Head chip, liquid ejection head, liquid ejection recording apparatus, and method for manufacturing head chip

Abstract

To inhibit variations of jetting performance from occurring in products due to passage resistance in a bypass passage which connects a liquid supply chamber, which supplies a liquid to a jet channel, with a liquid outflow chamber, through which the liquid flows out from the jet channel.SOLUTION: A head chip 50 includes a cover plate 53 laminated on an actuator plate. The cover plate 53 is provided with: an inlet side common ink chamber 100 which supplies an ink to a discharge channel of the actuator plate; an outlet side common ink chamber 110 through which the ink flows out from the discharge channel; and a bypass passage 130 which connects the inlet side common ink chamber 100 with the outlet side common ink chamber 110. In the cover plate 53, surface roughness in the bypass passage 130 is smaller than surface roughness in the inlet side common ink chamber 100 and the outlet side common ink chamber 110.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a head chip, a liquid ejection head, a liquid ejection recording apparatus, and a method for manufacturing a head chip.

Background Art

[0002] Patent Document 1 below discloses a liquid ejection head (liquid injection head) including a plurality of nozzles, a plurality of pressure chambers (injection channels) respectively communicating with the plurality of nozzles, a supply-side common flow path (liquid supply chamber) connected to the plurality of pressure chambers via a plurality of supply paths, a circulation-side common flow path (liquid outflow chamber) connected to the plurality of pressure chambers via a plurality of circulation paths, and a bypass flow path (bypass channel) connecting the supply-side common flow path and the circulation-side common flow path.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the above configuration, in order to sufficiently supply liquid from the liquid supply chamber to the injection channel, it is necessary to increase the flow path resistance of the bypass flow path to a certain extent and limit the flow rate of the liquid flowing through the bypass flow path. And in order to increase the flow path resistance of the bypass flow path, it is necessary to reduce the flow path cross-sectional area of the bypass flow path. However, if the flow path cross-sectional area of the bypass flow path is reduced, variations in dimensions are likely to occur, so there is a risk that variations in ejection performance will occur for each product.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to suppress variations in ejection performance between products caused by the flow path resistance of a bypass flow path connecting a liquid supply chamber that supplies liquid to an injection channel and a liquid outflow chamber from which liquid flows out of the injection channel.

Means for Solving the Problem

[0006] (1) A head chip according to an aspect of the present disclosure includes an injection plate provided with injection holes for injecting a liquid, an actuator plate laminated on the injection plate and provided with injection channels communicating with the injection holes, and a cover plate laminated on the actuator plate. The cover plate is provided with a liquid supply chamber for supplying a liquid to the injection channels, a liquid outflow chamber from which the liquid flows out of the injection channels, and a bypass flow path connecting the liquid supply chamber and the liquid outflow chamber. The surface roughness of the cover plate in the bypass flow path is smaller than the surface roughness in the liquid supply chamber and the liquid outflow chamber.

[0007] According to the head chip of this aspect, even when the cross-sectional area of the bypass flow path connecting the liquid supply chamber and the liquid outflow chamber is small, by selecting a processing method such that the surface roughness of the bypass flow path is relatively smaller than that of the liquid supply chamber and the liquid outflow chamber, the flow path resistance of the bypass flow path can be accurately realized. Thereby, the variation in injection performance between products due to the flow path resistance of the bypass flow path can be suppressed.

[0008] (2) In the head chip of the aspect of (1), the cover plate may have a high-precision processing portion forming the bypass flow path, and a low-precision processing portion forming the liquid supply chamber and the liquid outflow chamber and having a relatively lower processing accuracy than the high-precision processing portion.

[0009] In this case, since the bypass flow path is processed with higher precision than the liquid supply chamber and the liquid outflow chamber, the variation in dimensions determining the cross-sectional area of the bypass flow path is reduced, and the flow path resistance of the bypass flow path can be accurately realized.

[0010] (3) In the head chip of the aspect of (1) or (2), cutting marks may be formed on the wall surface of the bypass flow path, and blast marks may be formed on the wall surfaces of the liquid supply chamber and the liquid outflow chamber.

[0011] In this case, since blast marks are formed on the wall surfaces of the liquid supply chamber and the liquid outflow chamber and the surfaces are uneven, the bypass flow path with cut marks formed on the wall surface has less variation in the dimensions that determine the flow path cross-sectional area, and the flow path resistance of the bypass flow path can be accurately realized.

[0012] (4) In the head chip according to any one of the aspects (1) to (3), on the first surface of the cover plate facing away from the actuator plate, the liquid supply chamber and the liquid outflow chamber, and a partition wall portion separating between the liquid supply chamber and the liquid outflow chamber are formed, and on the second surface of the cover plate facing the actuator plate side, the bypass flow path is formed, and the liquid supply chamber and the liquid outflow chamber may penetrate the cover plate and be provided with through holes communicating with the bypass flow path.

[0013] In this case, by forming through holes in the cover plate and connecting the liquid supply chamber and the liquid outflow chamber with a bypass flow path on the second surface side of the cover plate, the bypass flow path can be formed without cutting the partition wall portion on the first surface side of the cover plate. Therefore, it becomes easier to ensure the strength of the cover plate.

[0014] (5) In the head chip according to any one of the aspects (1) to (3), on the first surface of the cover plate facing away from the actuator plate, the liquid supply chamber and the liquid outflow chamber, a partition wall portion separating between the liquid supply chamber and the liquid outflow chamber, and the bypass flow path penetrating the partition wall portion may be formed.

[0015] In this case, the liquid supply chamber, the liquid outflow chamber, and the bypass flow path can be formed only by processing on the first surface side of the cover plate.

[0016] (6) In the head chip according to the aspect (5), the bypass flow path may be formed deeper than the bottom surfaces of the liquid supply chamber and the liquid outflow chamber, respectively, from the liquid supply chamber to the liquid outflow chamber.

[0017] In this case, since the cross-sectional area of the flow path can be increased without changing the width of the bypass flow path, dust, foreign matter, and bubbles mixed in the liquid flow more easily from the liquid supply chamber to the liquid outflow chamber through the bypass flow path.

[0018] (7) The liquid ejection head according to one aspect of the present disclosure includes the head chip according to any one of aspects (1) to (6).

[0019] According to the liquid ejection head according to this aspect, a product with excellent reliability can be provided.

[0020] (8) The liquid ejection recording apparatus according to one aspect of the present disclosure includes the liquid ejection head according to aspect (7).

[0021] According to the liquid ejection head according to this aspect, a product with excellent reliability can be provided.

[0022] (9) A method for manufacturing a head chip according to one aspect of the present disclosure is a method for manufacturing a head chip including an ejection plate provided with ejection holes for ejecting a liquid, an actuator plate laminated on the ejection plate and provided with ejection channels communicating with the ejection holes, and a cover plate laminated on the actuator plate and having a liquid supply chamber for supplying liquid to the ejection channels, a liquid outflow chamber from which the liquid flows out of the ejection channels, and a bypass flow path connecting the liquid supply chamber and the liquid outflow chamber, the method including, in the cover plate, a cover plate processing step of forming the bypass flow path, the liquid supply chamber, and the liquid outflow chamber such that the surface roughness in the bypass flow path is smaller than the surface roughness in the liquid supply chamber and the liquid outflow chamber.

[0023] According to the method for manufacturing a head chip according to this aspect, even when the cross-sectional area of the bypass channel connecting the liquid supply chamber and the liquid outflow chamber is small, by selecting a processing method such that the surface roughness of the bypass channel is relatively small with respect to the liquid supply chamber and the liquid outflow chamber, the channel resistance of the bypass channel can be accurately realized. Thereby, variations in injection performance between products due to the channel resistance of the bypass channel can be suppressed.

[0024] (10)(9) In the method for manufacturing a head chip according to the aspect, the cover plate processing step may include a blasting step of forming the liquid supply chamber and the liquid outflow chamber, and a dicing step of forming the bypass channel.

[0025] In this case, since blast marks are formed on the wall surfaces of the liquid supply chamber and the liquid outflow chamber and the surfaces are uneven, the variation in dimensions that determine the cross-sectional area of the bypass channel is smaller in the bypass channel with cutting marks formed on the wall surface, and the channel resistance of the bypass channel can be accurately realized.

[0026] (11)(9) or (10) In the method for manufacturing a head chip according to the aspect, the blasting step includes a first blasting step of forming the liquid supply chamber and the liquid outflow chamber on a first surface of the cover plate facing away from the actuator plate, and after the first blasting step, a second surface of the cover plate facing the actuator plate side is provided with a first through hole communicating with the liquid supply chamber and a second through hole communicating with the liquid outflow chamber. A second blasting step of forming, and after the second blasting step, a dicing step of forming the bypass channel connecting the first through hole and the second through hole on the second surface of the cover plate may be included.

[0027] In this case, by forming through holes in the cover plate and connecting the liquid supply chamber and the liquid outflow chamber with a bypass channel on the second surface side of the cover plate, the bypass channel can be formed without cutting the partition portion on the first surface side of the cover plate. Therefore, it becomes easier to ensure the strength of the cover plate.

Advantages of the Invention

[0028] According to one aspect of the present disclosure, it is possible to suppress variations in injection performance between products due to the flow path resistance of the bypass flow path that connects the liquid supply chamber that supplies liquid to the injection channel and the liquid outflow chamber from which the liquid flows out of the injection channel.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Mode for Carrying Out the Invention

[0030] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings.

[0031] In the embodiments and modifications described below, corresponding components may be denoted by the same reference numerals and the description thereof may be omitted. Further, in the following description, expressions indicating relative or absolute arrangements such as "parallel", "orthogonal", "center", "coaxial", etc. not only strictly represent such arrangements, but also represent states in which they are relatively displaced with tolerances and angles or distances that provide the same function.

[0032] In the following embodiments, an inkjet printer (hereinafter simply referred to as a printer) that performs recording on a recording medium using ink (liquid) will be described as an example. In the drawings used in the following description, the scale of each member is appropriately changed in order to make each member recognizable in size.

[0033] (First Embodiment) [Printer 1] FIG. 1 is a schematic configuration diagram of a printer 1 according to the first embodiment. As shown in FIG. 1, the printer 1 (liquid jet recording apparatus) of the present embodiment includes a pair of transport mechanisms 2 and 3, an ink tank 4, an inkjet head 5 (liquid jet head), an ink circulation mechanism 6, and a scanning mechanism 7.

[0034] In the following description, the orthogonal coordinate system of X, Y, and Z will be used as necessary. The X direction is the transport direction (sub-scanning direction) of the recording medium P (for example, paper or the like). The Y direction is the scanning direction (main scanning direction) of the scanning mechanism 7. The Z direction is the height direction (gravity direction) orthogonal to the X direction and the Y direction.

[0035] In the following description, among the X direction, Y direction, and Z direction, the side of the arrow in the figure is defined as the positive (+) side, and the side opposite to the arrow is defined as the negative (-) side. In this embodiment, the +Z side corresponds to the upper side in the direction of gravity, and the -Z side corresponds to the lower side in the direction of gravity.

[0036] The transport mechanisms 2 and 3 transport the recording medium P to the +X side. The transport mechanisms 2 and 3 each include, for example, a pair of rollers 11 and 12 extending in the Y direction. A plurality of ink tanks 4 are provided, and for example, four colors of ink, namely yellow, magenta, cyan, and black, are separately accommodated therein.

[0037] A plurality of inkjet heads 5 are provided and are configured to be able to eject four colors of ink, namely yellow, magenta, cyan, and black, according to the connected ink tanks 4. Note that the ink accommodated in the ink tank 4 can also be an aqueous ink (conductive ink) using water as a solvent.

[0038] FIG. 2 is a schematic configuration diagram of the inkjet head 5 and the ink circulation mechanism 6 according to the first embodiment. As shown in FIGS. 1 and 2, the ink circulation mechanism 6 circulates ink between the ink tank 4 and the inkjet head 5. Specifically, the ink circulation mechanism 6 includes a circulation flow path 23 having an ink supply pipe 21 and an ink discharge pipe 22, a pressure pump 24 connected to the ink supply pipe 21, and a suction pump 25 connected to the ink discharge pipe 22.

[0039] The pressure pump 24 pressurizes the inside of the ink supply pipe 21 and sends the ink to the inkjet head 5 through the ink supply pipe 21. As a result, the side of the ink supply pipe 21 becomes a positive pressure with respect to the inkjet head 5.

[0040] The suction pump 25 reduces the pressure inside the ink discharge pipe 22 and sucks ink from the inkjet head 5 through the ink discharge pipe 22. As a result, the side of the ink discharge pipe 22 becomes a negative pressure with respect to the inkjet head 5. The ink circulates between the inkjet head 5 and the ink tank 4 through the circulation channel 23 by driving the pressure pump 24 and the suction pump 25.

[0041] As shown in FIG. 1, the scanning mechanism 7 reciprocally scans the inkjet head 5 in the Y direction. The scanning mechanism 7 includes a guide rail 28 extending in the Y direction and a carriage 29 movably supported by the guide rail 28.

[0042] <Inkjet head 5> The inkjet head 5 is mounted on the carriage 29. In the example of FIG. 1, a plurality of inkjet heads 5 are mounted side by side in the Y direction on one carriage 29. The inkjet head 5 includes a head chip 50 (see FIG. 3), a flow path connection portion (not shown) connecting the ink circulation mechanism 6 and the head chip 50, and a control portion (not shown) that applies a drive voltage to the head chip 50.

[0043] <Head chip 50> FIG. 3 is an exploded perspective view of the head chip 50 according to the first embodiment. The head chip 50 shown in FIG. 3 is a so-called circulating side shoot type head chip 50 that discharges ink from the central portion in the extending direction (Y direction) of the discharge channel 61 described later.

[0044] The head chip 50 includes a nozzle plate 51 (injection plate), an actuator plate 52, and a cover plate 53. In the head chip 50, the nozzle plate 51, the actuator plate 52, and the cover plate 53 are laminated in this order in the Z direction.

[0045] The actuator plate 52 is formed of a piezoelectric material such as PZT (lead zirconate titanate). The actuator plate 52 is, for example, a so-called monopole substrate in which the polarization direction is unidirectional throughout the Z direction. However, the actuator plate 52 may be a so-called chevron substrate in which the polarization directions are different between the + side and the - side in the Z direction. In the present embodiment, an example in which the actuator plate 52 is configured by a single substrate will be described, but the configuration is not limited thereto. The actuator plate 52 may be configured by bonding a plurality of (for example, two) piezoelectric plates.

[0046] A channel row 60 is formed in the actuator plate 52. The channel row 60 has a discharge channel 61 (injection channel) filled with ink and a non-discharge channel 62 (non-injection channel) not filled with ink. The discharge channel 61 and the non-discharge channel 62 are alternately arranged in the actuator plate 52 at intervals in the X direction. In the present embodiment, a configuration in which the channel extending direction coincides with the Y direction will be described, but the channel extending direction may intersect the Y direction.

[0047] FIG. 4 is a cross-sectional view along the discharge channel 61 according to the first embodiment. As shown in FIG. 4, the discharge channel 61 is formed in an arc shape convex downward when viewed from the X direction. The discharge channel 61 penetrates the actuator plate 52 in the Z direction at the central portion in the Y direction. The discharge channel 61 gradually becomes shallower as it goes outward in the Y direction at both ends in the Y direction.

[0048] FIG. 5 is a cross-sectional view along the non-discharge channel 62 according to the first embodiment. As shown in FIG. 5, the non-discharge channel 62 extends linearly in the Y direction while penetrating the actuator plate 52 in the Z direction. As shown in FIG. 3, a drive wall 65 is provided in a portion of the actuator plate 52 located between the discharge channel 61 and the non-discharge channel 62.

[0049] The ejection channel 61 is sandwiched from both sides in the X direction by a pair of drive walls 65. In this embodiment, the channel row 60 is described by taking a single row of head tips 50 as an example, but the channel row 60 may be provided in a plurality of rows in the Y direction. In this case, when the number of the channel rows 60 is n, it is preferable that the ejection channels 61 constituting the adjacent channel rows 60 are arranged with a shift of 1 / n pitch for each array pitch of the ejection channels 61 in one channel row 60.

[0050] The actuator plate 52 includes an electrode portion (not shown) that bends and deforms the pair of drive walls 65 into a V shape when viewed from the Z direction. The electrode portion includes an individual electrode (not shown) provided individually for each ejection channel 61 and a common electrode (not shown) commonly connected to each of the ejection channels 61. The terminal of the common electrode and the terminal of the individual electrode extend to the tail portion 80 located on the -Y side with respect to the ejection channel 61 in the actuator plate 52.

[0051] The terminal of the common electrode is disposed on the -Y side with respect to the partition groove 81 formed in the tail portion 80, and the terminal of the individual electrode is disposed on the +Y side with respect to the partition groove 81. The terminal of the common electrode and the terminal of the individual electrode are electrically connected to the control unit via a flexible substrate (not shown) disposed so as to straddle the partition groove 81. When a drive voltage is applied from the control unit to the individual electrode with the common electrode as the reference potential GND, the pair of drive walls 65 bend and deform into a V shape so as to separate from each other. That is, the pair of drive walls 65 deforms so that the volume of the ejection channel 61 expands.

[0052] After increasing the volume of each ejection channel 61, the voltage applied between the common electrode and the individual electrode is set to zero. Then, the pair of drive walls 65 is restored, and the volume of the ejection channel 61 that has once increased returns to the original volume. As a result, the pressure inside the ejection channel 61 increases, and the ink is pressurized. As a result, the ink is ejected in the form of droplets through the nozzle holes 71 (injection holes). By landing the ink ejected from the nozzle holes 71 on the recording medium P shown in FIG. 1, characters, images, etc. can be recorded on the recording medium P.

[0053] <Nozzle plate 51> As shown in FIGS. 3 and 4, the nozzle plate 51 is joined to the lower surface (opening surface) of the actuator plate 52. The nozzle plate 51 is formed of a resin material such as polyimide to a thickness of about 50 μm. However, the nozzle plate 51 may have a single-layer structure or a laminated structure made of a metal material (such as SUS or Ni-Pd), glass, silicon, etc., in addition to the resin material.

[0054] A plurality of nozzle holes 71 penetrating the nozzle plate 51 in the Z direction are formed in the nozzle plate 51. Each nozzle hole 71 is arranged at intervals in the X direction. The nozzle holes 71 communicate separately with the central portion in the Y direction of the discharge channels 61. Therefore, each non-discharge channel 62 does not communicate with the nozzle holes 71 and is covered from below by the nozzle plate 51. Each nozzle hole 71 is formed in a tapered shape such that the inner diameter gradually decreases from above to below, for example.

[0055] <Cover plate 53> As shown in FIG. 3, the cover plate 53 is joined to the upper surface (opening surface) of the actuator plate 52. The cover plate 53 is formed of a metal material such as aluminum nitride or stainless steel, for example. In the cover plate 53, an inlet-side common ink chamber 100 (liquid supply chamber) is formed at a position overlapping the +Y side end of the channel row 60 in plan view. The inlet-side common ink chamber 100 extends in the X direction with a length straddling the channel row 60 and opens on the upper surface of the cover plate 53.

[0056] In the inlet-side common ink chamber 100, ink supply holes 101 (liquid supply holes) are provided at positions overlapping the discharge channels 61 in plan view. The ink supply holes 101 are formed in a slit shape extending in the Y direction. A plurality of ink supply holes 101 are provided and communicate separately between the +Y side ends of the respective discharge channels 61 and the inside of the inlet-side common ink chamber 100.

[0057] In the cover plate 53, an outlet-side common ink chamber 110 (liquid outflow chamber) is formed at a position overlapping with the -Y side end of the channel row 60 in a plan view. The outlet-side common ink chamber 110 extends in the X direction with a length spanning the channel row 60, for example, and is open on the upper surface of the cover plate 53. The inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 are separated by a partition portion 120.

[0058] In the outlet-side common ink chamber 110, an ink outflow hole 111 (liquid outflow hole) is formed at a position overlapping with the discharge channel 61 in a plan view. A plurality of ink outflow holes 111 are provided, and each communicates separately between the -Y side end of each discharge channel 61 and the inside of the outlet-side common ink chamber 110. The ink supply hole 101 and the ink outflow hole 111 each communicate with each discharge channel 61, while not communicating with the non-discharge channel 62.

[0059] FIG. 6 is a plan view of the cover plate 53 according to the first embodiment. FIG. 7 is a bottom view of the cover plate 53 according to the first embodiment. As shown in FIGS. 6 and 7, a bypass flow path 130 connecting the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 is provided in the cover plate 53. In FIGS. 6 and 7, the bypass flow path 130 provided at the -X side end of the cover plate 53 is shown, but a bypass flow path 130 is similarly provided at the +X side end of the cover plate 53.

[0060] As shown in FIG. 6, the inlet-side common ink chamber 100, the outlet-side common ink chamber 110, and the partition portion 120 separating the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 are formed on the first surface 53a facing the opposite side of the actuator plate 52 of the cover plate 53. In contrast, the bypass flow path 130 is formed on the second surface 53b facing the actuator plate 52 side of the cover plate 53, as shown in FIG. 7.

[0061] The inlet-side common ink chamber 100 includes a first through hole 102 that penetrates the cover plate 53 in the Z direction and communicates with the +Y-side end of the bypass flow path 130. Further, the outlet-side common ink chamber 110 includes a second through hole 112 that penetrates the cover plate 53 in the Z direction and communicates with the -Y-side end of the bypass flow path 130. The bypass flow path 130 passes through the back side of the partition portion 120 and connects between the first through hole 102 and the second through hole 112.

[0062] The first through hole 102 and the second through hole 112 have an elongated hole shape extending in the Y direction. The width dimension in the X direction of the first through hole 102 and the second through hole 112 is larger than that of the ink supply hole 101 and the ink outflow hole 111. The bypass flow path 130 extends linearly with a predetermined width in the Y direction. The width dimension in the X direction of the bypass flow path 130 of the present embodiment is larger than that of the ink supply hole 101 and the ink outflow hole 111 and smaller than that of the first through hole 102 and the second through hole 112. Note that the width dimension in the X direction of the bypass flow path 130 may be equal to or larger than that of the first through hole 102 and the second through hole 112. Also, the flow path cross-sectional area of the bypass flow path 130 may be equal to or larger than that of the first through hole 102 and the second through hole 112. In terms of controlling the flow path resistance of the bypass flow path 130, since the narrow portion is dominant, it is preferable to make the width dimension or the flow path cross-sectional area in the X direction of the bypass flow path 130 smaller than that of the first through hole 102 and the second through hole 112.

[0063] As shown in FIG. 6, the cover plate 53 includes a low-precision machining portion A that forms the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110, and a high-precision machining portion B that forms the bypass flow path 130 as shown in FIG. 7. Note that the low-precision machining portion A of the present embodiment means that the machining accuracy is relatively low with respect to the high-precision machining portion B, and does not mean that the machining accuracy of the low-precision machining portion A itself is low.

[0064] The low-precision machining part A is formed by, for example, blasting. That is, blast marks formed by the collision of blast particles are formed on the peripheral wall surfaces and bottom surfaces of the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110, the inner wall surfaces of the ink supply holes 101 and the ink outflow holes 111, and the inner wall surfaces of the first through holes 102 and the second through holes 112, and the surface is slightly uneven. The surface roughness in the low-precision machining part A is, for example, about 6500 [Å] when measured by the arithmetic mean roughness Ra.

[0065] The high-precision machining part B is formed by, for example, dicing. That is, cutting marks cut by a dicing blade are formed on the pair of side wall surfaces of the bypass flow path 130 and the machining bottom surface on the back side of the partition part 120. The surface roughness in the high-precision machining part B is, for example, about 890 [Å] when measured by the arithmetic mean roughness Ra. As a result of the measurement, there is no significant difference in the surface roughness between the pair of side wall surfaces and the machining bottom surface of the bypass flow path 130.

[0066] In the present embodiment, the surface roughness of the high-precision machining part B is 1 / 7 or less of the surface roughness of the low-precision machining part A. The surface roughness of the high-precision machining part B may be 1 / 2 or less of the surface roughness of the low-precision machining part A, preferably 1 / 3 or less, more preferably 1 / 5 or less, and even more preferably 1 / 7 or less as in the present embodiment.

[0067] Subsequently, a cover plate processing step for forming the bypass flow path 130, the inlet-side common ink chamber 100, and the outlet-side common ink chamber 110 so that the surface roughness in the bypass flow path 130 is smaller than the surface roughness in the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110, as in the cover plate 53, will be described. The cover plate processing step described below is one step in the manufacturing method of the head chip 50. By laminating and joining the cover plate 53 processed by this cover plate processing step on the actuator plate 52 laminated on the nozzle plate 51, the head chip 50 can be manufactured.

[0068] FIG. 8 is an explanatory diagram showing a first blasting step included in the cover plate processing step according to the first embodiment. As shown in FIG. 8, the cover plate processing step has a first blasting step of forming an inlet-side common ink chamber 100 and an outlet-side common ink chamber 110 on a first surface 53a of the cover plate 53 facing the opposite side of the actuator plate 52.

[0069] In this first blasting step, a resist pattern is formed on a portion of the first surface 53a of the cover plate 53 other than the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110, and blasting particles 200 are sprayed using this as a mask to half-etch (dry-etch) the first surface 53a of the cover plate 53.

[0070] FIG. 10 is an explanatory diagram showing a dicing step included in the cover plate processing step according to the first embodiment. As shown in FIG. 9, after the first blasting step, the cover plate processing step has a second blasting step of forming a first through hole 102 communicating with the inlet-side common ink chamber 100 and a second through hole 112 communicating with the outlet-side common ink chamber 110 on a second surface 53b of the cover plate 53 facing the actuator plate 52 side.

[0071] In this second blasting step, the first surface 53a and the second surface 53b of the cover plate 53 are turned upside down. Then, a resist pattern is formed on a portion of the second surface 53b of the cover plate 53 other than the first through hole 102, the second through hole 112, the ink supply hole 101, and the ink outflow hole 111, and blasting particles 200 are sprayed using this as a mask to dry-etch the second surface 53b of the cover plate 53 and penetrate the cover plate 53 to form the first through hole 102, the second through hole 112, the ink supply hole 101, and the ink outflow hole 111.

[0072] FIG. 10 is an explanatory diagram showing a dicing step included in the cover plate processing step according to the first embodiment. As shown in FIG. 10, the cover plate processing step includes a dicing step of forming a bypass channel 130 that connects the first through hole 102 and the second through hole 112 on the second surface 53b of the cover plate 53 after the second blasting step.

[0073] In this dicing step, the dicer 300 is moved so as to cut the back side of the partition wall portion 120 on the second surface 53b of the cover plate 53 with a predetermined width, and a groove (bypass channel 130) that connects the first through hole 102 and the second through hole 112 in the Y direction is formed. According to this method, since blast marks are formed on the wall surfaces of the inlet side common ink chamber 100 and the outlet side common ink chamber 110 and the surfaces are uneven, the bypass channel 130 with cutting marks formed on the wall surface has a smaller surface roughness.

[0074] In this way, even when the cross-sectional area of the bypass channel 130 connecting the inlet side common ink chamber 100 and the outlet side common ink chamber 110 is small, by selecting a processing method such that the surface roughness of the bypass channel 130 is relatively small with respect to the inlet side common ink chamber 100 and the outlet side common ink chamber 110, the flow resistance of the bypass channel 130 can be accurately realized. In the head chip 50, the ejection performance of the ink changes depending on the ratio of the ink flowing through the bypass channel 130 and each ejection channel 61. When the ink circulation mechanism 6 shown in FIG. 2 is provided, since the ink is circulated uniformly by the pressure of the pump, the flow resistance of the bypass channel 130 affects the ratio of the flowing ink. Therefore, by accurately realizing the flow resistance of the bypass channel 130, variations in ejection performance between products due to the flow resistance of the bypass channel 130 can be suppressed.

[0075] As described above, the head chip 50 according to the present embodiment includes a nozzle plate 51 provided with nozzle holes 71 for ejecting ink, an actuator plate 52 laminated on the nozzle plate 51 and provided with discharge channels 61 communicating with the nozzle holes 71, and a cover plate 53 laminated on the actuator plate 52. The cover plate 53 is provided with an inlet-side common ink chamber 100 for supplying ink to the discharge channels 61, an outlet-side common ink chamber 110 from which the ink flows out of the discharge channels 61, and a bypass flow path 130 connecting the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110. The surface roughness of the cover plate 53 in the bypass flow path 130 is smaller than the surface roughness in the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110. According to this configuration, it is possible to suppress variations in ejection performance between products due to the flow path resistance of the bypass flow path 130 that connects the inlet-side common ink chamber 100 for supplying ink to the discharge channels 61 and the outlet-side common ink chamber 110 from which the ink flows out of the discharge channels 61.

[0076] Further, in the head chip 50 of the present embodiment, the cover plate 53 has a high-precision machining portion B that forms the bypass flow path 130, and a low-precision machining portion A that forms the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 and has a relatively lower machining accuracy than the high-precision machining portion B. According to this configuration, since the bypass flow path 130 is machined with higher precision than the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110, variations in dimensions that determine the flow path cross-sectional area of the bypass flow path 130 are reduced, and the flow path resistance of the bypass flow path 130 can be accurately realized.

[0077] In addition, in the head chip 50 of the present embodiment, cutting marks are formed on the wall surface of the bypass flow path 130, and blast marks are formed on the wall surfaces of the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110. According to this configuration, since blast marks are formed on the wall surfaces of the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 and the surfaces are uneven, the bypass flow path 130 with cutting marks formed on the wall surface has less variation in the dimensions that determine the flow path cross-sectional area, and the flow path resistance of the bypass flow path 130 can be accurately realized.

[0078] In addition, in the head chip 50 of the present embodiment, on the first surface 53a of the cover plate 53 facing away from the actuator plate 52, the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110, and the partition wall portion 120 separating the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 are formed. On the second surface 53b of the cover plate 53 facing the actuator plate 52 side, the bypass flow path 130 is formed. The inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 penetrate the cover plate 53 and are provided with a first through hole 102 and a second through hole 112 communicating with the bypass flow path 130. According to this configuration, by forming the first through hole 102 and the second through hole 112 in the cover plate 53 and connecting the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 on the second surface 53b side of the cover plate 53 with the bypass flow path 130, the bypass flow path 130 can be formed without removing the partition wall portion 120 on the first surface 53a side of the cover plate 53. Therefore, it becomes easier to ensure the strength of the cover plate 53.

[0079] The inkjet head 5 according to the present embodiment includes the head chip 50 described above. According to this configuration, a product with excellent reliability can be provided.

[0080] The printer 1 according to the present embodiment includes the inkjet head 5 described above. According to this configuration, a product with excellent reliability can be provided.

[0081] The manufacturing method of the head chip 50 according to this embodiment includes a nozzle plate 51 provided with nozzle holes 71 for injecting ink, an actuator plate 52 laminated on the nozzle plate 51 and provided with discharge channels 61 communicating with the nozzle holes 71, and an actuator plate 52 laminated on the actuator plate 52, an inlet-side common ink chamber 100 for supplying ink to the discharge channels 61, an outlet-side common ink chamber 110 from which the ink flows out of the discharge channels 61, and a cover plate 53 in which a bypass flow path 130 connecting the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 is formed. The manufacturing method of the head chip 50 includes a cover plate processing step of forming the bypass flow path 130, the inlet-side common ink chamber 100, and the outlet-side common ink chamber 110 such that the surface roughness in the bypass flow path 130 in the cover plate 53 is smaller than the surface roughness in the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110.

[0082] According to this configuration, even when the flow path cross-sectional area of the bypass flow path 130 connecting the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 is small, by selecting a processing method such that the surface roughness of the bypass flow path 130 is relatively smaller than that of the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110, the flow path resistance of the bypass flow path 130 can be accurately realized. Thereby, the variation in the ejection performance between products due to the flow path resistance of the bypass flow path 130 can be suppressed.

[0083] Further, in the manufacturing method of the head chip 50 of this embodiment, the cover plate processing step includes a blasting process for forming the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110, and a dicing process for forming the bypass flow path 130. According to this configuration, since blast marks are formed on the wall surfaces of the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 and the surfaces are uneven, the variation in the dimensions that determine the flow path cross-sectional area is smaller in the bypass flow path 130 with cutting marks formed on the wall surface, and the flow path resistance of the bypass flow path 130 can be accurately realized.

[0084] In addition, in the method for manufacturing the head chip 50 of the present embodiment, the blasting process includes a first blasting process for forming the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 on the first surface 53a of the cover plate 53 facing the opposite side of the actuator plate 52, and after the first blasting process, on the second surface 53b of the cover plate 53 facing the actuator plate 52 side, a second blasting process for forming a first through hole 102 communicating with the inlet-side common ink chamber 100 and a second through hole 112 communicating with the outlet-side common ink chamber 110. After the second blasting process, the dicing process includes forming a bypass flow path 130 connecting the first through hole 102 and the second through hole 112 on the second surface 53b of the cover plate 53. According to this configuration, by forming through holes in the cover plate 53 and connecting the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 on the second surface 53b side of the cover plate 53 with the bypass flow path 130, the bypass flow path 130 can be formed without removing the partition portion 120 on the first surface 53a side of the cover plate 53. Therefore, it becomes easier to ensure the strength of the cover plate 53.

[0085] Thus, according to the present embodiment, variations in ejection performance between products due to the flow path resistance of the bypass flow path 130 connecting the inlet-side common ink chamber 100 that supplies ink to the ejection channel 61 and the outlet-side common ink chamber 110 from which ink flows out of the ejection channel 61 can be suppressed.

[0086] (Second Embodiment) Next, a second embodiment of the present invention will be described. In the following description, the same reference numerals are given to the same or equivalent configurations as those in the above-described embodiment, and the description thereof will be simplified or omitted.

[0087] FIG. 11 is a plan view of the cover plate 53 according to the second embodiment. FIG. 12 is a cross-sectional view along the bypass flow path 130 according to the second embodiment. As shown in FIG. 11, the bypass flow path 130 of the second embodiment is formed through the partition wall portion 120 that separates the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 on the first surface 53a side of the cover plate 53. According to this configuration, without forming the first through hole 102 and the second through hole 112, only by processing the first surface 53a side of the cover plate 53, the inlet-side common ink chamber 100, the outlet-side common ink chamber 110, and the bypass flow path 130 can be formed.

[0088] As shown in FIG. 12, the bypass flow path 130 of the second embodiment is formed at the same depth as the bottom surfaces of the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 respectively. This bypass flow path 130 is formed by dicing processing with a relatively small surface roughness with respect to the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110, similar to the first embodiment. By selecting such a processing method, the flow path resistance of the bypass flow path 130 can be accurately realized, and the variation in ejection performance between products due to the flow path resistance of the bypass flow path 130 can be suppressed.

[0089] (Third Embodiment) Next, a third embodiment of the present invention will be described. In the following description, the same reference numerals are given to the same or equivalent configurations as those in the above-described embodiments, and the description thereof will be simplified or omitted.

[0090] FIG. 13 is a plan view of the cover plate 53 according to the third embodiment. FIG. 14 is a cross-sectional view along the bypass flow path 130 according to the third embodiment. As shown in FIG. 13, the bypass flow path 130 of the second embodiment penetrates the partition wall portion 120 that separates the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 on the first surface 53a side of the cover plate 53, and is formed deeper than the bottom surfaces of the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 respectively.

[0091] Similar to the first and second embodiments, the bypass channel 130 is formed by dicing that results in a smaller surface roughness relative to the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110. According to this configuration, in addition to the effects of the second embodiment, since the cross-sectional area of the flow channel can be increased without changing the width of the bypass channel 130, dust, foreign matter, and bubbles mixed into the ink can flow more easily from the inlet-side common ink chamber 100 to the outlet-side common ink chamber 110 via the bypass channel 130.

[0092] As described above, the preferred embodiments of the present disclosure have been described and explained. However, it should be understood that these are exemplary of the present disclosure and should not be considered as limiting. Additions, omissions, substitutions, and other changes can be made without departing from the scope of the present disclosure. Therefore, the present disclosure should not be regarded as being limited by the foregoing description, but rather is limited by the claims.

[0093] For example, in the above-described embodiment, the cover plate processing step was described as having a blasting step for forming the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 and a dicing step for forming the bypass channel 130. However, in the cover plate 53, as long as the processing step for forming the bypass channel 130, the inlet-side common ink chamber 100, and the outlet-side common ink chamber 110 is such that the surface roughness in the bypass channel 130 is smaller than the surface roughness in the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110, the type of processing is not limited. For example, the inlet-side common ink chamber 100 and the outlet-side common ink chamber 110 may be formed by casting, forging, press working, etc., and the bypass channel 130 may be formed by wet etching, wire electrical discharge machining, etc., which are more precise than these processes.

[0094] Also, for example, in the above-described embodiment, as an example of the liquid ejection recording apparatus, an inkjet printer was given as an example for explanation. However, it is not limited to printers. For example, it may be a fax machine, an on-demand printer, or the like. In the above-described embodiment, the configuration in which the inkjet head moves relative to the recording medium during printing (so-called shuttle mechanism) has been described as an example, but the present disclosure is not limited to this configuration. The configuration according to the present disclosure may be adopted in a configuration in which the recording medium is moved relative to the inkjet head with the inkjet head fixed (so-called fixed head mechanism). In the above-described embodiment, the case where the recording medium P is paper has been described, but the present disclosure is not limited to this configuration. The recording medium P is not limited to paper, and may be a metal material, a resin material, or food, etc. In the above-described embodiment, the configuration in which the liquid ejection head is mounted on the liquid ejection recording apparatus has been described, but the present disclosure is not limited to this configuration. That is, the liquid ejected from the liquid ejection head is not limited to that which lands on the recording medium, and may be, for example, a chemical solution to be blended in a preparation, a food additive such as a seasoning or a fragrance to be added to food, an aromatic agent to be ejected into the air, etc. In the above-described embodiment, the configuration in which the Z direction coincides with the gravitational direction has been described, but the present disclosure is not limited only to this configuration, and the Z direction may be along the horizontal direction. In the above-described embodiment, the configuration in which the first direction coincides with the Z direction and the second direction coincides with the X direction has been described, but the present disclosure is not limited to this configuration. The first direction and the second direction may be defined separately from the X direction and the Z direction.

Explanation of Reference Numerals

[0095] 1... Printer (Liquid Ejection Recording Apparatus) 5... Inkjet Head (Liquid Ejection Head) 50... Head Chip 51... Nozzle Plate (Ejection Plate) 52... Actuator Plate 53... Cover Plate 53a... First Surface 53b... Second Surface 61... Discharge Channel (Ejection Channel) 62... Non-Discharge Channel 71... Nozzle Hole (Ejection Hole) 100... Inlet-Side Common Ink Chamber (Liquid Supply Chamber) 102…First through-hole (through-hole) 110…Outlet-side common ink chamber (liquid outflow chamber) 112…Second through-hole (through-hole) 120…Partition portion 130…Bypass flow path A…Low-precision machining portion B…High-precision machining portion

Claims

1. An injection plate provided with injection holes for injecting a liquid, An actuator plate laminated on the injection plate and provided with injection channels communicating with the injection holes, A cover plate laminated on the actuator plate, comprising: On the cover plate, A liquid supply chamber for supplying liquid to the injection channels, A liquid outflow chamber from which the liquid flows out of the injection channels, A bypass flow path connecting the liquid supply chamber and the liquid outflow chamber is provided, The surface roughness in the bypass flow path of the cover plate is smaller than the surface roughness in the liquid supply chamber and the liquid outflow chamber, Cutting marks are formed on the wall surface of the bypass flow path, Blast marks are formed on the wall surfaces of the liquid supply chamber and the liquid outflow chamber, characterized in that it is a head tip.

2. The cover plate, A high-precision machining part forming the bypass flow path, A low-precision machining part forming the liquid supply chamber and the liquid outflow chamber and having a relatively lower machining accuracy than the high-precision machining part, characterized in that it is the head tip according to claim 1.

3. On a first surface of the cover plate facing away from the actuator plate, a liquid supply chamber, a liquid outflow chamber, and a partition wall portion separating between the liquid supply chamber and the liquid outflow chamber are formed, On a second surface of the cover plate facing the actuator plate side, the bypass flow path is formed, The liquid supply chamber and the liquid outflow chamber penetrate the cover plate and are provided with through holes communicating with the bypass flow path, characterized in that it is the head tip according to claim 1 or 2.

4. An injection plate provided with injection holes for injecting a liquid, An actuator plate laminated on the injection plate and provided with injection channels communicating with the injection holes, A cover plate laminated on the actuator plate, comprising: On the cover plate, A liquid supply chamber for supplying liquid to the injection channels, A liquid outflow chamber from which the liquid flows out of the injection channels, A bypass flow path connecting the liquid supply chamber and the liquid outflow chamber is provided, The surface roughness in the bypass flow path of the cover plate is smaller than the surface roughness in the liquid supply chamber and the liquid outflow chamber, On the first surface of the cover plate facing away from the actuator plate, a liquid supply chamber, a liquid outflow chamber, and a partition wall portion separating the liquid supply chamber and the liquid outflow chamber are formed. On the second surface of the cover plate facing the actuator plate side, the bypass flow path is formed. The liquid supply chamber and the liquid outflow chamber penetrate through the cover plate and are provided with through holes communicating with the bypass flow path. A head chip characterized by this.

5. On the first surface of the cover plate facing away from the actuator plate, the liquid supply chamber and the liquid outflow chamber, a partition wall portion separating the liquid supply chamber and the liquid outflow chamber, and a bypass flow path penetrating through the partition wall portion are formed. The head chip according to claim 1 or 2, characterized by this.

6. An injection plate provided with injection holes for injecting liquid, an actuator plate laminated on the injection plate and provided with injection channels communicating with the injection holes, and a cover plate laminated on the actuator plate. On the cover plate, a liquid supply chamber for supplying liquid to the injection channels, a liquid outflow chamber from which liquid flows out of the injection channels, and a bypass flow path connecting the liquid supply chamber and the liquid outflow chamber are provided. The surface roughness of the cover plate in the bypass flow path is smaller than the surface roughness in the liquid supply chamber and the liquid outflow chamber. On the first surface of the cover plate facing away from the actuator plate, the liquid supply chamber and the liquid outflow chamber, a partition wall portion separating the liquid supply chamber and the liquid outflow chamber, and a bypass flow path penetrating through the partition wall portion are formed. A head chip characterized by this.

7. The bypass flow path is formed deeper than the bottom surfaces of the liquid supply chamber and the liquid outflow chamber respectively from the liquid supply chamber to the liquid outflow chamber. The head chip according to claim 5 or 6, characterized by this.

8. A liquid injection head comprising the head chip according to any one of claims 1 to 7.

9. A liquid injection recording apparatus comprising the liquid injection head according to claim 8.

10. An injection plate provided with injection holes for injecting liquid, An actuator plate laminated on the injection plate and provided with injection channels communicating with the injection holes; A cover plate laminated on the actuator plate, having a liquid supply chamber for supplying liquid to the injection channels, a liquid outflow chamber from which the liquid flows out of the injection channels, and a bypass flow path connecting the liquid supply chamber and the liquid outflow chamber; A method for manufacturing a head chip, comprising: In the cover plate, there is a cover plate processing step of forming the bypass flow path, the liquid supply chamber, and the liquid outflow chamber such that the surface roughness in the bypass flow path is smaller than the surface roughness in the liquid supply chamber and the liquid outflow chamber; The cover plate processing step includes: A blasting step of forming the liquid supply chamber and the liquid outflow chamber; A dicing step of forming the bypass flow path, characterized in that the method for manufacturing a head chip has these steps.

11. The blasting step includes: A first blasting step of forming the liquid supply chamber and the liquid outflow chamber on a first surface of the cover plate facing away from the actuator plate; After the first blasting step, a second blasting step of forming a first through hole communicating with the liquid supply chamber and a second through hole communicating with the liquid outflow chamber on a second surface of the cover plate facing the actuator plate side; After the second blasting step, the dicing step of forming the bypass flow path connecting the first through hole and the second through hole on the second surface of the cover plate, characterized in that the method for manufacturing a head chip according to claim 10 has this step.

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