Liquid dispensing head and method for manufacturing a liquid dispensing head

Abstract

This disclosure aims to suppress the concentration of liquid in the nozzle flow path and improve the liquid discharge performance. [Solution] The liquid dispensing head of this disclosure is A nozzle channel having a nozzle for discharging liquid, An individual supply channel for supplying liquid, comprising an individual supply channel connected perpendicularly to the nozzle channel at its longitudinal end, Includes, The nozzle channel is characterized in that, at its end, it has a wall surface aligned with the direction to which the individual supply channels are connected, and the wall surface is inclined.

Description

Technical Field

[0001] The present disclosure relates to a liquid ejection head and a method for manufacturing the liquid ejection head.

Background Art

[0002] An MEMS (Micro Electro Mechanical System) device is fabricated by joining members in which grooves and through holes serving as liquid flow paths are formed. As an example, there is a liquid ejection head that ejects liquid onto a recording medium.

[0003] The liquid ejection head includes an energy generating element that gives energy for ejecting a liquid such as ink. Examples of the energy generating element include an element that heats a liquid to boil it, such as a heater element, and an element that applies pressure to a liquid by utilizing a volume change, such as a piezo element.

[0004] As shown in Patent Document 1, a liquid ejection device that ejects liquid in a pressure chamber from a nozzle is known for the liquid ejection head.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The liquid ejection head includes a nozzle flow path connected to a nozzle, a supply flow path for supplying liquid, and the like. When the nozzle flow path and the supply flow path are connected at a right angle, liquid accumulates in the vicinity of the connection portion (corner portion) of these flow paths, and concentration of the liquid occurs. Such concentration of the liquid may reduce the liquid ejection performance from the nozzle.

[0007] This disclosure aims to suppress the concentration of liquid in the nozzle flow path and improve the liquid discharge performance. [Means for solving the problem]

[0008] The liquid discharge head of this disclosure includes a nozzle channel having a nozzle for discharging liquid, and an individual supply channel for supplying liquid, the individual supply channel being connected perpendicularly to the nozzle channel at its longitudinal end, wherein the nozzle channel has a wall surface at its end that is aligned with the direction to which the individual supply channel is connected, and the wall surface is inclined. [Effects of the Invention]

[0009] According to this disclosure, by reducing liquid stagnation in the nozzle flow path, liquid concentration can be suppressed and discharge performance can be stabilized. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a cross-sectional perspective view showing an example of the configuration of the liquid dispensing head of this disclosure. [Figure 2] Figure 2(a) is an enlarged cross-sectional view showing region (1A) of the liquid discharge head in Figure 1. Figure 2(b) is a cross-sectional view showing the shape of the nozzle flow path of the liquid discharge head of this disclosure. Figure 2(c) is a cross-sectional view showing an example of a conventional liquid discharge head. [Figure 3] Figures 3(a) and 3(b) are top views illustrating the shape of the nozzle flow path of the liquid discharge head of the present disclosure. [Figure 4] Figure 4 is a top view showing another example of the shape of the nozzle flow path of the liquid discharge head of this disclosure. [Figure 5] Figures 5(a) to 5(d) are partial cross-sectional views illustrating the shape of the nozzle flow path of the liquid discharge head of the present disclosure. [Figure 6] Figure 6 is a schematic cross-sectional view showing an example of a liquid dispensing head of the present disclosure. [Figure 7] Figure 7 is a schematic cross-sectional view showing another example of the liquid dispensing head of this disclosure. [Figure 8] Figure 8 is a schematic cross-sectional view showing another example of a liquid dispensing head of the present disclosure. [Figure 9] Figures 9(a) to 9(c) are schematic diagrams illustrating part of the manufacturing process of the liquid dispensing head of this disclosure. [Figure 10] Figures 10(a) to (d) are schematic diagrams illustrating part of the manufacturing process of the liquid dispensing head of this disclosure. [Figure 11] Figures 11(a) to (e) are schematic diagrams illustrating part of the manufacturing process of the liquid dispensing head of this disclosure. [Figure 12] Figures 12(a) to (c) are schematic diagrams illustrating a part of another manufacturing process for the liquid dispensing head of this disclosure. [Figure 13] Figures 13(a) to (e) are schematic diagrams illustrating parts of another manufacturing process for the liquid dispensing head of this disclosure. [Figure 14] Figures 14(a) to (e) are schematic diagrams illustrating part of the manufacturing process for another liquid dispensing head of this disclosure. [Figure 15] Figures 15(a) to (d) are schematic diagrams illustrating part of the manufacturing process for another liquid dispensing head of this disclosure. [Figure 16] Figures 16(a) and (b) are schematic diagrams illustrating part of the manufacturing process for another liquid dispensing head of this disclosure. [Modes for carrying out the invention]

[0011] The liquid dispensing head of this disclosure will be described below with reference to the drawings. The disclosure will be described in detail below based on specific embodiments. While this description may include specific details, these are merely examples of technically preferred features and are not intended to limit the scope of this disclosure.

[0012] In the following description, a liquid ejection head that ejects a liquid such as ink will be described as an example, but the present disclosure is not limited to this example. The liquid ejection head of the present disclosure is applicable to devices such as printers, copiers, facsimiles having a communication system, word processors having a printer unit, and industrial recording devices that are combined in a complex manner with various processing devices. For example, it can also be used for applications such as biochip fabrication or electronic circuit printing. Further, the liquid to be ejected is not limited to ink.

[0013] <Summary of the Present Disclosure> The liquid ejection head of the present disclosure includes a nozzle flow path having a nozzle, a supply flow path for supplying a liquid, and the like. For example, FIG. 1 is a schematic diagram showing a partial configuration of the liquid ejection head of the present disclosure. The liquid ejection head in FIG. 1 is an example of a liquid ejection head including a circulation system. Specifically, the liquid ejection head 100 has five substrates: a nozzle forming substrate 20, a vibration substrate 22, a liquid supply substrate 24, a flow path forming substrate 26, and a damper substrate 28. The liquid ejection head 100 has a structure in which a damper substrate 28 having a damper member 30 is bonded between the flow path forming substrate 26 and the liquid supply substrate 24. The nozzle forming substrate 20 has a nozzle (discharge port) 202.

[0014] In this disclosure, directions may be defined by the X, Y, and Z axes. These axes are indicated by the directional axes with arrows shown in each drawing. In each of these directional axes, the direction in which the arrow points is defined as the "+" direction of the axis. When the direction of an axis is referred to without specifying whether it is "+" or "-", it is simply referred to as the "X-axis direction", "Y-axis direction", or "Z-axis direction". In descriptions of nozzle flow paths in this disclosure, the direction in which the liquid flows through the nozzle flow path is defined as the "first direction". In this disclosure, the "first direction" without specifying whether it is "+" or "-" is referred to as the "longitudinal direction" of the nozzle flow path. In embodiments of this disclosure, the "longitudinal direction" specifically refers to the "X-axis direction". The direction perpendicular (orthogonal) to the "first direction", i.e., the direction toward the nozzle side within the nozzle flow path, is defined as the "second direction" or "+Z" direction. In one embodiment of this disclosure, the nozzle flow path corresponds to a flow path having the first direction. In one embodiment of the present disclosure, individual supply channels among the liquid supply channels correspond to channels perpendicular to the longitudinal direction (or first direction) of the nozzle channel. In one embodiment of the present disclosure, individual recovery channels among the liquid recovery channels correspond to channels perpendicular to the longitudinal direction (or first direction) of the nozzle channel. In another embodiment of the present disclosure, the individual supply channels are connected perpendicularly to the nozzle channel at its longitudinal end (this connection is also referred to as the first connection). In another embodiment of the present disclosure, the individual recovery channels are connected perpendicularly to the nozzle channel at the end of the nozzle channel opposite to the end where the first connection exists (this connection is also referred to as the second connection). In the present disclosure, the direction in which the nozzle channel connects to the liquid supply channel (particularly the individual supply channels) or the liquid recovery channel (particularly the individual recovery channels) at the first and second connection points is also referred to as the "connection direction". In a preferred embodiment of the present disclosure, this "connection direction" is perpendicular. In this disclosure, there is a pair of opposing ends in the longitudinal direction of the nozzle flow path, with a first connection at one end and a second connection at the other end. In this disclosure, the nozzle flow path has walls in a second direction at each of the two opposing ends. In other words, the nozzle flow path has walls perpendicular to the longitudinal direction of the nozzle flow path at the two opposing ends.Of these wall surfaces, the wall surface at the end with the first connection portion is referred to as the first wall surface, and the wall surface at the other end with the second connection portion is also referred to as the second wall surface. The liquid ejection head of the present disclosure has a characteristic in the structure of the nozzle flow path. The nozzle flow path of the present disclosure has wall surfaces along the first direction (+X direction in FIG. 1) and the second direction (+Z direction in FIG. 1), and is characterized in that the wall surface along the second direction has an inclination.

[0015] Hereinafter, referring to FIGS. 2 to 3, the characteristics of the liquid ejection head of the present disclosure will be specifically described.

[0016] In the following description with reference to FIGS. 2 to 3, a liquid ejection head including a circulation system will be taken as an example to describe a configuration example of the liquid ejection head of the present disclosure. However, the present disclosure is also applicable to a liquid ejection head that does not include a circulation system.

[0017] FIG. 2(a) is an enlarged cross-sectional view of the region (1A) in FIG. 1. The liquid ejection head of the present disclosure includes a nozzle flow path 204 having a nozzle 202, and individual supply flow paths 206 and individual recovery flow paths 208. In the example of FIG. 2(a), in addition to the configuration of these nozzle flow paths, it can have an energy generating element 210, a diaphragm 212, and individual cavities 214. The liquid ejection head of the present disclosure further has an opening 216 at the connection portion between the nozzle flow path 204 and the individual supply flow path 206. Also, the liquid ejection head of the present disclosure has an opening 218 at the connection portion between the nozzle flow path 204 and the individual recovery flow path 208. There are wall surfaces 220 and 222 of the nozzle flow path 204 near the opening 216 and near the opening 218. The liquid ejection head of the present disclosure is characterized in that an inclination is provided on these wall surfaces 220 and 222. In a specific embodiment of the present disclosure, the connection portion between the nozzle flow path 204 and the individual supply flow path 206 corresponds to the first connection portion, and the connection portion between the nozzle flow path 204 and the individual recovery flow path 208 corresponds to the second connection portion. Also, in a specific embodiment of the present disclosure, the wall surface 220 of the nozzle flow path 204 present near the opening 216 corresponds to the first wall surface. Also, the wall surface 222 of the nozzle flow path 204 present near the opening 218 corresponds to the second wall surface.

[0018] Next, with reference to Figure 2(b), the liquid discharge head of this disclosure will be described in more detail. Figure 2(b) is an enlarged cross-sectional view of the nozzle flow path 204 of the liquid discharge head of this disclosure.

[0019] As shown in Figure 2(b), the liquid discharge head of this disclosure has an opening 216 at the connection point between the nozzle flow path 204 and the individual supply flow path 206. Near this opening 216 is the wall surface 220 of the nozzle flow path 204. This wall surface 220 is inclined in the longitudinal direction of the nozzle flow path 204 (also referred to as the "first direction" in this specification). In this specification, the direction from the wall surface 220 toward 222 (the first direction) corresponds to the direction in which the liquid flows. In this disclosure, the nozzle flow path 204 is provided with such an inclined wall surface (hereinafter also referred to as the inclined surface) 220. By providing such an inclined surface 220 at the connection point between the nozzle flow path 204 and the individual supply flow path 206, the flow of liquid passing through these flow paths is made smoother, and liquid stagnation at this connection surface is reduced. As a result, liquid concentration in the nozzle flow path 204 is reduced, and the liquid discharge performance from the nozzle 202 can be improved.

[0020] In this disclosure, as shown in Figure 2(b), the inclined surface may be provided on the wall surface where the connection portion (the portion of the opening 216) between the nozzle flow path 204 and the individual supply flow path 206 exists. Alternatively, the inclined surface may be provided on the wall surface of the nozzle flow path 204, where the connection portions (the portions of the openings 216 and 218) between the nozzle flow path 204 and the individual supply flow path 206 and the individual recovery flow path 208 exist. That is, in one embodiment of this disclosure, of the two inclined surfaces shown in Figure 2(b), only the inclined surface 220 may be provided, or both inclined surfaces 220 and 222 may be provided. By providing two inclined surfaces, the liquid discharge performance from the nozzle can be further improved.

[0021] As shown in Figure 2(b), in the nozzle channel 204 of this disclosure, the inclined surface 220 has an angle 224(θ1) with the surface on which the nozzle 202 of the nozzle channel is formed. Also, in the nozzle channel 204 of this disclosure, the inclined surface 222 has an angle 226(θ2) with the surface on which the nozzle 202 of the nozzle channel is formed. These angles 224(θ1) and 226(θ2) are preferably 25° or more and less than 90°, respectively. The angles 224(θ1) and 226(θ2) may be the same or different, but from the viewpoint of the manufacturing process of the nozzle channel, they are preferably the same.

[0022] Here, with reference to Figure 2(c), a commonly used nozzle flow path shape will be described as a comparative example. In the comparative example liquid discharge head, at the connection point between the nozzle flow path 204 and the individual supply flow path 206 and individual recovery flow path 208, the walls 220a and 222a of the nozzle flow path are vertical. At such connection points (for example, corners like areas (2A) and (2B) in Figure 2(c)), the direction of the liquid flow through the flow path changes by 90°. In this case, the liquid may stagnate at the connection point of each flow path, and the liquid may become concentrated near the connection point. If liquid concentration occurs in the nozzle flow path closest to the nozzle, the liquid discharge performance may be significantly reduced compared to when the liquid is concentrated in other flow paths. The purpose of this disclosure is to suppress such a reduction in liquid discharge performance.

[0023] Referring to Figure 3, the nozzle channel with the inclined surface of this disclosure will be described in more detail. A silicon substrate or the like is used as the material for the nozzle channel with the inclined surface of this disclosure.

[0024] Figure 3(a) shows one embodiment of the nozzle channel of the present disclosure. As shown in Figure 3(a), in the present disclosure, the inclination of the nozzle channel can be set such that the width of the four walls of the nozzle channel narrows toward the surface on which the nozzle is formed. For example, by making the etching time during channel formation shorter than the time required when forming the walls of the nozzle channel vertically, a nozzle channel with the shape shown in Figure 3(a) can be formed.

[0025] In this disclosure, the angles (θ1 and θ2) of the inclined surfaces 220 and 222 are defined as the angles as viewed in the a-a section of Figure 3(a).

[0026] The nozzle channel of this embodiment can be fabricated, for example, using the Bosch process, which is a type of reactive ion etching. In this embodiment, the inclined surface of the nozzle channel 204 can be formed not only on the inclined surfaces 220 and 222 of the nozzle channel 204 shown in Figure 2(b), but also on the surface 230 along the flow direction of the nozzle channel. The nozzle channel of this disclosure can also be formed by a method that combines wet etching with an alkaline aqueous solution and hole processing with a laser.

[0027] Figure 3(b) shows another embodiment of the nozzle channel of the present disclosure. This embodiment is an example in which a nozzle channel 204 is fabricated using a silicon substrate having a crystal plane (100). The nozzle channel 204 can be fabricated by the method described above. In this embodiment, a slope is also formed on the surface 230 (hereinafter also referred to as the side surface of the nozzle channel) along the flow direction of the nozzle channel. In this embodiment, the inclined surfaces of the nozzle channel 204 are formed on the inclined surfaces 220 and 222 of the nozzle channel 204 shown in Figure 2(b), and on the side surface of the nozzle channel, and have a truncated square pyramidal shape. In this embodiment, the inclined surfaces 220 and 222 and the side surface of the nozzle channel have the same inclination angle. For example, the inclination angle of the inclined surfaces 220 and 222 in the cross section along line aa in Figure 3(b) is 54.7°.

[0028] Figure 4 shows another embodiment of the nozzle channel of the present disclosure. This embodiment is an example in which a nozzle channel 204 is created using a silicon substrate having a crystal plane (110). In this embodiment, the inclined surfaces 220 and 222 of the nozzle channel have inclined surfaces in a direction different from the direction in which the liquid flows in the nozzle channel 204 (the first direction or +X direction in Figure 4). For example, as shown in Figure 4, the inclined surfaces 220 and 222 have inclined surfaces along the bb line. For example, in the cross section along the bb line in Figure 4, the inclined surfaces 220 and 222 have an angle of 35.3°. On the other hand, in the cross section along the aa line, these inclination angles are 28.1°. Here, even if the inclined surfaces are different from the X-axis direction of the nozzle channel as in this embodiment, the angles of the inclined surfaces (θ1 and θ2) are the angles when viewed in a cross section along the direction of the aa line (the X-axis direction in Figure 4) of the nozzle channel.

[0029] Referring to Figures 5(a) to 5(d), the positional relationship between the inclined surfaces 220 and 222 of the nozzle flow path 204 and the openings 216 and 218 will be explained. In Figures 5(a) to 5(d), the positional relationship between the inclined surface 220 and the opening 216 is used as an example, but the positional relationship between the inclined surface 222 of the nozzle flow path 204 and the opening 218 is similar.

[0030] As shown in Figures 5(a) to 5(d), the width of the opening 216 connected to the nozzle flow path in the X-axis direction is defined as W1. Also, as shown in these figures, the width of the inclination of the cross-section of the inclined surface 220 of the nozzle flow path in the X-axis direction (i.e., at the position and in the direction of line aa in Figures 3 and 4) is defined as S1.

[0031] The positional relationship between W1 and S1 can take the form shown in Figures 5(a) to 5(d) below. (1) Figure 5(a): Figure 5(a) shows an example where the width W1 of the opening 216 and the width S1 of the inclined surface 220 partially overlap. In this example, the position 504 where the inclined surface 220 contacts the nozzle surface 502 of the nozzle flow path 204 is located within the width W1. On the other hand, the end 506 of the inclined surface 220 on the opening 216 side is located at a position shifted in the -X direction from the width W1. (2) Figure 5(b): Figure 5(b) shows another example where the width W1 of the opening 216 and the width S1 of the inclined surface 220 partially overlap. In this example, the position 504 where the inclined surface 220 contacts the nozzle surface 502 of the nozzle flow path 204 is located at a position shifted in the +X direction (first direction) from the width W1. On the other hand, the end 506 of the inclined surface 220 on the opening 216 side is located within the width W1. (3) Figure 5(c): Figure 5(c) shows an example where both the end 506 on the opening 216 side of the inclined surface 220 and the position 504 that contacts the nozzle surface 502 of the nozzle flow path 204 are within the width W1 range. (4) Figure 5(d): Figure 5(d) shows an example where both the end 506 on the opening 216 side of the inclined surface 220 and the position 504 that contacts the nozzle surface 502 of the nozzle flow path 204 are located outside the width W1. In this disclosure, any of the embodiments shown in Figures 5(a) to 5(d) are preferred. The example shown in Figure 5(b) or Figure 5(c) is preferred because it does not create an overhang of the diaphragm 212 over the opening 216, but it narrows the width of the opening 216. For this reason, it is important to appropriately set the relationship between W1 and S1. On the other hand, the embodiment shown in Figure 5(a) or Figure 5(d) creates an overhang of the diaphragm 212, but does not narrow the opening 216. Even in embodiments with an overhang, as in these examples, by reducing the angle of the inclined surface, it is possible to create a flow towards the underside of the overhang (towards the inclined surface 220), which is in the shadow of the diaphragm 212 in the direction of liquid flow. This suppresses liquid stagnation in the overhang portion. Therefore, in these cases as well, it is important to appropriately set the relationship between W1 and S1.

[0032] Furthermore, when the width of S1 is larger than the width of W1, the cross-sectional area of ​​the nozzle channel 204 in the Z-axis direction (second direction) is narrowed, and the region through which the liquid passes through the nozzle channel is reduced. Moreover, in the configuration where the width S1 is larger than the width W1, the slope of the inclined surface 220 becomes gentler. This reduces the component of the liquid in the +X direction (first direction) of the nozzle channel when the liquid flow is changed direction at the inclined surface 220. Such a reduction makes the liquid flow in the +X direction gentler, increasing the possibility of liquid stagnation within the nozzle channel.

[0033] From the above viewpoint, in order to maintain the effect of reducing stagnation by providing the inclined surface 220 in this disclosure, the relationship between width W1 and width S1 is preferably in the range of (S1 / W1) < 4 (where S1 < 0 and W < 0).

[0034] Figures 5(a) to 5(d) show an example where the width of the opening 216 is narrower than the width of the individual supply channel 206. Therefore, the width of the opening 216 (the width of the two diaphragms 212 flanking the individual supply channel 206) is defined as W1. Conversely, if the width of the diaphragms 212 flanking the individual supply channel 206 is wider than the individual supply channel 206 (the opening 216 is the same width as the individual supply channel 206), then the width of the individual supply channel becomes W1.

[0035] The liquid discharge head having the nozzle flow path described above will be explained below.

[0036] 1. Liquid dispensing head Specific embodiments of the liquid discharge head including the nozzle flow path of the present disclosure are described below. Note that the following embodiments are examples illustrating the configuration of the liquid discharge head of the present disclosure and are not intended to limit the present disclosure.

[0037] <First Embodiment> This embodiment is an example of a liquid discharge head that includes a nozzle channel of the present disclosure and a liquid circulation system including a liquid supply channel, a liquid recovery channel, and other similar components.

[0038] The liquid discharge head of this embodiment will be described with reference to Figure 6. The liquid discharge head of this embodiment includes a first flow channel substrate 602, a second flow channel substrate 604, and a third flow channel substrate 606.

[0039] The first flow channel substrate 602 is a substrate including the nozzle flow channel 204 of the present disclosure. The first flow channel substrate 602 includes the nozzle 202, the nozzle flow channel 204, and the inclined surfaces 220 and 222 of the inclined nozzle flow channel. Multiple nozzle flow channels can be provided in the liquid discharge head of the present disclosure. The nozzle flow channel 204 included in the first flow channel substrate includes the configuration of the nozzle flow channel described in the "Summary of the Present Disclosure" section.

[0040] Because this embodiment includes a liquid circulation system, the liquid discharge head includes individual supply channels 206 and individual recovery channels 208. In one embodiment of a liquid discharge head with such a configuration, the nozzle channel 204 of the first channel substrate may include both inclined surfaces 220 and 222. In another embodiment, the nozzle channel of the first channel substrate may include only the inclined surface 220. In this disclosure, it is preferable to include both inclined surfaces 220 and 222 in the nozzle channel 204 in order to better prevent liquid stagnation and concentration.

[0041] The second flow channel substrate 604 includes individual supply channels 206, individual recovery channels 208, energy generating elements 210, diaphragms 212, and individual cavities 214. The second flow channel substrate 604 further includes a first common supply channel 608 and a first common recovery channel 610.

[0042] The diaphragm 212 includes an electrical connection section (not shown) for connecting an energy generating element 210, a driver IC, etc. The diaphragm 212 has openings 216 and 218 for connecting to the nozzle channel 204 of this disclosure at the locations of the individual supply channel 206 and the individual recovery channel 208. In the second channel substrate 604, the material of the substrate on which the individual supply channel 206, individual recovery channel 208, individual cavity 214, etc. are formed can be, for example, a silicon substrate.

[0043] In the liquid discharge head of this disclosure, the individual supply channel 206, individual recovery channel 208, energy generating element 210, diaphragm 212, and individual cavity 214 can be provided in multiple quantities depending on the number of nozzles in the liquid discharge head.

[0044] In this embodiment, an example of the energy generating element 210 is a piezoelectric element. The piezoelectric element comprises a lower electrode formed on a diaphragm, a piezoelectric element formed on the lower electrode, and an upper electrode formed on the piezoelectric element.

[0045] The liquid discharge head of this embodiment includes a circulation system in which liquid flows in from an individual supply channel 206 and is recovered from an individual recovery channel 208.

[0046] The liquid discharge head of this embodiment includes a third flow path substrate 606. The third flow path substrate is equipped with a damper 612 for reducing fluctuations in the rear pressure during liquid discharge and a damper cavity 614 for moving the damper 612. The material of the damper 612 can be an elastic member. For example, the elastic member can be a resin member such as polyimide or polyamide. In addition, a silicon substrate or the like can be used as the base material for the third flow path substrate 606.

[0047] The third channel substrate 606 further includes a second common supply channel 616 and a second common recovery channel 618, which are connected to the first common supply channel 608 and the first common recovery channel 610 of the second channel substrate, respectively.

[0048] In the liquid discharge head of this disclosure, liquid is supplied from the second common supply channel 616 and the first common supply channel 608 to the nozzle channel 204 via the individual supply channel 206. The liquid is pressurized by the vibrating plate 212 and discharged as droplets from the nozzle 202 of the nozzle channel 204. After the liquid is discharged, the remaining liquid is recovered via the individual recovery channel 208, the first common recovery channel 610, and the second common recovery channel. In the liquid discharge head of this disclosure, by providing inclined surfaces 220 and 222 in the nozzle channel 204, stagnation of the liquid in the nozzle channel can be prevented, thereby reducing liquid concentration and preventing a deterioration in the quality of the discharged liquid.

[0049] <Second Embodiment> The liquid dispensing head of the second embodiment will be explained with reference to Figure 7.

[0050] The liquid discharge head of the second embodiment has a first flow path substrate 702, a second flow path substrate 704, and individual nozzle flow paths 706. The structure of the individual nozzle flow paths 706 is the same as that of the first embodiment, except that the nozzle flow paths are provided in a single form having one nozzle.

[0051] As shown in Figure 7, the first flow channel substrate 702 includes a plurality of individual flow channels 708, 710, 712, and 714, as well as a pressure chamber 716. The first flow channel substrate 702 further includes common flow channels 718 and 720, a damper 722, etc. A silicon substrate or the like can be used for the base material 730 of the first flow channel substrate on which each of the above flow channels is formed.

[0052] The first flow channel substrate 702 includes a diaphragm 724 and an energy generating element 726. The first flow channel substrate 702 also includes a pressure chamber substrate 728. The pressure chamber substrate 728 forms a pressure chamber 716 with, for example, the diaphragm 724 and the energy generating element 726 and the portion of the base material 730 of the first flow channel substrate between the individual flow channels 708 and 710. The diaphragm 724 and the energy generating element 726 are protected within individual cavities 734 by a protective substrate 732. A silicon substrate or the like can be used as the protective substrate. The second flow channel substrate 704 has flow channels 736 and 738 connected to common flow channels 718 and 720. The material of the second flow channel substrate 704 can be, for example, a silicon substrate. The liquid discharge head of the second embodiment may also include a wiring board 740.

[0053] <Third Embodiment> The third embodiment is an example of a liquid discharge head that does not include a circulation system for recovering and circulating liquid, such as individual recovery channels, a first common recovery channel, and a second common recovery channel. The third embodiment will be described with reference to Figure 8.

[0054] In the third embodiment, the liquid discharge head includes a first flow channel substrate 802, a second flow channel substrate 804, and a third flow channel substrate 806.

[0055] In this embodiment, the first flow channel substrate 802 is a substrate that includes a nozzle flow channel 204. As shown in Figure 8, in the first flow channel substrate 802 of this embodiment, the nozzle 202 is provided at the end opposite to the position of the opening 216 of the nozzle flow channel 204. In Figure 8, the nozzle flow channel 204 has a symmetrical shape with respect to the central portion, but this embodiment is not limited to this.

[0056] In this embodiment, the structure of each element of the nozzle flow path of the first flow path substrate 802, other than the nozzle 202, is the same as in the first embodiment.

[0057] The second flow channel substrate 804 of this embodiment includes individual supply channels 206, energy generating elements 210, diaphragms 212, and individual cavities 214. The second flow channel substrate 804 further includes a first common supply channel 808.

[0058] The configuration and materials of the energy generating element 210, the diaphragm 212, the individual cavities 214, etc., are as described in the first embodiment.

[0059] In the liquid discharge head of this disclosure, the individual supply channels 206, energy generating elements 210, diaphragms 212, and individual cavities 214 can be provided in multiple quantities depending on the number of nozzles in the liquid discharge head.

[0060] The third flow channel substrate 806 includes a damper 612, a damper cavity 614, and a second common supply channel 810. In the third flow channel substrate, the damper cavity 614 is located at a position corresponding to the individual supply channel 206.

[0061] Other components and materials of the liquid dispensing head in the third embodiment are the same as those described in the first embodiment.

[0062] <Manufacturing method for liquid dispensing heads> The method for manufacturing the liquid dispensing head of this disclosure will be described below. The first to third embodiments of the liquid dispensing head described above will be used as examples in the following description.

[0063] <First Embodiment of a Method for Manufacturing a Liquid Dispensing Head> As shown in Figure 6, the liquid discharge head of the first embodiment includes a first flow channel substrate 602, a second flow channel substrate 604, and a third flow channel substrate 606. The liquid discharge head of the first embodiment can be manufactured by fabricating these first, second, and third flow channel substrates separately and then bonding them together. The manufacturing processes for the first, second, and third flow channel substrates will be described below in order.

[0064] First, the process for fabricating the first channel substrate 602 will be described with reference to Figure 9. As shown in Figure 9(a), a nozzle channel forming substrate 910 is prepared. The nozzle channel forming substrate 910 includes a nozzle forming layer 918 made of an SOI (Silicon on Insulator) substrate containing a nozzle channel layer 912, oxide films 914, 914' and a silicon layer 916, and a support substrate 920. Each of these layers can be obtained or prepared by known procedures, and the nozzle channel forming substrate 910 can also be prepared by known procedures.

[0065] Next, nozzle channels 204 are formed in the nozzle channel formation substrate 910. The nozzle channels 204 have inclined surfaces 220 and 222, where opposing walls in the channel direction (X-axis direction) are inclined. One method for creating inclined surfaces in the nozzle channels is processing using the Bosch process, known as a type of reactive ion etching. The Bosch process is a method for forming etching grooves perpendicular to the substrate by alternately coating and etching the material to be etched. Reactive ion etching uses accelerated ions for etching. The etching apparatus has a separate plasma source for generating ions and a reaction chamber for etching. For example, an ICP (Inductively Coupled Plasma) dry etching apparatus capable of producing high-density ions as the ion source can be used. Using this apparatus, etching grooves perpendicular to the substrate can be formed by alternately coating and etching. For example, SF6 gas can be used as the etching gas. For example, C4F8 gas or CHF3 gas can be used as the gas for forming the passivation layer.

[0066] To form the inclined surfaces 220 and 222 of the nozzle channel 204, the etching conditions in the Bosch process described above must be set such that the width in the channel direction (X-axis direction) narrows in the direction of etching (+Z direction in Figure 9). For example, the etching time can be set shorter than the time required to form the wall surface of the nozzle channel vertically. By gradually shortening this processing time, the proportion of etching of the wall surface of the nozzle channel can be reduced. By repeating this process, the width of the wall surface of the nozzle channel layer 912 can be narrowed in the direction of etching (+Z direction). The etching time can be appropriately set by those skilled in the art depending on the desired angle of the inclined surface of the nozzle channel.

[0067] When the nozzle channel 204 is formed according to the etching procedure described above, the inclination angles (θ1 and θ2) of the inclined surfaces 220 and 222 can be set, for example, to 25° or more and less than 90°. Preferably, these inclination angles can be set to a range of 50° or more and less than 90°, more preferably 70° or more and less than 90°. The definitions of the angles of the inclined surfaces 220 and 222 are as previously explained with reference to Figure 2(b).

[0068] In addition to the reactive ion etching method described above, an etching method for shaping the nozzle channel in this disclosure can be described as a method that combines laser-based hole processing in the channel substrate with wet etching using an alkaline aqueous solution.

[0069] Examples of alkaline aqueous solutions used in wet etching include aqueous solutions of tetramethylammonium hydroxide (TMAH) and alkali metal hydroxides (e.g., potassium hydroxide (KOH)).

[0070] For example, in this disclosure, as described in Figures 3(a) and 3(b), if the crystal plane of the silicon substrate forming the nozzle channel 204 is (100), the nozzle channel 204 shown in Figure 3(a) or Figure 3(b) is formed. In the examples described in these examples, the inclination angles (θ1 and θ2) of the inclined surfaces 220 and 222 of the nozzle channel 204 are 54.7°.

[0071] Furthermore, if the crystal plane of the silicon substrate forming the nozzle channel 204 is (110), an inclined surface is formed in the cross-section along line bb shown in Figure 4. The inclination angle of the inclined surface in the cross-section along line bb is 35.3°. The angle of the inclined surface in the cross-section along line aa shown in Figure 4 is 28.1°.

[0072] Next, the fabrication of the second flow channel substrate 604 will be described. As shown in Figure 6, the second flow channel substrate 604 has a plurality of individual supply channels 206 and a plurality of individual recovery channels 208. The second flow channel substrate 604 also has a first common supply channel 608 connected to the plurality of individual supply channels 206 and a first common recovery channel 610 connected to the plurality of individual recovery channels 208. Furthermore, the second flow channel substrate 604 includes individual cavities 214 for housing the diaphragm 212.

[0073] The fabrication process for the second channel substrate 604 will be explained with reference to Figure 10.

[0074] First, a flow channel substrate 1000, as shown in Figure 10(a), is formed. Multiple individual supply channels 206 and multiple individual recovery channels 208 are formed on the flow channel substrate 1000. In addition, the flow channel substrate 1000 is formed with a portion corresponding to the first common supply channel 608, a portion corresponding to the first common recovery channel 610, and a portion 214' corresponding to the individual cavities.

[0075] The channel substrate 1000 can be made from, for example, a silicon substrate. The processing of the portions 214' corresponding to each channel and individual cavity can be carried out by the Bosch process, which is a type of reactive ion etching. As described above, the Bosch process is a method of forming etching grooves perpendicular to the substrate by alternately coating and etching the material to be etched. In addition to this method, processing methods include, for example, forming through holes in the substrate and back-grinding the substrate, or thinning the substrate by chemical mechanical polishing (CMP). These methods can be used to form through holes corresponding to each channel, portions 214' corresponding to individual cavities, etc., in the substrate. Furthermore, another processing method is to process the substrate by combining laser drilling and wet etching with an alkaline aqueous solution. Examples of alkaline aqueous solutions used for wet etching include tetramethylammonium hydroxide (TMAH) and alkali metal hydroxides (e.g., KOH).

[0076] Next, the actuator substrate 1002 shown in Figure 10(b) is fabricated. The actuator substrate 1002 includes an energy generating element 210, a diaphragm 212, and wiring and electrical connections (not shown) connecting the energy generating element 210 and the driver IC.

[0077] An example of an energy generating element 210 is a piezoelectric element. The piezoelectric element comprises a lower electrode (not shown) formed on a diaphragm 212, a piezoelectric element formed on the lower electrode, and an upper electrode (not shown) formed on the piezoelectric element. The diaphragm 212, the lower electrode, and the upper electrode are formed, for example, by plasma CVD. The piezoelectric body of the piezoelectric element can be formed by known methods such as the sol-gel method or the sputtering method. For example, PZT (lead zirconate titanate) can be used as the material for the piezoelectric body. Such a piezoelectric body may be in the form of a sintered metal oxide crystal. Next, an interlayer film, wiring, etc., can be formed to drive the piezoelectric element, and the actuator substrate 1002 can be formed.

[0078] The diaphragm 212 and oxide film 1006 of the actuator substrate 1002 are provided with openings 216 and 218 corresponding to the individual supply channels 206 and individual recovery channels 208 of the second flow channel substrate 604. In the method for forming these openings, first, a resist film is formed on the actuator substrate 1002 and patterned by photolithography. Next, the openings 216 and 218 are formed on the diaphragm 212 and oxide film 1006 by dry etching.

[0079] The channel substrate 1000 shown in Figure 10(a) and the actuator substrate 1002 shown in Figure 10(b) are joined by wafer bonding via an adhesive (Figure 10(c)). A material with high adhesion to the substrate is preferably used as the adhesive. Furthermore, a material with low coating properties and minimal inclusion of air bubbles is preferred. In addition, a low-viscosity material that allows for a thin adhesive layer is preferred. The adhesive preferably contains a resin selected from epoxy resin, acrylic resin, silicone resin, benzocyclobutene resin, polyamide resin, polyimide resin, or urethane resin. Multiple adhesives can also be used in mixture form. Examples of adhesive curing methods include thermosetting and UV delayed curing. If any of the above-mentioned substrates are UV-transmitting, the UV curing method can also be used.

[0080] One method for applying the adhesive is an adhesive transfer method using a transfer substrate. Specifically, a transfer substrate is prepared, and the adhesive is thinly and uniformly applied to the transfer substrate by a spin coating method or a slit coating method. Next, the adhesive surface of the channel substrate 1000 is brought into contact with the applied adhesive, thereby transferring the adhesive only to the adhesive surface of the channel substrate 1000. The size of the transfer substrate is preferably the same as or larger than the channel substrate 1000. Suitable transfer substrates include inorganic materials such as silicon and glass, and films made of resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyimide (PI). In addition to the above method, a method of directly applying the adhesive to the channel substrate 1000 can also be employed. Examples of such methods include screen printing and dispensing.

[0081] Next, the flow channel substrate 1000 and the actuator substrate 1002, to which adhesive has been applied, are joined. The joining is performed by heating each substrate to a predetermined temperature in a joining device, and then applying pressure for a predetermined time under a predetermined pressure. The conditions for this joining are appropriately set according to the material of the adhesive. Furthermore, from the viewpoint of suppressing the inclusion of air bubbles in the areas to be joined, it is preferable to join each substrate in a vacuum.

[0082] If the adhesive is thermosetting, each substrate may be heated in the bonding device until the adhesive hardens. Alternatively, after bonding each substrate in the bonding device, the bonded substrates may be removed from the device and heated separately using an oven or the like to accelerate the hardening of the adhesive.

[0083] If the adhesive is UV-delayed, it is preferable to irradiate the adhesive with a specified amount of UV light before bonding the substrates. Then, the bonded substrates are further heated to sufficiently accelerate the curing of the adhesive.

[0084] If the adhesive is UV-curing, after joining the substrates, a specified amount of UV light is irradiated onto the adhesive through a UV-transmitting substrate to cure it. Subsequently, it is preferable to further heat each joined substrate to sufficiently accelerate the curing of the adhesive.

[0085] By following the above procedure, a bonded substrate 1008 can be obtained.

[0086] Next, the support substrate 1004 of the bonded substrate 1008 is removed (Figure 10(d)). A method combining back grinding and dry etching can be used for removal. This allows the second channel substrate 604 to be obtained.

[0087] Next, with reference to Figure 11, the manufacturing process of the liquid dispensing head of the first embodiment of this disclosure will be described.

[0088] As shown in Figure 11(a), the nozzle channel formation substrate 910, as described using Figure 9, and the second channel substrate 604, as described using Figure 10, are joined together. Known methods such as wafer bonding and adhesive bonding can be used for joining. The specific method is as described above.

[0089] Next, as shown in Figure 11(b), the support substrate 920 of the nozzle channel forming substrate 910 is removed by grinding and dry etching to produce the substrate 1100.

[0090] A nozzle 202 is formed on the nozzle-forming layer 918 of the obtained substrate 1100 (Figure 11(c)). The nozzle formation method involves patterning a resist on the oxide film 914' of the nozzle-forming layer 918. Using this patterned resist as a mask, the nozzle-forming layer 918 is treated with dry etching using the Bosch process. This forms the nozzle 202 on the nozzle-forming layer 918. This results in obtaining an ejection channel substrate 1110 including a first channel substrate 602 and a second channel substrate 604.

[0091] Next, a third flow channel substrate 606 is fabricated (Figure 11(d)). As shown in Figure 6, the third flow channel substrate 606 has a damper 612 to reduce fluctuations in the rear pressure during liquid discharge and a damper cavity 614 for moving the damper. The third flow channel substrate 606 is equipped with a second common supply channel 616 and a second common recovery channel 618. These are connected to the first common supply channel 608 and the first common recovery channel 610 of the second flow channel substrate 604, respectively.

[0092] The portion corresponding to the damper cavity, the second common supply channel 616, and the second common recovery channel 618 of the third channel substrate 606 can be formed by the same method as the processing method described in Figure 11(a) for the fabrication of the channel substrate 1000. The method for forming the damper 612 is as follows: First, a dry film damper member is laminated onto the third channel substrate, which has the second common supply channel, the second common recovery channel, and the portion corresponding to the damper cavity formed on it. Next, a resist film is formed on this damper member and patterned. Then, the damper member is processed by dry etching to remove the resist. This forms the damper 612.

[0093] Alternatively, the following procedure can be used. First, a support substrate (e.g., a silicon substrate) with an oxide film formed on it is prepared, and a damper material is spin-coated onto the substrate to form a film of damper material. The resulting film is baked and cured. A resist film is formed on the resulting cured film, and patterning is performed by photolithography. The cured film is processed by dry etching using the patterned resist as a mask. This patterns the cured film. The resist is removed from the patterned cured film to obtain a damper film. The support substrate with the damper film is bonded to a third channel substrate, which has a second common supply channel, a second common recovery channel, and parts corresponding to the damper cavity formed on it, via an adhesive. Then, the support substrate is ground using a backgrinding apparatus, leaving a thickness of several tens of micrometers, and the silicon is completely etched off using the oxide film of the support substrate as an etching stop layer. The oxide film used as the etching stop layer can be removed with buffered hydrofluoric acid.

[0094] A third channel substrate can be obtained by segmenting the resulting substrate into individual chips.

[0095] Next, the first channel substrate, the second channel substrate, and the third channel substrate described above are joined together. For joining, for example, the adhesive method described in Figure 10 can be used.

[0096] By following the above procedure, a liquid dispensing head of the first embodiment can be obtained.

[0097] <Second Embodiment of a Method for Manufacturing a Liquid Dispensing Head> This embodiment is another manufacturing process for the liquid dispensing head of the first embodiment. The manufacturing method of this embodiment will be described with reference to Figures 12 to 13.

[0098] The second flow channel substrate 604 is prepared according to the first embodiment of the manufacturing method.

[0099] As shown in Figure 12(a), the second channel substrate 604 and the silicon wafer (support substrate) 1210 are joined to form the nozzle forming substrate 1200. The joining can be done using methods described in the first embodiment, such as bonding with adhesive. Next, as shown in Figure 12(b), the support substrate 1210 is ground to a desired thickness. The grinding shown in Figure 12(b) can be done using the methods described above, such as back grinding.

[0100] Next, as shown in Figure 12(c), a nozzle channel 204 is formed in the ground support substrate 1210 to obtain a substrate 1220 having a nozzle channel. The method for forming the nozzle channel involves first applying a resist material to the support substrate 1210 and patterning it using photolithography. The exposed silicon of the support substrate is then etched using a Bosch process to form a nozzle channel 204 having a cross-sectional shape that widens in the direction of etching (towards the diaphragm 212 (-Z direction)). By making the etching time for forming the nozzle channel 204 longer than the time required to form the walls of the nozzle channel vertically, the support substrate 1210 having the nozzle channel 204 of this embodiment can be formed. This support substrate 1210 has a nozzle channel 204 having an inverted trapezoidal cross-section as shown in Figure 12(c). In this method, the inclination angles (θ1 and θ2) of the inclined surfaces 220 and 222 of the nozzle channel 204 can be set to 25° or more and less than 90°. In this disclosure, these inclination angles can preferably be set in the range of 50° or more and less than 90°, and more preferably 70° or more and less than 90°.

[0101] Next, a substrate 1300 for providing the nozzle is prepared, as shown in Figure 13(a). The substrate 1300 includes a support substrate 1302 and an SOI substrate layer 1308 composed of an oxide film 1304, a silicon layer 1306, and an oxide film 1304'. The substrate 1300 for providing the nozzle can be obtained by known methods.

[0102] As shown in Figure 13(b), the substrate 1220 having the nozzle channel 204, obtained by the procedure described with reference to Figure 12, and the substrate 1300 for providing the nozzle, obtained in Figure 13(a), are joined by wafer bonding. The bonding can be selected from the bonding methods described above. Next, as shown in Figure 13(c), the support substrate 1302 is removed by grinding and dry etching. Then, a resist is patterned on the oxide film 1304' of the obtained substrate 1100. Using this patterned resist as a mask, the SOI substrate layer 1308 is treated with dry etching using the Bosch process. This forms the nozzle 202 on the SOI substrate layer 1308, and an ejection channel substrate 1110 is obtained, which includes a first channel substrate 602 and a second channel substrate 604 having the nozzle 202 (Figure 13(d)). The obtained ejection channel substrate 1110 can be separated into chips from the wafer.

[0103] Next, the obtained discharge channel substrate 1110 is joined to the third channel substrate 606 to obtain the liquid discharge head of the first embodiment (Figure 13(e)). The joining can be performed using any of the joining methods described above.

[0104] <Third Embodiment of a Method for Manufacturing a Liquid Dispensing Head> A third embodiment of the manufacturing method of the present disclosure is a method for manufacturing the liquid dispensing head of the second embodiment described above.

[0105] A third embodiment of the manufacturing method of the present disclosure will be described with reference to Figures 14 to 16.

[0106] The liquid discharge head of the second embodiment described above has the structure explained with reference to Figure 7. The liquid discharge head of the second embodiment is manufactured by joining together the first flow channel substrate 702, the second flow channel substrate 704, and the individual nozzle flow channels 706 shown in Figure 7.

[0107] First, a protective substrate 732 as shown in Figure 14(a) is prepared. The protective substrate 732 has portions 1414 corresponding to individual cavities 734 that protect the energy generating elements 210, and openings 1412 for connection terminals to expose the electrical connection parts. A silicon substrate can be used as the material for the protective substrate 732. Methods for forming the above elements include dry etching using the Bosch process, or a method combining wet etching with an alkaline aqueous solution and hole processing with a laser. Examples of alkaline aqueous solutions used for wet etching include tetramethylammonium hydroxide (TMAH) and alkali metal hydroxides (e.g., potassium hydroxide (KOH)). The silicon substrate for the protective substrate 732 can have crystal planes (100) or (110). When performing anisotropic etching using an alkaline aqueous solution, it is preferable to use a crystal plane (110) that can process vertical walls.

[0108] Next, a silicon substrate 1416 is prepared as shown in Figure 14(b). On this silicon substrate, the energy generating element 210, the diaphragm 212, and the wiring and electrical connection parts (not shown) for connecting the driver IC are formed. As with the protective substrate 732, silicon with a crystal plane of (100) or (110) can be used for the silicon substrate 1416. The energy generating element 210, the diaphragm 212, etc. on the silicon substrate 1416 can be manufactured using the same method as described using Figure 10(b).

[0109] Next, as shown in Figure 14(c), the silicon substrate 1416 on which the energy generating element 210, diaphragm 212, and driver IC are mounted is bonded to the protective substrate 732 via adhesive. Then, as shown in Figure 14(d), the silicon substrate 1416 is ground to the desired thickness.

[0110] Next, a resist is applied to the ground surface of the silicon substrate 1416 and patterned using photolithography to form an etching mask. By etching through this mask, a portion 1418 corresponding to the pressure chamber 716 is formed on the silicon substrate 1416. Next, the resist is removed to obtain the pressure chamber formation substrate 1400 (Figure 14(e)). If necessary, openings may be made in the obtained pressure chamber formation substrate 1400 along the cutting line used for chipping. Methods for making openings along the cutting line include dry etching using the Bosch process, or a method combining wet etching with an alkaline aqueous solution and hole processing with a laser. Examples of alkaline aqueous solutions used for etching include tetramethylammonium hydroxide (TMAH) and alkali metal hydroxides (e.g., potassium hydroxide (KOH)). After removing the resist, the exposed side of the silicon substrate 1416 that comes into contact with liquids such as ink may be protected with a protective film. Methods for forming a protective film include chemical vapor deposition (CVD), sputtering, and atomic layer deposition (ALD). Among these, atomic layer deposition is preferred due to its good penetration characteristics. For protective films against liquids such as ink, metal oxides such as Ti, Zr, Hf, V, Nb, and Ta can be used as materials. Multiple metal oxides can be combined. A particularly preferred material is tantalum oxide (TaO). Note that if a film containing these metal oxides is present at the electrical connection, the electrical properties will change. Therefore, a protective film against liquids such as ink should not be provided at the electrical connection. Methods for forming a protective film without providing one at the electrical connection include film formation using a single-sided ALD apparatus, and a method of applying a protective tape to the protective substrate before forming the protective film. The obtained substrate can be made into chips by separating it into individual pieces.

[0111] Next, the manufacturing process of the individual nozzle channels 706 will be described with reference to Figure 15. First, a nozzle plate 1510 is prepared as shown in Figure 15(a). As the nozzle plate 1510, a silicon substrate with a crystal plane of (100) or (110) can be used, similar to the protective substrate 732. Next, as shown in Figure 15(b), the plate is ground, leaving the outer periphery of the nozzle plate 1510 intact. The grinding is performed using the TAIKO process (a registered trademark of DISCO Corporation) to thin only the inside of the nozzle plate 1510 to the desired thickness. A resist is applied to the thinned plate portion and patterned by photolithography. This forms an etching mask inside the thinned plate. By performing etching through this mask, the nozzle channels 204 are formed. The method for forming the nozzle channels 204 is the same as in the first embodiment of the manufacturing method of this disclosure. This makes it possible to obtain nozzle channels 204 having inclined surfaces 220 and 222.

[0112] Next, after removing the resist, an etching mask is formed on the side opposite to the nozzle channel 204 using the resist material. The nozzle 202 is formed by etching through this mask. The method for forming the nozzle 202 is as described in the first embodiment. Then, a protective film against liquids such as ink can be formed inside the thinned plate of the nozzle plate 1510 or on the portion of the nozzle channel 204. Then, the plate having the obtained nozzles is pieced into individual nozzle channel chips. This gives us individual nozzle channels 706.

[0113] Next, with reference to Figure 16, the manufacturing process of a liquid dispensing head according to a second embodiment of the present disclosure will be described.

[0114] First, a channel substrate 1602 is prepared as shown in Figure 16(a). A silicon substrate with a crystal plane of (100) or (110) can be used as the channel substrate 1602. Common channels 718 and 720, and individual channels 708, 710, 712, and 714 are formed on the channel substrate 1602. As a method for forming these channels, dry etching using the Bosch process, or a method combining wet etching with an alkaline aqueous solution and hole processing with a laser can be employed. Examples of alkaline aqueous solutions used for etching include tetramethylammonium hydroxide (TMAH) or alkali metal hydroxide (for example, potassium hydroxide (KOH)). After forming the common channels 718 and 720 and the individual channels 708, 710, 712, and 714, a protective film against liquids such as ink can be formed on each of the channels. The protective film can be formed by the method described above. After that, the obtained channel substrate 1602 can be separated into individual pieces. Next, the pressure chamber forming substrate 1400, as explained using Figure 14, is joined to the flow channel substrate 1602 and the damper 722 to fabricate the first flow channel substrate 702.

[0115] Next, a second flow channel substrate 704 is prepared, and the first flow channel substrate 702 and the individual nozzle flow channels 706 are joined together using an adhesive to obtain the liquid discharge head of the second embodiment.

[0116] Alternatively, as shown in Figure 16(a), a pressure chamber forming substrate 1400, a flow channel substrate 1602, a second flow channel substrate 704, a damper 722, and individual nozzle flow channels 706 are prepared, respectively. These are then joined together using an adhesive to obtain the liquid discharge head of the second embodiment.

[0117] By electrically connecting a drive driver IC to the obtained liquid ejection head, and further connecting a circulation system for circulating liquids such as ink, a liquid ejection head including the circulation system can be obtained.

[0118] <Fourth embodiment of a method for manufacturing a liquid dispensing head> A fourth embodiment of the manufacturing method of this disclosure is a method for manufacturing the liquid dispensing head of the third embodiment (the liquid dispensing head shown in Figure 8).

[0119] The liquid discharge head of the third embodiment can be manufactured using the same procedure as the liquid discharge head of the first embodiment described above, without providing individual recovery channels, a first common recovery channel, and a second common recovery channel. For example, the elements of the first channel substrate, the second channel substrate, and the third channel substrate are formed so as to be arranged symmetrically with respect to the center of the liquid discharge head, as shown in Figure 8. Next, the first channel substrate, the second channel substrate, and the third channel substrate are joined together in the same manner as the first embodiment of the manufacturing method of the present disclosure described above. [Examples]

[0120] The liquid dispensing head of this disclosure will be described in more detail below based on examples. The following examples are not intended to limit the liquid dispensing head of this disclosure to any particular embodiment.

[0121] (Example 1) This embodiment is an example of manufacturing a liquid dispensing head according to the first embodiment of the present disclosure (see Figures 9 to 11).

[0122] First, the channel substrate 1000 of the second channel substrate 604 was prepared (Figure 10(a)). A 600 μm thick silicon substrate was prepared, and the channel substrate 1000, including the first common supply channel, individual supply channels 206, portions 214' corresponding to individual cavities, individual recovery channels 208, and the first common recovery channel, was formed from both sides by dry etching using the Bosch process.

[0123] Next, an actuator substrate 1002 was prepared, which had an energy generating element 210 and electrodes (not shown) on a substrate in which an oxide film 1006 and a diaphragm 212 were laminated on a support substrate 1004 (Figure 10(b)). Silicon was used for the support substrate 1004 and the diaphragm 212. A PZT (lead zirconate titanate) film was used for the piezoelectric material of the energy generating element 210. In addition, upper and lower electrodes connected to the PZT (lead zirconate titanate) film, electrical connection parts connected to the driver IC, wiring connecting the upper and lower electrodes to the electrical connection parts, interlayer insulating films, etc., were formed by known methods. Openings 216 and 218 corresponding to the individual supply channels 206 and individual recovery channels 208 of the second flow channel substrate 604, respectively, were formed on the diaphragm 212 and oxide film 1006 by dry etching (Figure 10(b)).

[0124] Next, an adhesive film was transferred to the bonding surface of the channel substrate 1000 to form an adhesive layer. Then, the channel substrate 1000 with the adhesive applied and the actuator substrate 1002 were bonded by wafer bonding, and the adhesive was heat-cured (Figure 10(c). Benzocyclobutene (BCB) was used as the adhesive.

[0125] Next, the support substrate 1004 of the actuator substrate 1002 was ground to a thickness of 10 μm by back grinding. Then, without setting a resist mask, the remaining support substrate 1004 was removed by dry etching, using the oxide film 1006 between the diaphragm 212 and the support substrate 1004 as a stop layer. This obtained the second channel substrate 604.

[0126] Next, a nozzle channel forming substrate 910 was prepared by laminating a support substrate 920, an oxide film 914, a silicon layer 916, an oxide film 914', and a nozzle channel layer 912 (Figure 9(a)). A novolac-based photoresist was applied to the nozzle channel layer side of this nozzle channel forming substrate 910, and exposure and development were performed to form a resist film having an aperture pattern. Silicon was used for the support substrate, silicon layer, and nozzle channel layer.

[0127] Next, the nozzle channel 204 was formed using dry etching with the Bosch process (Figure 9(b)). The etching conditions were set to a passivation process time of 10 seconds per cycle and an etching process time of 10 seconds per cycle. This cycle was repeated. The processing conditions for reactive ion etching at this time were a vacuum gas pressure (absolute pressure) of 5 Pa, a flow rate of SF6 gas of 500 sccm, and a flow rate of C4F8 gas of 500 sccm. Under these conditions, the shape of the nozzle channel was processed so that its width narrowed in the direction of etching. The inclination angles 224(θ1) and 226(θ2) of the inclined surfaces 220 and 222 of the nozzle channel at this time were 80°.

[0128] Next, an adhesive film was transferred onto the nozzle channel forming substrate 910, on which the nozzle channel 204 was formed. The adhesive was applied to the side on which the nozzle channel was formed. The nozzle channel forming substrate 910 with the adhesive applied and the second channel substrate 604 obtained according to the procedure described above were bonded together, and then the adhesive was heat-cured (Figure 11(a)). Benzocyclobutene (BCB) was used as the adhesive.

[0129] Next, the support substrate 920 of the nozzle channel formation substrate 910 was ground to a thickness of 10 μm by back grinding. Then, without setting a resist mask, the remaining support substrate 920 was removed by dry etching, using the oxide film 914' between the silicon layer 916 and the support substrate 920 as a stop layer. After that, the nozzle 202 was formed on the first channel substrate side by dry etching using the Bosch process. The obtained substrate was diced to obtain the ejection channel substrate 1110 (Figure 11(c)).

[0130] A third channel substrate 606 was prepared separately, which included a second common supply channel 616, a second common recovery channel 618, and a damper 612 made of polyimide film. This third channel substrate 606 was joined to the discharge channel substrate 1110 to obtain a liquid discharge head chip (Figure 11(e)). A drive driver IC was electrically connected to this liquid discharge head chip, and a supply system including an ink circulation system was connected to obtain a liquid discharge head.

[0131] In this embodiment, the liquid discharge head, with its inclined surfaces 220 and 222 of the nozzle channel 204 formed by dry etching using the Bosch process, suppresses liquid concentration and achieves stable discharge function.

[0132] (Example 2) This embodiment is an example of another embodiment (Figure 3(b)) of the nozzle channel 204 of Example 1. Therefore, the steps other than the method of forming the nozzle channel 204 are the same as in Example 1. For this reason, the explanation of the redundant steps will be omitted.

[0133] A nozzle channel forming substrate 910 was prepared by laminating a support substrate 920, an oxide film 914, a silicon layer 916, an oxide film 914', and a nozzle channel layer 912. A novolac-based photoresist was applied to the nozzle channel layer side of this nozzle channel forming substrate 910. The resulting resist film was exposed and developed to form an aperture pattern. Silicon was used for the support substrate, silicon layer, and nozzle channel layer. In particular, silicon crystals with a crystal plane of (100) were used for the silicon layer 916.

[0134] Next, a protective film was formed on the support substrate surface and the wafer edge of the silicon layer, and the nozzle channel 204 was processed by anisotropic etching using a 22% aqueous solution of TMAH (tetramethylammonium hydroxide) heated to 83°C. The inclination angles 224(θ1) and 226(θ2) of the inclined surfaces 220 and 222 of the obtained nozzle channel 204 were 54.7°.

[0135] (Example 3) This embodiment is an example of another embodiment (Figure 4) of the nozzle channel 204 of Example 1. Therefore, the steps other than the method of forming the nozzle channel 204 are the same as in Example 1. For this reason, the explanation of the redundant steps will be omitted.

[0136] A nozzle channel forming substrate was prepared by laminating a support substrate 920, an oxide film 914, a silicon layer 916, an oxide film 914', and a nozzle channel layer 912. A novolac-based photoresist was applied to the nozzle channel layer side of this nozzle channel forming substrate 910. The resulting resist film was exposed and developed to form an aperture pattern. Silicon was used for the support substrate, silicon layer, and nozzle channel layer. In particular, silicon crystals with a crystal plane of (110) were used for the silicon layer 916.

[0137] Next, a protective film was formed on the support substrate surface and the wafer edge of the silicon layer, and the nozzle channel 204 was processed by anisotropic etching using a 22% aqueous solution of TMAH (tetramethylammonium hydroxide) heated to 83°C. The inclination angles 224(θ1) and 226(θ2) of the inclined surfaces 220 and 222 of the obtained nozzle channel 204 were 28.1°.

[0138] (Example 4) This embodiment is another example of the method for forming the nozzle channel 204 and nozzle 202 in Example 1. Other steps are the same as in Example 1. Therefore, the explanation of redundant steps will be omitted.

[0139] A nozzle-forming substrate 1200 is prepared, having a second channel substrate 604 and a silicon wafer (support substrate) 1210 (Figure 12(a)). The nozzle-forming substrate 1200 can be formed by joining the second channel substrate 604 and the silicon wafer (support substrate) 1210. Known methods such as bonding with adhesive can be used for joining. The support substrate 1210 of this nozzle-forming substrate 1200 was ground by back-grinding to leave a thickness of 100 μm (Figure 12(b)).

[0140] Next, a novolac-based photoresist was applied to the surface of the support substrate 1210, and exposure and development were performed to form an opening pattern corresponding to the nozzle channel 204.

[0141] Next, a nozzle channel 204 was formed in the support substrate 1210 by dry etching using the Bosch process, and a substrate 1220 having a nozzle channel was obtained (Figure 12(c)). The etching conditions were set to a passivation process time of 5 seconds per cycle and an etching process time of 25 seconds per cycle. This cycle was repeated. The processing conditions for reactive ion etching at this time were a vacuum gas pressure (absolute pressure) of 5 Pa, an SF6 gas flow rate of 500 sccm, and a C4F8 flow rate of 500 sccm. Under these conditions, the portion that would become the nozzle channel was processed into a shape that widens in the direction of etching. The inclination angles 224(θ1) and 226(θ2) of the inclined surfaces 220 and 222 of the nozzle channel at this time were 80°.

[0142] Next, a substrate 1300 for mounting a nozzle was prepared on a support substrate 1302, with an oxide film 1304, a silicon layer 1306, and an oxide film 1304' laminated on it (Figure 13(a)). The substrate 1300 for mounting the nozzle includes an SOI substrate layer 1308 containing the oxide film 1304, the silicon layer 1306, and the oxide film 1304'. The substrate 1300 for mounting the nozzle and the substrate 1220 having a nozzle channel were bonded together via an adhesive to obtain a bonded substrate 1310 (Figure 13(b)). Next, the adhesive was heat-cured. Benzocyclobutene (BCB) was used as the adhesive.

[0143] Next, the support substrate 1302 of the bonded substrate 1310 obtained as described above was ground to a thickness of 10 μm (Figure 13(c)). Then, without providing a resist mask, the support substrate 1302 was removed by dry etching using the oxide film 1304' of the SOI substrate layer 1308 as a stop layer. After that, the nozzle 202 was formed on the SOI substrate layer 1308 by dry etching using the Bosch process (Figure 13(d)).

[0144] (Example 5) This embodiment is an example of manufacturing a liquid dispensing head having the structure shown in Figure 7. The following explanation will be given with reference to Figures 14 to 16.

[0145] As shown in Figure 14, a pressure chamber forming substrate 1400 is formed. First, as shown in Figure 14(a), a protective substrate 732 having portions 1414 corresponding to individual cavities 734 is prepared. The protective substrate 732 is a silicon substrate with a crystal plane (110) and a thickness of 400 μm, and a thermal oxide film (not shown) is deposited on this silicon substrate. A resist film is formed on the thermal oxide film. This resist film has an opening pattern corresponding to portions 1414 corresponding to individual cavities 734 that protect the energy generating elements, and an opening 1412 for connection terminals (not shown) that expose connection terminals for connection to the wiring board. The openings were formed by anisotropic etching using potassium hydroxide (KOH).

[0146] Next, as shown in Figure 14(b), a substrate including a diaphragm 212 and an energy generating element 210 is prepared on a silicon substrate 1416. Although not shown in Figure 14(b), this silicon substrate can be provided with an upper electrode, a lower electrode, wiring, connection terminals, and a base layer between the lower electrode and the diaphragm 212. The silicon substrate 1416 is silicon with a crystal plane (110), the diaphragm is SiO2, the energy generating element is PZT (lead zirconate titanate), the upper and lower electrodes are Ir, the wiring and connection terminals are Au, and the base layer is zirconium oxide (ZrO2).

[0147] Next, as shown in Figure 14(c), the protective substrate 732 and the silicon substrate 1416 on which the diaphragm 212, energy generating element 210, etc., were attached were bonded together by wafer bonding using an adhesive. This obtained a bonded substrate. An amide-based adhesive was used for bonding. The adhesive was applied by preparing an adhesive sheet on a film and transferring the adhesive to the bonding surface of the protective substrate 732.

[0148] Next, as shown in Figure 14(d), the silicon substrate 1416 of the bonded substrate was ground to a thickness of 70 μm. Then, as shown in Figure 14(e), a pattern corresponding to the pressure chamber was formed on the silicon substrate side using photoresist. Next, a portion 1418 corresponding to the pressure chamber was formed by wet etching using potassium hydroxide (KOH) to obtain the pressure chamber forming substrate 1400. At this time, an opening for separating the obtained pressure chamber forming substrate 1400 into individual pieces was provided on the dicing line. Furthermore, tantalum oxide (TaO) was deposited as a protective film on the silicon substrate side of the obtained pressure chamber forming substrate. Then, the substrate with the deposited tantalum oxide (TaO) was separated into individual pieces by laser stealth dicing.

[0149] Next, as shown in Figure 15(a), a silicon substrate with a crystal plane (110) that would become the nozzle plate 1510 was prepared, and the plate was ground down until the thickness of the inside of the plate was 130 μm, leaving 2 mm at the edges of the plate.

[0150] Next, as shown in Figure 15(b), a resist film having an opening pattern corresponding to the nozzle channel was formed in the recess using photolithography with a resist. Using the resist film as a mask, a nozzle channel 204 with a depth of up to 100 μm was formed by anisotropic etching with potassium hydroxide (KOH). The inclination angle of the inclined surfaces 220 and 222 of the nozzle channel at this time was 28.1°.

[0151] Next, as shown in Figure 15(c), the nozzle 202 was formed by dry etching using the Bosch process from the side opposite to the nozzle channel 204.

[0152] Next, as shown in Figure 15(d), the substrate obtained as described above was separated into individual pieces by laser stealth dicing.

[0153] As shown in Figure 16(a), a channel substrate 1602 made of a silicon substrate with a crystal plane (110) was formed. Common channels 718 and 720 and individual channels 708, 710, 712 and 714 were formed on the channel substrate 1602 by laser hole processing and anisotropic etching using potassium hydroxide (KOH). In addition, a second channel substrate 704 having channels 736 and 738, and a damper 722 were prepared separately. The individual nozzle channels 706, the pressure chamber forming substrate 1400 obtained by the procedure described in Figure 14, the channel substrate 1602, and the damper 722 were joined together using adhesive. Subsequently, a wiring board for connecting the driver IC, connection terminals, etc. were connected to the obtained liquid discharge head chip, and then a liquid supply unit and a liquid circulation unit were connected.

[0154] <<Other Embodiments>> The disclosures described in each of the above embodiments include configurations represented by the following example of a liquid dispensing head.

[0155] <Configuration 1> A nozzle channel having a nozzle for discharging liquid, An individual supply channel for supplying liquid, comprising an individual supply channel connected perpendicularly to the nozzle channel at its longitudinal end, Includes, A liquid discharge head characterized in that the nozzle flow path has a wall surface at its end that is aligned with the direction in which the individual supply flow paths are connected, and the wall surface is inclined.

[0156] <Configuration 2> The liquid discharge head according to configuration 1, characterized in that the angle of inclination of the wall surface along the direction of the individual supply channel is 25° or more and less than 90°.

[0157] <Structure 3> The liquid discharge head according to configuration 1, further comprising an individual recovery channel connected perpendicularly to the nozzle channel at another end of the nozzle channel facing the aforementioned end, wherein the nozzle channel has a wall surface aligned with the direction of the individual recovery channel at the other end, and the wall surface aligned with the direction of the individual recovery channel is inclined.

[0158] <Structure 4> The liquid discharge head according to configuration 3, characterized in that the angle of inclination of the wall surface along the direction of the individual recovery channel is 25° or more and less than 90°.

[0159] <Composition 5> The liquid discharge head according to configuration 1, characterized in that the connection portion between the nozzle flow path and the individual supply flow path has an opening width W1, the inclination of the wall surface along the direction of the individual supply flow path has a width S1 in the longitudinal direction of the nozzle flow path, and a part of the width W1 and a part of the width S1 overlap.

[0160] <Composition 6> The liquid discharge head according to configuration 3, characterized in that the connection portion between the nozzle flow path and the individual recovery flow path has an opening width W1, the inclination of the wall surface along the direction of the individual recovery flow path has a width S1 in the longitudinal direction of the nozzle flow path, and a part of the width W1 and a part of the width S1 overlap.

[0161] <Composition 7> The liquid dispensing head according to configuration 5 or 6, characterized in that the width S1 is included within the range of the width W1.

[0162] <Structure 8> The liquid dispensing head according to configuration 5 or 6, characterized in that the width W1 is included within the range of the width S1.

[0163] <Composition 9> A liquid dispensing head according to any one of configurations 5 to 8, characterized in that the ratio of the width W1 to the width S1 is (S1 / W1) < 4.

[0164] <Composition 10> The liquid dispensing head according to any one of configurations 1 to 8, characterized in that the liquid dispensing head has a circulation system.

[0165] <Composition 11> A nozzle channel having a nozzle for discharging liquid, An individual supply channel for supplying liquid, comprising an individual supply channel connected perpendicularly to the nozzle channel at its longitudinal end, Includes, A method for manufacturing a liquid discharge head, wherein the nozzle flow path has a wall surface at its end that is aligned with the direction in which the individual supply flow paths are connected, and the wall surface is inclined, The process of forming the nozzle channel, The process includes forming the individual supply channels in the nozzle channel, A method for manufacturing a liquid discharge head, characterized in that the inclination is formed in the step of forming the nozzle channel. [Explanation of symbols]

[0166] 202 Nozzles 204 Nozzle flow path 206 Individual supply channels 208 Individual recovery channels 210 Energy generating element 212 Diaphragm 216 Aperture 218 Aperture 220 Slope 222 Slope

Claims

1. A nozzle channel having a nozzle for discharging liquid, An individual supply channel for supplying liquid, comprising an individual supply channel connected perpendicularly to the nozzle channel at its longitudinal end, Includes, A liquid discharge head characterized in that the nozzle flow path has a wall surface at its end that is aligned with the direction in which the individual supply flow paths are connected, and the wall surface is inclined.

2. The liquid discharge head according to claim 1, wherein the angle of inclination of the wall surface along the direction of the individual supply channel is 25° or more and less than 90°.

3. The liquid discharge head according to claim 1, further comprising an individual recovery channel connected perpendicularly to the nozzle channel at another end of the nozzle channel facing the aforementioned end, wherein the nozzle channel has a wall surface at the other end that is aligned with the direction of the individual recovery channel, and the wall surface aligned with the direction of the individual recovery channel is inclined.

4. The liquid discharge head according to claim 3, characterized in that the angle of inclination of the wall surface along the direction of the individual recovery channel is 25° or more and less than 90°.

5. The liquid discharge head according to claim 1, characterized in that the connection portion between the nozzle flow path and the individual supply flow path has an opening width W1, the inclination of the wall surface along the direction of the individual supply flow path has a width S1 in the longitudinal direction of the nozzle flow path, and a part of the width W1 and a part of the width S1 overlap.

6. The liquid discharge head according to claim 3, characterized in that the connection portion between the nozzle flow path and the individual recovery flow path has an opening width W1, the inclination of the wall surface along the direction of the individual recovery flow path has a width S1 in the longitudinal direction of the nozzle flow path, and a part of the width W1 and a part of the width S1 overlap.

7. The liquid dispensing head according to claim 5 or 6, characterized in that the width S1 is included within the range of the width W1.

8. The liquid dispensing head according to claim 5 or 6, characterized in that the width W1 is included within the range of the width S1.

9. The liquid discharge head according to claim 5, characterized in that the ratio of the width W1 to the width S1 is (S1 / W1) < 4.

10. The liquid dispensing head according to claim 1, characterized in that the liquid dispensing head has a circulation system.

11. A nozzle channel having a nozzle for discharging liquid, An individual supply channel for supplying liquid, comprising an individual supply channel connected perpendicularly to the nozzle channel at its longitudinal end, Includes, A method for manufacturing a liquid discharge head, wherein the nozzle flow path has a wall surface at its end that is aligned with the direction in which the individual supply flow paths are connected, and the wall surface is inclined, The process of forming the nozzle channel, The process includes forming the individual supply channels in the nozzle channel, A method for manufacturing a liquid discharge head, characterized in that the inclination is formed in the step of forming the nozzle channel.

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