Liquid dispensing head, head unit, and liquid dispensing device

Abstract

Suppresses deformation of the liquid dispensing head. [Solution] The liquid discharge head 20 comprises a plurality of nozzles for discharging liquid, a plurality of pressure chambers communicating with the plurality of nozzles, a plurality of individual flow paths communicating with the plurality of pressure chambers, a plurality of common flow path branches 241a, 241b that are arranged to overlap with the plurality of pressure chambers when viewed from the direction of liquid discharge from the nozzles and communicate with the plurality of individual flow paths, and a plurality of common flow path mains 240a, 240b that communicate with the plurality of common flow path branches 241a, 241b. The plurality of common flow path branches 241a, 241b are arranged at an angle greater than 45° and less than 90° relative to the common flow path mains 240a, 240b, and projections 30 that are the same height as the side wall surface 41 protrude from the side wall surface 41 of the groove 39 that constitute the common flow path branches 241a, 241b.

Description

Technical Field

[0001] The present invention relates to a liquid ejection head, a head unit, and a liquid ejection device.

Background Art

[0002] As a liquid ejection head mounted on an inkjet type image forming apparatus or the like, there is known one including a nozzle that ejects a liquid, a pressure chamber communicating with the nozzle, and an individual flow path communicating with the pressure chamber.

[0003] Further, in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2021-102287), a liquid ejection head having one or a plurality of main common flow paths and a plurality of branched common flow paths branching from the main common flow path as common flow paths communicating with a plurality of individual flow paths is disclosed.

[0004] In the liquid ejection head disclosed in Patent Document 1, a plurality of branched common flow paths are provided so as to extend obliquely with respect to the main common flow path. In such a configuration in which a plurality of branched common flow paths extend obliquely with respect to the main common flow path, due to the branched common flow paths extending obliquely, there is a risk that the liquid ejection head may be deformed such as twisted. However, in Patent Document 1, no countermeasures against such deformation have been studied.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, an object of the present invention is to suppress deformation of a liquid ejection head.

Means for Solving the Problems

[0006] To solve the above problems, the liquid discharge head according to the present invention comprises a plurality of nozzles for discharging liquid, a plurality of pressure chambers communicating with the plurality of nozzles, a plurality of individual flow paths communicating with the plurality of pressure chambers, a plurality of common flow path branches arranged to overlap with the plurality of pressure chambers when viewed from the discharge direction of the liquid discharged from the nozzles and communicating with the plurality of individual flow paths, and a common flow path main flow communicating with the plurality of common flow path branches, wherein the plurality of common flow path branches are arranged at an angle greater than 45° and less than 90° with respect to the common flow path main flow, and projections of the same height as the height of the side wall surface are provided to protrude from the side wall surface of the groove constituting the common flow path branch. [Effects of the Invention]

[0007] According to the present invention, deformation of the liquid dispensing head can be suppressed. [Brief explanation of the drawing]

[0008] [Figure 1] This is a plan view of a common flow path member included in a liquid discharge head according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view of the common flow channel member cut along line AA in Figure 1. [Figure 3] This diagram shows an example where a projection protrudes in a direction perpendicular to the tributary. [Figure 4] This diagram shows an example where a projection protrudes obliquely from a tributary. [Figure 5] This figure shows another example where the projection protrudes obliquely from the tributary. [Figure 6] This diagram shows an example where the protrusions are offset from each other. [Figure 7] This is a diagram showing a modified example of the protrusion. [Figure 8] This figure shows other variations of the protrusion. [Figure 9] This figure shows yet another variation of the protrusion. [Figure 10] This figure shows the results and details of the effectiveness verification test. [Figure 11]This is an exploded perspective view showing the overall configuration of a head unit to which the present invention can be applied. [Figure 12] Figure 11 is a cross-sectional view of the head unit. [Figure 13] This is a schematic diagram showing the overall configuration of an inkjet-type image forming apparatus, which is an example of a liquid ejection device to which the present invention can be applied. [Figure 14] This is a plan view showing the configuration of a line-type head unit. [Figure 15] This is a plan view showing the configuration of a serial-type head unit. [Figure 16] This is a schematic diagram showing the overall configuration of an electrode manufacturing apparatus to which the present invention can be applied. [Figure 17] This is an exploded perspective view showing the overall configuration of the liquid dispensing head in the comparative example. [Figure 18] This is an exploded perspective view showing a magnified portion of the liquid dispensing head related to the comparative example. [Figure 19] This is a plan view of the individual and common flow path members of a liquid discharge head in a comparative example, viewed from the direction of their stacking or from the direction of liquid discharge from the nozzle. [Figure 20] This diagram illustrates the deformation that occurs in the liquid dispensing head of the comparative example. [Figure 21] This diagram shows a configuration in which a pressure chamber is provided between tributaries. [Modes for carrying out the invention]

[0009] First, before describing the liquid dispensing head according to the present invention, we will describe the configuration and problems of a comparative example liquid dispensing head that differs from the present invention. In the drawings used in the following description, components such as members and parts having the same function or shape will be denoted by the same reference numerals as far as possible to distinguish them, and their description will be omitted after they have been described once.

[0010] <Structure of the comparative example> Figure 17 is an exploded perspective view showing the overall configuration of the liquid dispensing head 200 according to a comparative example.

[0011] As shown in FIG. 17, the liquid ejection head 200 according to the comparative example includes a nozzle plate 201, an individual flow path member 202, a diaphragm member 203, a common flow path member 204, a damper member 205, a damper frame member 206, a frame member 207, a wiring board 209 on which a drive circuit 208 is mounted, and the like.

[0012] The nozzle plate 201, the individual flow path member 202, the diaphragm member 203, the common flow path member 204, the damper member 205, the damper frame member 206, and the frame member 207 are laminated and joined in this order. Further, the frame member 207 is provided with a supply port 210 for supplying liquid from an external liquid circulation path and a recovery port 211 for returning the liquid to the external liquid circulation path.

[0013] FIG. 18 is an exploded perspective view showing an enlarged part of the liquid ejection head 200 according to the comparative example.

[0014] As shown in FIG. 18, the nozzle plate 201 is provided with a plurality of nozzles 215 for ejecting liquid. The plurality of nozzles 215 are arranged in a two-dimensional matrix and constitute a nozzle group.

[0015] The individual flow path member 202 is a member having a plurality of pressure chambers (individual liquid chambers) 220 communicating with the plurality of nozzles 215 and a plurality of individual flow paths 221 communicating with each pressure chamber 220. The plurality of pressure chambers 220 are provided one by one corresponding to each nozzle 215. Therefore, when the individual flow path member 202 is joined to the nozzle plate 201, the pressure chambers 220 are arranged to communicate with the corresponding nozzles 215. The individual flow paths 221 include an individual supply flow path 221a and an individual recovery flow path 221b which are arranged on opposite sides of each other with the pressure chamber 220 interposed therebetween. Both the individual supply flow path 221a and the individual recovery flow path 221b communicate with the pressure chamber 220.

[0016] The diaphragm member 203 is a deformable member that is joined to the individual flow channel member 202 on the side opposite to the nozzle plate 201. By joining the diaphragm member 203 to the individual flow channel member 202, the opening of the groove constituting the pressure chamber 220 of the individual flow channel member 202 is sealed by the diaphragm member 203, and a deformable wall surface is formed by the diaphragm member 203 at the sealed location. In addition, a piezoelectric element 230 is provided at the location of the diaphragm member 203 corresponding to the pressure chamber 220. The piezoelectric element 230 is a member made up of, for example, piezoelectric layers and internal electrodes stacked alternately. The internal electrodes of the piezoelectric element 230 are connected to the wiring board 209 (see Figure 17) via external electrodes. As a result, when a driving voltage is applied to the piezoelectric element 230 via the wiring board 209, the piezoelectric element 230 expands and contracts, causing the diaphragm member 203 to deform. Furthermore, the diaphragm member 203 is provided with a supply-side opening 231 that communicates with the individual supply channel 221a and a recovery-side opening 232 that communicates with the individual recovery channel 221b.

[0017] The common flow channel member 204 is a member having a plurality of common main flow channels 240 and a plurality of common branch flow channels 241 that branch off from each common main flow channel 240. The common main flow channel 240 includes a common supply flow channel 240a that communicates with the supply port 210 (see Figure 17) and a common recovery flow channel 240b that communicates with the recovery port 211 (see Figure 17). The common branch flow channels 241 include a plurality of common supply flow channel branches 241a that branch off from the common supply flow channel 240a and a plurality of common recovery flow channel branches 241b that branch off from the common recovery flow channel 240b. Each common supply flow channel branch channel 241a is provided with a plurality of supply ports 242 that communicate with each supply-side opening 231 of the diaphragm member 203. On the other hand, each common recovery flow channel branch channel 241b is provided with a plurality of recovery ports 243 that communicate with each recovery-side opening 232 of the diaphragm member 203. As a result, the common flow channel member 204 and the diaphragm member 203 are joined together, and when the diaphragm member 203 and the individual flow channel member 202 are joined together, the common supply channel branch 241a communicates with the individual supply channel 221a via the supply-side opening 231 of the diaphragm member 203, and the common recovery channel branch 241b communicates with the individual recovery channel 221b via the recovery-side opening 232 of the diaphragm member 203.

[0018] The damper member 205 is a deformable member that is joined to the common flow channel member 204 on the side opposite to the diaphragm member 203 of the common flow channel member 204. By joining the damper member 205 to the common flow channel member 204, the openings of the grooves that make up the common supply channel main flow 240a, the common recovery channel main flow 240b, the common supply channel branch 241a, and the common recovery channel branch 241b are sealed.

[0019] In a comparative example of such a configuration, when liquid is supplied from an external liquid circulation path via the supply port 210, the supplied liquid is delivered to the pressure chamber 220 via the common supply channel main flow 240a, the common supply channel branch 241a, the supply port 242, the supply side opening 231, and the individual supply channels 221a.

[0020] The liquid supplied to the pressure chamber 220 is then pushed out of the pressure chamber 220 and discharged from the nozzle 215 as the diaphragm member 203 deforms due to the expansion and contraction of the piezoelectric element 230. At this time, pressure fluctuations may occur in the liquid flow path (for example, the individual supply flow path 221a) due to the liquid discharge. However, in the liquid discharge head 200 according to the comparative example, a damper member 205 is provided, which can suppress the propagation of pressure fluctuations to other nozzles 215. This reduces the effect of pressure fluctuations propagating to other nozzles 215 (crosstalk) and stabilizes the liquid discharge accuracy.

[0021] Furthermore, any liquid that is not discharged from the nozzle 215 is returned from the pressure chamber 220 to the external liquid circulation path via the individual recovery channel 221b, the recovery side opening 232, the recovery port 243, the common recovery channel branch 241b, the common recovery channel main channel 240b, and the recovery port 211.

[0022] <Challenges in the comparative example> Next, I will explain the challenges in the comparative example.

[0023] Figure 19 is a plan view of the individual flow path members 202 and common flow path member 204 of the liquid discharge head 200 according to the comparative example, viewed from the direction of their stacking or from the direction of liquid discharge from the nozzle 215.

[0024] As shown in Figure 19, in the comparative example, the common supply channel main stream 240a and the common recovery channel main stream 240b are arranged to extend parallel to each other in the vertical direction of the figure (arrows P1, P2 direction). In contrast, the multiple common supply channel branches 241a extend from the common supply channel main stream 240a toward the left side of Figure 19 (towards the common recovery channel main stream 240b side), and the multiple common recovery channel branches 241b are arranged between the multiple common supply channel branches 241a so as to extend from the common recovery channel main stream 240b toward the right side of Figure 19 (towards the common supply channel main stream 240a side). In other words, the common supply channel branches 241a and the common recovery channel branches 241b are arranged alternately between the common supply channel main stream 240a and the common recovery channel main stream 240b, across their respective extension directions (arrows P1, P2 direction).

[0025] Furthermore, as shown in Figure 19, the common supply channel branch 241a is arranged to overlap with each individual supply channel 221a so as to communicate with each individual supply channel 221a in order to supply liquid to multiple pressure chambers 220. On the other hand, the common recovery channel branch 241b is arranged to overlap with each individual recovery channel 221b so as to communicate with each individual recovery channel 221b in order to recover liquid from multiple pressure chambers 220. In addition, the pressure chambers 220 do not overlap with the common supply channel main channel 240a and the common recovery channel main channel 240b, but are arranged to overlap with the common supply channel branch 241a and the common recovery channel branch 241b.

[0026] Here, the common supply channel tributary 241a and common recovery channel tributary 241b in the comparative example are arranged to be inclined (intersect) with respect to the common supply channel main channel 240a and common recovery channel main channel 240b. In this case, the directions of arrows Q1 and Q2 in Figure 19, which are the extension directions of the common supply channel tributary 241a and common recovery channel tributary 241b, are inclined with respect to the directions of arrows P1 and P2 in the same figure, which are the extension directions of the common supply channel main channel 240a and common recovery channel main channel 240b, by angles θ1 and θ2 in the range of greater than 45° and less than 90° (45° < θ1, θ2 < 90°).

[0027] In this context, "extension direction" refers to the direction in which the flow path primarily extends. Therefore, as in the example in Figure 19, if both the common supply channel tributary 241a and the common recovery channel tributary 241b bend and extend along their course, the main "extension directions" are defined as the directions Q1 and Q2 in which the common supply channel tributary 241a and the common recovery channel tributary 241b extend for the longest distance.

[0028] Thus, in the comparative example, both the common supply channel tributary 241a and the common recovery channel tributary 241b are inclined with respect to the common supply channel main channel 240a and the common recovery channel main channel 240b. As a result of the inclination of each tributary 241a and 241b, bending stress acts on the common channel member 204 in the directions of arrows R1 and R2 in Figure 20, causing deformation (strain). In particular, in a configuration like the comparative example, where the member having the common supply channel tributary 241a and the common recovery channel main channel 240b (common channel member 204) and the member having the pressure chamber 220 (individual channel member 202) are composed of separate members, and the tributaries 241a and 241b and the pressure chamber 220 are arranged to overlap, deformation as shown in Figure 20 is likely to occur. In other words, while a configuration like the comparative example allows for a more compact common flow channel member 204 by bringing the tributaries 241a and 241b closer together, compared to a configuration where, for example, a pressure chamber 220 is provided between each tributary 241a and 241b as shown in Figure 21 (see Japanese Patent Publication No. 5495385), the partition wall separating the tributaries 241a and 241b becomes thinner, making it difficult to obtain rigidity and prone to deformation.

[0029] Therefore, in the comparative example, if deformation occurs in the common flow channel member 204, when the members including the common flow channel member 204 are joined together, the deformation may reduce the discharge performance of the liquid discharge head. For example, if twisting occurs as shown in Figure 20, the liquid discharge speed may decrease in the area where bending stress acts in the direction of arrow R1.

[0030] Therefore, the objective of the present invention is to suppress deformation of the liquid discharge head and to obtain good discharge performance. The features of the present invention will be described below with reference to embodiments of the present invention.

[0031] <Configuration of the liquid dispensing head according to the present invention> Figure 1 is a plan view of a common flow path member 204 provided in a liquid discharge head 20 according to an embodiment of the present invention.

[0032] As shown in Figure 1, in the common flow path member 204 of the liquid discharge head 20 according to the embodiment of the present invention, the common supply flow path branch 241a and the common recovery flow path branch 241b are both inclined with respect to the common supply flow path main flow 240a and the common recovery flow path main flow 240b, similar to the comparative example described above. That is, the extension directions Q1 and Q2 in which the common supply flow path branch 241a and the common recovery flow path branch 241b extend are inclined at angles θ1 and θ2 greater than 45° and less than 90° with respect to the extension directions P1 and P2 in which the common supply flow path main flow 240a and the common recovery flow path main flow 240b extend (45° < θ1, θ2 < 90°).

[0033] In Figure 1, the common supply channel main stream 240a, common recovery channel main stream 240b, common supply channel branch 241a, and common recovery channel branch 241b are shown in a simplified manner compared to the comparative example. However, the liquid discharge head 20 according to the embodiment of the present invention has basically the same configuration as the liquid discharge head 200 according to the comparative example, except for the characteristic parts described below.

[0034] As shown in Figure 1, in the liquid discharge head 20 according to the embodiment of the present invention, unlike the liquid discharge head 200 according to the comparative example, a plurality of protrusions 30 are provided on the side wall surface 41 of each groove 39 constituting the common supply channel branch 241a and the common recovery channel branch 241b. The protrusions 30 are provided so as to protrude from both or one of the opposing pair of side wall surfaces 41 of each groove 39 constituting the common supply channel branch 241a and the common recovery channel branch 241b. In this case, the protrusions 30 protrude from both of the pair of side wall surfaces 41 in each branch 241a, 241b, except for the outermost common supply channel branch 241a and the outermost common recovery channel branch 241b, while in the outermost common supply channel branch 241a and the outermost common recovery channel branch 241b, the protrusions 30 protrude from only one of the pair of side wall surfaces 41. In other words, the projections 30 are provided to protrude from each (or both) of the opposite side wall surfaces 41 of the partition wall 40 that separates the tributaries 241a and 241b.

[0035] Figure 2 is a cross-sectional view obtained by cutting the common flow channel member 204 along line AA in Figure 1.

[0036] As shown in Figure 2, the projections 30 are provided to be at a height T2 that is the same as the height T1 (depth of the groove 39) of the side wall surface 41 of each groove 39 that constitutes the common supply channel branch 241a and the common recovery channel branch 241b. Furthermore, the amount of projection (length of projection 30) L that the projection 30 protrudes from the side wall surface 41 is set to an amount that does not obstruct the appropriate flow of liquid. Specifically, it is preferable that the proportion of the width W of the groove 39 occupied by the projection L of one projection 30 is 30% or less.

[0037] As described above, in the liquid discharge head 20 according to the embodiment of the present invention, the multiple protrusions 30 are provided so as to protrude from the side wall surface 41 constituting the common supply channel branch 241a and the common recovery channel branch 241b at the same height T2 as the height T1 of the side wall surface 41, thereby suppressing deformation of the common channel member 204. That is, since the multiple protrusions 30 function as reinforcing parts that reinforce the common channel member 204, even in a configuration where the common supply channel branch 241a and the common recovery channel branch 241b are arranged at an angle with respect to the common supply channel main channel 240a and the common recovery channel main channel 240b, deformation such as twisting caused by the inclination of these branches 241a and 241b can be suppressed. Accordingly, according to the liquid discharge head 20 according to the embodiment of the present invention, a decrease in discharge speed due to deformation can be avoided, and good discharge performance can be ensured.

[0038] In particular, in a configuration as in the embodiment of the present invention, where each branch 241a, 241b and the pressure chamber 220 are provided in separate members (common flow channel member 204 and individual flow channel members 202), and the branches 241a, 241b and the pressure chamber 220 are arranged to overlap (see Figures 17 to 19), while the common flow channel member 204 can be made compact, the partition wall portion 40 between the branches 241a and 241b tends to become thinner. However, by applying the configuration of the present invention, the partition wall portion 40 can be reinforced to ensure rigidity. As a result, a decrease in discharge performance due to deformation can be avoided, and good discharge performance can be obtained.

[0039] Furthermore, in order to effectively suppress deformation of the liquid discharge head, it is preferable that the protruding direction of the projection 30 is perpendicular to the extension directions Q1 and Q2 of each branch 241a and 241b. The "protruding direction" of the projection 30 refers to the direction of the straight line B connecting the midpoint m at the base (root) of the projection 30 and the furthest tip v of the projection 30, as shown in Figure 3, when the projection 30 is viewed from the stacking direction of each member or the liquid discharge direction (plan view). In the embodiment of the present invention, the protruding direction of the projection 30 (direction of the straight line B) is configured to be perpendicular to the extension directions Q1 and Q2 of each branch 241a and 241b.

[0040] The projection direction of the projection 30 (direction of straight line B) does not necessarily have to be perpendicular to the extension directions Q1 and Q2 of each tributary 241a and 241b. For example, as shown in Figure 4 or Figure 5, the projection direction of the projection 30 (direction of straight line B) may be oblique to the extension directions Q1 and Q2 of each tributary 241a and 241b. In that case, it is preferable that the projection direction of the projection 30 (direction of straight line B) is inclined within a range of 30° or less (0° < α, β ≤ 30°) from the direction perpendicular to the extension directions Q1 and Q2 of each tributary 241a and 241b, and more preferably within a range of 10° or less (0° < α, β ≤ 10°).

[0041] Furthermore, in the example shown in Figure 1, the protrusions 30 are arranged at equal intervals along the extension directions Q1 and Q2 of the common supply channel tributary 241a and the common recovery channel tributary 241b, and are also arranged along a straight line perpendicular to the extension directions Q1 and Q2 of each tributary 241a and 241b (on line AA in Figure 1). However, the arrangement of the protrusions 30 is not limited to the example in Figure 1. For example, as in the example in Figure 6, the protrusions 30 protruding from opposing side wall surfaces 41 may be offset from each other in the extension directions Q1 and Q2 of each tributary 241a and 241b. In this way, when the protrusions 30 are offset from each other in the extension directions Q1 and Q2 of each tributary 241a and 241b, a wider width can be secured for each tributary 241a and 241b. The position of the projection 30 can be changed as appropriate, as long as it does not block the supply port 242 (see Figure 18) provided in the common supply channel branch 241a and the recovery port 243 (see Figure 18) provided in the common recovery channel branch 241b.

[0042] Furthermore, the projection 30 may be formed in a semicircular shape (only a semicircle) as shown in Figure 7, in addition to the case where it protrudes linearly from the side wall surface 41 and the tip is formed in a semicircular shape, as shown in Figure 3. When the tip of the projection 30 is formed in a convex curved surface such as a semicircle, as shown in Figure 3 or Figure 7, it is possible to suppress the accumulation of air bubbles and the increase in pressure loss in each tributary 241a, 241b, thereby making the liquid flow smoother. Moreover, the projection 30 is not limited to cases where the tip is formed in a convex curved surface; it may be a rectangle as shown in Figure 8, a triangle as shown in Figure 9, or any other polygonal shape.

[0043] Furthermore, the projection 30 may be made of a different material (e.g., Si (silicon)) than the material that constitutes each branch 241a and 241b, or it may be made of the same material. If the projection 30 is made of the same material as each branch 241a and 241b, the projection 30 can be molded together with each branch 241a and 241b, thus simplifying the manufacturing process.

[0044] <Effectiveness Confirmation Test> Next, based on the table in Figure 10, we will explain the effectiveness verification test for confirming the effects of the present invention.

[0045] In this efficacy verification test, multiple samples (liquid dispensing heads) were prepared, and the dispensing speed of each sample was evaluated. Specifically, a sample without the protrusion 30 according to the present invention was created as "Comparative Example 1," and the dispensing speed of "Comparative Example 1" was used as a baseline to evaluate how much the dispensing speed of the other samples improved.

[0046] In addition to "Comparative Example 1," we also prepared "Comparative Example 2," in which the height T2 of the projection 30 is only half the height T1 of the side wall surface 41, and "Examples 1" to "Examples 10" of the present invention, in which the projection 30 has the same height T2 as the height T1 of the side wall surface 41.

[0047] In the table in Figure 10, "Protrusion Amount / Tributary Width" indicates the proportion of the width W (see Figure 2) of the grooves 39 constituting each tributary 241a, 241b that is occupied by the protrusion amount L of one projection 30. In other words, the larger the protrusion amount L of the projection 30, the larger the value of "Protrusion Amount / Tributary Width". Also, in Figure 10, "Presence or Absence of Misalignment with Opposing Projections" indicates whether the projections 30 protruding from opposing sidewall surfaces 41 are offset from each other in the extension directions Q1, Q2 of each tributary 241a, 241b. That is, as in Figure 1, if the projections 30 are arranged on a straight line perpendicular to the extension directions Q1, Q2 of each tributary 241a, 241b (on line AA in Figure 1), it is indicated as "No Misalignment", and as in Figure 6, if the projections 30 are arranged offset from each other in the extension directions Q1, Q2 of each tributary 241a, 241b, it is indicated as "Misalignment Present". Furthermore, the "projection angle" in Figure 10 indicates how much the projection direction of the projection 30 is inclined from the direction perpendicular to the extension directions Q1 and Q2 of each tributary 241a and 241b. Here, as in Figure 4, the inclination angle α when the projection 30 is inclined to the left is represented by a negative value, and conversely, as in Figure 5, the inclination angle β when the projection 30 is inclined to the right is represented by a positive value. The values ​​and conditions of "projection amount / tributary width," "presence or absence of displacement with opposing projections," and "projection angle" for "Comparative Example 2" and "Examples 1" to "Examples 10" of the present invention are as shown in Figure 10.

[0048] As shown in Figure 10 under "Improvement Rate of Discharge Speed," the test results indicate that in all cases of "Example 1" to "Example 10" of the present invention, the discharge speed was improved. On the other hand, no improvement in discharge speed was observed in "Comparative Example 2." From this, it was confirmed that by setting the height T2 of the projection 30 to the same height T1 as the side wall surface 41, as in "Example 1" to "Example 10" of the present invention, a good reinforcing effect by the projection 30 can be obtained, and the decrease in discharge speed due to deformation can be effectively improved. Furthermore, among the examples of the present invention, the discharge speed was significantly improved, especially in "Example 3" to "Example 10," where the "projection amount / stream width" was 20% or more. Therefore, it can be said that a larger projection amount of the projection 30 is preferable in suppressing deformation of the liquid discharge head.

[0049] Although not reflected in the results in Figure 10, in "Example 9" and "Example 10," where the "protrusion amount / branch width" was 30%, a slight decrease in discharge speed was observed compared to the case where the "protrusion amount / branch width" was 20%. If the proportion occupied by the protrusion amount L of the projection 30 is increased further, there is a concern that discharge failures may occur, so it is preferable that the proportion occupied by the protrusion amount L of the projection 30 is 30% or less. Accordingly, it can be said that the proportion occupied by the protrusion amount L of the projection 30 ("protrusion amount / branch width") of the width W of the groove 39 is preferably 20% or more and 30% or less (20% ≤ L / W × 100 ≤ 30%). In addition, in "Example 4" and "Example 5," where the "protrusion angle" was ±30°, a slight decrease in fluidity was observed around the base of the projection 30. If the inclination angles α and β in the direction of projection of the projection 30 are increased further, there is a concern that problems may occur due to immobile ink, so it is preferable that the inclination angles α and β in the direction of projection of the projection 30 are 30° or less. Therefore, it is preferable that the inclination angles α and β in the direction of projection of the projection 30 are greater than 0° and 30° or less (0° < α, β ≤ 30°).

[0050] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and can be modified as appropriate without departing from the spirit of the invention.

[0051] In embodiments of the present invention, as in the comparative example, the pressure chamber 220 is arranged such that, when viewed from the stacking direction or discharge direction of each component (see Figure 19), it does not overlap with the main common supply channel 240a and the main common recovery channel 240b, but overlaps with the common supply channel tributary 241a and the common recovery channel tributary 241b. However, the present invention is not limited to this configuration and can be applied to liquid discharge heads with other configurations.

[0052] Furthermore, in the embodiment of the present invention, the pressure chamber 220 is provided to extend in a direction different from the extension directions Q1 and Q2 in which the common supply channel tributary 241a and the common recovery channel tributary 241b extend (for example, in the direction toward the upper right in Figure 19). However, the arrangement and orientation of the pressure chamber 220 are not limited to this and can be changed as appropriate.

[0053] <Head unit configuration> The present invention is also applicable, for example, to a liquid discharge head 20 mounted on a head unit 13 shown in Figures 11 and 12. An example of a head unit 13 to which the present invention can be applied will be described below based on Figures 11 and 12.

[0054] Figure 11 is an exploded perspective view showing the overall configuration of a head unit 13 to which the present invention can be applied. Figure 12 is a cross-sectional view of the head unit 13 shown in Figure 11.

[0055] As shown in Figure 11, the head unit 13 comprises a plurality of liquid discharge heads 20, a base member 22, a cover member 23, a heat dissipation member 24, a manifold 25, a printed circuit board (PCB) 26, and a module case 27.

[0056] Multiple liquid discharge heads 20 are held by a base member 22 which acts as a holding member. To attach the liquid discharge heads 20 to the base member 22, first, the liquid discharge heads 20 are inserted into openings 22c (see Figure 12) provided in the base member 22. Next, the liquid discharge heads 20 are joined to a cover member 23 which is joined to the base member 22. The cover member 23 has holes 23a (see Figure 11) corresponding to each liquid discharge head 20, and the peripheral edges of the liquid discharge heads 20 are joined to the edges of these holes 23a. The liquid discharge heads 20 are then fixed to the base member 22 by fastening them with screws. Specifically, flange portions of a common flow path member 35 (see Figure 12) of the liquid discharge heads 20 are provided on the front and back sides in the longitudinal direction (orthogonal to the plane of the paper in Figure 12), and these flange portions are fastened to the base member 22 with screws. From this point, the common flow path member 35 is held by the base member 22, and the liquid discharge head 20 is fixed in place. Note that the method of attaching the liquid discharge head 20 and the base member 22 is not limited to fastening with screws; other methods such as adhesive or crimping may also be used.

[0057] As shown in Figure 12, the liquid discharge head 20 includes a nozzle plate 31 on which a nozzle 21 is provided, individual flow path members 32 in which a pressure chamber 36 leading to the nozzle 21 is formed, a diaphragm member 33 including a piezoelectric element 42, a holding substrate 34 laminated on the diaphragm member 33, and a common flow path member 35 as a frame member laminated on the holding substrate 34.

[0058] The individual flow path member 32 has a pressure chamber (individual liquid chamber) 36, as well as an individual supply flow path 37 leading to the pressure chamber 36 and an individual recovery flow path 38 leading to the pressure chamber 36. The holding substrate 34 has a supply-side intermediate individual flow path 44 that connects to the individual supply flow path 37 via the supply-side opening 33a of the diaphragm member 33, and a recovery-side intermediate individual flow path 45 that connects to the individual recovery flow path 38 via the recovery-side opening 33b of the diaphragm member 33.

[0059] The common flow channel member (frame member) 35 has a common supply channel 46 that leads to the supply-side intermediate individual channel 44 and a common recovery channel 47 that leads to the recovery-side intermediate individual channel 45. The common supply channel 46 leads to the supply port 48 via the channel 51 of the manifold 25, and the common recovery channel 47 leads to the recovery port 49 via another channel 52 of the manifold 25.

[0060] The printed circuit board 26 is electrically connected to the piezoelectric element 42 in the liquid discharge head 20 via a flexible wiring member 50. A drive circuit (driver IC) 53 is mounted on the flexible wiring member 50.

[0061] In a liquid discharge head 20 mounted on a head unit 13 having the above configuration, if at least one of the common supply channel 46 and the common recovery channel 47 is composed of one or more common main channels and multiple common branch channels branching off from the common main channels, and the common branch channels are formed to be inclined with respect to the common main channels, there is a risk of deformation occurring due to the inclination of the common branch channels. For this reason, it is preferable to apply the present invention to suppress deformation. That is, by providing a projection on the side wall surface of the groove constituting the common branch channel that is the same height as the height of the side wall surface, deformation of the liquid discharge head 20 can be suppressed, and good discharge performance can be ensured.

[0062] <Configuration of the liquid dispensing device> Next, an example of a liquid dispensing device to which the present invention can be applied will be described.

[0063] Figure 13 is a schematic diagram showing the overall configuration of an inkjet-type image forming apparatus 1000, which is an example of a liquid ejection apparatus to which the present invention can be applied.

[0064] The image forming apparatus 1000 shown in Figure 13 comprises a sheet supply unit 1, a sheet transport unit 3, an image forming unit 2, a drying unit 4, and a sheet recovery unit 5.

[0065] The sheet supply unit 1 is the part that supplies the sheet S on which the image is formed. Specifically, the sheet supply unit 1 comprises a supply roller 11 on which a long sheet S is wound in a roll shape, and a tension adjustment mechanism 12 for adjusting the tension of the sheet S. The supply roller 11 is configured to be rotatable in the direction of the arrow in Figure 13, and the sheet S is fed out as the supply roller 11 rotates. The tension adjustment mechanism 12 has a plurality of adjustment rollers that stretch over the sheet S and apply tension. The tension of the sheet S is adjusted by changing the distance between the adjustment rollers, and the sheet S is supplied with a constant tension.

[0066] The sheet transport unit 3 functions as a transport means for transporting the sheet S. The sheet transport unit 3 includes, for example, a plurality of transport rollers 15 for transporting the sheet S. When the sheet S is supplied from the sheet supply unit 1 to the sheet transport unit 3, the sheet S is transported to the image forming unit 2 by the plurality of transport rollers 15.

[0067] The image forming unit 2 is the part that forms an image on the sheet S. Specifically, the image forming unit 2 includes a head unit 13 that ejects a liquid such as ink onto the sheet S, and a platen 14 that serves as a sheet support member for supporting the sheet S. The sheet S, which has been transported by the transport rollers 15, passes below the head unit 13 while being supported by the platen 14. At this time, the head unit 13 ejects a liquid (ink) onto the sheet S based on the input image information, thereby forming an image on the sheet S.

[0068] The drying section 4 is the part that dries the sheet S to which the liquid has been applied (discharged). The drying section 4 includes, for example, a heating drum 16 as a heating means for heating the sheet S. The heating drum 16 is a cylindrical heating member that houses a heating source such as a halogen heater inside. When the sheet S, to which an image has been formed in the image forming section 2, is transported to the drying section 4, the sheet S is heated by contact with the outer surface of the heating drum 16, and the sheet S is dried. In addition to contact-type heating means such as the heating drum 16, the heating means for heating the sheet S may also be non-contact-type heating means such as a hot air generator that blows hot air onto the sheet S.

[0069] The sheet retrieval unit 5 is the part that retrieves the sheet S on which the image has been formed. Specifically, the sheet retrieval unit 5 includes a retrieval roller 17 that winds up and retrieves the sheet S, and a tension adjustment mechanism 18 that adjusts the tension of the sheet S. The retrieval roller 17 is configured to rotate in the direction of the arrow in Figure 13, and as the retrieval roller 17 rotates, the sheet S is wound up into a roll and retrieved. The tension adjustment mechanism 18 has multiple adjustment rollers, similar to the tension adjustment mechanism 12 of the sheet supply unit 1. By changing the distance between the adjustment rollers, the tension of the sheet S is adjusted, and the sheet S is wound up with a constant tension and retrieved by the retrieval roller 17.

[0070] The head unit 13 mounted in the inkjet-type image forming apparatus 1000 described above includes a so-called line-type head unit that ejects liquid without moving relative to the conveyed sheet S, and a so-called serial-type head unit that ejects liquid while moving relative to the sheet S in a direction perpendicular to the conveying direction of the sheet S (sheet width direction). The present invention can be applied to either line-type or serial-type head units, and can suppress deformation of the liquid ejection head of each head unit. The configuration of each type of head unit will be briefly described below.

[0071] <Configuration of a line-type head unit> Figure 14 is a plan view showing the configuration of the line-type head unit 13A.

[0072] The line-shaped head unit 13A shown in Figure 14 includes a head holding member 55 that holds a plurality of liquid dispensing heads 20. The plurality of liquid dispensing heads 20 are arranged in a staggered pattern, for example, as shown in Figure 14. When the sheet S is transported in the direction of arrow Y in Figure 14 and reaches a position facing the head unit 13A, liquid is dispensed from the liquid dispensing heads 20. At this time, the head unit 13A does not move relative to the transported sheet S, and an image is formed on the sheet S by the dispensing of liquid from the liquid dispensing heads 20.

[0073] <Configuration of a serial-type head unit> Next, we will explain the configuration of a serial-type head unit.

[0074] Figure 15 is a plan view showing the configuration of the serial-type head unit 13B.

[0075] The serial head unit 13B shown in Figure 15 comprises a carriage 62 on which multiple liquid discharge heads 20 are mounted, a guide member (guide rod) 63 for guiding the carriage 62 in the main scanning direction X, which is the sheet width direction (a direction perpendicular to the transport direction Y), and a drive device 64 for moving the carriage 62.

[0076] The drive unit 64 includes, for example, a motor 65 which is a drive source, and a timing belt 68 wrapped around a drive pulley 66 and a driven pulley 67. When the motor 65 is driven and the drive pulley 66 rotates, the timing belt 68 rotates, causing the carriage 62 to move along the guide member 63 in the main scanning direction X. Also, by switching the rotation direction of the motor 65 between one direction and the opposite direction, the carriage 62 moves back and forth in the main scanning direction X.

[0077] As shown in Figure 15, the sheet S is transported in the direction of arrow Y, and when the sheet S reaches a predetermined image formation position, the movement of the sheet S stops temporarily. Then, the carriage 62 moves in the direction of the main scanning X, and liquid (ink) is ejected from the liquid ejection head 20. This forms one line of image on the stationary sheet S. Subsequently, the sheet S moves intermittently in the direction of arrow Y, and the reciprocating movement of the carriage 62 and the ejection operation of the liquid ejection head 20 are repeated, so that images are formed sequentially on the sheet S.

[0078] Furthermore, the liquid ejection head and head unit according to the present invention can be applied not only to image forming apparatuses, which are an example of liquid ejection devices, but also to other liquid ejection devices.

[0079] For example, the liquid dispensing head and head unit according to the present invention can also be applied to an electrode manufacturing apparatus that dispenses a liquid composition to manufacture electrodes. An example of an electrode manufacturing apparatus to which the present invention can be applied will be described below.

[0080] <Configuration of electrode manufacturing equipment> Figure 16 is a schematic diagram showing the overall configuration of an electrode manufacturing apparatus 700 to which the present invention can be applied.

[0081] Here, as an example of an electrode manufacturing apparatus 700, a manufacturing apparatus for forming an electrode composite layer containing an active material on an electrode substrate (current collector) will be described. The electrode composite layer is used, for example, as part of the configuration of an electrochemical element. There are no particular restrictions on the components of the electrochemical element other than the electrode composite layer, and known components can be appropriately selected. For example, components other than the electrode composite layer include a positive electrode, a negative electrode, and a separator.

[0082] The electrode manufacturing apparatus 700 shown in Figure 16 includes an ejection process section 110 which includes a step of applying a liquid composition for manufacturing electrodes onto a printing substrate 704 having an object to be ejected to form a liquid composition layer, and a heating process section 130 which includes a heating step of heating the liquid composition layer to obtain an electrode composite layer.

[0083] Furthermore, the electrode manufacturing apparatus 700 includes a transport unit 705 for transporting the printing substrate 704. The transport unit 705 transports the printing substrate 704 at a preset speed in the order of the discharge process unit 110 and the heating process unit 130. There are no particular restrictions on the method for manufacturing the printing substrate 704 having an object to be discharged, such as an active material layer, and known methods can be appropriately selected. The discharge process unit 110 includes a liquid discharge head 281a that realizes a dispensing process for applying a liquid composition onto the printing substrate 704, a container 281b that contains the liquid composition 707, and a supply tube 281c that supplies the liquid composition 707 contained in the container 281b to the liquid discharge head 281a.

[0084] In the discharge process section 110, the liquid composition 707 is discharged from the liquid discharge head 281a and applied to the printing substrate 704, forming a thin film layer of the liquid composition. The containment container 281b may be integrated with the electrode manufacturing apparatus or may be detachable from the electrode manufacturing apparatus. Alternatively, the containment container 281b may be a container used for adding to a containment container integrated with the electrode manufacturing apparatus or a containment container detachable from the electrode manufacturing apparatus.

[0085] The containment container 281b and the supply tube 281c can be arbitrarily selected as long as they are capable of stably containing and supplying the liquid composition 707.

[0086] In the heating section 130, a solvent removal step is performed in which the solvent remaining in the liquid composition layer is heated and removed. Specifically, the solvent remaining in the liquid composition layer is heated and dried by the heating device 703 of the heating section 130, thereby removing the solvent from the liquid composition layer. This forms the electrode composite layer. Furthermore, the solvent removal step in the heating section 130 may be performed under reduced pressure.

[0087] There are no particular restrictions on the heating device 703, and it can be appropriately selected according to the purpose. For example, the heating device 703 can be a substrate heater, an IR heater, or a hot air heater. Alternatively, the heating device 703 may be a combination of at least two of the substrate heater, IR heater, and hot air heater. Furthermore, the heating temperature and heating time can be appropriately selected according to the boiling point of the solvent contained in the liquid composition 707 or the film thickness to be formed.

[0088] The object onto which the liquid composition is discharged (hereinafter sometimes referred to as the "discharge target") is not particularly limited as long as it is an object on which a layer containing electrode material is formed, and can be appropriately selected according to the purpose. For example, the target object may be an electrode substrate (current collector), an active material layer, or a layer containing solid electrode material. The target object may also be an electrode composite layer containing active material on an electrode substrate (current collector). Furthermore, the discharge means and discharge process may be means and processes for forming a layer containing electrode material by directly discharging the liquid composition, as long as it is possible to form a layer containing electrode material on the discharge target. Alternatively, the discharge means and discharge process may be means and processes for forming a layer containing electrode material by indirectly discharging the liquid composition.

[0089] By applying the present invention to the electrode manufacturing apparatus 700 described above, deformation of the liquid discharge head can be suppressed and good discharge performance can be ensured, making it possible to discharge the liquid composition to the target location of the object to be discharged.

[0090] Furthermore, the liquid dispensing device according to the present invention may be a device that dispenses liquid onto an object to which liquid adheres and solidifies, as long as it can at least temporarily adhere to such an object. Also, the liquid dispensing device according to the present invention may be a device that dispenses liquid onto an object to which liquid adheres and penetrates. Objects to which liquid is dispensed include, in addition to paper, resin films, wallpaper, electronic circuit boards, and the like. The materials of the objects to which liquid is dispensed include paper, leather, metal, plastic, glass, wood, and ceramics.

[0091] Furthermore, the liquid discharged by the liquid dispensing device according to the present invention is not particularly limited, but may include solutions, suspensions, emulsions, etc., containing water, solvents such as organic solvents, colorants such as dyes and pigments, functional materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids and proteins, and calcium, and edible materials such as natural pigments. These are used, for example, in inkjet inks, surface treatment liquids, components of electronic elements and light-emitting elements, liquids for forming electronic circuit resist patterns, and material liquids for 3D molding.

[0092] To summarize the embodiments of the present invention described above, the present invention includes at least the following embodiments.

[0093] [First aspect] The first embodiment is a liquid discharge head comprising: a plurality of nozzles for discharging liquid; a plurality of pressure chambers communicating with the plurality of nozzles; a plurality of individual flow paths communicating with the plurality of pressure chambers; a plurality of common flow path branches arranged to overlap with the plurality of pressure chambers when viewed from the discharge direction of the liquid discharged from the nozzles and communicating with the plurality of individual flow paths; and a common flow path main flow communicating with the plurality of common flow path branches, wherein the plurality of common flow path branches are arranged at an angle greater than 45° and less than 90° with respect to the common flow path main flow, and projections of the same height as the height of the side wall surface protrude from the side wall surface of the groove constituting the common flow path branch.

[0094] [Second aspect] In the second embodiment, the projections are provided at equal intervals on the side wall surface, in the first embodiment.

[0095] [Third aspect] In a third embodiment, the projection protrudes in a direction perpendicular to the common channel tributary, in the first or second embodiment.

[0096] [Fourth aspect] A fourth aspect is that, in the first or second aspect, the projection protrudes in a direction within a range of 30° or less from a direction perpendicular to the common channel tributary.

[0097] [Fifth aspect] The fifth embodiment is one of the first to fourth embodiments, in which the amount of projection of the protrusion occupies the width of the groove, which is between 20% and 30%.

[0098] [Sixth aspect] In the sixth embodiment, in any one of the first to fifth embodiments, the tip of the projection is formed on a convex curved surface.

[0099] [Seventh aspect] The seventh embodiment is one of the first to sixth embodiments in which the projection is made of the same material as the member constituting the common channel tributary.

[0100] [Eighth aspect] The eighth embodiment is one of the first to seventh embodiments, in which, when viewed from the discharge direction, the pressure chamber, the main common flow channel, and the branch common flow channel are arranged such that the pressure chamber does not overlap with the main common flow channel but overlaps with the branch common flow channel.

[0101] [Ninth aspect] The ninth embodiment is one of the first to eighth embodiments, wherein the individual flow path includes an individual supply flow path and an individual recovery flow path, the common flow path branch includes a common supply flow path branch communicating with the individual supply flow path and a common recovery flow path branch communicating with the individual recovery flow path, and the side wall surface of the groove constituting the common flow path branch is the side wall surface of the partition wall between the common supply flow path branch and the common recovery flow path branch.

[0102] [Tenth aspect] The tenth embodiment is such that, in any one of the first to ninth embodiments, the pressure chamber is provided to extend in a direction different from the direction in which the common channel tributary extends.

[0103] [The 11th aspect] The eleventh embodiment is a head unit comprising a plurality of liquid dispensing heads according to any one embodiment from the first to the tenth.

[0104] [The 12th aspect] The twelfth embodiment is a liquid dispensing device comprising a liquid dispensing head according to any one of the first to tenth embodiments, or a head unit according to the eleventh embodiment. [Explanation of Symbols]

[0105] 13 Head Unit 20 liquid dispensing heads 30 protrusions 39 Groove 40 Bulkhead 41 Side wall surface 215 nozzles 220 Pressure Chamber 221 Individual channel 240 Common channel main stream 240a Common supply channel main flow 240b Common recovery channel main stream 241 Common channel tributaries 241a Common supply channel tributary 241b Common collection channel tributary 1000 Image forming device (liquid ejection device) [Prior art documents] [Patent Documents]

[0106] [Patent Document 1] Japanese Patent Publication No. 2021-102287

Claims

1. Multiple nozzles for dispensing liquid, Multiple pressure chambers communicating with the aforementioned multiple nozzles, Multiple individual flow paths communicating with the aforementioned multiple pressure chambers, A plurality of common channel branches are arranged so as to overlap with the plurality of pressure chambers when viewed from the direction of discharge of the liquid discharged from the nozzle, and communicate with the plurality of individual channels, A common main channel that communicates with the aforementioned multiple common channel tributaries, Equipped with, The aforementioned multiple common channel tributaries are arranged at an angle greater than 45° and less than 90° relative to the main common channel. A liquid discharge head characterized in that a projection is provided so as to protrude from the side wall surface of a groove constituting the common channel branch, with the same height as the side wall surface.

2. The liquid dispensing head according to claim 1, wherein the protrusions are provided in multiple equal intervals on the side wall surface.

3. The liquid discharge head according to claim 1, wherein the projection protrudes in a direction perpendicular to the common channel tributary.

4. The liquid discharge head according to claim 1, wherein the projection protrudes in a direction within a range of 30° or less from a direction perpendicular to the common channel branch.

5. The liquid dispensing head according to claim 1, wherein the proportion of the width of the groove that is occupied by the protrusion of the projection is 20% or more and 30% or less.

6. The liquid dispensing head according to claim 1, wherein the tip of the projection is formed on a convex curved surface.

7. The liquid discharge head according to claim 1, wherein the projection is made of the same material as the member constituting the common channel branch.

8. The pressure chamber, the main common channel, and the branch common channel are viewed from the discharge direction, The liquid discharge head according to claim 1, wherein the pressure chamber is arranged so as not to overlap with the main flow of the common flow path, but to overlap with the branch flow of the common flow path.

9. The individual channels include an individual supply channel and an individual recovery channel. The common channel branch includes a common supply channel branch that communicates with the individual supply channel and a common recovery channel branch that communicates with the individual recovery channel. The liquid discharge head according to claim 1, wherein the side wall surface of the groove constituting the common channel branch is the side wall surface of the partition between the common supply channel branch and the common recovery channel branch.

10. The liquid discharge head according to claim 1, wherein the pressure chamber is provided to extend in a direction different from the direction in which the common channel tributary extends.

11. A head unit characterized by comprising a plurality of liquid discharge heads as described in claim 1.

12. A liquid dispensing device characterized by comprising the liquid dispensing head described in claim 1.

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