JP5455805B2 - Liquid discharge head and liquid discharge apparatus - Google Patents

Description

  The present invention relates to a liquid discharge head and a liquid discharge apparatus, and more particularly, to a liquid discharge head and a liquid discharge apparatus with improved maintainability of the liquid discharge head.

  In general, as a general-purpose image forming apparatus, an ink jet recording apparatus that forms a desired image by ejecting ink droplets from an ink jet head onto a recording medium is widely used. In an ink jet recording apparatus, wiping maintenance with a web (cloth) or the like is employed in order to remove ink adhering to the periphery of a nozzle due to ink ejection. Wiping maintenance is performed by wiping off ink residues adhering to the nozzle surface at regular intervals with a web impregnated with a cleaning liquid for cleaning the nozzles. However, in the case of a long line head in which the head modules are connected, it becomes difficult to hold the cleaning liquid impregnated in the web as the length increases. Further, if the cleaning liquid is increased, the cleaning liquid enters the nozzle, which causes a reduction in ink concentration and clogging of dust from the outside of the nozzle. On the other hand, if the amount of the cleaning liquid is too small, sufficient cleaning liquid is not retained at the end portion of the line head, which causes deterioration of wiping property and damage to the nozzle surface due to the dry web.

  In particular, the surface of the nozzle surface is generally coated with a water-repellent material that allows water repellency to function. Deterioration of the water-repellent material due to the dry web leads to easy adhesion of ink and dust to the vicinity of the nozzles, causing unstable ink discharge and causing uneven printing.

  In order to solve such a problem, for example, the following Patent Document 1 describes that a hydrophilic region is provided in the vicinity of the nozzle surface, which is a water-repellent region, and cleaning is performed well using a blade. Patent Document 2 describes a recording head in which a moisture retention member is disposed in the vicinity of an ejection port and the humidity at the ejection port is kept constant. Patent Document 3 describes a recording head in which a plurality of moisturizing holes are provided in the vicinity of an ejection port to suppress drying of the ejection port.

JP-A-8-58096 JP 2006-88689 A JP 2004-209741 A

  However, when a moisture retention maintaining mechanism is provided on the head side as described in Patent Documents 1 to 3, it is difficult to dispose the moisture retention maintaining mechanism near the nozzle periphery in the case of a high-density nozzle arrangement. there were. In addition, a design change to the web mechanism can be given to enhance the moisture retention of the web, but there is a problem that leads to an increase in cost due to a complicated design.

  The present invention has been made in view of such circumstances, and by providing a moisture retention mechanism on the liquid ejection head side, it is possible to improve ink ejection reliability by wiping maintenance without providing a complicated system. A liquid discharge head and a liquid discharge apparatus are provided.

According to a first aspect of the present invention, in order to achieve the above object, a three-dimensional structure in which a nozzle for discharging a liquid, a pressure chamber filled with the liquid, and a flow path for supplying the liquid to the pressure chamber are formed. A plurality of head modules arranged in a line, and a drive element for discharging the liquid in the pressure chamber from the nozzle and a water repellent film provided on the surface of the substrate on which the nozzle is formed. A liquid discharge head formed by disposing a moisture retention member on at least one of an end portion of the substrate surface of the plurality of head modules or a boundary region of the plurality of head modules , It is composed of a plurality of materials, the components are different between the substrate side and the surface side of the moisturizing member, the component on the substrate side is a highly moisturizing material, and the component on the surface side is a material with high hardness liquid, characterized in that it is To provide a discharge head.

According to the first aspect, since the moisturizing member is arranged at the end of the head module of the liquid discharge head or the boundary region, the wiper that wipes the substrate surface (nozzle surface) of the liquid discharge head contacts the moisturizing member. By doing so, the moisture retention of the wiper soaked with the nozzle cleaning liquid can be stabilized. Therefore, it is possible to prevent the wiper from drying during the maintenance by the wiper, and thus the water-repellent film on the surface of the substrate is not damaged by wiping with the dry wiper. Therefore, the wipe durability of the water repellent film on the substrate surface can be improved.
Further, the moisture retaining member is made of a plurality of materials, the surface side of the moisture retaining member is made of a material having high hardness, and the substrate side of the moisture retaining member is made of a material having high moisture retention, thereby maintaining the moisture retaining property of the moisture retaining member. The durability of the moisturizing member surface can be improved.

In the present invention, the “line shape” includes not only a configuration in which the head modules are arranged in a single row but also a configuration in which the head modules are arranged in a plurality of rows and arranged in a line shape throughout the liquid ejection head. .
A second aspect of the present invention is the first aspect of the present invention, wherein the moisturizing member has a friction resistance on the surface side of the moisturizing member by changing the composition ratio of the raw material diamine, dicarboxylic acid anhydride, and isocyanate. The composition is characterized by having a gradient composition in which the blending amount of excellent polyimide is large and the blending amount of urea excellent in moisture retention is increased toward the base material side of the moisturizing member.
According to the second aspect, since the interface due to the difference in the composition of the moisturizing member itself can be eliminated by using the gradient composition, the durability of the moisturizing member can be improved.
According to a third aspect of the present invention, in order to achieve the object, a three-dimensional structure in which a nozzle for discharging a liquid, a pressure chamber filled with the liquid, and a flow path for supplying the liquid to the pressure chamber are formed. A plurality of head modules arranged in a line, and a drive element for discharging the liquid in the pressure chamber from the nozzle and a water repellent film provided on the surface of the substrate on which the nozzle is formed. A liquid ejection head formed by disposing a moisturizing member on at least one of an end portion of the substrate surface of the plurality of head modules or a boundary region of the plurality of head modules; Provided is a liquid discharge head characterized in that a film thickness protruding from a substrate is 5 μm or more and 500 μm or less.
According to claim 3, by setting the film thickness of the portion protruding from the base material of the moisturizing member within the above range, the surface of the base material can be cleaned without considering the effect of providing the moisturizing member. .

A fourth aspect is characterized in that, in the first or third aspect , the moisturizing member is formed of a urea-based resin.

A fifth aspect of the present invention is characterized in that, in the fourth aspect , the urea resin includes at least one of a resin obtained by polymerizing a diamine and a diisocyanate or a dicarboxylic acid anhydride.

According to the fourth and fifth aspects, since the urea-based resin having a high water content is used as the moisture retaining member, the moisture retention of the wiper during the wiping maintenance can be stabilized over a long period of time. The urea-based resin is preferably made from any one of the above substances.

A sixth aspect of the present invention is characterized in that, in any one of the first to fifth aspects, the moisturizing member is a thin film.

According to the sixth aspect , since the moisturizing member is a thin film, the substrate surface can be cleaned without considering the influence of the moisturizing member.

A seventh aspect of the present invention is characterized in that, in any one of the first to sixth aspects, the surface of the moisturizing member has an embossed structure or an uneven structure.

An eighth aspect of the present invention is characterized in that, in any one of the first to seventh aspects, the moisturizing member has a porous structure.

According to claim 7 or 8 , since the surface area of the moisturizing member can be increased, the contact area between the moisturizing member and the wiper can be increased, and the moisturizing property of the wiper can be improved.

  In a ninth aspect of the present invention, in any one of the first to eighth aspects, the base material has a concave shape at a position where the moisturizing member is disposed, and the moisturizing member is embedded in the base material. Features.

  According to the ninth aspect, since the base material itself has a concave shape and the moisturizing member is disposed in the concave portion of the base material, the film thickness of the moisturizing member can be increased, so that the moisture retaining property of the wiper can be increased over a long period of time. Can be stabilized.

According to a tenth aspect of the present invention, there is provided a liquid ejection apparatus comprising the liquid ejection head according to any one of the first to ninth aspects, in order to achieve the object.

Since the liquid discharge head according to any one of claims 1 to 9 can improve the durability of the water-repellent film on the surface of the substrate, the reliability of the ink discharge performance can be improved by applying the liquid discharge head to the liquid discharge device. Can do.

  According to the liquid discharge head and the liquid discharge apparatus of the present invention, since the moisturizing member is disposed at the end of each head module of the line-shaped liquid discharge head formed by a plurality of head modules or at the boundary region, It is possible to stabilize the moisture retention of the wiper that wipes off the substrate surface. Therefore, the durability of the water repellent film on the surface of the substrate can be improved, so that the reliability of ink ejection can be improved.

1 is an overall configuration diagram showing an outline of an inkjet recording apparatus. It is a figure explaining the head module of an inkjet head. It is a figure explaining arrangement | positioning of the other head module of an inkjet head. It is a figure explaining the manufacturing method of a head module. It is a figure explaining the shape of the moisture retention member of the moisture retention member after surface processing. It is a figure explaining the other structure of a moisture retention member. It is a figure explaining other composition of a moisture retention member. FIG. 3 is a graph showing the results of Example 1.

  Hereinafter, preferred embodiments of a liquid discharge head and a liquid discharge apparatus according to the present invention will be described with reference to the accompanying drawings.

[Overall configuration of inkjet recording apparatus]
As an example of a liquid discharge apparatus including the liquid discharge head of the present invention, an ink jet recording apparatus including an ink jet head as a liquid discharge head will be described.

  FIG. 1 is a configuration diagram of an 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 processing 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.

  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. The drawing drum 170 includes a claw-shaped holding means (gripper) 171 on its outer peripheral surface. 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 aggregating action, and includes a drying drum 176 and a solvent drying device 178, as shown in FIG.

  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.

  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.

  The fixing roller 188 is a roller member that heats and pressurizes the dried ink to weld the self-dispersing thermoplastic resin fine particles in the ink to form a film of the ink, and heats and pressurizes the recording medium 124. Composed.

  According to the fixing unit 120 configured as described above, 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. Can be fixed and fixed.

  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. 1, 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 the drum conveyance type inkjet recording apparatus has been described with reference to FIG. 1, it 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 indicated by reference numeral 200 as a representative of these.

  FIG. 2 is a diagram for explaining the base material surface (nozzle surface) of the inkjet head 200. The present invention is a line-shaped head formed by arranging a plurality of head modules 250 in a line shape.

  In order to increase the dot pitch printed on the recording medium 124, it is necessary to increase the nozzle pitch in the head module 250. As shown in FIG. 2, the head module 250 of this example has a structure in which the nozzles 251 that are ink ejection ports are arranged in a staggered matrix (two-dimensionally), and thereby the head longitudinal direction ( High density of the substantial nozzle interval (projection nozzle pitch) projected so as to be aligned in the direction M) perpendicular to the conveyance direction S of the recording medium 124 is achieved.

  When the head module 250 is joined in a line shape, in order to prevent nozzle defects at the joined portion, as shown in FIG. 2, the end portion is cut obliquely and the oblique angle is set to an acute angle in order to secure an overburp portion. It is necessary to.

  In the present invention, when performing wiping maintenance with the wiper 270 along the direction of the arrow M shown in FIG. 2, in order to stabilize the moisture retention of the wiper 270 soaked with the cleaning liquid, the end of each head module 250 or each A moisturizing member 260 is provided in the boundary region of the head module 250. As the width of the moisturizing member 260 becomes wider, it is necessary to make the angle of the end portion of the head module 250 an acute angle in order to secure an overlap portion.

  In addition, one or more nozzle rows are arranged in a direction corresponding to the entire width of the image forming area of the recording medium 124 in a direction (arrow M in FIG. 2) substantially orthogonal to the conveyance direction of the recording medium 124 (arrow S in FIG. 2). The form to configure is not limited to the example of FIG. In the example shown in FIG. 2, since the nozzle layout is complicated, as shown in FIG. 3, the head module 250 ′ is rectangular, and when arranged in a line, it can be fitted into the case 280 to form a staggered arrangement. It is. In this case, the moisturizing member 260 'can be disposed at the end of the head module 250' as shown in FIG. It is also possible to arrange the case 280 between the head modules 250 ′. In this case, a plurality of moisturizing members 260 ′ can be arranged between the head modules 250 ′.

  As the size of the moisturizing member 260, the length of the wiper 270 in the cleaning direction (arrow M in FIGS. 2 and 3) is preferably 0.1 mm or more and 5 mm or less, more preferably 0.5 mm or more and 3 mm or less. Further, the length of the moisturizing member in the direction perpendicular to the cleaning direction of the wiper (arrow S in FIGS. 2 and 3) is set to a range larger than the nozzle formation area according to the length of the nozzle formation area. By setting it as the said range, the moisture retention of the wiper at the time of washing | cleaning can be stabilized over a long period of time.

  Further, the moisturizing member 260 is preferably a thin film. Specifically, the film thickness is preferably 10 μm or more and 500 μm or less, and more preferably 50 μm or more and 200 μm or less. By setting the film thickness within the above range, the surface of the base material can be maintained without being affected by the arrangement of the moisturizing member 260.

  The wiper 270 is preferably made of a material that can be moisturized soaked with the nozzle cleaning liquid. As such a material, a cloth made of synthetic fiber made of PET (polyethylene terephthalate) or the like can be used.

[Method for manufacturing head module]
A method for manufacturing a liquid discharge head (head module) according to the present invention will be described with reference to FIG. FIG. 4 is described with one ink chamber unit formed in the head module.

(1) Lower Electrode Formation Step FIG. 4A shows a metal film serving as a lower electrode on an SOI substrate (a silicon substrate having a SiO ₂ insulating film, hereinafter referred to as a substrate) 10 which is a surface insulating substrate. A state in which 18 is formed is illustrated. The substrate 10 has a structure in which a silicon base material, an insulating film made of a silicon oxide film, a silicon base material, and an insulating layer made of a silicon oxide film are stacked in order from the bottom.

  The metal film 18 is formed on the upper surface (surface on which the insulating layer is formed) of the substrate 10 by using a technique such as sputtering or vapor deposition. Thereafter, the metal film 18 is processed into a predetermined shape using reactive ion etching (RIE). For the metal film (lower electrode) 18, iridium (Ir), platinum (Pt), titanium (Ti), or the like is preferably used.

  The arrangement pattern of the lower electrode 18 is an arrangement pattern of a piezoelectric actuator including a piezoelectric element (structure indicated by reference numeral 25 in FIGS. 4D to 4F), and ink corresponding to the arrangement pattern of the piezoelectric actuator is applied. Discharge nozzles and pressure chambers (shown by reference numeral 124 in FIG. 4 (f)) are arranged. In other words, the arrangement pattern of the lower electrode 18 is determined corresponding to the arrangement of nozzles and pressure chambers that eject ink.

(2) Piezoelectric film forming step When the lower electrode (metal film) 18 is processed into a predetermined shape (pattern), the upper electrode of the lower electrode 18 (on the side opposite to the substrate 10 of the lower electrode 18) The piezoelectric film 20 having an orientation is formed by using a thin film formation process by an epitaxial growth method such as a sputtering method, a CVD method, or a sol-gel method. PZT (lead zirconate titanate, Pb (Zr, Ti) O ₃ ) is preferably used for the piezoelectric film 20. FIG. 4B shows a state where the piezoelectric film 20 is formed.

(3) Upper electrode film forming step When the piezoelectric film 20 is formed, a method such as sputtering or vapor deposition is applied to the upper surface of the piezoelectric film 20 (on the side opposite to the lower electrode 18 of the piezoelectric film 20). A metal film 22 serving as an upper electrode is formed using the film. For the metal film (upper electrode) 22, iridium (Ir), platinum (Pt), titanium (Ti), gold (Au), or the like is preferably used.

  Thereafter, the metal film (upper electrode) 22 is patterned into a predetermined shape. Etching is preferably used for patterning the upper electrode 22 and patterning the lower electrode 18, and the patterning (etching process) of the upper electrode 22 (lower electrode 18) is performed at a temperature of about 150 ° C. FIG. 4C shows a state in which the metal film 22 to be the upper electrode is formed.

(4) Pressure Chamber Formation Step Next, an opening (shape) 24 that becomes a pressure chamber is formed in the substrate 10 using a technique such as etching. FIG. 4D illustrates a state in which the opening 24 serving as a pressure chamber is formed.

(5) Flow path substrate bonding step, nozzle substrate bonding step As shown in FIG. 4E, when the pressure chamber 24 is formed, an ink flow path is formed on the side of the substrate 10 where the pressure chamber 24 is formed. A flow path substrate 26 having a structure (groove, hole, etc.) is joined. When the substrate 10 and the flow path substrate 26 are joined, the ink flow path and the pressure chamber 24 are accurately aligned.

  Further, the nozzle substrate 28 formed with the fine holes 27 serving as nozzles is bonded to the opposite side of the flow path substrate 26 from the substrate 10 to form a liquid discharge head structure. When the nozzle substrate 28 and the flow path substrate 26 are joined, the fine holes 27 and the discharge-side flow path are accurately aligned. FIG. 4E illustrates a state in which the flow path substrate 26 and the nozzle substrate 28 are joined.

(6) Water-repellent film forming step Thereafter, a water-repellent film 29 is formed on the opposite side of the nozzle substrate 28 to which the nozzle substrate 28 is bonded. FIG. 4F illustrates a state where the water repellent film 29 is formed. By forming the water repellent film, it is possible to prevent the ink from adhering after the ejection, and thus it is possible to suppress variations in the ejection direction of the ink droplets.

  Examples of the water repellent film include dry process methods such as physical vapor deposition methods (evaporation method, sputtering method, etc.) and chemical vapor deposition methods (CVD method, ALD method, etc.), sol-gel methods, coating methods, etc. Metal alkoxide-based liquid repellent film, silicon-based liquid repellent film, fluorine-containing liquid-repellent film formed by wet process method etc. (As a commercial product of fluorine-containing liquid-repellent film, it has excellent adhesion on Si substrate. There are Cytop from Asahi Glass Co., NANOS from T & K, Optool from Daikin Industries, and silane coupling agents sold by Gelest. Any film may be used. In particular, it is preferable to use a fluorine-based silane coupling agent because the organic film can be provided with water repellency by including fluorine atoms in the organic film.

  In the above-described method, the method of forming a film on the substrate by a method such as sputtering or vapor deposition has been described. However, the liquid discharge head of the present invention is not limited to this, and bulk baking formed in a bulk shape by sintering is performed. It is also possible to manufacture the bonded piezoelectric body by adhering it to the head casing (silicon) with an adhesive or the like.

[Method of forming moisturizing member]
Next, the moisture retaining member 260 is formed at the end of the head module formed as described above. The moisturizing member 260 is preferably formed by a thin film forming process from the viewpoint of compatibility with the lithography process. Monomers can be co-deposited and a polymer film can be obtained by sequential polymerization on the substrate surface. Patterning of the moisturizing member on the nozzle surface can be performed by lift-off using a resist material.

  As a method by lift-off, a resist pattern is formed only in the peripheral portion where the moisture retaining member is disposed. It should be noted that a water-repellent film non-formation region is formed in advance so that the water-repellent film is not formed on the edge of the module corresponding to the peripheral part of the moisturizing member arrangement (if the water-repellent film is formed, resist patterning is performed Can not). In addition, a metal mask is disposed on the region where the water repellent film is formed so that the moisture retaining material is not deposited in the form of the water repellent film. The resist pattern left after vapor deposition of the moisture retaining member is removed with an organic solvent. By using the lift-off and the metal mask in this way, it is possible to form a moisturizing agent in a desired pattern at a desired position at the end of the module. The water repellent film forming step may be performed after the moisturizing agent arranging step. In this case, a desired moisturizing agent and water repellent film formation pattern can be obtained by first forming a moisturizing agent by lift-off and then forming a water repellent film by disposing a metal mask in the moisturizing agent portion.

  Further, when the head modules 250 ′ as shown in FIG. 3 are arranged in a staggered manner and the moisture retaining member 260 ′ is disposed between the head modules 250 ′, the moisture retaining member 260 ′ is placed on the case 280 into which the head module 250 ′ is fitted. Form. Also in this case, the moisturizing member can be formed by the same method as described above.

  In addition, in order to improve the moisturizing power, it is preferable to perform surface processing of the moisturizing member. Examples of the surface processing treatment include a method of roughening the surface and increasing the surface area as shown in FIG. 5A by irradiating with atmospheric pressure plasma. In addition, by forming a lithography pattern mask on the moisture retaining member with a resist material and processing the mask opening by dry etching, as shown in FIGS. 5B and 5C, an embossed structure or an uneven structure is formed. Can be formed. Thereby, the surface area of a moisture retention member can be increased.

  The adjustment of the surface area can be controlled by adjusting the plasma intensity and time in the case of plasma irradiation. Further, in the case of dry etching, the depth and cross-sectional shape of the hole processed portion can be arbitrarily controlled by arbitrarily laying out the density and size of the uneven pattern.

[Moisturizing material]
As a raw material for the moisturizing member that can be used in the present invention, it is preferable to use a urea-based resin or a polyurea compound. Since urea-based resins and polyurea compounds can retain a large amount of moisture, drying of the wiper during wiping can be prevented. Moreover, since the matching with the ink is good, even if the moisture retaining member touches the ink, it does not deteriorate. As the urea-based resin and the polyurea-based compound, for example, a material obtained by polymerization from diamine, diisocyanate, or dicarboxylic acid anhydride can be used.

  However, since the stabilization of the moisturizing member can be controlled by adjusting the ink composition, other materials include glycerin, polyglycerin, 1,3-butylene glycol, sorbitol, xylitol, maltitol, erythritol, mucopolysaccharide. , Mucopolysaccharides such as hyaluronic acid, chondroitin sulfate, dermatan sulfate, heparan sulfate, heparin and keratan sulfate and salts thereof, proteins such as collagen, elastin, keratin and derivatives thereof and salts thereof, sorbitol, inositol, trehalose, Pyrrolidone carboxylic acid and its salt can also be used.

[Other configurations of moisturizing member]
FIG. 6 shows another configuration of the moisturizing member. When the hardness of the moisturizing member is lowered by increasing the moisturizing ability of the moisturizing member, the moisturizing member is easily deteriorated by the wiper during maintenance, and the friction resistance of the moisturizing member becomes a problem. Therefore, as shown in FIG. 6, the moisturizing member is provided with a thin film 361 having a relatively high hardness on the surface portion of the moisturizing member, and a material having a relatively high moisturizing property on the substrate (head module 250) side. By setting it as the laminated thin film structure to arrange | position, the hardness of the surface of a moisture retention member can be improved in the state which maintained the moisture retention capability of the moisture retention member 360. FIG.

  In order to obtain such a structure, for example, it can be formed as follows. By polymerizing diamine and dicarboxylic acid anhydride as raw materials, a polyimide having excellent abrasion resistance can be formed, and by polymerizing diamine and isocyanate, a urea thin film having excellent moisture retention can be formed. First, a diamine and isocyanate are polymerized on the base material side to form a urea thin film, and then a polyimide is formed from the diamine and dicarboxylic acid anhydride, so that the moisture retaining member has high moisture retention and excellent surface abrasion resistance. Can be formed. In addition, the film thickness of each layer can be appropriately changed depending on the strength and moisture retention performance of the target moisture retention member. Further, the laminated thin film structure is not limited to two layers, and may be a structure of three or more layers.

  In addition, the moisturizing member can have an inclined structure so that the property of having high rub resistance is changed to the property of having high moisturizing properties as it goes from the surface side to the substrate side instead of the laminated structure. In order to set it as such a structure, it can form by superposing | polymerizing, changing the composition ratio of diamine, dicarboxylic acid anhydride, and isocyanate described above, for example. By adopting such a configuration, it is possible to improve the strength of the moisturizing member itself because it is excellent in abrasion resistance and moisturizing property, and the interface of the layer due to the material can be eliminated in the moisturizing member.

  FIG. 7 is a diagram showing still another configuration of the moisturizing member. In the present embodiment, in order to further enhance the moisture retention, the film thickness of the apparent moisture retention member 460 is not changed by disposing the moisture retention member 460 with the base material (head module 250) of the moisture retention member disposition portion as a concave structure. In addition, the moisture retention performance can be improved.

  In order to form a concave shape on the nozzle surface, first, an opening pattern of a resist mask is formed on a portion of the nozzle surface corresponding to the moisturizing member arrangement (a non-processed portion including the nozzle portion). Thereafter, the opening of the resist opening is processed by dry etching. The depth of the hole is controlled by the plasma irradiation time of dry etching. Then, after forming the moisture retaining member while leaving the resist mask as it is, the resist portion is removed by a lift-off method, whereby the moisture retaining member can be patterned only at a desired portion.

  The film thickness protruding from the base material (head module 250) of the moisturizing member 460 is preferably the same as the film thickness described above.

[Example]
Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

[Example 1]
A driving piezoelectric element composed of a lower electrode, a piezoelectric film, and an upper electrode was formed on the SOI substrate, and then the SOI substrate was etched to form a concave structure serving as a pressure chamber by etching. A nozzle plate having a nozzle hole of 20 μmφ was bonded and bonded thereto by dry etching. Thereafter, a water-repellent material was deposited on the nozzle plate surface. As the water repellent material, a commercially available fluorine polymer material was used.

  Next, a moisture retaining member was formed at the end of the head module. The moisturizing member was formed by simultaneously depositing diamine and isocyanate and sequentially polymerizing on the substrate surface to form a polyurea thin film. The film thickness was 300 μm. The moisturizing member was patterned using a lift-off method. Moreover, the moisturizing member surface processing was performed to improve the moisturizing power. The surface treatment of the moisturizing member was performed by irradiating the atmospheric pressure plasma for 5 minutes to roughen the surface and increase the surface area.

  The durability test of the water repellent film of the formed liquid discharge head was performed. As a comparative example, it was used as a comparative example with a conventional liquid ejection head that does not have a moisturizing member. The durability test was performed by wiping with a cloth made of PET (polyethylene terephthalate) with the nozzle surface of a single module wetted with water. Judgment of water repellency was made by the contact angle (water) of the nozzle surface after 10,000 wipings. The results are shown in FIG. In the case of Comparative Example 1 in which the moisturizing member was not disposed, the contact angle was 80 ° before wiping, whereas the contact angle after 10,000 times was reduced to 30 °. On the other hand, in Example 1 in which the moisturizing member was arranged, the contact angle after 10,000 times was 70 °, and it was confirmed that the water repellency deterioration was suppressed.

[Example 2]
The ejection head was formed by the same method as in Example 1 except that the material of the moisture retaining member was changed.

  Use diamine, dicarboxylic acid anhydride, diisocyanate as raw materials for moisturizing members, change the mixing ratio of raw materials so that the substrate side is the urea thin film as the main component, and the surface side is the urea polyimide as the main component By changing the composition ratio, the moisturizing member could be a gradient composition thin film. The bonding strength was improved due to the non-interface of the moisturizing member. Moreover, since the strength of the moisture retaining member on the surface side can be increased, the moisture retention of the wiper can be stabilized over a long period of time.

[Example 3]
In order to make the nozzle surface substrate into a concave shape, first, a resist mask opening pattern was formed in a portion corresponding to the moisturizing member arrangement on the nozzle surface. Then, the hole process of the resist opening part was performed by dry etching. The depth of the hole was controlled by the dry etching plasma irradiation time to 200 μm. The moisture retaining member was formed while leaving the resist mask. As the raw material for the moisturizing member, diamine and diisocyanate were used, and these two kinds of monomers were vapor-deposited simultaneously and polymerized on the surface of the substrate to produce a polymer thin film (moisturizing member) having moisturizing properties. The thin film of the moisturizing member was 500 μm. Thereafter, the resist portion was removed by a lift-off method, thereby forming a pattern in which the moisturizing member was arranged in a desired portion. Although the thickness protruding from the substrate is 300 μm, the thickness of the moisturizing member is 500 μm. Therefore, when the durability of the water-repellent film was confirmed by the contact angle, the thickness of the moisturizing member was 300 μm. It was improved about 1.5 times.

  Further, it was confirmed that when the film thickness of the moisturizing member was increased without performing the hole processing of the base material, the film was reduced or the film was easily peeled off when the wiper was scanned. Therefore, only by increasing the film thickness, the moisture retention of the moisture retention member is improved, but it is thought that the durability of the film deteriorates due to the increase in pressure at the time of wiper contact due to the increase in film thickness and the increase in film stress of the film itself. . Therefore, the effectiveness of substrate processing could be confirmed by combining nozzle surface processing and film thickness increase.

  DESCRIPTION OF SYMBOLS 10 ... SOI substrate (substrate), 18 ... Lower electrode (metal film), 20 ... Piezoelectric film, 22 ... Upper electrode (metal film), 24 ... Pressure chamber, 26 ... Channel substrate, 28 ... Nozzle substrate, 29 ... Water repellent film, 100 ... inkjet recording apparatus, 112 ... paper feeding unit, 114 ... treatment liquid application unit, 116 ... drawing unit, 118 ... drying unit, 120 ... fixing unit, 122 ... discharge unit, 124 ... recording medium, 172, 200 ... Inkjet head, 250 ... Head module, 251 ... Nozzle, 260, 360, 460 ... Moisturizing member, 270 ... Wiper, 280 ... Case

Claims (10)

A nozzle for discharging the liquid, a pressure chamber filled with the liquid, a three-dimensional structure formed with a flow path for supplying the liquid to the pressure chamber, and a liquid for discharging the liquid in the pressure chamber from the nozzle A liquid discharge head formed by arranging a plurality of head modules each having a drive element and a water-repellent film provided on the surface of a substrate on which the nozzle is formed, in a line shape,
A moisturizing member is disposed at an end of the substrate surface of the plurality of head modules or at least one of boundary regions of the plurality of head modules ,
The moisturizing member is composed of a plurality of materials, the components are different between the base material side and the surface side of the moisturizing member, the base material side component is a highly moisturizing material, and the surface side component Is a material having high hardness . The moisturizing member is composed of a raw material diamine, dicarboxylic acid anhydride, and isocyanate to change the composition ratio, so that the surface side of the moisturizing member has a large amount of polyimide with excellent abrasion resistance. The liquid ejection head according to claim 1 , wherein the liquid ejection head has a gradient composition in which a blending amount of urea excellent in moisture retention is increased toward the substrate side of the moisture retention member . A nozzle for discharging the liquid, a pressure chamber filled with the liquid, a three-dimensional structure formed with a flow path for supplying the liquid to the pressure chamber, and a liquid for discharging the liquid in the pressure chamber from the nozzle A liquid discharge head formed by arranging a plurality of head modules each having a drive element and a water-repellent film provided on the surface of a substrate on which the nozzle is formed, in a line shape,
A moisturizing member is disposed at an end of the substrate surface of the plurality of head modules or at least one of boundary regions of the plurality of head modules,
The liquid ejection head, wherein a film thickness of the moisturizing member protruding from the base material is 5 μm or more and 500 μm or less. The moisturizing member, the liquid discharge head according to claim 1 or 3, characterized in that it is formed by urea-based resins. The liquid ejection head according to claim 4 , wherein the urea resin includes at least one of a resin obtained by polymerizing diamine and diisocyanate or dicarboxylic anhydride. The moisturizing member liquid discharge head according to claims 1 to 5 any one, which is a thin film. Wherein the surface of the moisturizing member, the liquid discharge head according to any of the preceding claims 1 to, characterized in that the embossed structure or irregular structure. The moisturizing member, the liquid discharge head according to claims 1 7 any one, which is a porous structure.   The said base material has the concave shape in the position which arrange | positions the said moisture retention member, This moisture retention member is embedded in this base material, The any one of Claim 1 to 8 characterized by the above-mentioned. Liquid discharge head. A liquid ejection apparatus comprising the liquid discharge head according to 9 any one of claims 1.

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