JP2008162187A - Liquid discharge head, method for manufacturing the liquid discharge head, and liquid discharge apparatus including the liquid discharge head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid ejection head or the like made to appropriately eject a liquid. <P>SOLUTION: The liquid ejection head 33 ejects the liquid filling liquid chambers 45 from nozzles 71. A nozzle sheet 43 which is installed in the liquid ejection head 33, forms a wall surface of the liquid chamber 45 and is formed of a metal material with the nozzle 71 formed by electrocasting. A primary surface 73 to be at least the liquid chamber side of the nozzle sheet 43 is subjected to hydrophilic treatment by electrolytic polishing, and further subjected to heat treatment. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid discharge head including a nozzle sheet with improved wettability with respect to a liquid filled in a liquid chamber, a method for manufacturing the liquid discharge head, and a liquid discharge apparatus including the liquid discharge head.

  As an apparatus for ejecting liquid, for example, there is an ink jet type printer apparatus (hereinafter referred to as a printer apparatus) that prints an image or characters by ejecting ink onto a recording paper that is a target. This ink jet type printer device has features such that noise during printing is extremely low, high speed printing is possible, and no special processing for fixing ink to plain paper is required.

  This printer apparatus ejects ink by various methods such as a thermal ink jet method in which ink is heated by a heating resistor and the ink is pressed and ejected by the growth of generated bubbles. This printer apparatus includes an ink discharge head that discharges ink, an ink tank that stores ink, and an ink supply system that supplies ink from the ink tank to the ink discharge head.

  The ink discharge head is formed from a nozzle sheet on which nozzles for discharging ink are formed, and a circuit board on which a heating resistor is provided as a pressure generating element that presses ink to discharge ink from the nozzles. ing. This ink discharge head is formed by adhering the nozzle sheet and the circuit board through a film so that the nozzle of the nozzle sheet and the heating resistor of the circuit board face each other. The ink discharge head is provided with a liquid chamber that surrounds one heating resistor with a circuit board, a film, and a nozzle sheet. In the printer device, the ink chamber is filled with ink from the ink tank through the ink flow path system, and the ink filled in the liquid chamber is heated by a heating resistor to be generated in the ink in the liquid chamber. As the bubbles grow, ink is pushed out from the nozzles and ejected.

  The ink supply system forms a supply path for supplying ink from the ink tank to the liquid chambers and nozzles of the ink discharge head. This ink supply system is an important component of the printer device, because it supplies ink to the ink discharge head continuously and instantaneously during printing to perform printing smoothly.

  The material constituting the ink supply system is excellent in ink resistance especially on the liquid contact surface with the ink, and in addition, the ink is continuously and smoothly transferred to the ink discharge head without causing the ink to stagnate during printing. It is required to have physical characteristics such as a small contact angle with ink and good wettability. Further, the material constituting the ink supply system is required to have characteristics in the manufacturing process of the printer device, such as easy processing, molding and assembly of the material. Selection of the material constituting the ink supply system is performed based on these viewpoints.

  For example, various materials, glass, various metals, etc. are used as the material constituting the ink supply system. In an ink supply system formed of such a material, for example, when ink is again supplied to the ink ejection head when printing is stopped for a long time or printing is resumed after a pause, bubbles adhere to the liquid contact surface with the ink. It becomes easy to do. For this reason, in an ink supply system formed of such a material, it is obstructed by bubbles, and ink cannot be supplied appropriately from the ink tank to the ink discharge head. The ink cannot be properly supplied to the head, and the ejection of ink droplets from the ink ejection head becomes unstable, resulting in problems such as the ejection of ink droplets being interrupted and the inability to eject ink.

  The problem with such an ink supply system is that air enters the ink supply system, especially when the ink as described above is used up and refilled, or when the ink evaporates from the nozzle during a long printing pause. This is likely to occur when there is no ink stagnation throughout or partially in the ink supply system.

  In addition, the problem caused by bubbles occurs not only when bubbles enter the ink supply system but also when they enter the liquid chamber of the ink discharge head provided with the nozzles. When bubbles are mixed in the liquid chamber, unstable problems such as unstable ejection and non-ejection are more likely to occur than when bubbles are mixed in the ink supply system, and print quality is likely to deteriorate.

  The problems with the ink supply system and the liquid chamber as described above are, for example, oxide films among various materials, glass, and various metals on the liquid contact surface in contact with the ink in the liquid chamber of the ink supply system and the ink discharge head. This is conspicuously observed when a resin material such as a metal that is easy to form, polyethylene, or silicone resin is used. The reason for this is that when an ink supply system or liquid chamber is formed with these materials, the wettability of the liquid contact surface with ink becomes insufficient, and bubbles adhere to the liquid contact surface with insufficient wettability. Is due to.

  Incidentally, in the printer device, it is required to increase the printing speed in addition to being able to supply ink to the ink ejection head continuously and instantaneously. One means for increasing the printing speed is to increase the number of nozzles that eject ink.

  Examples of the method for producing the nozzle sheet include press working, ablation processing using excimer laser, electric discharge machining, and electroforming. However, when a large number of nozzles are produced in the nozzle sheet, the nozzle pitch becomes narrow, so that it is difficult to form the nozzles by press working. Further, when a nozzle sheet having a large number of nozzles is produced by excimer laser processing, since the resin is a base, the durability of the obtained nozzle sheet is slightly poor.

  In contrast to such press working and excimer laser processing, electroforming technology can increase the nozzle pitch, and the resulting nozzle sheet is metallic, so durability is at a level where there is no problem. (For example, refer to Patent Document 1). Therefore, the electroforming technique has a large number of nozzles and can produce a durable nozzle sheet as compared with other press processing, excimer laser processing, and the like.

The metal used for electroforming is nickel, gold, palladium or the like. Among these, nickel is a general-purpose metal. Since nickel has a strong ionization tendency and the surface is very easily oxidized, when it is left in the air, several kinds of oxides such as Ni ₂ O ₃ , NiO ₂ and Ni ₃ O ₄ are generated on the surface. Among these oxides, Ni ₂ O ₃ has good ink wettability, and NiO ₂ and Ni ₃ O ₄ are oxides with poor ink wettability. For example, when the nozzle sheet is formed of nickel, the portion of the nozzle sheet where Ni ₂ O ₃ or the like is formed becomes hydrophilic, the contact angle with the ink becomes small, and it becomes easy to get wet with the ink. On the other hand, the portion of the nozzle sheet on which NiO ₂ or Ni ₃ O ₄ is formed has a large ink contact angle, making it difficult for ink to blend. Therefore, in the nozzle sheet mainly composed of nickel formed by electroforming, when it is exposed to air after production, Ni ₂ O ₃ with good ink wettability, NiO ₂ with poor wettability, Ni ₃ O _4, etc. Since several types of oxides are generated on the surface, the wettability of the ink on the surface is not uniform.

  Since the nozzle sheet forms the bottom surface of the liquid chamber and the nozzle and comes into contact with the ink, it is necessary to make the wettability uniform, so that one kind of oxide film needs to be formed uniformly. As a method for homogenizing the nickel oxide film, a physical treatment method by plasma treatment can be mentioned. Although this plasma treatment has the advantage that it can be easily treated with an apparatus, the surface treatment of the metal surface is less durable than the surface modification of the organic material, and the time elapses. As a result, natural oxidation is performed again, resulting in a surface with non-uniform wettability.

  In such an ink discharge head having a nozzle sheet with non-uniform wettability, the nozzle sheet forms the bottom surface and nozzles of the liquid chamber, so that the wettability of ink on the bottom surface of the liquid chamber and the wall surface of the nozzle is poor. In addition, bubbles in the ink easily adhere to the bottom surface of the liquid chamber and the wall surface of the nozzle. In such an ink discharge head, bubbles adhere to the bottom surface of the liquid chamber and the wall surface of the nozzle, thereby obstructing the bubbles, and the ink is not uniformly filled throughout the liquid chamber or the nozzle, or is stably supplied. There is not. As a result, in this ink discharge head, even if the nozzle sheet is produced by electroforming, the number of nozzles is increased, and the printing speed is increased, bubbles easily adhere to the bottom surface of the liquid chamber and the wall surface of the nozzle. As described above, the ejection of the ink droplets becomes unstable or the ink cannot be ejected, and the quality of the printed image is deteriorated.

JP 2003-136728 A

  Accordingly, an object of the present invention is to provide a liquid discharge head including a nozzle sheet that has high wettability with liquid and is uniform, and this wettability is maintained, a method of manufacturing the liquid discharge head, and a liquid discharge apparatus. To do.

  The liquid discharge head according to the present invention that achieves the above-described object is a nozzle sheet that discharges liquid filled in a liquid chamber from a nozzle, forms a wall surface of the liquid chamber, and is made of a metal material on which the nozzle is formed. The nozzle sheet is formed by electroforming, and at least the main surface on the liquid chamber side is subjected to a hydrophilic treatment by electrolytic polishing and further subjected to a heat treatment.

  The method of manufacturing a liquid discharge head according to the present invention that achieves the above-described object forms a head chip that presses the liquid filled in the liquid chamber and a wall surface of the liquid chamber, and discharges the liquid pressed by the head chip. A method of manufacturing a liquid discharge head having a nozzle sheet made of a metal material on which nozzles are formed. After the nozzle sheet is produced by electroforming, at least the main surface on the liquid chamber side of the nozzle sheet is hydrophilic by electropolishing. A liquid chamber is formed by applying a treatment, further performing a heat treatment, and bonding the head chip to the main surface subjected to the electrolytic polishing and the heat treatment of the nozzle sheet.

  A liquid ejection apparatus according to the present invention that achieves the above-described object includes a liquid ejection head that ejects a liquid filled in a liquid chamber from a nozzle. The liquid ejection head forms a wall surface of the liquid chamber, and the nozzle The nozzle sheet is formed by electroforming, and at least the main surface on the liquid chamber side is subjected to hydrophilic treatment by electropolishing and further subjected to heat treatment.

  In the present invention, by subjecting at least the main surface on the liquid chamber side of the nozzle sheet to hydrophilic treatment, the main surface on the liquid chamber side becomes hydrophilic and the contact angle of the liquid becomes small, so that wettability is improved and hydrophilicity is improved. By performing the heat treatment after the treatment, the wettability of the main surface on the liquid chamber side is maintained. Thus, in the present invention, after the nozzle sheet was produced, the wettability was maintained even when the nozzle sheet touched the air, so that the wettability was good and the liquid discharge head could be incorporated and obtained. Bubbles can be prevented from adhering to the main surface of the liquid discharge head on the liquid chamber side, and the bubbles are discharged. In the present invention, by discharging the bubbles, the liquid can be stably supplied to the liquid chamber without being obstructed by the bubbles, and the discharge of the liquid becomes unstable or the discharge of the liquid is interrupted. It is possible to prevent the discharge from becoming impossible.

  A nozzle sheet, an ink discharge head, and an ink jet printer apparatus to which the present invention is applied will be described in detail with reference to the drawings. An ink jet printer apparatus 1 (hereinafter referred to as a printer apparatus 1) shown in FIG. 1 is a line type ink jet printer apparatus that prints over the width direction (W direction) of a recording paper P on which images and characters are printed.

  As shown in FIGS. 1 and 2, the printer apparatus 1 includes an ink jet printer head cartridge (hereinafter referred to as a head cartridge) 2 that ejects ink i onto a recording paper P, and an apparatus in which the head cartridge 2 is mounted. A main body 3. In the printer apparatus 1, the head cartridge 2 can be attached to and detached from the apparatus main body 3.

  First, the head cartridge 2 constituting the printer apparatus 1 will be described. The head cartridge 2 ejects the ink i using, for example, a heating resistor using an electrothermal conversion type as a pressure generating element, and causes the ink i to land on the main surface of the recording paper P. As shown in FIGS. 2 and 3, the head cartridge 2 is mounted with an ink cartridge 21 containing ink i. For each color, the ink cartridge 21 includes a yellow ink cartridge 21y, a magenta ink cartridge 21m, a cyan ink cartridge 21c, and a black ink cartridge 21k.

  Here, the ink i filled in each ink cartridge 21 is as follows. The ink i is obtained by dissolving or dispersing at least a dye in a solvent containing water, a water-soluble organic solvent, or the like.

  As the water-soluble organic solvent contained in the ink i, aliphatic monohydric alcohol, polyhydric alcohol, polyhydric alcohol derivative and the like can be used.

  Specifically, as the aliphatic monohydric alcohol, lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, s-butyl alcohol and t-butyl alcohol can be used. . Of these aliphatic monohydric alcohols, ethyl alcohol, i-propyl alcohol, and n-butyl alcohol are particularly preferably used.

  These aliphatic monohydric alcohols are highly effective in adjusting the surface tension of the ink i and improving the penetrability of recording paper P such as plain paper and special paper, dot formation, and drying of printed images. Ink i is preferably contained.

  Examples of the polyhydric alcohol include alkylene glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol and glycerol, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, and thiodiglycol.

  As the polyhydric alcohol derivative, the above-mentioned lower alkyl ethers of polyhydric alcohol such as ethylene glycol dimethyl ether, the above-mentioned lower carboxylic acid esters of polyhydric alcohol such as ethylene glycol diacetate, and the like can be used.

  Since these polyhydric alcohols and polyhydric alcohol derivatives are less likely to evaporate and lower the freezing point of ink i, they have the effect of increasing the storage stability of ink i and preventing clogging of nozzles 71 of printer apparatus 1. It is preferable to make it contain in i.

  As the dye, any of water-soluble dyes such as direct dyes, acid dyes and reactive dyes can be used.

  Specifically, examples of yellow direct dyes include C.I. I. Direct Yellow 1, 8, 11, 12, 24, 26, 27, 28, 33, 39, 44, 50, 58, 85, 86, 87, the same 88, 89, 98, 100, 110, etc. can be used.

  Examples of magenta direct dyes include C.I. I. Direct Red 1, 2, 2, 4, 9, 13, 17, 20, 23, 24, 28, 31, 31, 33, 37, 39, 44, the same 46, 62, 63, 75, 79, 80, 81, 83, 84, 89, 95, 99, 113, 197, 201, 218, 220, 224, 225, 226, 227, 228, 229, 230, 321 and the like can be used.

  Examples of cyan direct dyes include C.I. I. Direct Blue 1, 2, 6, 8, 15, 22, 25, 41, 71, 76, 77, 78, 80, 86, 90, 98, the same 106, 108, 120, 158, 160, 163, 165, 168, 192, 193, 194, 195, 196, 199, 199, 200, 201, 202, 203, 207, 225, 226, 236, 237, 246, 248, 249, etc. can be used.

  Examples of black direct dyes include C.I. I. Direct Black 17, 19, 22, 32, 38, 51, 56, 62, 71, 74, 75, 77, 94, 105, 106, 107, 108, 112, 113, 117, 118, 132, 133, 146, etc. can be used.

  Examples of yellow acid dyes include C.I. I. Acid Blue 1, 3, 7, 7, 19, 19, 23, 25, 29, 36, 38, 40, 42, 44, 49, 59, 61, 70, 72, 75, 76, 78, 79, 98, 99, 110, 111, 112, 114, 116, 118, 119, 127, 128, 131, 135, 141, 142, 161, 162, 163, 164, 165, etc. can be used.

  Examples of magenta acid dyes include C.I. I. Acid Red 1, 6, 8, 9, 13, 14, 18, 26, 27, 32, 35, 37, 42, 51, 52, 57, 75, 77, 80, 82, 83, 85, 87, 88, 89, 92, 94, 97, 106, 111, 114, 115, 117, 118, 119, 129, 130, 131, 133, 134, 138, 143, 145, 154, 155, 158, 168, 180, 183, 184 186, 194, 198, 199, 209, 209, 211, 215, 216, 217, 219, 249, 252, 254, 256, 257, 262, 262 265, 266, 274, 276, 282, 283 The 303, the 317, the 318, the 320, the 321, the same 322, etc. can be used.

  Examples of cyan acid dyes include C.I. I. Acid Blue 1, 7, 9, 15, 22, 23, 25, 27, 29, 40, 41, 43, 45, 54, 59, 60, 62, 72, 74, 78, 80, 82, 83, 90, 92, 93, 100, 102, 103, 104, 112, 113, 8117, 120, 126, 127, 129, 130, 131, 138, 140, 142, 143, 151, 154, 158, 161, 166, 167, 168 170, 171, 175, 182, 183, 183, 184, 187, 192, 199, 203, 204, 205, 229, 234, 236, etc. can be used.

  Examples of black acid dyes include C.I. I. Acid Black 1, 2, 2, 7, 26, 29, 31, 31, 44, 48, 50, 51, 52, 58, 60, 62, 63, 64, 67, 72, 76, 77, 94, 107, 108, 109, 110, 112, 115, 118, 119, 121, 122, 131, 132, 139, 140, 155, 156, 157, 158, 159, 191 and the like can be used.

  In addition to the water-soluble organic solvent and the dye described above, the ink i may contain additives such as a surfactant, a pH adjuster, a preservative, and a chelating agent as necessary.

  The ink cartridge 21 filled with the ink i is formed in a substantially rectangular shape having substantially the same dimensions as the width of the recording paper P. As shown in FIGS. 2 and 3, the ink cartridge 21 is provided with an ink supply unit 22 for supplying ink i to a cartridge main body 31 of the head cartridge 2 described later.

  The ink supply unit 22 is provided at a substantially central portion below the ink cartridge 21. The ink supply unit 22 is a substantially protruding nozzle, and the tip of the nozzle is fitted into a connection unit 35 of the head cartridge 2 described later, whereby the ink cartridge 21 and the cartridge main body 31 of the head cartridge 2 are connected. Connect between them so that ink can be supplied. The ink supply unit 22 includes a valve mechanism, and the supply of ink i to the cartridge body 31 is adjusted by the valve mechanism. The head cartridge 2 and the ink cartridge 21 may be integrally formed.

  The head cartridge 2 to which the ink cartridge 21 is mounted has a cartridge body 31 as shown in FIGS. The cartridge body 31 includes a mounting portion 32 to which the ink cartridge 21 is mounted, an ink discharge head 33 that discharges the ink i, and a head cap 34 that protects the ink discharge head 33.

  A connection part 35 connected to the ink supply part 22 of the ink cartridge 21 attached to the attachment part 32 is provided at substantially the center of the attachment part 32. The connection portion 35 serves as a supply path for supplying the ink i from the ink supply portion 22 of the ink cartridge 21 attached to the attachment portion 32 to the ink discharge head 33 for discharging the ink i provided on the bottom surface of the cartridge main body 31. . The connection unit 35 adjusts the supply of ink i from the ink cartridge 21 to the ink discharge head 33 by a valve mechanism.

  The ink ejection head 33 to which the ink i is supplied from the connection portion 35 is disposed on the bottom surface of the cartridge body 31 as shown in FIGS. In the ink discharge head 33, nozzles 71, which will be described later, which are discharge ports for discharging the ink i supplied from the connecting portion 35 are arranged in a line substantially in the width direction of the recording paper P, that is, in the direction of the arrow W in FIGS. It is installed. The ink ejection head 33 does not move in the width direction (W direction) of the recording paper P when ejecting the ink i, but the yellow nozzle line 72y, the magenta nozzle line 72m, the cyan nozzle line 72c, and the black nozzle line 72c. Ink i is ejected for each nozzle line 72k.

  As shown in FIGS. 4 and 5, the ink ejection head 33 is supplied with the ink i from the connection portion 35 of the head cartridge 2, and is supplied with the flow path plate 41 that guides the supplied ink i to each nozzle 71. The head chip 42 that ejects the ink i, the nozzle sheet 43 on which the nozzles 71 for ejecting the ink i are formed, and the frame 44 that supports the nozzle sheet 43. As shown in FIG. 5, the ink discharge head 33 is formed with an ink liquid chamber 45 that is supplied with ink i from an ink flow path 51 to be described later and discharges the ink i by pressing it.

  The flow path plate 41 is provided for each color of the ink i, and is formed of a material such as metal that has rigidity that does not easily deform and ink resistance to the stored ink i. As shown in FIGS. 4 and 5, the flow path plate 41 has the nozzles 71 arranged in parallel so that the ink i is supplied to all of the plurality of nozzles 71 forming the nozzle lines 72 of the respective colors to be described later. The recording paper P is formed in the width direction (W direction) over a length corresponding to the width of the recording paper P. The flow path plate 41 is formed toward the connection part 35 side at the approximate center of the upper surface of the flow path forming part 52 and the flow path forming part 52 for forming the ink flow path 51 having a length corresponding to the width of the recording paper P. And a flow path connection portion 53 that connects the connection portion 35 provided in the cartridge main body 31 and the flow path forming portion 52. In the flow path forming part 52, a head chip 42 to be described later for supplying the ink i is disposed on the surface opposite to the side where the flow path connecting part 53 is provided. In the flow path plate 41, the flow path connection portion 53 is connected to the connection portion 35 provided in the cartridge main body 31, and the ink i supplied from the ink cartridge 21 via the connection portion 35 is used as the ink of the flow path forming portion 52. The ink i is supplied to the flow path 51 and the head chip 42 is supplied.

  As shown in FIG. 5, the head chip 42 includes a circuit board 61 provided with an electrothermal change type heating resistor 61 a and a film 62 interposed between the circuit board 61 and the nozzle sheet 43. The As shown in FIG. 4, the head chip 42 is a set of a predetermined number among a plurality of nozzles 71 provided in a substantially line shape across the width direction of the recording paper P (W direction in FIG. 4). It is provided for each set. As shown in FIGS. 4 and 5, the head chip 42 is arranged in a substantially line shape in the width direction of the recording paper P in a zigzag manner for each color with the ink flow path 51 interposed therebetween, and ends of the adjacent head chips 42. The parts are provided so as to face each other.

  The circuit board 61 is formed with a control circuit made up of a logic IC (Integrated Circuit), a driver transistor, etc. on a board made of a silicon-containing material such as a silicon wafer or a glass substrate. As shown in FIG. 5, the circuit board 61 forms the upper surface of the ink liquid chamber 45.

  The film 62 is made of, for example, a thermosetting dry film resist epoxy resin or the like. As shown in FIG. 5, the film 62 is formed on the circuit board 61 by a photolithography process so as to surround one heating resistor 61 a except for the portion communicating with the ink flow path 51 described above. The film 62 forms a side surface of the ink liquid chamber 45 and constitutes the ink liquid chamber 45 together with the circuit board 61. Further, the nozzle sheet 43 is bonded to the film 62 on the surface opposite to the circuit board 61.

  As shown in FIGS. 4 and 5, the nozzle sheet 43 includes a plurality of nozzles 71 including through holes formed in a substantially line shape in a staggered manner so as to face the heating resistor 61 a. In the nozzle sheet 43, the nozzle lines 72y, 72m, 72c, and 72k of the respective colors are integrally formed as one sheet. In the nozzle sheet 43, the main surface 73 on the ink liquid chamber 45 side forms the bottom surface of the ink liquid chamber 45.

  The nozzle sheet 43 is formed by electroforming, for example, using a metal material such as nickel (Ni) as a main component. The nozzle sheet 43 may be formed of a nickel-cobalt alloy containing cobalt (Co) in addition to Ni, and a material having physical properties required according to the application and use environment can be used. In the nozzle sheet 43, by forming the nozzles 71 by electroforming, a large number of nozzles 71 can be formed even if the interval between the adjacent nozzles 71 is narrow. Thereby, in the printer apparatus 1, since the number of nozzles that can eject ink i increases, the printing speed can be improved.

At least the main surface 73 on the ink liquid chamber 45 side of the nozzle sheet 43 is subjected to a hydrophilic treatment and then a heat treatment. The main surface 73 of the nozzle sheet 43 is uniformly formed with a hydrophilic oxide film 74a made of Ni ₂ O ₃ which is an oxide of Ni by a hydrophilic treatment, and the wettability with respect to the ink i is improved. As a result, the wettability of the main surface 73 is maintained.

  As a hydrophilic treatment method, there is a method of, for example, electrolytic polishing the main surface 73 of the nozzle sheet 43 on the ink liquid chamber 45 side. Electropolishing is a polishing method that utilizes the fact that the metal of the anode dissolves during electrolysis.

That is, when the nozzle sheet 43 containing Ni as a main component is electrolytically polished, the nozzle sheet 43 is placed in an electrolytic solution of a strong acid or strong alkali having an appropriate concentration using the metal object to be polished, that is, the nozzle sheet 43 as an anode. When immersed and electrolyzed with a large current density, the surface of the nozzle sheet 43 is removed, and a uniform passive film is formed while removing irregularities of about 0.1 μm on the surface. In such electropolishing, acetic anhydride, phosphoric acid, or the like is used as the electrolytic solution and an oxidizing acid (perchloric acid, chromic acid, etc.) is added to the electrolytic solution, so that the polished surface of the nozzle sheet 43 is oxidized. A chemical treatment is performed with a characteristic acid, and as a result, not only unevenness but also a uniform passive film is formed. This passive film is a hydrophilic oxide film 74 a made of Ni oxide Ni ₂ O ₃ which is the main component of the nozzle sheet 43. Since Ni ₂ O ₃ has higher hydrophilicity than other oxides such as NiO ₂ and Ni ₃ O ₄ , the obtained oxide film 74a has a small contact angle with the ink i and wettability with the ink i. Is high. The main surface 73 on which the oxide film 74a of the nozzle sheet 43 is formed has a contact angle with the ink i described above of 40 ° or less, preferably 20 ° or less. Further, by forming the obtained oxide film 74a by electropolishing, it is possible to obtain a very smooth and glossy surface that cannot be obtained by the mechanical polishing method.

In the nozzle sheet 43, at least the main surface 73 that forms the bottom surface of the ink liquid chamber 45 is subjected to electropolishing hydrophilic treatment, and a hydrophilic oxide film 74 a made of Ni ₂ O ₃ is uniformly formed. Since the wettability to the ink i is high and uniform, it is possible to prevent bubbles mixed in the ink i from adhering to the bottom surface of the ink liquid chamber 45. Thereby, in the ink liquid chamber 45, bubbles do not stay, and the bubbles are easily removed from the nozzles 71 by the ejection of the ink i or the like.

Further, as shown in FIG. 5, in the wall surface 75 of the nozzle 71 which is continuous with the main surface 73 of the ink chamber 45 side, when the electrolytic polishing the main surface 73, electropolished simultaneously, Ni ₂ O _The hydrophilic oxide film 74b made of ₃ is uniformly formed. In the nozzle sheet 43, the formation of the hydrophilic oxide film 74 b on the wall surface 75 of the nozzle 71 can prevent bubbles from adhering to the wall surface 75 of the nozzle 71. Thereby, in the nozzle sheet 43, it is possible to prevent bubbles from staying not only in the ink liquid chamber 45 but also in the nozzle 71, so that the bubbles flowing from the ink liquid chamber 45 can be further easily removed from the nozzle 71.

  The nozzle sheet 43 is subjected to heat treatment so that the wettability of the main surface 73 forming the bottom surface of the ink liquid chamber 45 and the wall surface 75 of the nozzle 71 with respect to the ink i can be maintained in a high and uniform state. When the nozzle sheet 43 is heat-treated, the wettability with respect to the ink i can be maintained even if the oxide films 74a and 74b are in contact with air.

That is, in the nozzle sheet 43, when the hydrophilic oxide films 74 a and 74 b are formed by electrolytic polishing on the main surface 73 and the wall surface 75 of the nozzle 71, simply leaving it in a general indoor environment and touching the air, The persistence of wettability is about one month, and after this period, the wettability is gradually lost. This is because if the nozzle sheet 43 is exposed to the air, because the oxidation of nickel proceeds, poor oxide NiO _{2-wettability} is generated. In the nozzle sheet 43, when the oxidation of nickel proceeds and the oxide NiO ₂ is generated, the wettability with respect to the ink i of the main surface 73 and the wall surface 75 of the nozzle 71 is deteriorated, and bubbles easily adhere to the ink liquid chamber. It becomes difficult for bubbles to be removed from the nozzle 45 and the nozzle 71. The ink discharge head 33 using such a nozzle sheet 43 has poor air bubble discharge performance, and produces the same results as when the nozzle sheet 43 not subjected to electrolytic polishing is used. In addition, the nozzle sheet 43 produced by electroforming does not undergo electropolishing and only undergoes a heat treatment in the air, so that the oxidation of nickel is further promoted. The wettability of the main surface 73 on the chamber 45 side with respect to the ink i is poor and uneven.

  Therefore, the nozzle sheet 43 made of nickel as a main component by electroforming and subjected to electropolishing has a main surface 73 on the ink liquid chamber 45 side on which the hydrophilic oxide films 74 a and 74 b are formed and the nozzle 71. In order to maintain the wettability of the wall surface 75, heat treatment is performed. In the nozzle sheet 43, acetic anhydride and phosphoric acid in the electrolytic solution used in the electrolytic polishing attached to the main surface 73 on the ink liquid chamber 45 side and the wall surface 75 of the nozzle 71 are removed by performing heat treatment. In response, wettability is further imparted, and the wettability of the main surface 73 on the ink liquid chamber 45 side and the wall surface 75 of the nozzle 71 can be improved and sustained. Since the wettability of the nozzle sheet 43 can be improved and maintained in this manner, when the nozzle sheet 43 is manufactured, it is manufactured before the ink discharge head 33 is assembled by performing heat treatment after electrolytic polishing. Even if the nozzle sheet 43 is left for a while and touched with air, the wettability of the main surface 73 on the ink liquid chamber 45 side and the wall surface 75 of the nozzle 71 with respect to the ink i can be maintained in a uniform state, and the wettability is high. The ink discharge head 33 can be assembled using the uniform nozzle sheet 43. Also, even if the nozzle sheet 43 is stored for a long period of time before being assembled to the ink discharge head 33 and the wettability is deteriorated, the wettability is improved again by heat treatment before the ink discharge head 33 is assembled. Can be improved.

  As a method for heating the nozzle sheet 43, the nozzle sheet 43 on which the oxide films 74a and 74b are formed by electropolishing is heated alone in an environment of 60 ° C. or higher, preferably 80 ° C. or higher, more preferably 100 ° C. or higher. Further, as a heating method of the nozzle sheet 43, when the ink discharge head 33 is manufactured, if there is a heating process of 60 ° C. or more, the nozzle sheet 43 is not heated alone, and the heat of the heating process is used. The nozzle sheet 43 may be heated.

  The nozzle sheet 43 as described above has nickel as a main component, is formed by electroforming, and is electropolished, so that the main surface 73 serving as the bottom surface of the ink liquid chamber 45 and the wall surface 75 of the nozzle 71 are hydrophilically oxidized. Since the films 74a and 74b are formed, the wettability with respect to the ink i is high and uniform, and the heat treatment is performed, the high and uniform wettability of the main surface 73 and the wall surface 75 of the nozzle 71 is maintained. Can be incorporated into the ink discharge head 33 without deteriorating the wettability of the main surface 73 and the wall surface 75 of the nozzle 71 even if left for a while.

  Further, in this nozzle sheet 43, the oxide film 74a, 74b, that is, the passive film is formed on the main surface 73 on the ink liquid chamber 45 side and the wall surface 75 of the nozzle 71, thereby improving the wettability of the ink i. In addition, the corrosion resistance to the ink i is improved.

  Such a nozzle sheet 43 is produced by electroforming in order to form many fine nozzles as follows. As shown in FIG. 6, the nozzle sheet 43 is made of stainless steel, for example, SUS304, and is formed on a mother die 81 having a flat surface. First, as shown in FIG. 6A, on the flat main surface 81a of the mother die 81, a negative resist 82 is patterned by photolithography at a portion where the nozzle 71 is to be formed. The resist 82 has a columnar shape whose diameter is reduced on the side of the mother die 81 and has a height of about 15 μm.

  Next, as shown in FIG. 6B, an electroformed layer 83 to be the nozzle sheet 43 is formed on the mother die 81 by electroforming. Specifically, the matrix 81 on which the pattern of the resist 82 is formed is immersed in a plating solution containing nickel, and the nickel-based electroformed layer 83 is formed by, for example, an electrolytic plating method.

Next, as shown in FIG. 6C, the resist pattern is dissolved with a predetermined solution, the resist 82 formed by patterning is removed from the main surface 81 a of the matrix 81, and a plurality of nozzles 71 are provided in the electroformed layer 83. Form. In the matrix 81 Ueno electroformed layer 83, by touching the air on the wall 75 opposite to the main surface 83a and the nozzle 71 and the mold 81 of the bottom to become electroformed layer 83 of the ink liquid chamber 45, Ni ₂ An oxide such as O ₃ will be formed.

Next, while the electroformed layer 83 is formed on the matrix 81, it is immersed in an electrolytic solution, and the main surface 83a of the electroformed layer 83 and the wall surface 75 of the nozzle 71 are electropolished to dissolve or scrape the oxide on the surface. Thus, hydrophilic oxide films 74 a and 74 b made of Ni ₂ O ₃ are uniformly formed on the main surface 83 a of the electroformed layer 83 and the wall surface 75 of the nozzle 71.

  Next, the electroformed layer 83 is heat-treated at a temperature of 60 ° C. or higher while the electroformed layer 83 is formed on the mother die 81.

  Next, the electroformed layer 83 is peeled from the matrix 81 to obtain the nozzle sheet 43.

In the manufacturing method of the nozzle sheet 43 as described above, after the electroformed layer 83 to be the nozzle sheet 43 is formed on the matrix 81, it is immersed in an electrolytic solution and subjected to electrolytic polishing, whereby the ink liquid chamber 45 side is obtained. Hydrophilic oxide films 74a and 74b made of Ni ₂ O ₃ are uniformly formed on the main surface 83a of the electroformed layer 83 to be the main surface 73 and the wall surface 75 of the nozzle 71, and are uniform and highly wettable with respect to the ink i. Further, by performing the heat treatment, uniform and high wettability with respect to the ink i of the main surface 83a of the electroformed layer 83 and the wall surface 75 of the nozzle 71 can be maintained. Thereby, in this nozzle sheet 43, in order to improve the printing speed by forming a plurality of nozzles 71, even if formed by electroforming, by performing electrolytic polishing and heat treatment, an ink liquid chamber that is in direct contact with ink i Since the wettability of the main surface 73 forming the bottom surface of 45 and the wall surface 75 of the nozzle 71 can be made high and uniform, and this wettability can be maintained, bubbles adhere to the bottom surface of the ink liquid chamber 45 and the wall surface 75 of the nozzle 71. Can be prevented.

  As shown in FIGS. 4 and 5, the frame 44 that supports the nozzle sheet 43 has an opening 44 a into which the flow path plate 41 and the head chip 42 are fitted. A nozzle sheet 43 is bonded to the surface of the frame 44 on the side where the head chip 42 is disposed. The frame 44 has a nozzle sheet so that the nozzle 71 of the nozzle sheet 43 and the heating resistor 61a of the head chip 42 face each other, and the head chip 42, the flow path plate 41, and the nozzle sheet 43 can be bonded together. 43 is supported.

  The ink discharge head 33 configured as described above is manufactured as follows. First, the nozzle sheet 43 in which the hydrophilic oxide films 74 a and 74 b are formed on the main surface 73 serving as the bottom surface of the ink liquid chamber 45 and the wall surface 75 of the nozzle 71 is manufactured by the method for manufacturing the nozzle sheet 43 described above.

  Next, it is placed on a support jig (not shown) having a flat surface so that the main surface 73 on which the oxide film 74a of the obtained nozzle sheet 43 is formed faces up. At this time, in the nozzle sheet 43, the main surface 73 which is the bottom surface of the ink liquid chamber 45 on which the hydrophilic oxide films 74a and 74b are formed and the wall surface 75 of the nozzle 71 are subjected to heat treatment, so that high and uniform wetting is performed. Therefore, even when the ink discharge head 33 is assembled with the nozzle sheet 43 placed on a support jig and in contact with air, the ink discharge head 33 can be assembled with high and uniform wettability. it can.

  Next, on the main surface 73 on which the oxide film 74a of the nozzle sheet 43 placed on the support jig is formed, the nozzle line 72 faces the opening 44a provided in the frame 44 as shown in FIG. Then, the frame 44 is placed and the nozzle sheet 43 and the frame 44 are bonded together. The nozzle sheet 43 and the frame 44 are bonded together by interposing a thermosetting sheet adhesive such as an epoxy sheet adhesive between the nozzle sheet 43 and the frame 44 and thermosetting the sheet adhesive. The nozzle sheet 43 is bonded together by applying an adhesive that cures at room temperature to the frame. Since the nozzle sheet 43 is supported by the frame 44, it is peeled off from the support jig.

  Next, a plurality of head chips 42 are arranged in a staggered manner in the opening 44a of the frame 44 so that the nozzle 71 and the heating resistor 61a face each other, and the film 62 of the head chip 42 is heated to 100 ° C. to be thermoset. By doing so, the head chip 42 and the nozzle sheet 43 are bonded together. By bonding the head chip 42 and the nozzle sheet 43 together, an ink liquid chamber 45 surrounded by the head chip 42 and the nozzle sheet 43 is formed as shown in FIG.

  Next, the flow path forming portion 52 of the flow path plate 41 assembled in another process is fitted into the opening 44a of the frame 44, and the bottom surface of the flow path forming portion 52 and the circuit board 61 of the head chip 42 are bonded with an adhesive. Glue. By bonding the head chip 42 and the flow path forming portion 52, as shown in FIG. 5, the ink discharge head 33 in which the ink liquid chamber 45 and the ink flow path 51 are connected so as to be able to supply ink i is obtained. .

In the manufacturing method of the ink discharge head 33 as described above, the electroformed layer 83 on which the nozzles 71 are formed is electrolytically polished to form the main surface 73 on the ink liquid chamber 45 side of the nozzle sheet 43 and the wall surface 75 of the nozzle 71. Further, hydrophilic oxide films 74a and 74b made of Ni ₂ O ₃ are uniformly formed, and the wettability with respect to the ink i can be made high and uniform. Furthermore, in this method of manufacturing the ink discharge head 33, the nozzle sheet 43 in which the hydrophilic oxide films 74a and 74b are formed on the main surface 73 on the ink liquid chamber 45 side and the wall surface 75 of the nozzle 71 is heat-treated. Since the wettability with respect to the ink i is high and a uniform state is maintained, the nozzle sheet 43 can be combined with the flow path plate 41 and the head chip 42 without reducing the wettability.

  In the ink discharge head 33 obtained by the manufacturing method of the ink discharge head 33, even if bubbles are mixed in the ink i, the main surface 73 and the wall surface 75 of the nozzle 71 have high wettability. Adhering to the bottom surface of 45 and the wall surface 75 of the nozzle 71 can be prevented. As a result, in the ink discharge head 33, bubbles do not remain in the ink liquid chamber 45 or the nozzle 71, and are easily removed from the nozzle 71 by discharge of the ink i, etc., and the bubble discharge property is improved. Therefore, in the ink ejection head 33, the ink i is continuously and instantaneously supplied from the ink flow path 51 to the ink liquid chamber 45 without being hindered by bubbles, and without performing a suction operation or the like. The ink liquid chamber 45 is uniformly filled, and the ink i can be stably supplied to the nozzle 71. In the ink ejection head, the ink i is stably supplied to the nozzle 71, so that the ink droplet can be ejected stably from the nozzle 71, and the ejection of the ink droplet becomes unstable, the ink droplet is interrupted, or ejected. It can be prevented from becoming impossible. In particular, the ink discharge head 33 can prevent bubbles from staying in the nozzle 71, thereby further preventing the occurrence of ink i discharge failure.

In addition, since the ink discharge head 33 forms a large number of fine nozzles 71, even if the nozzle sheet 43 is formed by electroforming, the nozzle sheet 43 is electropolished and subjected to heat treatment, whereby the bottom surface of the ink liquid chamber 45 is formed. The hydrophilic oxide films 74a and 74b made of Ni ₂ O ₃ can be uniformly formed on the main surface 73 of the nozzle sheet 43 and the wall surface 75 of the nozzle 71, and the wettability can be improved. Bubbles can be prevented from adhering and the printing speed can be improved.

  In the manufacturing method of the ink discharge head 33 described above, in the manufacturing process of the nozzle sheet 43, the main surface 73 serving as the bottom surface of the ink liquid chamber 45 and the wall surface 75 of the nozzle 71 are subjected to electrolytic polishing, and then heat treatment is performed. However, when the film 62 of the head chip 42 is thermally cured using the nozzle sheet 43 that is only subjected to electropolishing without performing heat treatment, the nozzle sheet 43 and the head chip 42 are bonded together, for example, heated at 100 ° C. Therefore, the nozzle sheet 43 may be heat-treated using the heat of the heating process of the film 62. In such a method of manufacturing the ink discharge head 33, the step of heat-treating the nozzle sheet 43 alone can be eliminated, and the manufacturing process can be simplified.

  In the ink discharge head 33 obtained as described above, the ink i is discharged from the nozzle 71 as follows. In the ink discharge head 33, the ink i is supplied from the ink cartridge 21 to the ink flow path 51 formed by the flow path plate 41 through the connection portion 35 provided in the cartridge main body 31, and is not obstructed by bubbles. The ink i is supplied from the ink flow path 51 to the ink liquid chamber 45. In the ink ejection head 33, the control circuit of the circuit board 61 drives and controls the heating resistor 61a, supplies a pulse current to the selected heating resistor 61a, and rapidly heats the heating resistor 61a. In the ink discharge head 33, when the heating resistor 61a is heated, bubbles b are generated in the ink i in the ink liquid chamber 45 in contact with the heating resistor 61a, as shown in FIG. In the ink discharge head 33, as shown in FIG. 7B, the ink i is pressed in the ink liquid chamber 45 while the bubble b expands, and the displaced ink i is in a droplet state in the nozzle 71. More discharged. In the ink discharge head 33, the wettability of the wall surface 75 of the nozzle 71 is high and uniform, and bubbles do not adhere. Therefore, the ink i can be appropriately discharged in a predetermined direction without being blocked by the bubbles. After the ink i is ejected, the ink i is supplied to the ink liquid chamber 45 through the ink flow path 51 to return to the state before ejection again. In this manner, the ink ejection head 33 can repeatedly eject ink droplets by repeatedly pressing the ink i filled in the ink liquid chamber 45.

  As shown in FIG. 2, the head cap 34 for protecting the ejection surface 33a on which the ink droplets of the ink ejection head 33 are ejected does not eject the ink i and does not perform printing, as shown in FIG. The discharge surface 33a is closed to protect the nozzle 71 from drying and the like. When performing printing, the head cap 34 moves from the bottom surface of the head cartridge 2 to the front of the apparatus body 3, that is, in the direction of the arrow A1 in FIG. The discharge surface 33a is exposed to the outside. After printing, the head cap 34 moves from the front of the apparatus main body 3 to the bottom surface of the head cartridge 2, that is, in the direction of arrow A2 in FIG. Protect.

  The head cap 34 is provided with a cleaning roller 34a for wiping off excess ink i adhering to the ejection surface 33a. When opening the ejection surface 33a, the head cap 34 cleaned the ejection surface 33a with the cleaning roller 34a, and increased the viscosity of the excess ink i adhered to the ejection surface 33a and the surface of the nozzle 71. Ink i is sucked. The head cap 34 may clean the ejection surface 33a with the cleaning roller 34a when moving to the bottom surface of the head cartridge 2 after printing.

  As shown in FIG. 1, the head cartridge 2 is mounted on the head cartridge mounting portion 91 in the apparatus main body 3 to which the head cartridge 2 having the above-described configuration is mounted. Further, the apparatus main body 3 is attached with a paper feed tray 93 that stores and stores the recording paper P before being printed at a paper feed port 92 provided on the lower front side, and a discharge tray provided on the upper front side. A paper discharge tray 95 for storing the recording paper P after printing is attached to the paper port 94.

  The printer apparatus 1 configured as described above performs printing based on print data input from an information processing apparatus provided outside. That is, in the printer apparatus 1, the head cap 34 is moved from the bottom surface of the head cartridge 2 to the front side of the apparatus body 3 by a head cap opening / closing mechanism (not shown). As a result, the printer 1 can expose the nozzles 71 provided on the ejection surface 33a of the ink ejection head 33 to the outside and eject ink i.

  Next, the printer apparatus 1 records only one sheet from the sheet feed tray 93 by a plurality of sheet feed rollers 96, 97, and 98 as shown in FIG. 8 by operating the operation button 3a provided on the apparatus body 3. Pull out the paper P. The printer apparatus 1 reverses the recording paper P pulled out from the paper feed tray 93 to the head cartridge 2 side by the reverse roller 99 and conveys the recording paper P onto the platen plate 101 provided at a position facing the ejection surface 33a by the conveyance belt 100. The recording paper P comes to face the ejection surface 33a.

  Next, the printer apparatus 1 supplies a drive current to a plurality of heating resistors 61a provided for each color in the ink discharge head 33 based on a print data control signal, and heats the heating resistors 61a for each color. To do. The printer device 1 heats the heating resistor 61a to the recording paper P in the order of a yellow nozzle line 72y, a magenta nozzle line 72m, a cyan nozzle line 72c, and a black nozzle line 72k. As shown in FIG. 8, the ink 71 of each color described above is ejected from the nozzle 71 in the form of droplets for each color, and a color image or a character composed of a plurality of colors is printed.

  Next, the printer apparatus 1 feeds the recording paper P by the conveyance belt 100 that rotates the recording paper P that has been printed in the direction of the paper discharge port 94 and the paper discharge roller 102 provided to face the conveyance belt 100. The recording paper P is sent out to the paper discharge port 94 and discharged onto the paper discharge tray 95.

As described above, in the printer device 1, even if air bubbles are mixed in the ink i, the main surface 73 of the nozzle sheet 43 that forms the bottom surface of the ink liquid chamber 45 of the ink discharge head 33 and the wall surface 75 of the nozzle 71. Since the hydrophilic treatment such as electrolytic polishing and the heat treatment are performed to the hydrophilic oxide films 74a and 74b made of Ni ₂ O ₃ and the wettability to the ink i is high and uniform. Can be prevented from adhering to the bottom surface of the ink liquid chamber 45 and the wall surface 75 of the nozzle 71. As a result, in the printer 1, bubbles do not remain in the ink liquid chamber 45 or the nozzle 71, and are easily removed from the nozzle 71 by the discharge of the ink i or the like, so that the ink flow channel 51 passes through the ink liquid chamber 45. The ink i can be continuously and instantaneously supplied to the nozzle 71, and the ink i can be stably supplied to the nozzle 71. As a result, the printer apparatus 1 can stably discharge ink droplets from the nozzles 71, and can prevent the discharge of ink droplets from becoming unstable, the ink droplets from being interrupted, and being unable to be discharged. Simple images and characters can be printed.

Further, in the printer apparatus 1, a nozzle that forms the bottom surface of the ink liquid chamber 45 by electropolishing the nozzle sheet 43 even if the nozzle sheet 43 is formed by electroforming in order to form many fine nozzles 71. Since hydrophilic oxide films 74a and 74b made of Ni ₂ O ₃ can be uniformly formed on the main surface 73 of the sheet 43 and further on the wall surface 75 of the nozzle 71, and adhesion of bubbles can be prevented, a large number of nozzles 71 are provided. Printing speed can be improved by using the ink discharge head 33 which has. From the above, the printer device 1 can print high-quality images and characters at high speed.

  The example in which the present invention is applied to the printer apparatus 1 has been described above. However, the present invention is not limited to the printer apparatus 1 and can be widely applied to other liquid ejection apparatuses that eject liquid. is there. For example, the present invention can be applied to a discharge device for a DNA chip in a liquid, a liquid discharge device that discharges a liquid containing conductive particles for forming a wiring pattern of a printer wiring board, and the like. It is possible to prevent problems caused by

  In the printer device 1 described above, the ink discharge head 33 that heats and discharges the ink i by the single heating resistor 61a has been described as an example. This is also applicable to a liquid ejecting apparatus having a pressure generating element, and having a discharging means capable of controlling the discharge direction by supplying energy to each pressure generating element at different energy or at different timing. In the same way, it is possible to prevent problems caused by bubbles.

  Further, the above-described printer device 1 employs an electrothermal conversion method in which the ink i is heated from one nozzle 61 while being heated by one heating resistor 61a. However, the present invention is not limited to such a method, and for example, a piezo element. An electromechanical conversion method in which the ink i is electromechanically ejected from the nozzle 71 by an electromechanical conversion element such as a piezoelectric element may be employed, and may be caused by bubbles as in the case of using the heating resistor 61a. Problems can be prevented.

  The line type printer apparatus 1 has been described as an example. However, the present invention is not limited to this example. For example, the serial type liquid discharge in which the ink head moves in a direction substantially orthogonal to the running direction of the recording paper P is described. The present invention can also be applied to the apparatus, and the problem due to bubbles can be prevented as in the printer apparatus 1.

  Below, using the printer device to which the present invention is applied, the bubble discharge performance was evaluated by the presence or absence of the number of non-ejection nozzles.

<Sample 1>
In sample 1, the nozzle sheet was produced by electroforming. When producing a nozzle sheet, a resist pattern is formed on the part where the nozzle is formed on the matrix, and the matrix on which the resist pattern is formed is immersed in a plating solution containing nickel and cobalt. As a result, an electroformed layer serving as a nozzle sheet composed mainly of nickel, 90 wt% nickel, and 10 wt% cobalt was formed.

  Next, the resist was removed with a predetermined solution, a nozzle was formed in the electroformed layer, and a nozzle sheet was produced. The obtained nozzle sheet has a thickness of 13 μm and a nozzle diameter of 20 μm. The contact angle of the produced nozzle sheet with respect to ink was 60 °. The contact angle was measured using a measuring instrument CA-X manufactured by Kyowa Interface Science Co., Ltd.

  Next, the frame was bonded to the main surface of the obtained nozzle sheet with an adhesive that hardens at room temperature.

  Next, a head chip provided with a heating resistor is inserted into the opening of the frame, and the nozzle sheet and the head chip are bonded together with an adhesive that cures at room temperature so that heat is not applied to the nozzle sheet. It was. By bonding the head chip and the nozzle sheet together, an ink liquid chamber is formed in which one heating resistor is surrounded by the head chip and the nozzle sheet.

  Next, the flow path forming part of the flow path plate assembled in another process and the circuit board of the head chip were bonded with an adhesive to obtain an ink ejection head.

<Sample 2>
In Sample 2, an ink ejection head was produced in the same manner as Sample 1, except that the nozzle sheet was not electropolished and heated at 100 ° C. for 1 hour. The contact angle of the nozzle sheet with respect to the ink was 60 ° C.

<Sample 3>
In sample 3, the electroformed layer on which the nozzle is formed is formed on the matrix, and is immersed in an electrolytic solution, and the main surface of the electroformed layer that becomes the bottom surface of the ink liquid chamber and the wall surface of the nozzle are electropolished, An ink ejection head was produced in the same manner as Sample 1 except that a nozzle sheet in which a hydrophilic oxide film made of Ni ₂ O ₃ was uniformly formed was used.

  The electrolytic polishing conditions were a phosphoric acid solution as a polishing liquid (electrolytic solution), a current condition of 100 mA, and a treatment time of 5 minutes.

  The contact angle of the nozzle sheet after electropolishing was 15 °.

<Sample 4>
In sample 4, ink ejection was performed in the same manner as in sample 3, except that a nozzle sheet that was electropolished on the main surface of the electroformed layer and the wall surface of the nozzle serving as the bottom surface of the ink chamber was left at room temperature for 2 weeks. A head was produced. The contact angle of this nozzle sheet was 40 °.

<Sample 5>
In Sample 5, ink ejection was performed in the same manner as in Sample 3, except that the main surface of the electroformed layer and the nozzle wall surface, which become the bottom surface of the ink chamber, were electropolished and then used for one month at room temperature. A head was produced. The contact angle of this nozzle sheet was 55 °.

<Sample 6>
In Sample 6, the main surface of the electroformed layer serving as the bottom surface of the ink liquid chamber and the wall surface of the nozzle were electropolished and then heated at 60 ° C. for 1 hour and then left at room temperature for 1 month. Except for this, an ink ejection head was prepared in the same manner as Sample 3. The contact angle of this nozzle sheet was 40 °.

<Sample 7>
In Sample 7, the main surface of the electroformed layer that becomes the bottom surface of the ink liquid chamber and the wall surface of the nozzle were electropolished and then heated at 100 ° C. for 1 hour and then left at room temperature for 1 month. Except for this, an ink ejection head was prepared in the same manner as Sample 3. The contact angle of this nozzle sheet was 25 °.

<Sample 8>
In Sample 8, the main surface of the electroformed layer serving as the bottom surface of the ink liquid chamber and the wall surface of the nozzle were electropolished and then left at room temperature for 1 month, and then heated at 100 ° C. for 1 hour. Except for this, an ink ejection head was prepared in the same manner as Sample 3. The contact angle of this nozzle sheet was 15 °.

<Sample 9>
In Sample 9, the main surface of the electroformed layer that becomes the bottom surface of the ink liquid chamber and the wall surface of the nozzle were electropolished and then heated at 100 ° C. for 1 hour and then left at room temperature for 2 months. Except for this, an ink ejection head was prepared in the same manner as Sample 3. The contact angle of the nozzle sheet was 40 °.

  Table 1 shows a summary of the contact angles of the nozzle sheets of Samples 1 to 9.

  The ink discharge heads of Sample 1 to Sample 9 obtained as described above are attached to the above-described line type printer device (printer device LPR-5000, manufactured by Sony Corporation), and the discharge of bubbles is not discharged. Evaluation was made based on the presence or absence of a nozzle.

  As the evaluation method of the bubble discharge property, as evaluation 1, first, the number of non-ejection nozzles due to bubbles after counting ink at the initial stage, that is, after the ink was filled into the ink ejection head, was counted. As evaluation 2, the number of non-ejection nozzles due to bubbles was counted after printing 10,000 sheets. As evaluation 3, after evaluation 2, performance was recovered with a cleaning roller, and the number of non-ejection nozzles was counted. The nozzle positions counted in Evaluation 1 and Evaluation 2 are the same places in both Evaluation 1 and Evaluation 2, and the number of nozzles to be confirmed is 1000. Table 2 below shows the number of non-ejection nozzles in Evaluations 1 to 3.

  From the results shown in Tables 1 and 2, in Sample 1, when the nozzle sheet was produced, the main surface of the electroformed layer serving as the bottom surface of the ink liquid chamber and the wall surface of the nozzle were not subjected to electrolytic polishing. A hydrophilic oxide film was not formed on the main surface of the layer and the wall surface of the nozzle, the contact angle with respect to the ink was 60 °, and the wettability deteriorated. Thereby, in sample 1, since the ink discharge head is manufactured using this nozzle sheet, bubbles adhere to the bottom surface of the ink liquid chamber and the wall surface of the nozzle, and the number of non-discharge nozzles is evaluated by the bubbles. Many in all of the evaluations 3, white streaks occurred in the printed image. Therefore, from the sample 1, it was confirmed that the nozzle sheet not subjected to electropolishing deteriorates the bubble discharge performance.

  In Sample 2, when the nozzle sheet was produced, the electroformed layer was not subjected to electropolishing and only heat treatment was performed. Thus, as in Sample 1, an oxide film was not formed, and the contact angle with respect to ink was 60 °. And wettability deteriorated. As a result, in sample 2, as in sample 1, the number of non-ejection nozzles was large in all the evaluations 1 to 3, and white streaks occurred in the printed image. Therefore, it was confirmed from Sample 2 that the nozzle sheet that was not subjected to electropolishing and was subjected only to heat treatment deteriorated the bubble discharge performance.

  In Sample 3, since the electroformed layer was electropolished when the nozzle sheet was produced, a hydrophilic oxide film was formed, the contact angle with respect to the ink was 15 °, and the wettability was improved. As a result, in sample 3, since bubbles do not adhere to the bottom surface of the ink liquid chamber and the wall surface of the nozzle and are removed, non-ejection nozzles do not occur in all evaluations 1 to 3, and white streaks are generated. I was able to prevent it. Therefore, from the sample 3, it was confirmed that the nozzle sheet immediately after the electropolishing had good bubble discharging properties.

  However, as in Sample 4, when left at room temperature for 2 weeks after electrolytic polishing, the surface of the nozzle sheet was oxidized, the contact angle with respect to the ink was 40 °, and wettability was slightly reduced. As a result, in sample 4, only when 10,000 sheets of evaluation 2 were printed, the bubbles were obstructed and non-ejection nozzles were generated, but the non-ejection nozzles disappeared due to performance recovery. Therefore, from the sample 4, the nozzle sheet left for 2 weeks after electrolytic polishing produces non-ejection nozzles when 10,000 sheets are printed, but the number of non-ejection nozzles is small, the non-ejection nozzles disappear due to performance recovery, and white lines are generated. It was confirmed that the air bubble dischargeability was good.

  Further, as in Sample 5, when the nozzle sheet is electropolished and left for one month, the surface of the nozzle sheet is oxidized more than in the case of Sample 4 left for two weeks, and the contact angle with respect to ink becomes 55 °. The wettability decreased. As a result, sample 5 was already blocked by bubbles at the initial stage of evaluation 1, and non-ejection nozzles were generated. Further, when 10,000 sheets of evaluation 2 were printed, the number of non-ejection nozzles increased, and even after performance recovery, non-ejection nozzles The white streaks occurred. Therefore, from the sample 5, it was confirmed that the nozzle sheet left for one month after the electropolishing deteriorated the bubble discharge performance.

  In Sample 6 to which the present invention is applied, since the heat treatment is performed at 60 ° C. after the electropolishing, the contact angle with respect to the ink is 40 ° and the wettability is good even if left for one month after the heat treatment. It became. As a result, in Sample 6, only in the case of Evaluation 2 in which 10,000 sheets were printed, bubbles were obstructed and non-ejection nozzles were generated. However, due to performance recovery, non-ejection nozzles disappeared, and generation of white stripes could be prevented. Therefore, from the sample 6, the nozzle sheet that was heat-treated at 60 ° C. after being electropolished and left to stand for one month generated non-ejection nozzles when 10,000 sheets were printed, but the number of non-ejection nozzles was small and non-ejection due to performance recovery. Since the nozzles disappeared, it was confirmed that the bubble discharging property was good.

  Further, as in Sample 7, when heat treatment was performed at 100 ° C. after the electropolishing, the contact angle with respect to the ink was 25 ° C. and high wettability could be maintained even when left for one month after the heat treatment. As a result, in sample 7, as in sample 3 using the nozzle sheet immediately after electropolishing, bubbles are removed, no ejection nozzles are generated in all of evaluations 1 to 3, and the occurrence of white stripes can be prevented. It was. Therefore, from the sample 7, it was confirmed that the nozzle sheet heat-treated at 100 ° C. after the electrolytic polishing had good wettability and good bubble discharge properties, similar to the nozzle sheet immediately after the electrolytic polishing of the sample 3. .

  Further, in Sample 8, when the nozzle sheet was produced, electrolytic polishing was performed and left for one month, and then heat treatment was performed at 100 ° C., so that electrolytic polishing was performed and the heat treatment was performed after being left for one month. Compared with sample 5 that was not subjected to the test, the contact angle with respect to the ink was small, 25 ° C., and high wettability was obtained. Thereby, in the sample 8, bubbles were removed, and no ejection nozzle was generated in all of the evaluations 1 to 3, and generation of white streaks could be prevented. Therefore, it is confirmed from sample 8 that the heat-treated nozzle sheet has good wettability and good air bubble discharge even after being left for one month, just like the nozzle sheet immediately after electrolytic polishing. did it.

  Further, in sample 9, when the nozzle sheet was produced, electropolishing was performed, and after heat treatment at 100 ° C., the contact angle with respect to the ink was 40 ° even when left for two months, which was good. The wettability was maintained. As a result, in Sample 9, only when 10,000 sheets of evaluation 2 were printed, the bubbles were obstructed and non-ejection nozzles were generated. However, the non-ejection nozzles disappeared due to performance recovery, and the occurrence of white stripes could be prevented. Therefore, from the sample 9, the nozzle sheet left for two months after the heat treatment generates non-ejecting nozzles when 10,000 sheets are printed, but the number of non-ejecting nozzles generated is small, and the non-ejecting nozzles disappear due to performance recovery. It was confirmed that the bubble discharging property was good.

  When producing a nozzle sheet from Sample 6 to Sample 9 to which the present invention is applied, by subjecting the main surface of the electroformed layer and the nozzle to electropolishing, ink is generated by bubbles even at the initial time and during continuous use. Therefore, it is possible to prevent white streaks from occurring in the image, and further, by applying heat treatment, it becomes possible to maintain the improved wettability by electropolishing for a long period of time. It was confirmed that the reliability could be improved.

  As described above, in Samples 6 to 9, the electrolytic polishing and the heat treatment were performed when the nozzle sheet was produced. When the nozzle sheet and the head chip were bonded together, a film made of an epoxy resin of the head chip was used, and heat was applied. The heat treatment of the nozzle sheet may be performed by heat when curing, or the heat treatment may be performed after the ink discharge head is manufactured.

  In Sample 5 described above, an ink discharge head was manufactured using a nozzle sheet that was left at room temperature for 1 month after electrolytic polishing, and the manufactured ink discharge head was heated at 100 ° C. for 1 hour. Using this ink discharge head, Evaluations 1 to 3 were performed in the same manner as Samples 1 to 9 described above. The evaluation results of Evaluation 1 to Evaluation 3 are shown in Table 3.

  From the results shown in Table 3, even when the ink discharge head is heated and the nozzle sheet is heated, in all the evaluations 1 to 3, as in the case where the nozzle sheet is heated alone, non-ejection due to bubbles No nozzles were generated, and the bubble discharge was good. Thus, it was confirmed that the bubble sheet discharge performance was improved not only when the nozzle sheet was heat-treated, but also after the nozzle sheet alone.

1 is a perspective view showing a printer apparatus to which the present invention is applied. FIG. 2 is a perspective view showing a head cartridge provided in the printer apparatus. It is sectional drawing which shows the head cartridge. FIG. 3 is an exploded perspective view of an ink discharge head. It is sectional drawing of the same ink discharge head. It is sectional drawing which shows the manufacturing process of a nozzle sheet, (A) is sectional drawing in which the resist was pattern-formed on the mother mold, and (B) formed the electroformed layer on the mother mold. It is sectional drawing which shows a state, (C) is sectional drawing which shows the state which formed the oxide film in the main surface of an electroforming layer, and the wall surface of a nozzle, (D) peels an electroforming layer from a mother mold And it is sectional drawing which shows the state by which the nozzle sheet was obtained. FIG. 2 is a partial cross-sectional view showing an ink discharge head, where (A) is a cross-sectional view showing a state in which bubbles are generated on a heating resistor, and (B) in FIG. It is sectional drawing which shows the discharged state. FIG. 3 is a side view illustrating a part of the printer device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Printer apparatus, 2 Head cartridge, 3 Apparatus main body, 21 Ink cartridge, 31 Cartridge main body, 33 Ink discharge head, 34 Head cap, 35 Connection part, 41 Flow path plate, 42 Head chip, 43 Nozzle sheet, 44 Frame, 45 Ink liquid chamber, 51 ink flow path, 52 flow path section, 53 connecting pipe, 61 circuit board, 61a heating resistor, 62 film, 71 nozzle, 72 nozzle line, 73 main surface, 74 oxide film, 75 wall surface

Claims (6)

In the liquid discharge head for discharging the liquid filled in the liquid chamber from the nozzle,
Forming a wall surface of the liquid chamber, and having a nozzle sheet made of a metal material on which the nozzle is formed;
The liquid discharge head, wherein the nozzle sheet is formed by electroforming, and at least a main surface on the liquid chamber side is subjected to a hydrophilic treatment by electrolytic polishing and further subjected to a heat treatment.   The liquid discharge head according to claim 1, wherein the temperature of the heat treatment is 60 ° C. or higher. Liquid discharge having a head chip that presses the liquid filled in the liquid chamber, and a nozzle sheet made of a metal material that forms a wall surface of the liquid chamber and has a nozzle that discharges the liquid pressed by the head chip. In the head manufacturing method,
After producing the nozzle sheet by electroforming, at least the main surface of the nozzle sheet on the liquid chamber side is subjected to hydrophilic treatment by electrolytic polishing, and further subjected to heat treatment,
A method of manufacturing a liquid discharge head, wherein the liquid chamber is formed by bonding the head chip to a main surface of the nozzle sheet subjected to electropolishing and heat treatment.   The method of manufacturing a liquid discharge head according to claim 3, wherein the temperature of the heat treatment is 60 ° C. or higher. In a liquid ejection apparatus including a liquid ejection head that ejects liquid filled in a liquid chamber from a nozzle,
The liquid discharge head includes a nozzle sheet that forms a wall surface of the liquid chamber and is made of a metal material on which the nozzle is formed.
The nozzle sheet is formed by electroforming, and at least a main surface on the liquid chamber side is subjected to a hydrophilic treatment by electrolytic polishing and further subjected to a heat treatment.   The liquid ejection apparatus according to claim 5, wherein the temperature of the heat treatment is 60 ° C. or higher.

Images