JP2011131396A - Ink-jet head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink-jet head that can simplify a manufacturing process. <P>SOLUTION: The ink-jet head 1 includes a head body part having a head base material 2, a first piezoelectric member 3 and a second piezoelectric member 4, and a nozzle plate 8 mounted to an ejection surface of the head body part and having a plate base material 41 containing bacterial cellulose. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an inkjet head in which nozzles for ejecting ink are formed.

  2. Related Art An ink jet head that has a nozzle plate provided on an ejection surface and is provided in a printing apparatus is known.

  Patent Document 1 discloses a nozzle plate including a metal plate and a resin layer provided on a discharge side surface of the metal plate. The metal plate is formed thicker than the resin layer in order to improve mechanical strength. The nozzle is formed so as to penetrate the metal plate and the resin layer. Ink is ejected from this nozzle.

  In the nozzle plate manufacturing method of Patent Document 1, a resin layer is formed on one surface of a metal plate. Next, after forming a photoresist film having a desired pattern, the metal plate is etched. Thereafter, after forming a photoresist film of another pattern, the resin layer is etched. Thereby, the nozzle which penetrates the metal plate and the resin layer is formed.

Patent No. 3092134

  However, in the nozzle plate of Patent Document 1, since the metal plate needs to have mechanical strength, the metal plate is made thicker than the resin layer. For this reason, the manufacturing method of Patent Document 1 requires two etchings in order to form the nozzle. As a result, there is a problem that the manufacturing process becomes complicated.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an ink jet head that can simplify the manufacturing process.

  In order to achieve the above object, a first feature of an ink jet head according to the present invention is a head main body, and a nozzle plate that is attached to a discharge surface of the head main body and has a plate base material containing bacterial cellulose. I have.

  According to a second aspect of the inkjet head of the present invention, the nozzle plate includes a metal layer provided on the discharge side surface of the plate base material and sulfur provided on the discharge surface of the metal layer. And a protective layer having an organic material.

  According to a third feature of the inkjet head according to the present invention, the organic material of the protective layer is a thiol compound.

  A fourth feature of the ink jet head according to the present invention is that the organic material of the protective layer is a thiol compound containing an oleophobic group.

  A fifth feature of the ink jet head according to the present invention is that the organic material of the protective layer is a thiol compound containing a linear alkyl group.

The sixth feature of the ink jet head according to the present invention, the organic material of the protective layer, when the lipophobic based on _{X, SH-C m H 2m} -X-C n H 2n -SH (m, n : Even number) is a thiol compound represented by the chemical formula.

The seventh feature of the inkjet head according to the present invention is that the m and n are:
m = n
It is.

The eighth feature of the ink jet head according to the present invention is that the n is
8 ≦ n ≦ 18
It is.

  According to the first feature, since the nozzle plate having the plate base material made of high-strength bacterial cellulose is provided, it is possible to omit a relatively thick metal plate and the like necessary for maintaining the mechanical strength. it can. By omitting such a thick metal plate that is difficult to process, the first feature is that the manufacturing process can be simplified and the nozzle can be formed easily.

  According to the 2nd characteristic, since it has the plate base material containing a bacterial cellulose, while being easy to process, a metal layer can be thinned to the required minimum thickness which can exhibit a function. Thereby, the 2nd characteristic can form the nozzle which has electroconductivity easily. In addition, the metal layer can covalently bond the protective layer containing sulfur and the metal layer, thereby suppressing the peeling between the protective layer and the plate base material.

  According to the third feature, since the protective layer is made of a thiol compound, the protective layer can be composed of a self-assembled dense monomolecular film.

  According to the 4th characteristic, since the thiol compound which comprises a protective layer contains an oleophobic group, a protective layer can repel oil-based ink. Thereby, it can suppress that a protective layer is contaminated with an ink solvent.

  According to the fifth feature, since the thiol compound constituting the protective layer contains a linear alkyl group, the protective layer is made dense by self-organization compared to a thiol compound containing a branched alkyl group. be able to.

  According to the sixth feature, since the two integers (m, n) indicating the carbon number of the alkyl group of the thiol compound constituting the protective layer are even numbers, the molecules in the monomolecular film are likely to be regularly arranged on the nozzle surface. . Thereby, a protective layer can be made denser.

  According to the seventh feature, since the two integers (m, n) indicating the carbon number of the alkyl group of the thiol compound constituting the protective layer are equal, the rules for the arrangement of molecules in the monomolecular film constituting the protective layer The oleophobic group can be disposed on the outermost surface of the protective layer at the same time.

  According to the eighth feature, by setting “n” indicating the carbon number of the alkyl group of the thiol compound constituting the protective layer to 8 or more, the thiol compound molecule becomes a substantially cylindrical body. Thereby, a protective layer becomes denser. Moreover, by making “n” 18 or less, the macroscopic stereoregularity of the protective layer can be adjusted. The stereoregularity here means the surface smoothness of the protective layer, and the smoothness of the surface of the protective layer is improved by adjusting the stereoregularity of the protective layer.

1 is an overall perspective view of an inkjet head according to a first embodiment. It is a longitudinal cross-sectional view along the II-II line of FIG. It is a longitudinal cross-sectional view along the III-III line of FIG. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. It is a longitudinal cross-sectional view of the nozzle plate in the vicinity of the nozzle. It is a figure explaining the manufacturing process of an inkjet head. It is a figure explaining the manufacturing process of an inkjet head. It is a longitudinal cross-sectional view of the nozzle vicinity of the nozzle plate by 2nd Embodiment. It is a figure explaining the layer structure of a nozzle plate. FIG. 10 is a view corresponding to FIG. 9 of a nozzle plate according to a third embodiment. FIG. 10 is a view corresponding to FIG. 9 of a nozzle plate according to a fourth embodiment.

<First Embodiment>
Hereinafter, an inkjet head according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an overall perspective view of the inkjet head according to the first embodiment. 2 is a longitudinal sectional view taken along line II-II in FIG. FIG. 3 is a longitudinal sectional view taken along line III-III in FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a longitudinal sectional view of the nozzle plate in the vicinity of the nozzle. In the following description, the vertical and horizontal directions indicated by the arrows in FIG.

  As shown in FIGS. 1 to 5, the inkjet head 1 according to the first embodiment includes a head substrate 2, a first piezoelectric member 3, a second piezoelectric member 4, a fixture 5, a pair of electrodes 6, 7 and a nozzle plate 8. The head base 2, the first piezoelectric member 3, and the second piezoelectric member 4 correspond to the head main body of the claims.

  The head substrate 2 is made of resin. The head substrate 2 includes a standing member 15, a hollow member 16, and a side wall member 17. In addition, the standing member 15, the hollow member 16, and the side wall member 17 are integrally formed.

  The standing member 15 is formed in a rectangular parallelepiped shape. The standing member 15 is provided at the upper portion of the central portion in the horizontal direction of the inkjet head 1. The standing member 15 is configured to extend upward from the upper surface of the hollow member 16.

  The hollow member 16 is formed in a hollow rectangular parallelepiped shape. The hollow member 16 is configured to cover the upper part of the second piezoelectric member 4. The lower surface of the hollow member 16 is in close contact with the upper surface of the second piezoelectric member 4. As shown in FIGS. 3 and 4, an ink supply chamber 32 to which ink 31 is supplied from a main tank (not shown) of the printing apparatus is formed inside the hollow member 16. The lower surface and the left side surface of the ink supply chamber 32 are opened.

  The side wall member 17 is formed in a rectangular parallelepiped shape. The side wall member 17 is configured to cover the right side surface of the inkjet head 1. An ink supply hole 17 a is formed in the central portion of the side wall member 17 in the front-rear direction. The ink supply hole 17 a connects the outside and the ink supply chamber 32. A supply pipe 35 is connected to the ink supply hole 17a. The supply pipe 35 supplies the ink 31.

  The first piezoelectric member 3 applies pressure to the ink 31 by deformation. The first piezoelectric member 3 is made of PZT having a rectangular parallelepiped shape. The first piezoelectric member 3 is provided on the left side of the head substrate 2 and the second piezoelectric member 4. The upper portion of the right side surface of the first piezoelectric member 3 is fixed in close contact with the left side surface of the hollow member 16 of the head substrate 2. As a result, the left side surface of the ink supply chamber 32 is closed by the upper right side surface of the first piezoelectric member 3. The lower part of the right side surface of the first piezoelectric member 3 is fixed in close contact with the left side surface of the second piezoelectric member 4.

  As shown in FIGS. 2 and 4, a plurality of first grooves 21 are formed in the lower part of the right side surface of the first piezoelectric member 3. The plurality of first grooves 21 constitute part of the ink chamber 33 that stores the supplied ink 31. The plurality of first grooves 21 are formed at equal intervals in the front-rear direction. The first groove 21 is formed in a rectangular parallelepiped shape. The right side surface and the lower surface of the first groove 21 are opened. On the other hand, the front and rear surfaces, the left side surface, and the upper surface of the first groove 21 are closed.

  The second piezoelectric member 4 applies pressure to the ink 31 by being deformed together with the first piezoelectric member 3. The second piezoelectric member 4 is made of PZT having a rectangular parallelepiped shape. The second piezoelectric member 4 is provided on the lower surface of the hollow member 16 of the head substrate 2 and between the side wall member 17 and the first piezoelectric member 4. The left side surface of the second piezoelectric member 4 is fixed in close contact with the lower right side surface of the first piezoelectric member 3.

  As shown in FIGS. 3 and 4, a plurality of second grooves 22 are formed on the left side surface of the second piezoelectric member 4. The plurality of second grooves 22 constitute part of the ink chamber 33 that stores the supplied ink 31. The plurality of second grooves 22 are formed at equal intervals in the front-rear direction. The plurality of second grooves 22 are formed in a rectangular parallelepiped shape. The left side surface of the second groove 22 is opened. The second groove 22 is formed at a position facing the first groove 21. As a result, when the first piezoelectric member 3 and the second piezoelectric member 4 are combined, the first groove 21 and the second groove 22 constitute an ink chamber 33. In other words, the ink chamber 33 is formed by the first piezoelectric member 3 and the second piezoelectric member 4. The lower surface of the second groove 22 is opened in the same manner as the lower surface of the first groove 21. Thereby, the lower surface (ejection surface) of the ink chamber 33 is opened so that the ink 31 can be ejected. The upper surface of the second groove 22 is opened. As a result, the ink supply chamber 32 and the ink chamber 33 formed in the hollow member 16 of the head substrate 2 are connected. On the other hand, the front and rear surfaces and the right side surface of the second groove 22 are closed.

  The fixture 5 fixes the head base 2 and the piezoelectric members 3 and 4. The fixture 5 is made of resin. The fixture 5 presses the right side surface of the head base 2 and the left side surface of the first piezoelectric member 3 in the left-right direction. The fixture 5 presses the front surface and the rear surface of the head substrate 2 and the piezoelectric members 3 and 4 in the front-rear direction. Thereby, the head substrate 2 and the piezoelectric members 3 and 4 are in close contact with each other. An opening 5 a for discharging the ink 31 is formed on the bottom surface of the fixture 5.

  The electrodes 6 and 7 apply voltage to the piezoelectric members 3 and 4. As shown in FIGS. 2 to 4, the electrodes 6 and 7 are formed on the inner surfaces of the first groove 21 and the second groove 22 constituting the ink chamber 33. In other words, the electrodes 6 and 7 are formed on the inner surfaces of the piezoelectric members 3 and 4 constituting the ink chamber 33. The electrodes 6 and 7 are alternately provided in the front-rear direction. The electrodes 6 and 7 are connected to a control unit (not shown) mounted on a printing apparatus (not shown). A predetermined voltage for deforming the piezoelectric members 3 and 4 is applied between the electrodes 6 and 7 by the control unit. Thereby, the piezoelectric members 3 and 4 in the region sandwiched between the electrode 6 and the electrode 7 are deformed, and pressure can be applied to the ink 31.

  The nozzle plate 8 is provided across the lower surface (discharge surface) of the first piezoelectric member 3 and the lower surface (discharge surface) of the second piezoelectric member 4. The nozzle plate 8 is formed in a substantially rectangular planar shape. A plurality of nozzles 8 a are formed on the nozzle plate 8. The nozzle 8a is formed so as to penetrate the nozzle plate 8 in the vertical direction. The plurality of nozzles 8a are formed at equal intervals at positions corresponding to the ink chambers 33 in the front-rear direction. Thereby, the lower surface of each ink chamber 33 is penetrated with the exterior by each nozzle 8a. As shown in FIG. 1, the plurality of nozzles 8 a are formed so as to be alternately shifted left and right one by one in the left-right direction. That is, the nozzle 8 a is formed at a position corresponding to either the first groove 21 or the second groove 22. The nozzle plate 8 is composed of a plate base material 41.

  The plate substrate 41 is made of bacterial cellulose. Bacterial cellulose is crystalline cellulose fiber produced by acetic acid bacteria. Bacterial cellulose is uniaxially oriented. Thereby, bacterial cellulose becomes a high-strength material having about 1.5 times the strength of steel. Bacterial cellulose has a high Young's modulus. The basic skeleton of bacterial cellulose is cellulose microfibrils (nanofibers) of about 4 nm. Bacterial cellulose microfibrils have a microcrystalline structure in which stretched cellulose molecular chains are hydrogen-bonded. Bacterial cellulose microfibrils are highly water resistant. Bacterial cellulose microfibrils are composed of fibers with a diameter of 1/100 to 1/1000 compared to plant-derived cellulose. Several to tens of bacterial cellulose microfibrils are bundled. Further, this bundle has a highly regular network structure (higher order structure). Bacterial cellulose is molded without using an adhesive or the like.

(Operation of inkjet head)
Next, the operation of the inkjet head 1 will be described. First, the control unit of the printing apparatus switches on an ink pump (not shown). Thereby, the ink 31 is supplied from the main tank to the ink supply chamber 32 and the ink chamber 33 of the inkjet head 1. Next, the control unit applies a voltage to the electrodes 6 and 7 according to the input image data while conveying the printing paper. Thereby, the piezoelectric members 3 and 4 are deformed. In the ink chamber 33 compressed by the deformation of the piezoelectric members 3 and 4, pressure acts on the ink 31, so that the ink 31 in the ink chamber 33 is ejected from the nozzles 8 a of the nozzle plate 8 as droplets. The droplet-shaped ink 31 is applied to the printing paper, and an image is printed on the printing paper.

(Inkjet head manufacturing process)
Next, the manufacturing process of the inkjet head 1 will be described. 6 and 7 are diagrams for explaining the manufacturing process of the ink-jet head.

  First, manufacture of the nozzle plate 8 will be described. First, bacterial cellulose is cultured by liquid culture. Specifically, a medium mainly composed of fructose fructose and acetic acid bacteria are placed in 30 flasks and cultured for 10 days. The culture referred to here includes pre-culture to main culture. This produces about 600 mg of bacterial cellulose from each flask. Thus, about 18 g of bacterial cellulose is produced from 30 flasks.

  Here, acetic acid bacteria produce bacterial cellulose which is crystalline cellulose fiber. The acetic acid bacteria secrete cellulose fibers outside the cells. As a result, the acetic acid bacteria are moved by the jet energy power in the direction opposite to the direction of secretion. With this mobility, each acetic acid bacterium moves in an arbitrary direction. Thereby, the nanofiber secreted from the acetic acid bacteria becomes a network. As a result, a pellicle that is a gel-like film containing bacterial cellulose is formed. Here, the bacterial cellulose produced by the method of the present embodiment can be subjected to a treatment for removing impurities other than the cellulosic material containing the microbial cells contained in the material. As a method for removing impurities, washing with water, pressure dehydration, dilute acid washing, alkali washing, treatment with bleach such as sodium hypochlorite and hydrogen peroxide, treatment with cell lytic enzyme, surfactant such as sodium lauryl sulfate There is a method of carrying out the treatment by heating, heating washing up to 200 ° C. alone or in combination. By these methods, impurities can be almost completely removed from the cellulosic material.

  Next, after injecting the above-mentioned bacterial cellulose into a KOH (potassium hydroxide) aqueous solution, a dispersion treatment is performed by a high-speed homogenizer. Thereby, a cellulose microfibril disperse | distributes uniformly. Thereafter, the dispersion liquid in which cellulose microfibrils are dispersed is poured into a mold in the form of the plate base material 41. Next, the plate base material 41 in which the nozzles 8a are not formed is completed by pressing the dispersion of the mold.

  Next, the head substrate 2 and the first piezoelectric member 3 and the second piezoelectric member 4 on which the electrodes 6 and 7 are formed are assembled. Thereafter, the head base 2 and the piezoelectric members 3 and 4 are fixed by the fixing tool 5.

  Next, as shown in FIG. 6, the plate base material 41 is bonded to the discharge side surface (lower surface) of the piezoelectric members 3 and 4. In this state, as shown in FIG. 7, a laser beam 55a is irradiated from the laser device 55 to a desired position of the nozzle plate 8 to form the nozzle 8a. As a result, the inkjet head 1 is completed.

(Effect by 1st Embodiment)
Next, effects of the inkjet head 1 according to the first embodiment described above will be described.

  As described above, the nozzle plate 8 of the ink jet head 1 according to the first embodiment is composed of the plate base material 41 made of bacterial cellulose. Thereby, since the nozzle plate 8 can omit a metal plate or the like on which the nozzle 8a is difficult to be formed, the nozzle 8a can be easily formed by laser irradiation or the like. As a result, the nozzle plate 8 can simplify the manufacturing process.

  Bacterial cellulose constituting the plate substrate 41 of the nozzle plate 8 has microfibrils having a microcrystalline structure in which cellulose molecular chains are hydrogen-bonded as a basic skeleton. Thereby, since the nozzle plate 8 can improve water resistance, it can suppress that it deteriorates with the water | moisture content contained in the ink 31. FIG.

  Bacterial cellulose constituting the plate substrate 41 of the nozzle plate 8 is a uniaxially oriented high strength material having a strength about 1.5 times that of steel. Thereby, the strength of the nozzle plate 8 can be improved.

Second Embodiment
Next, a second embodiment in which the nozzle plate of the above-described embodiment is changed will be described. FIG. 8 is a longitudinal sectional view of the vicinity of the nozzles of the nozzle plate according to the second embodiment. FIG. 9 is a diagram illustrating the layer structure of the nozzle plate. In addition, the same code | symbol is attached | subjected to the structure similar to embodiment mentioned above, and description is abbreviate | omitted.

  As shown in FIGS. 8 and 9, the nozzle plate 8 </ b> A according to the second embodiment includes a plate base 41, a metal layer 42, and a soot ink layer (corresponding to a protective layer in claims) 43.

  The metal layer 42 has a function of suppressing the ink layer 43 from peeling from the plate base material 41. The metal layer 42 has conductivity and is made of silver which is a late transition metal. Silver functions as a Lewis acid. The metal layer 42 is formed on the entire discharge surface (lower surface) of the plate base material 41. The metal layer 42 is grounded. Thereby, the metal layer 42 removes the charge of the ink. The metal layer 42 may be configured in multiple layers. In the case of a multilayer structure, it is preferable to form a metal layer having a low standard electrode potential on the side in contact with the plate substrate 41 made of bacterial cellulose, because the metal layer 42 hardly rusts.

The soot ink layer 43 repels the ink 31. The ink layer 43 is formed on the entire discharge surface (lower surface) of the metal layer 42. The ink layer 43 is made of bis (mercaptooctyl) ether, which is a kind of organic material thiol compound. Incidentally, the chemical formula of bis (mercaptomethyl octyl) ethers _{are SH-C 8 H 16 -O-} C 8 H 16 -SH. Bis (mercaptooctyl) ether has an ether group which connects an alkyl group and an alkyl group and has a polar component and oleophobic properties (hydrophilicity). That is, the bis (mercaptooctyl) ether constituting the ink layer 43 has a property of repelling oil-based ink (oleophobic). Moreover, both ends of bis (mercaptooctyl) ether have a pair of mercapto groups (SH-). Here, the sulfur (S) of the mercapto group functions as a Lewis base because of its high covalent bond. Accordingly, as shown in FIG. 9, mercapto groups (—SH) at both ends of the bis (mercaptooctyl) ether form a covalent bond with the metal layer 42 containing silver. As a result, the ether group exhibiting oleophobicity is oriented outward (discharge side). Bis (mercaptooctyl) ether has a structure in which a pair of identical linear alkyl groups (—C ₈ H ₁₆ —: octyl group) are bonded to both sides of an ether group. The soot ink layer 43 made of a thiol compound is formed as a self-assembled monomolecular film. The ink layer 43 has a thickness of about 2 nm to about 200 nm.

(Operation of inkjet head)
In the inkjet head 1A according to the second embodiment, as with the inkjet head 1 according to the first embodiment, when a voltage is applied between the electrode 6 and the electrode 7, the ink 31 becomes a droplet and the nozzle 8a of the nozzle plate 8A. It is discharged from. Then, an image is printed on the printing paper by the droplet-like ink 31. Here, the ejected droplet-shaped ink 31 is charged by a voltage applied between the electrodes 6 and 7. When the charged ink 31 is in an energy state exceeding the surface tension, the droplet state cannot be maintained, causing a split (Rayleigh split). Once this Rayleigh split occurs, it occurs continuously. This causes an electrostatic atomization phenomenon in which the droplets of the ink 31 become mist-like. The mist-like ink 31 reaches the lower surface of the nozzle plate 8A. However, the conductive ink layer 43 is provided on the lower surface of the nozzle plate 8A and neutralizes charged ink droplets. Even if Rayleigh splitting of ink droplets occurs, the ink 31 is repelled by the ink layer 43 because the ink layer 43 made of oleophobic bis (mercaptooctyl) ether is formed. As a result, it is possible to suppress the ink 31 from adhering to the lower surface of the nozzle plate 8A.

(Nozzle plate manufacturing method)
Next, a method for manufacturing the nozzle plate 8 will be described. First, the plate base material 41 is created by the same manufacturing method as in the first embodiment. Next, a metal layer 42 made of silver is formed on the discharge side surface of the plate base material 41 by an electroless plating method.

  Next, bis (mercaptooctyl) ether is dissolved in an alcohol such as ethanol to prepare an ink layer solution having a volume molar concentration of bis (mercaptooctyl) ether of 1 mol / l. Thereafter, the ink layer solution is applied (dip coating) on the discharge surface of the metal layer 42. In this state, the plate substrate 41 is left at room temperature. As a result, the alcohol in the soot ink layer solution evaporates and a soot ink layer 43 made of bis (mercaptooctyl) ether is formed on the ejection surface of the metal layer 42. Here, bis (mercaptooctyl) ether, which is a thiol compound, self-assembles into a monomolecular film. Thereby, the nozzle plate 8A is completed. The nozzle 8a is opened by the laser beam 55a after being attached to the inkjet head 1A, as in the first embodiment.

(Effect of 2nd Embodiment)
Next, the effect of the nozzle plate 8A of the second embodiment described above will be described.

  The nozzle plate 8A according to the second embodiment has the same effect as that of the first embodiment because it has the plate base material 41 made of bacterial cellulose.

  Further, as described above, the nozzle plate 8A has the plate base material 41 made of bacterial cellulose. For this reason, the metal layer 42 containing a metal can be made thin. Thereby, the nozzle 8a can be easily formed by the laser beam 55a.

  In addition, the nozzle plate 8A includes a conductive metal layer 42 containing a post-period transition metal and a soot ink layer 43 made of bis (mercaptooctyl) ether having an oleophobic ether group formed on the ejection surface. . Thereby, the charged ink droplet can be neutralized during printing. Further, even if the ejected ink 31 in the form of a mist is generated, the ink 31 is not repelled by the soot ink layer 43 and deposited on the soot ink layer 43. As a result, it is possible to suppress the discharge surface of the nozzle plate 8A from becoming dirty, so that the cleaning work by a wiper or the like can be reduced. Further, by reducing the cleaning work by the wiper, it is possible to suppress the scratch that is one of the causes of ink adhesion from being generated in the soot ink layer 43. As a result, the nozzle plate 8 </ b> A can more effectively suppress the ink 31 from adhering to the soot ink layer 43.

  Further, the nozzle plate 8 </ b> A can prevent the nozzle 8 a from being blocked by the color material of the aggregated ink 31 by suppressing the adhesion of the ink 31 by the soot ink layer 43. Thereby, since the nozzle plate 8A can reduce the discharge of the ink 31 in a direction different from the desired direction (directly downward direction), it is possible to suppress deterioration of the printed image quality.

  Further, the ink-ink layer 43 of the nozzle plate 8A is composed of bis (mercaptooctyl) ether having a mercapto group. Thereby, the nozzle plate 8A can be constituted by a dense monomolecular film in which the ink layer 43 is self-organized.

  Further, the ink-ink layer 43 of the nozzle plate 8A is composed of bis (mercaptooctyl) ether having a pair of mercapto groups. Thereby, the mercapto groups at both ends of the bis (mercaptooctyl) ether molecule are covalently bonded to the metal layer 42 containing silver. As a result, the nozzle plate 8 </ b> A can further strengthen the bond between the ink layer 43 and the metal layer 42, and thus can suppress the peeling of the ink layer 43.

  Further, the fountain ink layer 43 of the nozzle plate 8A is made of bis (mercaptooctyl) ether having the same linear octyl group on both sides of the ether group. Thereby, the nozzle plate 8A can make the ink layer 43 denser than that of the thiol compound having a branched octyl group.

<Third Embodiment>
Next, a third embodiment in which the soot ink layer of the nozzle plate of the above-described embodiment is changed will be described. FIG. 10 is a view corresponding to FIG. 9 of the nozzle plate according to the third embodiment. In addition, the same code | symbol is attached | subjected to the structure similar to embodiment mentioned above, and description is abbreviate | omitted.

As shown in FIG. 10, the nozzle plate 8 </ b> B according to the third embodiment includes a fountain ink layer 43 </ b> B made of mercaptooctyl ether containing one mercapto group (—SH). The chemical formula of mercaptooctyl ether is OH—C ₈ H ₁₆ —SH. Even in such a configuration, the mercapto group (—SH) of the mercaptooctyl ether is covalently bonded to silver of the metal layer 42. On the other hand, since the ether group is disposed on the ejection side, the oil-based ink 31 is repelled.

  Thereby, also in the nozzle plate 8B by 3rd Embodiment, there can exist an effect similar to 2nd Embodiment.

<Fourth embodiment>
Next, a description will be given of a fourth embodiment in which the soot ink layer of the nozzle plate of the above-described embodiment is changed. FIG. 11 is a view corresponding to FIG. 9 of the nozzle plate according to the fourth embodiment. In the fourth embodiment, the present invention is applied to a nozzle plate for water-based ink. The same components as those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

As shown in FIG. 11, the nozzle plate 8 </ b> C according to the fourth embodiment includes a soot ink layer 43 </ b> C composed of n-octanethiol. Incidentally, the chemical formula of n- octane thiol _is C ₈ H 17 -SH. Even in such a configuration, the mercapto group (—SH) of n-octanethiol is covalently bonded to silver of the metal layer 42. On the other hand, since the hydrophobic alkyl group (—C ₈ H ₁₇ ) is disposed on the ejection side, the ink layer 43C repels the aqueous ink 31.

  Thereby, the nozzle plate 8 </ b> C according to the fourth embodiment can achieve the same effects as the first embodiment with respect to the water-based ink 31.

  As mentioned above, although this invention was demonstrated in detail using embodiment, this invention is not limited to embodiment described in this specification. The scope of the present invention is determined by the description of the scope of claims and the scope equivalent to the description of the scope of claims. Hereinafter, modified embodiments in which the above-described embodiment is partially modified will be described.

  The material, shape, numerical value, arrangement, and the like of the configuration of each embodiment described above can be changed as appropriate.

  Moreover, the manufacturing method of the nozzle plate mentioned above can be changed suitably. For example, bacterial cellulose may be cultured by solid culture, anaerobic culture, dialysis culture, batch culture, continuous culture or the like instead of liquid culture. The culture is performed in a bioreactor (bioreactor) that is transported at room temperature using a biocatalyst.

  Further, the ink layer (protective layer) may be composed of an organic material containing sulfur such as a disulfide group (—S—S—), a monosulfide group (—S—), and thiophene.

  In the case of a nozzle plate for oil-based ink, an oleophobic group (hydrophilic group) in the ink layer may have a polar component such as a carbonyl group other than an ether group, an ester group, or an imino group. Furthermore, the ink layer may be made of a material having a plurality of oleophobic groups (hydrophilic groups). On the other hand, in the case of a nozzle plate for water-based ink, a hydrophobic group other than an alkyl group may be applied as the hydrophobic group.

  Further, in the case of a nozzle plate for oil-based ink, the soot ink layer may be composed of an organic material such as bis (mercaptooctyl) ether or a thiol compound having an oleophobic group (hydrophilic group) other than mercaptooctylether. On the other hand, in the case of a nozzle plate for water-based ink, the soot ink layer may be composed of an organic material such as a thiol compound having a hydrophobic group other than n-octanethiol.

Here, when the ink-jet layer is composed of a thiol compound, the alkyl group (—C _n H _2n —) is preferably linear. As a result, the ink layer that is self-organized can be made denser.

May also be constituted by a thiol compound represented the發ink layer by the chemical formula _{SH-C m H 2m -X-} C n H 2n -SH. Furthermore, the relationship between m and n indicating the number of carbon atoms is preferably “m = n”. Here, X is an oleophobic group. More specifically, an ether group is preferable, but it may be a carbonyl group, an ester group or an imino group.

The structure, formula _{OH-C n} H 2n -SH an發ink layer, the formula _{SH-C n H 2n -O-} C n H 2n -SH, or by thiol compound represented by chemical formula _C n _{H 2n} + 1 -SH In this case, it is preferable that “8 ≦ n ≦ 18”.

_OH-C n _H 2n _-SH is "8 ≦ _{n", SH-C n H 2n -O} -C n H 2n -SH or, in _the case of C _{n H 2n} + 1 -SH, semiempirical molecular orbital calculation software It can be seen that the heat of formation of the thiol compound calculated by MOPAC (NMDO as a Hamiltonian) is relatively low at “−43.48 kcal / mol” or less, so that alteration and decomposition of the thiol compound can be further suppressed.

In the case of OH—C _n H _2n —SH or “SH—C _n H _2n —O—C _n H _2n —SH” or “C _n H _{2n + 1} —SH” where “8 ≦ n”,
CPP ≒ 1
(CPP: Critical Packing Parameter)
Therefore, the molecule becomes a substantially cylindrical body shape. Thereby, the self-organization of the thiol compound can be improved, and the denseness of the ink layer can be improved. CPP is
CPP = V / (A ・ L)
V: Occupied volume of hydrophobic part (alkyl group) of alkanethiol
A: Occupied area of mercapto group (-SH) of alkanethiol
L: Expressed by the length of the hydrophobic portion (alkyl group) of alkanethiol.

On the other hand, in the case of OH—C _n H _2n —SH, SH—C _n H _2n —O—C _n H _2n —SH, or C _n H _{2n + 1} —SH where “n ≦ 18”, polyhydric alcohol, etc. It is easily dissolved in a solvent and can be easily handled in the step of forming the ink layer. In addition, the thiol compound of “n ≧ 19” has a high viscosity and generally exhibits a property of being hardly soluble in a solvent.

Further,發ink layer formula _{OH-C n H 2n -SH,} SH-C n H 2n -O-C n H 2n -SH _, or when configuring a thiol compound represented by C _{n H 2n} + 1 -SH , “M” and “n” are preferably even numbers. As a result, the alkyl chains of the thiol compound are somewhat regularly arranged horizontally with respect to the lower surface of the metal layer, and the denseness of the soot ink layer can be improved. As a result, the stability and durability of the soot ink layer can be improved.

  The step of forming the soot ink layer described above can be changed as appropriate.

  In addition, after the ink layer is formed, the ink layer may be treated with polyethylene glycol or propylene glycol. Thereby, the ink layer can be made denser.

  In addition, when the terminal of the soot ink layer (protective layer) is a thiol compound having a hydroxyl group, the surface of the soot ink layer may be treated with a silane coupling agent (polysiloxane). As a result, molecules having polysiloxane as the main chain are introduced into the ink layer. As a result, it is possible to improve the wear resistance when wiping the ink layer.

  Moreover, the metal contained in a metal layer can be changed suitably. The metal layer may be configured in multiple layers. In the case of a multilayer structure, it is preferable to form a metal layer having a low standard electrode potential on the side in contact with the plate substrate made of bacterial cellulose, because the metal layer hardly rusts. In addition, the material applied instead of silver (Ag) of the metal layer can be arbitrarily selected from late transition metals. This is because sulfide (mercapto group (S-H)) acts as a soft Lewis base due to its high covalent bond, and easily forms a strong bond with a late transition metal. Among the late transition metals, gold (Au) and silver (Ag) are particularly suitable because they act as strong Lewis acids (electron acceptors) (Source: Novel Sterically Hindered Substituted Ferrocenes and Their Transition Metal Complexes. Author: GREGSON CKA et al., Material: Organometallics, Volume page: Vol.23, No.15, Page.3674-3682 (2004.07.19)). Other late transition metals that can be suitably used include platinum group elements (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), platinum (Pt)), or Iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), etc. can be raised.

  Further, the metal layer may be composed of a metal thin film formed by CVD (chemical vapor deposition) or the like. Here, as the material of the metal thin film constituting the metal layer, the above-described silver, gold, or the like can be applied. The metal layer may be grounded.

  Moreover, the manufacturing method of a nozzle plate can be changed suitably. In the embodiment described above, the soot ink layer formed from the liquid phase may be formed from the gas phase.

DESCRIPTION OF SYMBOLS 1, 1A Inkjet head 2 Head base material 3 Piezoelectric member 4 Piezoelectric member 5 Fixture 5a Opening part 6, 7 Electrode 8, 8A, 8B, 8C Nozzle plate 8a Nozzle 15 Standing member 16 Hollow member 17 Side wall member 17a Ink supply hole 21 First groove 22 Second groove 31 Ink 32 Ink supply chamber 33 Ink chamber 35 Supply pipe 41 Plate base material 42 Metal layers 43, 43B, 43C Ink layer 55 Laser device 55a Laser light

Claims (8)

The head body,
An ink jet head comprising: a nozzle plate attached to a discharge surface of the head main body and having a plate base material containing bacterial cellulose. The nozzle plate is
A metal layer provided on the discharge side surface of the plate substrate;
The inkjet head according to claim 1, further comprising a protective layer having an organic material containing sulfur provided on a discharge surface of the metal layer.   The inkjet head according to claim 2, wherein the organic material of the protective layer is a thiol compound.   The inkjet head according to claim 2, wherein the organic material of the protective layer is a thiol compound containing an oleophobic group.   The inkjet head according to any one of claims 2 to 4, wherein the organic material of the protective layer is a thiol compound containing a linear alkyl group. The organic material of the protective layer, when the lipophobic based on _{X, SH-C m H 2m} -X-C n H 2n -SH (m, n: even number) and characterized in that it is a thiol compound represented by the chemical formula The inkjet head according to any one of claims 2 to 5. M and n are
m = n
The inkjet head according to claim 6, wherein: N is
8 ≦ n ≦ 18
The inkjet head according to claim 7, wherein: