Liquid ejecting head and recording apparatus

Abstract

The liquid ejection head includes a flow path member, a pressurizing portion, a flexible substrate, and a liquid reservoir. The flow path member has an ejection hole that ejects the liquid. The pressurizing part is located on the flow path member. The flexible substrate is electrically connected with the pressurizing part. The liquid reservoir has a slit portion through which the flexible substrate is inserted, and supplies liquid to the flow path member. The protective sheet is located between an inner wall surface facing the flexible substrate in the width direction of the slit portion and the flexible substrate.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a liquid ejection head and a recording apparatus. Background Art

[0002] As a printing device, an inkjet printer and an inkjet plotter using an inkjet recording method are known. Such an inkjet printing device is equipped with a liquid ejection head for ejecting liquid.

[0003] The liquid ejection head has a flexible substrate connected to a pressurizing portion on a flow path member for ejecting liquid. The flexible substrate is inserted through a slit portion of a liquid reservoir for supplying liquid to the flow path member and is led out from the slit portion to a position above the liquid reservoir.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2010-227759 Summary of the invention

[0007] A liquid ejection head of one embodiment includes a flow path member, a pressurizing portion, a flexible substrate, a liquid reservoir, and a protective sheet. The flow path member has an ejection hole for ejecting liquid. The pressurizing portion is located on the flow path member. The flexible substrate is electrically connected to the pressurizing portion. The liquid reservoir has a slit portion for inserting the flexible substrate, and supplies liquid to the flow path member. The protective sheet is located between the inner wall surface of the slit portion that is opposite to the flexible substrate and the flexible substrate in the width direction of the slit portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a front view schematically showing the outline of the printer according to the embodiment.

[0009] Figure 2 It is a top view schematically showing the outline of the printer according to the embodiment.

[0010] Figure 3 It is an exploded perspective view showing a schematic structure of a liquid ejection head according to an embodiment.

[0011] Figure 4 It is a perspective view showing the structure of a main part of the liquid ejection head according to the embodiment.

[0012] Figure 5 It is an enlarged top view of the head body according to the embodiment.

[0013] Figure 6 yes Figure 5 An enlarged view of the area enclosed by the dash-dotted line is shown.

[0014] Figure 7It is along Figure 5 A cross-sectional view taken along line VII-VII is shown.

[0015] Figure 8 It is along Figure 4 An enlarged cross-sectional view taken along line VIII-VIII is shown.

[0016] Fig. 9 This is a side view of the protective sheet viewed from the negative direction of the X-axis.

[0017] Fig.10 This is an explanatory diagram for explaining an example of a method of bonding a protective sheet. DETAILED DESCRIPTION

[0018] Hereinafter, embodiments of the liquid ejection head and recording device disclosed in the present application will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the embodiments shown below. In addition, it should be noted that the accompanying drawings are schematic diagrams, and the relationship between the dimensions of the elements, the ratio of the elements, etc. are sometimes different from the actual. Moreover, the drawings sometimes contain parts with different dimensional relationships and ratios.

[0019] In the embodiments shown below, expressions such as "constant", "orthogonal", "perpendicular", or "parallel" are sometimes used, but these expressions do not need to be strictly "constant", "orthogonal", "perpendicular", or "parallel". That is, the above expressions allow for deviations in manufacturing accuracy, setting accuracy, etc.

[0020] In addition, the respective embodiments can be combined as appropriate within the scope of not making the processing contents contradict each other. In addition, in the following respective embodiments, the same reference numerals are attached to the same parts, and the repeated description is omitted.

[0021] <Printer Structure>

[0022] First, refer to Figure 1 and Figure 2 The outline of a printer 1 as an example of a recording device according to the embodiment will be described. Figure 1 This is a front view schematically showing the outline of the printer 1 according to the embodiment. Figure 2 It is a top view schematically showing the outline of the printer 1 according to the embodiment. The printer 1 according to the embodiment is, for example, a color inkjet printer.

[0023] like Figure 1 As shown, the printer 1 includes a paper feed roller 2, a guide roller 3, a coater 4, a head housing 5, a plurality of conveying rollers 6, a plurality of frames 7, a plurality of liquid ejecting heads 8, a conveying roller 9, a dryer 10, a conveying roller 11, a sensor unit 12, and a recovery roller 13.

[0024] The printer 1 also includes a control unit 14 that controls various parts of the printer 1. The control unit 14 controls the operation of the paper feed roller 2, the guide roller 3, the coater 4, the head housing 5, the plurality of conveying rollers 6, the plurality of frames 7, the plurality of liquid ejection heads 8, the conveying roller 9, the dryer 10, the conveying roller 11, the sensor unit 12, and the recovery roller 13.

[0025] The printer 1 records images and texts on the printing paper P by causing liquid droplets to land on the printing paper P. The printing paper P is an example of a recording medium. The printing paper P is wound around a paper feed roller 2 before use. The printer 1 conveys the printing paper P from the paper feed roller 2 to the interior of a head case 5 via a guide roller 3 and a coater 4.

[0026] The coater 4 uniformly coats the coating agent on the printing paper P. Thus, the surface treatment of the printing paper P can be performed, and thus the printing quality of the printer 1 can be improved.

[0027] The head case 5 accommodates a plurality of conveying rollers 6, a plurality of frames 7, and a plurality of liquid ejecting heads 8. The head case 5 has a space isolated from the outside except for a portion such as a portion for taking printing paper P in and out that is connected to the outside.

[0028] The internal space of the head case 5 is controlled by the control unit 14 as required under at least one of the temperature, humidity, and air pressure. The transport roller 6 transports the printing paper P to the vicinity of the liquid ejection head 8 inside the head case 5 .

[0029] The frame 7 is a rectangular flat plate and is located near the top of the printing paper P transported by the transport roller 6. Figure 2 As shown, the frame 7 is arranged so that the longitudinal direction is perpendicular to the conveying direction of the printing paper P. Furthermore, inside the head case 5, a plurality of (eg, four) frames 7 are arranged along the conveying direction of the printing paper P at predetermined intervals.

[0030] Liquid, for example, ink, is supplied from a liquid tank (not shown) to the liquid ejecting head 8. The liquid ejecting head 8 ejects the liquid supplied from the liquid tank.

[0031] The control unit 14 controls the liquid ejection head 8 based on data such as images and characters to eject liquid toward the printing paper P. The distance between the liquid ejection head 8 and the printing paper P is, for example, about 0.5 to 20 mm.

[0032] The liquid ejection head 8 is fixed to the frame 7. The liquid ejection head 8 is arranged so that the longitudinal direction thereof is perpendicular to the conveyance direction of the printing paper P.

[0033] That is, the printer 1 of the embodiment is a so-called line printer in which the liquid ejection head 8 is fixed inside the printer 1. It should be noted that the printer 1 of the embodiment is not limited to a line printer, but may be a so-called serial printer.

[0034] A serial printer refers to a printer that alternately performs the following actions and the conveyance of printing paper P, in which recording is performed while the liquid ejection head 8 is moved back and forth in a direction intersecting the conveyance direction of printing paper P, such as a direction approximately orthogonal to the conveyance direction of printing paper P.

[0035] like Figure 2 As shown, a plurality of (for example, 5) liquid ejection heads 8 are fixed to a frame 7. Figure 2 , an example is shown in which three liquid ejection heads 8 are arranged in front of the conveying direction of the printing paper P and two liquid ejection heads 8 are arranged in the rear. In the conveying direction of the printing paper P, the liquid ejection heads 8 are arranged in a manner such that the centers of the liquid ejection heads 8 do not overlap.

[0036] Furthermore, a plurality of liquid ejection heads 8 located in one frame 7 constitute a head group 8A. Four head groups 8A are arranged along the conveying direction of the printing paper P. The same color of ink is supplied to the liquid ejection heads 8 belonging to the same head group 8A. Thus, the printer 1 can perform printing based on four colors of ink using the four head groups 8A.

[0037] The colors of ink ejected from each head group 8A are, for example, magenta (M), yellow (Y), cyan (C), and black (K). The control unit 14 can print a color image on the printing paper P by controlling each head group 8A to eject ink of a plurality of colors onto the printing paper P.

[0038] Note that, in order to perform the surface treatment of the printing paper P, a coating agent may be ejected toward the printing paper P from the liquid ejection head 8 .

[0039] In addition, the number of liquid ejection heads 8 included in one ejection head group 8A and the number of ejection head groups 8A mounted on the printer 1 can be appropriately changed according to the printed object and printing conditions. For example, as long as the color printed on the printing paper P is monochrome and the printable range is printed by one liquid ejection head 8, the number of liquid ejection heads 8 mounted on the printer 1 may be one.

[0040] The printing paper P which has been printed inside the head case 5 is transported to the outside of the head case 5 by the transport roller 9 and passes through the inside of the dryer 10. The dryer 10 dries the printing paper P after the printing process. The printing paper P which has been dried by the dryer 10 is transported by the transport roller 11 and recovered by the recovery roller 13.

[0041] In the printer 1 , by drying the printing paper P using the dryer 10 , it is possible to reduce adhesion between the printing paper P that are stacked and wound around the recovery roller 13 or friction caused by undried liquid.

[0042] The sensor unit 12 is composed of a position sensor, a speed sensor, a temperature sensor, etc. The control unit 14 can determine the status of each part of the printer 1 based on information from the sensor unit 12 and control each part of the printer 1 .

[0043] In the printer 1 described above, the case where printing paper P is used as a printing target (ie, recording medium) is shown. However, the printing target in the printer 1 is not limited to printing paper P, and a roll of cloth or the like may be used as a printing target.

[0044] In addition, the printer 1 may be placed on a conveyor belt and conveyed instead of directly conveying the printing paper P. By using a conveyor belt, the printer 1 can print on single sheets of paper, cut cloth, wood, tiles, and the like.

[0045] Furthermore, the printer 1 may print a wiring pattern of an electronic device or the like by ejecting a liquid containing conductive particles from the liquid ejection head 8 .

[0046] Furthermore, the printer 1 may prepare chemicals by ejecting a predetermined amount of liquid chemicals or liquid containing chemicals from the liquid ejection head 8 toward a reaction container or the like.

[0047] Furthermore, the printer 1 may include a cleaning unit that cleans the liquid ejection head 8. The cleaning unit cleans the liquid ejection head 8 by, for example, a wiping process or a capping process.

[0048] The wiping process refers to a process of removing the liquid adhering to the liquid ejecting head 8 by wiping the surface of the portion where the liquid is ejected, for example, with a flexible wiper.

[0049] In addition, the capping process is performed, for example, as follows. First, the portion where the liquid is ejected, for example, the second surface 21b of the flow path member 21 (see Figure 7 ) is covered with a cover (referred to as a cover). Thus, a substantially closed space is formed between the second surface 21b and the cover.

[0050] Next, the liquid is repeatedly ejected in such a closed space. Thus, the liquid clogged in the ejection hole 163 (see Figure 7 ), liquids with higher viscosity than the standard state, foreign matter, etc.

[0051] <Structure of liquid ejection head>

[0052] Next, refer to Figure 3 and Figure 4 The structure of the liquid ejection head 8 according to the embodiment will be described. Figure 3 It is an exploded perspective view showing a schematic structure of the liquid ejecting head 8 according to the embodiment. Figure 4 It is a perspective view showing the structure of the main part of the liquid ejecting head 8 according to the embodiment.

[0053] The liquid ejection head 8 includes a head body 20, a wiring section 40, and a support member 50. The head body 20 includes a flow path member 21, a piezoelectric actuator substrate 22, and a reservoir 70. The wiring section 40 includes flexible substrates 41 and 42, and a driver IC 43.

[0054] It should be noted that in order to facilitate the understanding of the description, Figure 3 and Figure 4 A three-dimensional orthogonal coordinate system including a Z-axis with the vertical downward direction as the positive direction and the vertical upward direction as the negative direction is illustrated in the figure. This orthogonal coordinate system may also be shown in other drawings used in the following description. In addition, in the following description, the direction in which the flow path component 21 of the head body 20 is provided in the liquid ejection head 8, that is, the positive direction of the Z-axis, is sometimes referred to as "down", and the direction in which the liquid reservoir 70 is provided relative to the flow path component 21, that is, the negative direction of the Z-axis, is referred to as "up". In addition, in Figure 3 and Figure 4 The shapes of the components are simplified in FIG.

[0055] The flow path member 21 is substantially in the shape of a flat plate and has a main surface, namely, a first surface 21a (see Figure 7 ), and a second surface 21b located on the opposite side to the first surface 21a (refer to Figure 7 The first surface 21a has an opening 161a (see Figure 5 ), liquid is supplied from the liquid reservoir 70 to the interior of the flow path member 21 through the opening 161a.

[0056] A plurality of ejection holes 163 (see Figure 5 ) is located on the second surface 21b. Furthermore, a flow path is formed inside the flow path member 21, through which liquid flows from the first surface 21a to the second surface 21b.

[0057] The piezoelectric actuator substrate 22 is located on the first surface 21a of the flow path member 21. The piezoelectric actuator substrate 22 has a plurality of displacement elements 170 (see Figure 7 ). The displacement element 170 is an example of a pressurizing unit. The displacement element 170 is located on the first surface 21a of the flow path member 21. Figure 7 The piezoelectric actuator substrate 22 is described.

[0058] Flexible substrates 41 and 42 are electrically connected to the piezoelectric actuator substrate 22. The flexible substrates 41 and 42 are flexible wiring substrates and have the function of transmitting a predetermined signal sent from the outside to the head body 20. Figure 3 As shown in FIG. 1 , the liquid ejection head 8 of the embodiment has two flexible substrates 41 and 42. Figure 4 In the figure, the flexible substrates 41 and 42 are omitted.

[0059] The ends 41a and 42a of the flexible substrates 41 and 42 (see Figure 8 ) is located on the piezoelectric actuator substrate 22 of the head body 20. The one end portions 41a, 42a are electrically connected to the piezoelectric actuator substrate 22 of the head body 20. The other end portions of the flexible substrates 41, 42 are inserted into the slit portion 70b of the reservoir 70 and are led out from the slit portion 70b to the upper side of the support member 50 (see Figure 8 ), and is electrically connected to other wiring substrates not shown. It should be noted that the flexible substrates 41 and 42 have a connection surface connected to the piezoelectric actuator substrate 22 of the head body 20 and a back surface located on the opposite side of the connection surface.

[0060] The driver IC 43 is mounted on each of the flexible substrates 41 and 42 . The driver IC 43 controls the driving of each displacement element 170 in the piezoelectric actuator substrate 22 .

[0061] like Figure 3 As shown, two driving ICs 43 are respectively provided on the flexible substrates 41 and 42. It should be noted that the number of driving ICs 43 respectively provided on the flexible substrates 41 and 42 is not limited to two.

[0062] The support member 50 is located on the liquid reservoir 70 and supports Figure 3 and Figure 4 The supporting member 50 is a rectangular frame extending in the longitudinal direction of the liquid ejection head 8 and is located on the liquid reservoir 70 so as to surround a predetermined area including the slit portion 70b in a plan view.

[0063] The liquid reservoir 70 is located on the first surface 21a side of the head body 20 and is in contact with the first surface 21a other than the piezoelectric actuator substrate 22. The liquid reservoir 70 has a flow path inside and liquid is supplied from the outside through the opening 70a. The liquid reservoir 70 has the function of supplying liquid to the flow path member 21 and the function of storing the supplied liquid.

[0064] It should be noted that the liquid ejection head 8 may also include Figure 3 , Figure 4 Members other than the members shown, for example, a frame that houses the wiring portion 40 .

[0065] <Head body structure>

[0066] Next, refer to Figure 5 to Figure 7 The structure of the head main body 20 according to the embodiment will be described. Figure 5 It is an enlarged plan view of the head main body 20 according to the embodiment. Figure 6 yes Figure 5 Shown is an enlarged view of the area enclosed by the dash-dotted line. Figure 7 It is along Figure 5 The sectional view along line VII-VII is shown in FIG. Figure 5 The middle right area represents the transmitted area.

[0067] like Figure 5 As shown, the head main body 20 includes a flow path member 21 and a piezoelectric actuator substrate 22. The flow path member 21 includes a supply manifold 161, a plurality of pressurizing chambers 162, and a plurality of ejection holes 163.

[0068] The plurality of pressurizing chambers 162 are connected to the supply manifold 161. The plurality of ejection holes 163 are connected to the plurality of pressurizing chambers 162, respectively.

[0069] The pressurizing chamber 162 is formed on the first surface 21a of the flow path member 21 (see Figure 7 ) is opened. In addition, the first surface 21a of the flow path member 21 has an opening 161a connected to the supply manifold 161. Moreover, from the reservoir 70 (refer to Figure 3 ) supplies liquid to the interior of the flow path member 21 through the opening 70a.

[0070] exist Figure 5 In the example shown, the head body 20 has four supply manifolds 161 inside the flow path member 21. The supply manifold 161 has an elongated shape extending along the length direction of the flow path member 21, and openings 161a of the supply manifold 161 are formed on the first surface 21a of the flow path member 21 at both ends.

[0071] A plurality of pressurized chambers 162 are formed two-dimensionally on the flow path member 21. The pressurized chamber 162 is a hollow area having a substantially rhombus-shaped planar shape with rounded corners. The pressurized chamber 162 opens on the first surface 21a of the flow path member 21 and is blocked by bonding the piezoelectric actuator substrate 22 to the first surface 21a.

[0072] The pressure chambers 162 form a pressure chamber row arranged in the longitudinal direction. The pressure chambers 162 of the pressure chamber row are arranged in a zigzag pattern between two adjacent pressure chamber rows. Two pressure chamber rows connected to one supply manifold 161 form one pressure chamber group. Figure 5 In the example shown, the flow path member 21 has four pressurizing chamber groups.

[0073] In addition, the relative arrangement of the pressurized chambers 162 in each pressurized chamber group is the same, and each pressurized chamber group is located at a position slightly offset in the longitudinal direction.

[0074] The ejection hole 163 is disposed at a position in the flow path member 21 that avoids a region facing the supply manifold 161. That is, when the flow path member 21 is viewed from the first surface 21a side, the ejection hole 163 does not overlap with the supply manifold 161.

[0075] Furthermore, in a plan view, the ejection holes 163 are arranged so as to be located in the mounting region of the piezoelectric actuator substrate 22. Such ejection holes 163 occupy a region having substantially the same size and shape as the piezoelectric actuator substrate 22 as a group.

[0076] Then, by making the corresponding piezoelectric actuator substrate 22, namely the displacement element 170 (see Figure 7 ) is displaced and droplets are ejected from the ejection hole 163.

[0077] like Figure 7 As shown, the flow path member 21 has a stacked structure in which a plurality of plates are stacked. These plates are arranged in order from the first surface 21a side of the flow path member 21, a cavity plate 21A, a base plate 21B, a slit (throttling portion) plate 21C, a supply plate 21D, manifold plates 21E, 21F, 21G, a cover plate 21H, and a nozzle plate 21I.

[0078] A plurality of holes are formed on the plates constituting the flow path member 21. The thickness of each plate is about 10 μm to 300 μm. This can improve the accuracy of hole formation. The plates are aligned and stacked so that the holes are connected to each other to form the independent flow paths 164 and the supply manifold 161.

[0079] In the flow path member 21, the supply manifold 161 and the ejection holes 163 are connected via the individual flow paths 164. The supply manifold 161 is located on the second surface 21b side of the flow path member 21, and the ejection holes 163 are located on the second surface 21b of the flow path member 21.

[0080] The individual flow path 164 includes a pressurizing chamber 162 and an independent supply flow path 165. The pressurizing chamber 162 is located on the first surface 21a of the flow path member 21, and the independent supply flow path 165 is a flow path connecting the supply manifold 161 and the pressurizing chamber 162.

[0081] In addition, the independent supply flow path 165 includes a throttle portion 166 having a narrower width than other portions. The throttle portion 166 has a narrower width than other portions of the independent supply flow path 165, and thus has a high flow path resistance. Thus, when the flow path resistance of the throttle portion 166 is high, it is difficult for the pressure generated in the pressurizing chamber 162 to escape to the supply manifold 161.

[0082] The piezoelectric actuator substrate 22 includes piezoelectric ceramic layers 22A and 22B, a common electrode 171, an independent electrode 172, a connection electrode 173, a dummy connection electrode 174, and a surface electrode 175 (see Figure 5 ).

[0083] The piezoelectric actuator substrate 22 includes a piezoelectric ceramic layer 22B, a common electrode 171 , a piezoelectric ceramic layer 22A, and an individual electrode 172 stacked in this order.

[0084] The piezoelectric ceramic layers 22A and 22B each have a thickness of about 20 μm. Each of the piezoelectric ceramic layers 22A and 22B extends across the plurality of compression chambers 162. The piezoelectric ceramic layers 22A and 22B can be made of a ceramic material of the lead zirconate titanate (PZT) system having a strong dielectric property.

[0085] The common electrode 171 is formed across substantially the entire surface in the plane direction in the region between the piezoelectric ceramic layer 22A and the piezoelectric ceramic layer 22B. That is, the common electrode 171 overlaps all the pressurizing chambers 162 in the region facing the piezoelectric actuator substrate 22. The thickness of the common electrode 171 is about 2 μm. For example, a metal material such as Ag-Pd can be used for the common electrode 171.

[0086] The independent electrode 172 includes an independent electrode body 172a and an extraction electrode 172b. The independent electrode body 172a is located in a region of the piezoelectric ceramic layer 22B facing the pressurized chamber 162. The independent electrode body 172a is slightly smaller than the pressurized chamber 162 and has a shape substantially similar to the pressurized chamber 162.

[0087] The lead-out electrode 172b is led out from the individual electrode body 172a. The connection electrode 173 is located at a portion of one end of the lead-out electrode 172b that is led out of a region facing the pressurizing chamber 162. The individual electrode 172 can be made of, for example, a metal material such as Au.

[0088] The connection electrode 173 is located on the lead-out electrode 172b, has a thickness of about 15 μm, and is convex. Figure 3 The connection electrode 173 can be made of, for example, silver-palladium containing glass frit.

[0089] The dummy connection electrode 174 is located on the piezoelectric ceramic layer 22A and is located at a position that does not overlap with various electrodes such as the independent electrode 172. The dummy connection electrode 174 connects the piezoelectric actuator substrate 22 and the flexible substrates 41 and 42 to improve the connection strength.

[0090] In addition, the dummy connection electrode 174 makes the distribution of the contact position between the piezoelectric actuator substrates 22 uniform, thereby stabilizing the electrical connection. The dummy connection electrode 174 can be formed of the same material and in the same process as the connection electrode 173 .

[0091] The surface electrode 175 is formed on the piezoelectric ceramic layer 22A at a position away from the independent electrode 172. The surface electrode 175 is connected to the common electrode 171 via a through hole formed in the piezoelectric ceramic layer 22A. Therefore, the surface electrode 175 is grounded and maintained at a ground potential. The surface electrode 175 can be formed by the same material and the same process as the independent electrode 172.

[0092] The plurality of independent electrodes 172 are independently electrically connected to the control unit 14 (see FIG. 1 ) via the flexible substrates 41 and 42 and wirings in order to independently control the potential. Figure 1 ). When the independent electrode 172 and the common electrode 171 have different potentials and an electric field is applied in the polarization direction of the piezoelectric ceramic layer 22A, the portion of the piezoelectric ceramic layer 22A to which the electric field is applied acts as an active portion that is deformed by the piezoelectric effect.

[0093] That is, in the piezoelectric actuator substrate 22, the individual electrodes 172, the piezoelectric ceramic layer 22A, and the common electrode 171, the portion facing the pressurization chamber 162, function as the displacement element 170. Then, the unimorph is deformed by the displacement element 170, so that the pressurization chamber 162 is pressed, and liquid is ejected from the ejection hole 163.

[0094] Next, the driving sequence of the liquid ejection head 8 of the embodiment is described. First, the independent electrode 172 is set to a higher potential (hereinafter referred to as a high potential) than the common electrode 171. Moreover, whenever there is a request for ejection, the independent electrode 172 is temporarily set to the same potential as the common electrode 171 (hereinafter referred to as a low potential), and then is set to a high potential again at a predetermined timing.

[0095] Thus, when the independent electrode 172 reaches a low potential, the piezoelectric ceramic layers 22A and 22B return to their original shapes, and the volume of the pressurizing chamber 162 increases compared to the initial state (a state in which the potentials of the two electrodes are different).

[0096] At this time, negative pressure is applied to the pressurized chamber 162, and liquid is sucked into the pressurized chamber 162 from the supply manifold 161. Then, when the independent electrode 172 is again set to a high potential, the piezoelectric ceramic layers 22A and 22B are deformed in a convex manner toward both sides of the pressurized chamber 16, and the volume of the pressurized chamber 162 is reduced, and the pressure in the pressurized chamber 162 becomes positive pressure.

[0097] As a result, the pressure applied to the liquid in the pressurizing chamber 162 increases, and liquid droplets are ejected. That is, in order to eject liquid droplets, a driving signal including a pulse based on a high potential is supplied to the individual electrode 172 .

[0098] The pulse width may be set to AL (Acoustic Length), which is the length of time it takes for the pressure wave to propagate from the throttle portion 166 to the ejection hole 163. Thus, when the pressure chamber 162 is reversed from a negative pressure state to a positive pressure state, the pressures of both are equal, and droplets can be ejected at a higher pressure.

[0099] In grayscale printing, grayscale is expressed by the number of droplets continuously ejected from the ejection holes 163, that is, the droplet amount (volume) adjusted by the number of droplet ejection times. Therefore, droplet ejection is continuously performed from the ejection holes 163 corresponding to the designated dot area the number of times corresponding to the designated grayscale expression.

[0100] Generally, in the case of continuous liquid ejection, the interval between pulses supplied to eject droplets can also be set to AL. As a result, the residual pressure wave of the pressure generated when the first droplet is ejected is consistent with the period of the pressure wave of the pressure generated when the later droplet is ejected. Therefore, the residual pressure wave and the pressure wave overlap, and the pressure for ejecting the droplets can be amplified. It should be noted that in this case, the speed of the droplets ejected later becomes faster, and the landing points of multiple droplets are close.

[0101] <Structure of the main part of the liquid ejection head>

[0102] Next, refer to Figure 8 The structure of the main part of the liquid ejection head 8 according to the embodiment will be described. Figure 8 It is along Figure 4 An enlarged cross-sectional view taken along line VIII-VIII is shown.

[0103] like Figure 8 As shown, the reservoir 70 is located on the first surface 21 a of the flow path member 21 and has a housing portion 70 c and a slit portion 70 b .

[0104] As described above, the piezoelectric actuator substrate 22 and the ends 41a and 42a of the flexible substrates 41 and 42 are sequentially located on the first surface 21a of the flow path member 21. The housing portion 70c is a space for housing the piezoelectric actuator substrate 22 and the ends 41a and 42a of the flexible substrates 41 and 42 between the first surface 21a.

[0105] The slit portion 70b is a groove-shaped gap extending along the longitudinal direction (Y-axis direction) of the reservoir 70. The slit portion 70b is open on the upper surface of the reservoir 70, and allows the outside of the reservoir 70 to communicate with the space formed inside the reservoir 70, that is, the receiving portion 70c. The flexible substrates 41 and 42 connected to the piezoelectric actuator substrate 22 are inserted through the slit portion 70b and are led out of the reservoir 70 from the slit portion 70b.

[0106] In addition, the reservoir 70 has a protective sheet 200 on the inner wall surface 70b1 of the slit portion 70b, which faces the flexible substrates 41 and 42 in the width direction of the slit portion 70b. The inner wall surface 70b1 of the slit portion 70b is located on the outer side of the short side direction (X-axis direction) of the reservoir 70, and faces the connection surface of the flexible substrates 41 and 42 inserted through the slit portion 70b. That is, the slit portion 70b has an inner wall surface located on the inner side of the short side direction (X-axis direction) of the reservoir 70 and an inner wall surface 70b1 located on the outer side of the short side direction (X-axis direction) of the reservoir 70. Moreover, the protective sheet 200 is located between the inner wall surface 70b1 on the outer side of the slit portion 70b and the flexible substrate 41, and between the inner wall surface 70b1 on the outer side of the slit portion 70b and the flexible substrate 42.

[0107] As described above, the reservoir 70 includes the protective sheet 200 on the inner wall surface 70b1 of the slit portion 70b, thereby preventing the inner wall surface 70b1 from contacting the flexible substrates 41 and 42 inserted through the slit portion 70b. Therefore, the risk of damage to the flexible substrates 41 and 42 can be reduced.

[0108] As a material of the protection sheet 200, for example, polyethylene terephthalate, polycarbonate, etc. can be used. The rigidity of the protection sheet 200 is higher than that of the flexible substrates 41 and 42. Since the rigidity of the protection sheet 200 is high, the protection sheet 200 can play the role of a guide for guiding the flexible substrates 41 and 42 inserted into the slit portion 70b, and the working efficiency is improved.

[0109] In addition, the protective sheet 200 has a first surface and a second surface having a surface roughness greater than that of the first surface. For example, the ten-point average surface roughness (Rz) of the first surface of the protective sheet 200 is about 5 μm, and the ten-point average surface roughness (Rz) of the second surface of the protective sheet 200 is about 15 μm. Moreover, the second surface of the protective sheet 200 having a large surface roughness faces the flexible substrates 41 and 42. By making the second surface of the protective sheet 200 face the flexible substrates 41 and 42, the contact area between the protective sheet 200 and the flexible substrates 41 and 42 is reduced, and the flexible substrates 41 and 42 can be easily led out of the slit portion 70b. Such a protective sheet 200 can be produced by stacking protective sheets having the above-mentioned surface roughness on each other, or by surface processing in a manner to obtain the above-mentioned surface roughness.

[0110] In addition, the protective sheet 200 is bonded to the inner wall surface 70b1 of the slit portion 70b via the adhesive member 300. The adhesive member 300 is, for example, a double-sided tape. By bonding the protective sheet 200 and the inner wall surface 70b1 of the slit portion 70b, the position of the protective sheet 200 can be fixed relative to the inner wall surface 70b1 of the slit portion 70b. In addition, there is a gap between the lower end of the protective sheet 200 and the piezoelectric actuator substrate 22. Therefore, it is difficult for the lower end of the protective sheet 200 to contact the piezoelectric actuator substrate 22, and the piezoelectric actuator substrate 22 is difficult to be damaged.

[0111] In addition, if Figure 8 As shown, the liquid reservoir 70 has a stacked structure formed by stacking a plurality of plates. As the plurality of plates, for example, plates 70A to 70E are sequentially arranged from the upper surface side of the liquid reservoir 70. A plurality of holes are formed in the plurality of plates 70A to 70E constituting the liquid reservoir 70. The plurality of plates 70A to 70E are positioned and stacked in such a manner that the holes are interconnected to form a receiving portion 70c and a slit portion 70b. For example, the holes of the plates 70A to 70C are interconnected to form a slit portion 70b, and the holes of the plates 70D and 70E are interconnected to form a receiving portion 70c. The protective sheet 200 is bonded to the inner wall surface 70b1 in the hole of at least the thickest plate among the plates 70A to 70C via the adhesive member 300. In Figure 8 In the example, since plate 70C is the thickest among plates 70A to 70C, the protective sheet 200 is bonded to the inner wall surface 70b1 in the hole of plate 70C via the adhesive member 300. By bonding the protective sheet 200 to at least the inner wall surface 70b1 in the hole of the thickest plate, the bonding strength between the protective sheet 200 and the inner wall surface 70b1 of the slit portion 70b can be maintained. It should be noted that in addition to the inner wall surface 70b1 in the hole of plate 70C, the protective sheet 200 may also be bonded to the inner wall surface 70b1 in the hole of plate 70B or plate 70D adjacent to plate 70C via the adhesive member 300.

[0112] In addition, the protective sheet 200 has a protrusion 201 that protrudes from the slit portion 70b to the upper side than the upper end portion of the support member 50. Therefore, the protective sheet 200 can function as a guide for guiding the support member 50 to be arranged on the reservoir 70, and can accurately position the support member 50 on the reservoir 70. In addition, the protective sheet 200 can function as a shielding of the wall of the slit portion 70b from the interface between the reservoir 70 and the support member 50, and can reduce the risk of the adhesive 400, which bonds the reservoir 70 and the support member 50, to enter the slit portion 70b.

[0113] In addition, the protection sheet 200 contacts the flexible substrates 41 and 42 drawn out from the slit portion 70b to the upper side than the upper end portion of the support member 50 through the protrusion 201. Therefore, it is possible to avoid contact between the upper end portion of the support member 50 and the flexible substrates 41 and 42 drawn out to the upper side than the upper end portion of the support member 50, and the risk of damage to the flexible substrates 41 and 42 can be further reduced.

[0114] In addition, if Fig. 9 As shown, the protection sheet 200 has a chamfered portion 201 a at a corner of the protrusion 201 . Fig. 9 The protective sheet 200 is a side view viewed from the negative direction of the X axis. The protective sheet 200 has chamfered portions 201a at the corners of the protrusion 201, thereby reducing interference between the protective sheet 200 and the support member 50 when the support member 50 is arranged on the reservoir 70 using the protective sheet 200 as a guide, thereby improving work efficiency.

[0115] return Figure 8 The protective sheet 200 has an end portion 202 that is not bonded to the inner wall surface 70b1 of the slit portion 70b. The end portion 202 is located near the connection portion between the flexible substrates 41, 42 and the piezoelectric actuator substrate 22 (i.e., one end portion 41a, 42a of the flexible substrates 41, 42). Therefore, the end portion 202 of the protective sheet 200, which is not restricted in movement, can be located near the connection portion between the flexible substrates 41, 42 and the piezoelectric actuator substrate 22, and the flexible substrates 41, 42 can be easily drawn out from the slit portion 70b.

[0116] In addition, if Figure 8 As shown, the support member 50 is bonded to the reservoir 70 via the adhesive 400. A portion of the adhesive 400 seeps out from the interface between the support member 50 and the reservoir 70 and is located between the inner wall surface of the support member 50 and the protective sheet 200. Since a portion of the adhesive 400 is located between the inner wall surface of the support member 50 and the protective sheet 200, the protective sheet 200 is bonded to the inner wall surface 70b1 of the slit portion 70b via the adhesive member 300, and is bonded to the inner wall surface of the support member 50 via the adhesive 400. Therefore, the bonding strength of the protective sheet 200 is improved, and the possibility of the protective sheet 200 and the inner wall surface 70b1 of the slit portion 70b being peeled off can be reduced.

[0117] <How to attach the protective sheet>

[0118] Next, refer to Fig.10 A method of bonding the protective sheet 200 will be described. Fig.10 This is an explanatory diagram for explaining an example of a method of bonding the protection sheet 200 .

[0119] The jig 500 is used in the bonding method of the protection sheet 200. The jig 500 has a plate-like base portion 501 and a seat portion 502 that rises from the base portion 501 and has a tapered surface 502a.

[0120] First, the protective sheet 200 is placed on the base portion 502 in a state of being inclined along the tapered surface 502a, and is inserted into the slit portion 70b of the reservoir 70 together with the base portion 502. Fig.10 In FIG. 5 , the protective sheet 200 placed on the base portion 502 is indicated by a dotted line. An adhesive member 300 made of a double-sided tape is attached to the protective sheet 200 in advance.

[0121] Next, the protective sheet 200 is rotated on the base portion 502 in a direction away from the tapered surface 502a, so that the adhesive member 300 is attached to the inner wall surface 70b1 of the slit portion 70b. Thus, the protective sheet 200 is attached to the inner wall surface 70b1 of the slit portion 70b via the adhesive member 300. Then, the base portion 502 is pulled out from the slit portion 70b of the reservoir 70.

[0122] <Other embodiments>

[0123] In the above embodiment, the protection sheet 200 has the protrusion 201 protruding from the slit portion 70b to the upper side of the upper end of the support member 50, but it is also possible to adopt a structure in which the protrusion 201 is omitted. That is, the protection sheet 200 may extend from the slit portion 70b to the upper end of the support member 50.

[0124] As described above, the liquid ejection head (e.g., liquid ejection head 8) of the embodiment includes a flow path member (e.g., flow path member 21), a pressurizing portion (e.g., displacement element 170), a flexible substrate (e.g., flexible substrates 41, 42), and a liquid reservoir (e.g., liquid reservoir 70). The flow path member has a discharge hole (e.g., discharge hole 163) for discharging liquid. The pressurizing portion is located on the flow path member. The flexible substrate is electrically connected to the pressurizing portion. The liquid reservoir has a slit portion (e.g., slit portion 70b) through which the flexible substrate is inserted, and supplies liquid to the flow path member. The liquid reservoir has a protective sheet (e.g., protective sheet 200) on the inner wall surface (e.g., inner wall surface 70b1) on the side opposite to the flexible substrate in the width direction of the slit portion. Therefore, according to the liquid ejection head of the embodiment, the risk of damage to the flexible substrate can be reduced.

[0125] In addition, the liquid ejection head of the embodiment may also include a frame-shaped supporting member (e.g., supporting member 50), which is located on the liquid reservoir in a manner that surrounds a specified area including the slit portion when viewed from above. The protective sheet may also have a protrusion (e.g., protrusion 201) that protrudes from the slit portion to a position above the upper end of the supporting member. Thus, according to the liquid ejection head of the embodiment, the supporting member on the liquid reservoir can be positioned with high precision. In addition, the risk of an adhesive (e.g., adhesive 400) that bonds the liquid reservoir to the supporting member intruding into the slit portion can be reduced.

[0126] In addition, the protection sheet may be in contact with the flexible substrate drawn out from the slit portion to the upper side than the upper end portion of the support member at the protruding portion. Thus, according to the liquid ejection head of the embodiment, the risk of damage to the flexible substrate can be further reduced.

[0127] In addition, the protection sheet may have chamfered portions at corners of the protruding portion. Thus, according to the liquid ejection head of the embodiment, workability is improved when the support member is arranged on the liquid reservoir using the protection sheet as a guide.

[0128] In addition, the protective sheet may include a first surface and a second surface having a surface roughness greater than that of the first surface, and the second surface faces the flexible substrate. Thus, according to the liquid ejection head of the embodiment, it is possible to facilitate the extraction of the flexible substrate from the slit portion.

[0129] In addition, the rigidity of the protective sheet may be higher than that of the flexible substrate. Thus, according to the liquid ejection head of the embodiment, the workability when inserting the flexible substrate through the slit portion is improved.

[0130] Alternatively, the protection sheet may be bonded to one inner wall surface of the slit portion via an adhesive member (eg, adhesive member 300 ). Thus, according to the liquid ejection head of the embodiment, the position of the protection sheet can be fixed relative to one inner wall surface of the slit portion.

[0131] In addition, the liquid reservoir may also have a stacked structure in which a plurality of plates (e.g., plates 70A to 70E) are stacked. The plurality of plates may also include one or more plates (e.g., plates 70A to 70C) having a hole forming a slit portion. The protective sheet may also be bonded to the inner wall surface of one side of the hole of at least the thickest plate (e.g., plate 70C) among the one or more plates via an adhesive member. Thus, according to the liquid ejection head of the embodiment, the bonding strength between the protective sheet and the inner wall surface of one side of the slit portion can be maintained.

[0132] In addition, the protective sheet may have an end portion (e.g., end portion 202) that is not bonded to the inner wall surface of one side of the slit portion. The end portion may also be located near the connection portion between the flexible substrate and the pressurizing portion. Thus, according to the liquid ejection head of the embodiment, it is possible to facilitate the extraction of the flexible substrate from the slit portion.

[0133] In addition, the support member may be bonded to the liquid reservoir via an adhesive (e.g., adhesive 400). A portion of the adhesive may be located between the inner wall surface of the support member and the protective sheet. Thus, according to the liquid ejection head of the embodiment, the possibility of the protective sheet and the inner wall surface of one side of the slit portion being peeled off can be reduced.

[0134] Those skilled in the art can easily derive further effects and other embodiments. Therefore, the broader aspects of the present invention are not limited to the specific detailed and representative embodiments shown and described above. Therefore, various changes can be made without departing from the spirit or scope of the concept of the general invention defined by the technical solution and its equivalents.

[0135] Description of reference numerals:

[0136] 1 Printer

[0137] 8Liquid spray head

[0138] 20 heads

[0139] 21Flow path components

[0140] 41, 42 Flexible substrate

[0141] 50 Supporting member

[0142] 70 Liquid reservoir

[0143] 70A~70E board

[0144] 70b Slit

[0145] 70b1 inner wall

[0146] 163 ejection hole

[0147] 170 displacement element

[0148] 200 protective film

[0149] 201 Prominence

[0150] 202 end

[0151] 300 bonding components

[0152] 400 adhesive.

Claims

1. A liquid ejection head, wherein: The liquid ejection head comprises: a flow path member having a spray hole for spraying liquid; a pressurizing portion located on the flow path member; a flexible substrate electrically connected to the pressurizing portion; a liquid reservoir having a slit portion through which the flexible substrate is inserted and supplying liquid to the flow path member; and A protective sheet is located between the flexible substrate and an inner wall surface of the slit portion that faces the flexible substrate in the width direction.

2. The liquid ejection head according to claim 1, wherein: The liquid ejection head further includes a frame-shaped support member, the support member being located on the liquid reservoir so as to surround a predetermined area including the slit portion when viewed from above. The protection sheet has a protrusion that protrudes from the slit portion upward from an upper end portion of the support member.

3. The liquid ejection head according to claim 2, wherein: The protection sheet is in contact with the flexible substrate drawn out from the slit portion to an upper side than the upper end portion of the support member through the protruding portion.

4. The liquid ejection head according to claim 2, wherein: The protection sheet has chamfered portions at corners of the protruding portion.

5. The liquid ejection head according to claim 1, wherein The protection sheet has a first surface and a second surface having a surface roughness greater than that of the first surface, and the second surface faces the flexible substrate.

6. The liquid ejection head according to claim 1, wherein The protection sheet has higher rigidity than the flexible substrate.

7. The liquid ejection head according to claim 1, wherein The protection sheet is bonded to the inner wall surface of the slit portion via an adhesive member.

8. The liquid ejection head according to claim 7, wherein: The liquid reservoir has a stacked structure in which a plurality of plates are stacked, The plurality of plates include at least one plate having a hole forming the slit portion, The protection sheet is bonded to the inner wall surface of the hole of at least the thickest plate among the one or more plates via the bonding member.

9. The liquid ejection head according to claim 7, wherein: The protection sheet has an end portion that is not bonded to the inner wall surface of the slit portion, The end portion is located close to a connection portion between the flexible substrate and the pressurizing portion.

10. The liquid ejection head according to claim 7, wherein: The liquid ejection head further includes a frame-shaped support member, the support member being located on the liquid reservoir so as to surround a predetermined area including the slit portion when viewed from above. The protection sheet has a protrusion that protrudes from the slit portion upward from the upper end portion of the support member. The supporting member is bonded to the liquid reservoir via an adhesive. A portion of the adhesive is located between the inner wall surface of the support member and the protection sheet.

11. The liquid ejection head according to claim 1, wherein The liquid ejection head further includes a frame-shaped support member, the support member being located on the liquid reservoir so as to surround a predetermined area including the slit portion when viewed from above. The protection sheet extends from the slit portion to an upper end portion of the support member.

12. A recording device, wherein: The recording device includes the liquid ejection head according to any one of claims 1 to 11.

Images