JP5828213B2 - Liquid droplet ejection head, ink jet recording apparatus - Google Patents

Description

  The present invention relates to a droplet discharge head and an ink jet recording apparatus.

  Conventionally, as a method of a droplet discharge head, there is a method in which a discharge pressure is generated by a change in volume of a pressure generation chamber and a droplet is discharged from a nozzle. This method is superior to the thermal method in that it can handle various droplets. In order to achieve high integration, a droplet discharge head that uses a lithography method to form a flow path / pressure generating element is widely used. Patent Documents 1 and 2 disclose a method of vibrating a diaphragm that forms one surface of a pressure generation chamber using an electrostatic force or a piezoelectric element in a bending mode.

  In highly integrated droplet discharge heads, the partition between the pressure generation chambers becomes thin, so it is necessary to reduce the partition height (pressure generation chamber height) to ensure the rigidity of the partition. If the flow path forming substrate defining the thickness is thin, handling becomes difficult. Therefore, the droplet discharge head is configured such that after the flow path substrate is bonded to another substrate such as an electrode substrate or a sealing substrate (protective substrate), the flow path substrate is polished to a desired thickness, and then the flow path such as the pressure generation chamber (See Patent Documents 1 and 2).

  In this droplet discharge head, non-destructive measurement / inspection is performed in the process for process control and F cost reduction. Patent Document 1 discloses a method for measuring diaphragm thickness, and Patent Document 3 discloses a method for measuring characteristics of piezoelectric elements. In the droplet discharge head, in addition to the measurement / inspection items described above, the diaphragm width is also an important measurement item. However, the diaphragm side interface of the pressure generating chamber that defines the diaphragm width is difficult to observe with a normal microscope because the step of the partition wall becomes an obstacle. Moreover, even if it tried to observe from the opposite surface side, an electrode substrate (patent document 1) and a sealing substrate (patent document 2) got in the way, and observation was not able to fully be performed. Further, in order to cut and observe the cross section, it is necessary to prepare a dedicated monitor wafer, and it takes time and labor, resulting in an increase in cost. In addition, since the feedback to the process is also delayed, the probability of producing a product that exceeds the dimensions is increased (yield reduction), resulting in an increase in cost.

  The present invention has been made in view of the above, and is to make it possible to easily and accurately observe and measure the diaphragm width of a droplet discharge head in a process.

In order to solve the above-described problems and achieve the object, the liquid droplet ejection head according to the present embodiment has a flow path in which a pressure generation chamber row in which a plurality of pressure generation chambers communicating with nozzle holes is arranged is formed. A forming substrate is provided corresponding to each pressure generating chamber via a diaphragm on one surface side of the flow path forming substrate, and a change in pressure is generated in each pressure generating chamber by changing the deflection of the diaphragm. Measure the width of the vibration plate formed on the flow path forming substrate, the protective substrate bonded in a state in which a space is secured on the piezoelectric element side so as not to hinder the movement of the piezoelectric element A through-hole connected to the diaphragm measurement monitor unit is formed in the protective substrate, and the diaphragm measurement monitor unit is configured to form the flow path. Pressure located at the extreme end of the pressure generation chamber row of the substrate Than generating chamber provided outside, and the dummy pressure generating chamber of the pressure generating chamber and the same width, the transparent or semi-transparent single-layer or laminated to visible light, and a partition plate corresponding to the diaphragm It is characterized by providing.

  According to the present invention, there is an effect that the diaphragm width of the droplet discharge head can be easily observed and measured in the process.

FIG. 1 is an exploded perspective view of a droplet discharge head according to an embodiment. FIG. 2 is a plan layout view when the first substrate and the second substrate are in a see-through state. FIG. 3 is a Y1-Y1 cross-sectional view. FIG. 4 is a Y2-Y2 cross-sectional view. FIG. 5 is a Y3-Y3 cross-sectional view. FIG. 6 is a sectional view taken along line X1-X1. FIG. 7 is an X2-X2 cross-sectional view. FIG. 8 is an X3-X3 cross-sectional view. FIG. 9 is an enlarged view of the vicinity of the pressure generation chamber of FIG. FIG. 10 is an enlarged view of the vicinity of the dimension measuring dummy pressure generating chamber of FIG. FIG. 11 is an exploded perspective view of a droplet discharge head according to a modification. FIG. 12 is a plan layout diagram in the case where the first substrate and the second substrate according to the modification are in a see-through state. FIG. 13 is a Y4-Y4 cross-sectional view. FIG. 14 is an X4-X4 cross-sectional view. FIG. 15 is an explanatory perspective view of the ink jet recording apparatus according to the present embodiment. FIG. 16 is an explanatory side view of the mechanism portion of the ink jet recording apparatus according to the present embodiment.

  Hereinafter, an embodiment of a droplet discharge head and an inkjet recording apparatus will be described in detail with reference to the accompanying drawings.

  First, details of a droplet discharge head according to an embodiment will be described with reference to FIGS. FIG. 1 is an exploded perspective view of a droplet discharge head 1 according to the embodiment. FIG. 2 is a plan layout view when the first substrate 10 and the second substrate 20 are in a see-through state. 3 to 8 are sectional views of Y1-Y1, Y2-Y2, Y3-Y3, X1-X1, X2-X2, and X3-X3 in FIG. FIG. 9 is an enlarged view of the vicinity of the pressure generation chamber 33 of FIG. FIG. 10 is an enlarged view of the vicinity of the dimension measuring dummy pressure generating chamber 34 of FIG.

  As shown in FIG. 1, the droplet discharge head 1 includes a first substrate 10, a second substrate 20, a nozzle plate 40, a backing plate 45, a frame driver IC (Integrated Circuit) not shown, and the like. ing.

  For the first substrate 10 that is a protective substrate (also referred to as a sealing substrate), it is preferable to use a material that does not greatly differ from the second substrate 20 and that is easy to process. In this embodiment, the surface orientation < A 100> single crystal silicon substrate was used. The first substrate 10 has a recess 11 (FIGS. 1, 3, 5, 6) for preventing the operation of the piezoelectric element 22 (see FIGS. 1-4, 6, 9) formed on the second substrate 20. The liquid supply path 17 (see FIGS. 1, 3 to 5 and 8) and the like were formed by anisotropic etching with an alkaline solution.

  The second substrate 20, which is a flow path forming substrate, is composed of a silicon single crystal substrate, and a vibration plate 21 having a thickness of about 1.5 μm (FIG. 3, FIG. 5-10) was formed. The diaphragm 21 is composed of a laminated film of a silicon oxide film, polysilicon, and silicon nitride film. Stress and stiffness are adjusted by stacking different films. In this embodiment, the oxide film and the nitride film are transparent to visible light, and the polysilicon is translucent (a film that transmits light that can be observed through transmission), but an opaque film (more In some cases, a film having a large light absorption or a film that is difficult to observe through transmission is laminated.

  On the diaphragm 21, corresponding to the pressure generation chamber 33 (see FIGS. 1 to 3, 6, and 9) that is a gap, the lower electrode film 22 a that is a common electrode, the piezoelectric layer 22 b, and the upper electrode that is an individual electrode. A piezoelectric element 22 made of the electrode film 22c was formed. Further, an insulating film 23 (see FIGS. 4 to 9) is formed so as to cover the side surfaces of the piezoelectric layer 22b and the upper electrode film 22c to prevent moisture absorption of the piezoelectric layer 22b, and the lower electrode film 22a and the upper electrode film 22c. Prevents electrical short circuit. The insulating film 23 is removed in the piezoelectric element forming portion except for the side surface and the vicinity thereof, so that the displacement of the piezoelectric element 22 is not hindered. A connection hole is opened at a connection portion between the lower electrode film 22a and the upper electrode film 22c, and is connected to the wiring 24 (see FIGS. 2 to 5 and 7 to 9).

  The wiring 24 is drawn out to the electrode terminal portion 25 formed integrally with the wiring 24, and is connected to the driver IC, the FPC on which the driver IC is mounted, or the like from the electrode terminal portion 25 by wire bonding, ACF, or the like. A voltage is applied to the lower electrode film 22a and the upper electrode film 22c.

  Further, the second substrate 20 has a portion corresponding to the liquid supply path 17 formed in the first substrate 10, a liquid supply portion 31, a fluid resistance portion 32, a pressure corresponding to each nozzle / piezoelectric element. The generation chamber 33 is integrally formed by a photolithography / etching process.

  The lower electrode film 22a is made of a material having a relatively high conductivity such as platinum (Pt) or iridium (Ir) having a thickness of about 0.1 μm, and is formed by a sputtering method or the like. The piezoelectric layer 22b is made of, for example, lead zirconate titanate (PZT) having a thickness of about 1.0 μm formed by a sol-gel method. The upper electrode film 22c is made of, for example, platinum (Pt), iridium (Ir), or the like having a thickness of 0.05 to 0.1 μm, and is formed by a sputtering method or the like. These thicknesses are desirably adjusted as appropriate according to the material used, the target specifications of the actuator, and the like.

Further, the insulating film 23 has a small electrical permeation and absorption of moisture and excellent electrical insulation, for example, alumina (Al ₂ O ₃ ) or trisilicon tetranitride (Si ₃ N ₄ ) has a thickness of about 0.2 μm. A thing was used. For the wiring 24, gold (Au) having excellent electrical conductivity and corrosion resistance was used, and the thickness was about 1.0 μm. The interface between the insulating film 23 and the wiring 24 is laid with 0.05 to 0.1 μm of chromium (Cr) as an adhesion layer. The 1st board | substrate 10 and the 2nd board | substrate 20 were bonded together by the adhesive agent 15 (refer FIGS. 3-8). In the configuration of the embodiment, the maximum difference in level of the wiring 24 occurs on the bonding surface. However, since the wiring 24 has a thickness of about 1.0 μm, it is sufficiently filled with the adhesive 15 to form the concave portion 11 (the piezoelectric element). The sealing property of the vibration space is ensured. Further, as a precaution, the wiring 24 is disposed so as to cover the periphery of the liquid supply unit 31 to ensure the sealing performance.

  For the nozzle plate 40, for example, glass ceramics, a silicon single crystal substrate, stainless steel or the like can be used. In the embodiment, after the nozzle hole 41 is opened by press working in stainless steel having a thickness of 30 μm, a fluorine-based resin is formed as a liquid repellent film on the surface on the liquid outlet side by vapor deposition. Further, the second substrate 20 is bonded with an adhesive 15. The backing plate 45 is formed by laminating a plurality of pressed stainless steels, thereby ensuring ink supply capability. The first substrate 10 is bonded with an adhesive 15.

  In the present embodiment, the liquid supply path 17 of the first substrate 10 is extended to the diaphragm width measurement monitor unit 2 (see FIGS. 5 and 8) disposed at the end of the row of pressure generation chambers 33 and opened. Yes. In the diaphragm width measurement monitor unit 2, a dimension measurement dummy pressure generation chamber 34 (see FIGS. 5 to 8 and 10) having a shape similar to the pressure generation chamber 33 is formed on the second substrate 20. On the first substrate 10 side of the dimension measuring dummy pressure generating chamber 34, a laminated film composed of the transparent film 21a of the diaphragm 21 and the insulating film 23 which is a transparent film in the present embodiment is formed. Unlike the pressure generation chamber 33, the piezoelectric element 22 is not formed. Further, the opaque film layer 21b of the diaphragm 21 is not formed.

  By providing the diaphragm width measurement monitor unit 2 having such a configuration, the width of the diaphragm 21 can be easily observed / measured in the process from the first substrate 10 side. However, what can be observed is between the flow path processing of the pressure generation chamber 33 and the like and the joining of the backing plate, and from the point of feedback to the process, it is desirable to immediately follow the flow path processing. As described above, in the droplet discharge head 1, the width of the diaphragm 21 can be easily observed / measured in the process from the first substrate 10 side, so that the yield is improved and the cost is reduced. It becomes possible to reduce.

  Of course, the dummy pressure generating chamber 34 for dimension measurement has the same photolithographic / etching characteristics as the pressure generating chamber 33, and it is of course possible to have a one-to-one correspondence between these dimensions. In the embodiment, the dimension measuring dummy pressure generating chamber 34 has the same width as the pressure generating chamber 33 that is actually used and does not have a constriction like the fluid resistance portion 32. Further, the longitudinal end portion of the dimension measuring dummy pressure generating chamber 34 extends beyond the actually used pressure generating chamber 33 so that the end portion 2 has no effect.

<Modification>
Here, a modified example of the above-described droplet discharge head 1 will be described. FIG. 11 is an exploded perspective view of a droplet discharge head 1a according to a modification. FIG. 12 is a plan layout diagram when the first substrate 10 and the second substrate 20 are in a see-through state. 13 and 14 are sectional views of Y4-Y4 and X4-X4 in FIG.

  As shown in FIGS. 11 to 14, the droplet discharge head 1 a has substantially the same configuration as the droplet discharge head 1 described above, but extends the arrangement of the actual pressure generation chambers 33 in the diaphragm width measurement monitor unit 2. Formed in the place. In addition, the dimension measuring dummy pressure generation chamber 34 in the droplet discharge head 1 a has the same shape as the actual pressure generation chamber 33. In the droplet discharge head 1a according to the modified example, it is necessary to open an extra through hole of the first substrate 10 in the diaphragm width measurement monitor unit 2 portion with respect to the droplet discharge head 1, but it is more actual. Photolithography / etching specification with a (same) shape close to the pattern is obtained, and measurement with higher accuracy is possible. Therefore, in the droplet discharge head 1a, since the through hole of the diaphragm width measurement monitor unit 2 formed on the protective substrate is formed integrally with the ink supply port leading to the liquid supply unit 31, the through hole The increase in space for formation can be minimized, and the cost can be reduced.

  Next, an example of an ink jet recording apparatus equipped with the above-described droplet discharge heads 1 and 1a will be described with reference to FIGS. FIG. 15 is an explanatory perspective view of the ink jet recording apparatus according to the present embodiment. FIG. 16 is an explanatory side view of the mechanism portion of the ink jet recording apparatus according to the present embodiment.

  As shown in FIGS. 15 and 16, an ink jet recording apparatus 50 is mounted on a carriage 93 that is movable in the main scanning direction inside a recording apparatus main body 81, and has the above-described droplet discharge heads 1 and 1a. A print mechanism unit 82 and the like including an ink cartridge 95 that supplies ink to the head 94 and the recording head 94 are housed. A sheet feeding cassette 84 (or a sheet feeding tray) on which a large number of sheets 83 can be stacked from the front side can be removably attached to the lower part of the recording apparatus main body 81, and the sheets 83 can be manually inserted. The manual feed tray 85 for feeding paper can be turned over, the paper 83 fed from the paper feed cassette 84 or the manual feed tray 85 is taken in, a required image is recorded by the printing mechanism unit 82, and then the rear side is placed. Paper is discharged to the attached paper discharge tray 86.

  The printing mechanism 82 holds a carriage 93 slidably in the main scanning direction by a main guide rod 91 and a sub guide rod 92 which are guide members horizontally mounted on left and right side plates (not shown). (Y), cyan (C), magenta (M), and black (Bk) ink droplets are ejected from a recording head 94 including the droplet ejection head formed by the above-described thin film formation. (Nozzles) are arranged in a direction crossing the main scanning direction, and are mounted with the ink droplet ejection direction facing downward. In addition, each ink cartridge 95 for supplying ink of each color to the recording head 94 is replaceably mounted on the carriage 93.

  The ink cartridge 95 has an air port that communicates with the atmosphere upward, a supply port that supplies ink to the inkjet head below, and a porous body filled with ink inside, and the capillary force of the porous body. Thus, the ink supplied to the recording head 94 is maintained at a slight negative pressure. Further, although the heads of the respective colors are used here as the recording head 94, a single head having nozzles for ejecting ink droplets of the respective colors may be used.

  Here, the carriage 93 is slidably fitted to the main guide rod 91 on the rear side (downstream side in the paper conveyance direction), and is slidably mounted on the sub guide rod 92 on the front side (upstream side in the paper conveyance direction). doing. In order to move and scan the carriage 93 in the main scanning direction, a timing belt 100 is stretched between a driving pulley 98 and a driven pulley 99 that are rotationally driven by a main scanning motor 97, and the timing belt 100 is moved to the carriage 93. The carriage 93 is driven to reciprocate by forward and reverse rotation of the main scanning motor 97.

  On the other hand, in order to convey the paper 83 set in the paper feed cassette 84 to the lower side of the recording head 94, the paper feed roller 101 and the friction pad 102 for separating and feeding the paper 83 from the paper feed cassette 84 and the paper 83 are guided. The guide member 103 to be transported, the transport roller 104 that reverses and transports the fed paper 83, the transport roller 105 that is pressed against the peripheral surface of the transport roller 104, and the feed angle of the paper 83 from the transport roller 104 are defined. A tip roller 106 is provided. The transport roller 104 is rotationally driven by a sub-scanning motor 107 through a gear train.

  A printing receiving member 109 is provided as a paper guide member that guides the paper 83 sent from the transport roller 104 below the recording head 94 in accordance with the movement range of the carriage 93 in the main scanning direction. A conveyance roller 111 and a spur 112 that are rotationally driven to send the paper 83 in the paper discharge direction are provided on the downstream side of the printing receiving member 109 in the paper conveyance direction, and the paper 83 is further delivered to the paper discharge tray 86. Rollers 113 and 114 and guide members 115 and 116 that form a paper discharge path are disposed.

  At the time of recording, the recording head 94 is driven according to the image signal while moving the carriage 93, thereby ejecting ink droplets onto the stopped sheet 83 to record one line, and after conveying the sheet 83 by a predetermined amount. Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 83 has reached the recording area, the recording operation is terminated and the paper 83 is discharged.

  Further, a recovery device 117 for recovering the ejection failure of the recording head 94 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 93. The recovery device 117 includes a cap unit, a suction unit, and a cleaning unit. The carriage 93 is moved to the recovery device 117 side during printing standby, and the recording head 94 is capped by the capping unit, and the ejection port portion is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.

  When a discharge failure occurs, the discharge port (nozzle) of the recording head 94 is sealed by the capping unit, and bubbles and the like are sucked out together with the ink from the discharge port by the suction unit through the tube. Etc. are removed by the cleaning means, and the ejection failure is recovered. The sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.

  In the above-described ink jet recording apparatus 50, since the recording head 94 with a reduced cost is mounted using the droplet discharge heads 1 and 1a in which the diaphragm width is easily and accurately observed in the process, it is stable. Ink droplet ejection characteristics can be obtained at low cost, and image quality is improved.

  DESCRIPTION OF SYMBOLS 1, 1a ... Droplet discharge head, 2 ... Diaphragm width measurement monitor part, 10 ... 1st board | substrate, 11 ... Recessed part, 15 ... Adhesive, 17 ... Liquid supply path, 20 ... 2nd board | substrate, 21 ... Vibration Plate, 21a ... Transparent film, 21b ... Opaque film layer, 22 ... Piezoelectric element, 22a ... Lower electrode film, 22b ... Piezoelectric layer, 22c ... Upper electrode film, 23 ... Insulating film, 24 ... Wiring, 25 ... Electrode terminal part 31 ... Liquid supply unit, 32 ... Fluid resistance unit, 33 ... Pressure generation chamber, 34 ... Dummy pressure generation chamber for dimension measurement, 40 ... Nozzle plate, 41 ... Nozzle hole, 45 ... Backing plate

JP 2002-248863 A Japanese Patent No. 3783781 Japanese Patent No. 3693115

Claims (3)

A flow path forming substrate in which a pressure generation chamber row in which a plurality of pressure generation chambers communicating with the nozzle holes are arranged in parallel is formed;
A piezoelectric element provided on one surface side of the flow path forming substrate in correspondence with each pressure generation chamber via a vibration plate, and causing a change in pressure in the pressure generation chamber by changing the deflection of the vibration plate; ,
A protective substrate bonded to the piezoelectric element side in a state where a space for preventing the movement of the piezoelectric element is secured;
A diaphragm measurement monitor for measuring the width of the diaphragm, formed on the flow path forming substrate,
In the protective substrate, a through-hole connected to the diaphragm measurement monitor unit is formed,
The diaphragm measurement monitor unit includes a dummy pressure generation chamber having the same width as the pressure generation chamber, provided outside the pressure generation chamber located at the end of the pressure generation chamber row of the flow path forming substrate. A liquid droplet ejection head comprising: a single layer or a laminate that is transparent or translucent to visible light , and a partition plate corresponding to the diaphragm. The through hole is formed integrally with an ink supply port for supplying ink to the pressure generating chamber;
The droplet discharge head according to claim 1.   An ink jet recording apparatus comprising the droplet discharge head according to claim 1.

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