such as SiO ₂ , a nitride insulating film such as Si ₃ N _4, or the like can be used.

  The insulating film can be formed by thermally oxidizing the vibration plate surface to form an oxide film or using a film forming method. Further, the flow path substrate 41 is provided with a common electrode. The common electrode is attached by sputtering (sintering heat) a metal such as Al, ensuring electrical continuity with the flow path substrate 41, and ohmic contact with the flow path substrate 41 made of a semiconductor substrate. Is taking.

An oxide film layer 42 a is formed on the electrode substrate 42, a recess 54 is formed in the oxide film layer 42 a, and an electrode 55, which is a second electrode facing the diaphragm 50, is provided on the bottom surface of the recess 54. A predetermined gap 56 (for example, a gap length of 0.2 μm) is formed between the diaphragm 50 and the electrode 55, and the diaphragm 50 and the electrode 55 constitute an actuator unit. An electrode protective film 57 made of an oxide insulating film such as a SiO ₂ film and a nitride insulating film such as a Si ₃ N ₄ film is formed on the surface of the electrode 55. An insulating film can be formed on the diaphragm 50 side without forming the protective film 57.

  The flow path substrate 41 and the electrode substrate 42 can be bonded by an adhesive, but more reliable physical bonding, for example, when the electrode substrate 42 is formed of silicon, an oxide film is used. A direct bonding method can be used. This direct bonding is performed at a high temperature of about 1000 ° C. Moreover, when the electrode substrate 42 is glass, anodic bonding can be performed. When the electrode substrate 42 is formed of silicon and anodic bonding is performed, Pyrex (registered trademark) glass is formed between the electrode substrate 42 and the flow path substrate 41, and anodic bonding is performed via this film. You can also. Furthermore, the flow path substrate 41 and the electrode substrate 42 can be bonded together by eutectic bonding using a silicon substrate and a binder such as gold interposed between the bonding surfaces.

  Further, the electrode 55 of the electrode substrate 42 has a low resistance due to a metal material such as Al, Cr, or Ni generally used in a process for forming a semiconductor element, a refractory metal such as Ti, TiN, or W, or impurities. A polycrystalline silicon material or the like can be used. When the electrode substrate 42 is formed of a silicon wafer, an insulating layer (the above-described oxide film layer 42a) needs to be formed between the electrode substrate 42 and the electrode 55. When an insulating material such as glass is used for the electrode substrate 42, it is not necessary to form an insulating layer between the electrodes 55.

  Further, when a silicon substrate is used for the electrode substrate 42, an impurity diffusion region can be used as the electrode 55. In this case, the impurity used for the diffusion is an impurity having a conductivity type opposite to that of the substrate silicon, a pn junction is formed around the diffusion region, and the electrode 55 and the electrode substrate 42 are electrically insulated.

  The nozzle plate 43 is formed by arranging a large number of nozzles 44 in two rows, and the discharge surface is subjected to water repellent treatment. Here, as will be described in detail later, the nozzle plate 43 is composed of a multilayer member of a resin member and a metal member. The nozzle plate 43 is bonded to the flow path substrate 41 with an adhesive.

  In this inkjet head 40, two rows of nozzles 44 are arranged, and two rows of pressurizing chambers 46, diaphragms 50, electrodes 55, etc. are arranged corresponding to each nozzle 44, and a common liquid chamber flow is provided at the center of each nozzle row. A configuration is adopted in which the passage 48 is arranged to supply ink to the left and right pressure chambers 46. Thus, a multi-nozzle head having a large number of nozzles can be configured with a simple head configuration.

  The electrode 55 of the ink jet head 40 is extended to the outside to form a connection portion (electrode pad portion) 55a, and an FPC cable 61 on which a driver IC 60 as a head drive circuit is mounted is connected to this via an anisotropic conductive film or the like. Connected. At this time, the gap between the electrode substrate 42 and the nozzle plate 43 is hermetically sealed with a gap sealant 62 using an adhesive such as an epoxy resin, as shown in FIG.

  Further, the entire inkjet head 40 is bonded onto the frame member 65 with an adhesive. The frame member 65 is formed with an ink supply hole 66 for supplying ink from the outside to the common liquid chamber channel 48 of the ink jet head 40, and the FPC cable 61 and the like are formed in the hole portion formed in the frame member 65. 67.

  The gap between the frame member 65 and the nozzle plate 43 is sealed with a gap sealant 68 using an adhesive such as an epoxy resin as shown in FIG. It is prevented from going around the electrode substrate 42, the FPC cable 61 and the like.

  A joint member 70 with the ink cartridge 15 is connected to the frame member 65 of the inkjet head 14, and ink is supplied from the ink cartridge 15 to the common liquid chamber channel 48 through the ink supply hole 66 via the filter 71. The

  In the ink jet head 40, the diaphragm 50 is used as a common electrode, the electrode 55 is used as an individual electrode, and a drive voltage is applied between the diaphragm 50 and the electrode 55, whereby the diaphragm 50 and the electrode 55 are interposed. The diaphragm 50 is deformed and displaced toward the electrode 55 by the generated electrostatic force, and the diaphragm 50 is restored and deformed by discharging electric charges between the diaphragm 50 and the electrode 55 from this state, so that the internal volume of the pressurizing chamber 46 is increased. As the (volume) / pressure changes, ink droplets are ejected from the nozzle 44.

  That is, when a pulse voltage is applied to the electrode 55 that is an individual electrode, a potential difference is generated between the diaphragm 50 that is a common electrode, and an electrostatic force is generated between the individual electrode 55 and the diaphragm 50. As a result, the diaphragm 50 is displaced according to the magnitude of the applied voltage. Thereafter, the applied pulse voltage is lowered to restore the displacement of the diaphragm 50, the pressure in the pressurizing chamber 46 is increased by the restoring force, and ink droplets are ejected from the nozzle 44.

Next, the details of the conventional example and the present invention will be described with reference to FIGS.
FIG. 7 is a diagram showing a schematic configuration of an excimer laser processing machine for processing nozzle holes.
In this processing machine, excimer laser beam 82 emitted from laser oscillator 81 is reflected by mirrors 83, 85, 88 and guided to processing table 90. A beam expander 84, a mask 86, a field lens 87, and an imaging optical system 89 are provided so that an optimal beam reaches the workpiece 91 (nozzle plate) in the optical path from the laser beam 82 to the processing table 90. It is provided at a predetermined position. The workpiece 91 is placed on the processing table 90 and receives a laser beam. The processing table 90 is configured by a known XYZ table or the like, and can move the workpiece 91 and irradiate a desired position with a laser beam as necessary.

FIG. 8 is a cross-sectional view showing a conventional nozzle plate according to the invention of the present applicant.
In the conventional nozzle plate shown in FIG. 8, the nozzle 44 is formed by excimer laser processing. The nozzle plate 43 joins the resin member 121 and the liquid chamber constituting member 125 with the thermoplastic adhesive 126, and the resin member 121. nozzle surface is obtained by sequentially stacking formed of SiO ₂ thin film 122 and the fluorine-based water repellent layer 123, a nozzle 44 of a required diameter is formed in the resin member 121, which communicates with the nozzle 44 in the liquid chamber constituting member 125 A communication port 127 is formed. The fluorine-based water repellent layer 123 is formed by depositing 1 to 30 liters of modified perfluoropolyoxetane (manufactured by Daikin Industries, trade name: OPTOOL DSX). An adhesive tape 124 obtained by applying an adhesive 129 to a resin film is attached to the surface of the fluorine-based water repellent layer 123.

FIG. 9 is a cross-sectional view showing an example of a nozzle plate used in the inkjet head of the present invention.
The basic configuration of the nozzle plate shown in FIG. 9 is the same as that of the conventional example shown in FIG. 8, and the nozzle plate 43 is formed by joining a resin member 121 and a liquid chamber constituting member 125 with a thermoplastic adhesive 126. The surface of 121 is formed by sequentially laminating a SiO ₂ thin film 122 and a fluorine-based water repellent layer 128. A nozzle 44 having a required diameter is formed in the resin member 121, and a nozzle communication port 127 communicating with the nozzle is formed in the liquid chamber constituting member 125.

Here, the thickness of the fluorine-based water repellent layer 128 is formed thicker than the thickness of the conventional fluorine-based water repellent layer 123 shown in FIG. The SiO ₂ thin film layer 122 is formed by a method that allows film formation at a temperature within a range that does not apply heat relatively, that is, does not cause thermal influence on the resin member 121. Specifically, it can be said that sputtering, ion beam vapor deposition, ion plating, CVD (chemical vapor deposition), P-CVD (plasma vapor deposition) and the like are suitable. In this embodiment, after sputtering of Si, the sputtering film is subjected to O ₂ treatment to generate a SiO ₂ film. It is advantageous from the viewpoint of process time and material cost that the thickness of the SiO ₂ thin film layer 122 is set to the minimum necessary thickness within a range where the adhesion can be secured. Further, if this film thickness becomes too thick, there may be a problem in nozzle hole processing with an excimer laser. That is, even if the shape of the nozzle 44 is finely processed in the resin member 121, a part of the SiO ₂ thin film layer 122 may not be sufficiently processed and may be left unprocessed.

Therefore, specifically, it can be said that a thickness of 1 to 300 mm is suitable as a range in which the adhesion can be secured and the SiO ₂ thin film layer 122 does not remain during excimer laser processing. More preferably, the range of 10 to 100 mm is suitable. In the experimental results, even when the SiO ₂ film thickness was 10 mm, the adhesion was sufficient, and there was no problem with excimer laser processability. In addition, a slight machining residue was observed at 300 mm, but it was within the usable range. When it exceeded 300 mm, a considerably large machining residue was generated, and an unusable nozzle profile was observed.

  Various materials are known for the fluorine-based water repellent material used for the fluorine-based water repellent layer 128. Here, modified perfluoropolyoxetane (trade name: OPTOOL DSX, manufactured by Daikin Industries, Ltd.) is 30%. Necessary water repellency is obtained by vapor deposition of ˜100 mm. In the conventional example, the thickness of the OPTOOL DSX is preferably 1 to 30 mm. This is set based on the experimental result that there is no difference in water repellency and wiping durability performance even when the thickness of the OPTOOL DSX is 10 mm, 20 mm, or 30 mm.

  However, according to the subsequent studies by the present inventors, it has been found that when the thickness of the fluorine-based water repellent layer is thin, the water repellency performance deteriorates due to liquid contact with alkaline ink. That is, if the water repellent film on the nozzle surface keeps touching the alkaline ink for a long time, the water repellency gradually deteriorates and normal ink droplet ejection cannot be performed. On the other hand, it was confirmed that when the thickness of the fluorine-based water repellent layer exceeds 30 mm, the water repellency is not deteriorated even if the liquid is alkaline liquid for a long time. In addition, in the direction of increasing the thickness, there is a demand to keep the thickness to the minimum necessary because the deposition process takes longer time and the consumption of the deposition material increases. . For these reasons, it is appropriate to set the appropriate thickness of the fluorine-based water repellent layer to 30 to 100 mm. Incidentally, in this embodiment, the thickness of the fluorine-based water repellent layer is a vapor deposition film having a thickness of 50 mm.

FIG. 11 is a graph showing the results of an experimental evaluation of the water repellency degradation state due to ink contact of a nozzle plate sample in which the film thickness of the fluorine-based water repellent layer was changed.
It can be seen that the samples having a thickness of 10 mm or 20 mm with a thin fluorine-based water repellent layer are deteriorated over time due to ink contact. On the other hand, samples with a fluorine-based water repellent layer thickness of 30 mm and 50 mm did not deteriorate over time.
From this result, it was confirmed that when the thickness of the fluorine-based water repellent layer is 30 mm or more, the water repellency with respect to the ink contact liquid does not deteriorate. The reason why ink wettability is improved by thickening the fluorine-based water repellent layer (Optool DSX) is that the fluorine-based water-repellent film molecules on the surface of the thick fluorine-based water-repellent layer (Optool DSX) Is considered to form a thin layer by dehydration polycondensation.

  Further, an adhesive tape 124 in which an adhesive material is applied to a resin film is attached to the surface of the fluorine-based water repellent layer 128 to prevent contamination of the nozzle outlet surface during excimer laser processing.

FIG. 10 is a diagram schematically showing the manufacturing process of the nozzle plate used in the inkjet head of the present invention.
FIG. 10A shows a material that becomes a base material of the nozzle forming member. For example, Kapton (registered trademark), which is a polyimide film made by Dupont, Upilex (registered trademark) made by Ube Industries, or the like is a suitable material. Here, as the resin member 121, an Upilex film having a thickness of 25 μm is used.

FIG. 10B shows a step of forming the SiO ₂ thin film layer 122 on the surface of the resin member 121. The SiO ₂ thin layer 122 is formed by a sputtering method performed in a vacuum chamber. A film thickness of about several to 200 mm is suitable, and a thickness of 10 to 50 mm is used here. Furthermore, as a sputtering method, after sputtering Si, forming an SiO ₂ film by applying O ₂ ions to the Si surface improves the adhesion of the SiO ₂ film to the resin film and is uniform. A dense film was obtained, which was found to be more effective in improving the wiping durability of the water-repellent film.

FIG. 10C shows a process of applying the fluorine-based water repellent layer 128. As an application method, a spin coater, a roll coater, screen printing, a spray coater, or the like can be used. The method of forming a film by vacuum vapor deposition is used, and it was confirmed that the use of this method improves the adhesion of the water-repellent film and leads to an improvement in wiping durability. Further, it has been found that the vacuum deposition can be further effectively performed in the vacuum chamber as it is after the SiO ₂ thin film layer 122 in FIG. 10B is formed. That is, after forming the SiO ₂ thin film layer 122, it is considered that once the work is taken out from the vacuum chamber, the adhesion or the like is impaired due to adhesion of impurities or the like to the surface.
Various materials are known for the fluorine-based water repellent material. Here, modified perfluoropolyoxetane (Optool DSX manufactured by Daikin Industries, Ltd.) is used as the amorphous fluorine compound, so that the necessary water repellency for the ink is obtained. Could get.

  FIG. 10D shows a joining process of liquid chamber constituent members. Various materials can be used as the material of the liquid chamber constituting member 125. In this embodiment, silicon is used. A thermoplastic adhesive 126 is applied in a thin film to the joining surface side of the liquid chamber constituent member 125 that has been subjected to necessary pattern etching in advance, and the water-repellent treated nozzle forming member shown in FIG. . A communication port 130 is etched in advance.

  FIG. 10E shows a process of attaching the adhesive tape 124, which is applied to the surface coated with the fluorine-based water repellent layer 128 with the adhesive 129 of the adhesive tape 124. When this adhesive tape 124 is applied, it is necessary to apply it so as not to entrap air bubbles. When there are bubbles, the nozzle holes opened at the positions where the bubbles are present may be poor in quality due to deposits or the like during processing.

  FIG. 10F shows a nozzle processing step in which an excimer laser is irradiated from the liquid chamber constituting member side through the communication port 130 to form the nozzle 44. The processing depth of excimer laser processing is good enough to be processed into the thickness of the adhesive tape 124. After the nozzle 44 is processed, the adhesive tape 124 is peeled off and the components are supplied to the head assembly in the next process.

1 is a perspective view showing an outline of a mechanism portion of an ink jet recording apparatus according to the present invention. It is a sectional side view of the mechanism part of the inkjet recording device shown in FIG. It is a disassembled perspective view which decomposes | disassembles and shows an inkjet head. It is sectional drawing shown along the diaphragm longitudinal direction of an inkjet head. It is an expanded sectional view which expands and shows the principal part in alignment with the diaphragm longitudinal direction of an inkjet head. It is an expanded sectional view showing the important section along the diaphragm short side direction of an ink jet head. It is a figure which shows the schematic structure of the excimer laser processing machine which processes a nozzle hole. It is sectional drawing which shows the conventional nozzle plate. It is sectional drawing which shows the Example of the nozzle plate used with the inkjet head of this invention. It is a figure which shows typically the manufacturing process of the nozzle plate used for the inkjet head of this invention. It is a graph which shows the result of having experimentally evaluated the water-repellent deterioration state by the ink contact liquid of the nozzle plate sample which changed the film thickness of the fluorine-type water repellent layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Recording device main body, 2 ... Printing mechanism part, 3 ... Paper, 4 ... Paper feed cassette, 5 ... Manual feed tray, 6 ... Paper discharge tray, 11 ... Main guide rod, 12 ... Sub guide rod, 13 ... Carriage, 14 DESCRIPTION OF SYMBOLS ... Recording head, 15 ... Ink cartridge, 17 ... Main scanning motor, 18 ... Drive pulley, 19 ... Driven pulley, 20 ... Timing belt, 21 ... Feed roller, 22 ... Friction pad, 23 ... Guide member, 24 ... Conveying roller , 25 ... conveying roller, 26 ... tip roller, 27 ... sub-scanning motor, 29 ... printing receiving member, 31 ... conveying roller, 32 ... spur, 33 ... paper discharge roller, 34 ... spur, 35, 36 ... guide member, 37 ... Recovery device, 40 ... Inkjet head, 41 ... Flow path substrate, 42 ... Electrode substrate, 42a ... Oxide film layer, 43 ... Nozzle plate, 44 ... Nozzle, 46 ... Pressurizing chamber, 47 ... Fluid resistance , 48 ... Common liquid chamber flow path, 50 ... Vibration plate, 54 ... Recess, 55 ... Electrode, 55a ... Connection part (electrode pad part), 56 ... Gap, 57 ... Electrode protective film, 60 ... Driver IC, 61 ... FPC cable, 62 ... gap sealant, 65 ... frame member, 66 ... ink supply hole, 67 ... hole, 68 ... gap sealant, 70 ... joint member, 71 ... filter, 81 ... laser oscillator, 82 ... excimer Laser beam, 83, 85, 88 ... mirror, 84 ... beam expander, 86 ... mask, 87 ... field lens, 89 ... imaging optical system, 90 ... processing table, 91 ... workpiece, 121 ... resin member, 122 ... SiO ₂ thin film, 123 ... fluorinated water repellent layer, 124 ... adhesive tape, 125 ... liquid chamber component, 126 ... thermoplastic adhesive, 127 ... nozzle communication port, 128 ... fluorinated repellent Liquid agent layer, 129 ... adhesive, 130 ... communication port.

Claims (4)

A nozzle forming member having a plurality of nozzles for ejecting ink droplets; and a plurality of ink liquid chambers in communication with the nozzles; and driving energy generating means corresponding to the nozzles to drive the ink in the ink liquid chamber. In an ink jet head that changes the volume and ejects ink droplets from the nozzle, a SiO ₂ film is formed on the surface of the nozzle forming member, and a fluorine-based water repellent layer is laminated on the SiO ₂ film. An ink jet head wherein the thickness of the water repellent layer is more than 30 mm.   2. The inkjet head according to claim 1, wherein the film thickness of the fluorine-based water repellent layer is 100 mm or less.   The inkjet head according to claim 1, wherein the fluorine-based water repellent layer is made of modified perfluoropolyoxetane.   The inkjet recording apparatus that records an image on a recording medium by ejecting ink droplets from a nozzle by driving energy generated by a driving element driven in accordance with a recording signal. An ink jet recording apparatus using an ink jet head.

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