Liquid injection head and liquid injection device

Abstract

The present invention provides a liquid spray head and liquid spray device that suppress cover deformation and paper jamming. [Solution] The nozzle plate has a nozzle surface 24a having a plurality of nozzles 23, and a cover 30 has one opening 41 that exposes a part of the nozzle surface 24a and covers at least a part of the outer peripheral edge of the nozzle surface 24a, wherein the cover 30 has a first edge portion 42 that covers the portion of the outer peripheral edge of the nozzle surface 24a that extends in a second direction perpendicular to a first direction, the first edge portion 42 has a first inner edge 44 that defines the inner edge of the opening 41, the first inner edge 44 has first portions 47, 48 that do not extend substantially parallel to the second direction, and the length of the first portions 47, 48 in the second direction is longer than the length of the first inner edge 44 in the second direction.

Description

Technical Field

[0001] The present invention relates to a liquid injection head for injecting a liquid from a nozzle and a liquid injection device, and particularly to an inkjet recording head for injecting ink as a liquid and an inkjet recording device.

Background Art

[0002] A liquid injection device typified by an inkjet recording device such as an inkjet printer or a plotter includes a liquid injection head capable of injecting a liquid such as ink stored in a cartridge, a tank, or the like. Such a liquid injection head includes a head body having a nozzle for injecting a liquid, a case member for holding the head body, and a cover having an opening through which the nozzle can be exposed (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the inner edge of the opening for exposing the nozzle surface of the cover is linear, when a medium that has floated up due to conveyance failure comes into contact with the linear inner edge, jamming may occur because the medium is sandwiched in the gap between the nozzle surface and the inner edge, or there is a risk of damage in which the cover turns up with respect to the nozzle plate.

Means for Solving the Problems

[0005] An aspect of the present invention that solves the above problems is a liquid spray head comprising: a nozzle plate having a nozzle surface having a plurality of nozzles for spraying liquid in a spraying direction; and a cover having one opening that exposes a part of the nozzle surface when viewed in the direction opposite to the spraying direction and covering at least a part of the outer peripheral edge of the nozzle surface, wherein the outer shape of the nozzle plate is rectangular or substantially rectangular when viewed in the spraying direction, including a pair of sides extending in a first direction and a pair of sides extending in a second direction perpendicular to the first direction; the cover has a first edge portion that covers the portion of the outer peripheral edge of the nozzle surface that extends in the second direction; the first edge portion has a first inner edge that defines the inner edge of the opening; the first inner edge has a first portion that does not extend substantially parallel to the second direction; and the length of the first portion in the second direction is longer than 50% of the length of the first inner edge in the second direction.

[0006] Another aspect of the present invention is a liquid spray head for spraying liquid in a spraying direction while moving relative to a medium in a first direction, comprising: a nozzle plate having a nozzle surface having a plurality of nozzles for spraying liquid; and a cover having one opening that exposes a part of the nozzle surface when viewed in the direction opposite to the spraying direction, and covering at least a part of the outer peripheral edge of the nozzle surface, wherein the cover has a first edge portion that covers the portion of the outer peripheral edge of the nozzle surface that extends in a second direction perpendicular to the first direction, the first edge portion has a first inner edge that defines the inner edge of the opening, and the ratio of one or more straight portions that are located at the same position in the first direction, define the first inner edge, and extend substantially parallel to the second direction to the length of the first inner edge in the second direction is less than 50%.

[0007] Another aspect of the present invention is a liquid spray head for spraying liquid in a spraying direction while moving relative to a medium in a first direction, comprising: a nozzle plate having a nozzle surface having a plurality of nozzles for spraying liquid; and a cover having an opening that exposes a part of the nozzle surface when viewed in the direction opposite to the spraying direction, and covering at least a part of the outer peripheral edge of the nozzle surface, wherein the cover has a first edge portion that covers the portion of the outer peripheral edge of the nozzle surface that extends in a second direction perpendicular to the first direction, the first edge portion has a first inner edge that defines the inner edge of the opening, and the first inner edge has, at least in the central portion in the second direction, an inclined portion that is inclined with respect to a straight line parallel to the second direction, or a curved portion that is curved.

[0008] Another aspect of the present invention is a liquid injection device characterized by comprising the liquid injection head described in the above aspect, a carriage that holds the liquid injection head and moves back and forth in the first direction, and a conveying mechanism that conveys a medium in the second direction at a position facing the nozzle surface.

[0009] Another aspect of the present invention is a liquid injection device comprising a line head configured with the liquid injection head described in the above aspect, and a conveying mechanism that conveys a medium in the first direction at a position facing the nozzle surface. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows the schematic configuration of the liquid injection device according to Embodiment 1. [Figure 2] This is a cross-sectional view of the main part of the liquid injection device according to Embodiment 1. [Figure 3] This is an exploded perspective view of the liquid injection head according to Embodiment 1. [Figure 4] This is a cross-sectional view of the liquid injection head according to Embodiment 1. [Figure 5] This is a plan view of the liquid injection head according to Embodiment 1. [Figure 6] This is a cross-sectional view of the main part of the liquid injection head according to Embodiment 1. [Figure 7] This is a plan view of the liquid injection head and medium according to Embodiment 1. [Figure 8] This is a cross-sectional view of a key part showing the contact state between the cover and the medium according to Embodiment 1. [Figure 9] This is a plan view of the liquid spray head and medium related to the comparative example. [Figure 10] This is a cross-sectional view of a key part showing the contact state between the cover and the medium in the comparative example. [Figure 11] This is a plan view of a liquid spray head showing a modified example of Embodiment 1. [Figure 12] This is a plan view of the liquid injection head according to Embodiment 2. [Figure 13] This is a plan view of the liquid injection head according to Embodiment 3. [Figure 14] This is a plan view of the liquid injection head according to Embodiment 4. [Figure 15] This is a plan view of the liquid injection head according to Embodiment 5. [Figure 16] This is a plan view of the liquid injection head according to Embodiment 6. [Figure 17] This figure shows a schematic configuration of a liquid injection device according to another embodiment. [Modes for carrying out the invention]

[0011] The present invention will be described in detail below based on embodiments. However, the following description represents one aspect of the present invention and can be arbitrarily modified within the scope of the invention. In each figure, the same reference numerals indicate the same components, and their descriptions are omitted as appropriate. In each figure, X, Y, and Z represent three mutually orthogonal spatial axes. In this specification, the directions along these axes are referred to as the X direction, Y direction, and Z direction. In each figure, the direction in which the arrow points is described as the positive (+) direction, and the opposite direction of the arrow is described as the negative (-) direction. Furthermore, the Z direction indicates the vertical direction, with the +Z direction indicating vertically downward and the -Z direction indicating vertically upward. In addition, the directions of the three spatial axes that are not limited to positive and negative directions will be described as the X-axis direction, Y-axis direction, and Z-axis direction.

[0012] (Embodiment 1) FIG. 1 is a diagram showing a schematic configuration of a liquid ejection device 1 of the present invention. FIG. 2 is a cross-sectional view of a main part of the liquid ejection device 1 according to Embodiment 1 as viewed in the Y-axis direction.

[0013] The liquid ejection device 1 includes a liquid ejection head H capable of ejecting ink, which is a kind of liquid, as ink droplets. The liquid ejection device 1 conveys a medium S in the X-axis direction, and while reciprocatingly moving the liquid ejection head H in the Y-axis direction, ejects ink droplets from the liquid ejection head H toward the medium S in the +Z direction (also referred to as ejection), so that the ink droplets land on the medium S such as printing paper, and performs printing such as an image by the arrangement of dots formed on the medium S. That is, it is a so-called serial printer. As the medium S, in addition to recording paper, any material such as a resin film or cloth can be used.

[0014] The liquid ejection device 1 includes a liquid ejection head H, a liquid storage unit 3, a control unit 4, a first conveyance mechanism 5 and a second conveyance mechanism 6 for conveying the medium S, a moving mechanism 7, and a support member 8.

[0015] The liquid ejection head H ejects the ink supplied from the liquid storage unit 3 as ink droplets in the +Z direction.

[0016] The support member 8 is disposed in the +Z direction of the liquid ejection head H and supports the back surface on the opposite side of the so-called printing surface, which is the surface on which the ink droplets of the medium S land. The ink droplets from the liquid ejection head H land on the printing surface of the medium S supported by the support member 8.

[0017] The liquid storage unit 3 stores the ink sprayed from the liquid spray head H. Examples of the liquid storage unit 3 include a cartridge that can be attached to and detached from the liquid spray device 1, a bag-shaped ink pack made of flexible film, and an ink tank that can be refilled with ink. Although not specifically shown in the figures, the liquid storage unit 3 may individually store multiple types of ink, for example, with different colors and components. The liquid storage unit 3 may also be divided into a main tank and a sub-tank. The sub-tank may be connected to the liquid spray head H, and the ink consumed by spraying ink droplets from the liquid spray head H may be replenished from the main tank to the sub-tank.

[0018] The control unit 4 includes, for example, a control device such as a CPU (Central Processing Unit) or FPGA (Field Programmable Gate Array), and a storage device such as a semiconductor memory. The control unit 4 comprehensively controls each element of the liquid injection device 1, namely the liquid injection head H, the first transport mechanism 5, the second transport mechanism 6, the moving mechanism 7, etc., by having the control device execute a program stored in the storage device.

[0019] The first transport mechanism 5 and the second transport mechanism 6 transport the medium S in the X-axis direction, with the first transport mechanism 5 positioned in the -X direction relative to the support member 8, and the second transport mechanism 6 positioned in the +X direction relative to the support member 8.

[0020] The first transport mechanism 5 comprises a first transport roller 5a and a first driven roller 5b that is driven by the first transport roller 5a. The first transport roller 5a is positioned on the back side of the medium S, and the first driven roller 5b is positioned on the printing side of the medium S. The first transport mechanism 5 transports the medium S in the X-axis direction by the rotational drive of the first transport roller 5a by a drive motor (not shown) or the like. In other words, the first transport mechanism 5 transports the medium S onto the support member 8 from one side in the X-axis direction, i.e., the -X direction side, and the ink droplets sprayed from the liquid spray head H land on the support member 8, which is supported by the support member 8. The first driven roller 5b contacts the printing surface of the medium S before printing to prevent the medium S from lifting off the first transport roller 5a. For this reason, the first driven roller 5b is a so-called rubber roller with rubber on its surface.

[0021] The second transport mechanism 6 comprises a second transport roller 6a and a second driven roller 6b that is driven by the second transport roller 6a. The second transport roller 6a is positioned on the back side of the medium S, and the second driven roller 6b is positioned on the printed side of the medium S. The second transport mechanism 6 transports the medium S in the X-axis direction by the rotational drive of the second transport roller 6a by a drive motor (not shown) or the like. In other words, the medium S on which ink droplets sprayed from the liquid spray head H have landed is transported in the +X direction from the support member 8 by the second transport mechanism 6. The second driven roller 6b contacts the printed surface of the medium S after printing to suppress the lifting of the medium S from the second transport roller 6a. For this reason, the second driven roller 6b is a so-called star wheel, with repeated bumps and grooves on its outer circumference in the circumferential direction. Of course, the second driven roller 6b is not limited to a star wheel and may be a rubber roller. Also, the first driven roller 5b is not limited to a rubber roll and may be a star wheel.

[0022] Furthermore, the first transport mechanism 5 and the second transport mechanism 6 that transport the medium S are not limited to those equipped with a first transport roller 5a and a second transport roller 6a, etc., but may also transport the medium S using, for example, a belt or a drum.

[0023] The moving mechanism 7 is a mechanism for reciprocating the liquid injection head H in the Y-axis direction. The moving mechanism 7 comprises a carriage 7a and a conveyor belt 7b. The carriage 7a is a roughly box-shaped structure that houses the liquid injection head H and is fixed to the conveyor belt 7b. The conveyor belt 7b is an endless belt installed along the Y-axis direction. The conveyor belt 7b is rotated by the drive of a conveyor motor (not shown). The control unit 4 controls the drive of the conveyor motor to rotate the conveyor belt 7b, thereby moving the liquid injection head H together with the carriage 7a along a guide rail (not shown) in the Y-axis direction. The liquid storage unit 3 can also be mounted on the carriage 7a together with the liquid injection head H.

[0024] Under the control of the control unit 4, the liquid spray head H performs a spraying operation in which ink supplied from the liquid reservoir 3 is ejected as ink droplets in the +Z direction from each of the multiple nozzles 23 (see Figure 3). This ink droplet spraying operation by the liquid spray head H is performed in parallel with the transport of the medium S by the first transport mechanism 5 and the second transport mechanism 6 and the reciprocating movement of the liquid spray head H by the moving mechanism 7, thereby forming an image with ink on the surface of the medium S, in other words, performing a printing operation.

[0025] Figure 3 is an exploded perspective view of the liquid injection head H of this embodiment. Figure 4 is a cross-sectional view of the liquid injection head H. Figure 5 is a plan view of the liquid injection head H in the -Z direction. Figure 6 is an enlarged view of the main part of Figure 4. Figure 7 is a plan view of the liquid injection head H and the medium S in the -Z direction. Figure 8 is a cross-sectional view showing the contact state between the cover 30 and the medium S according to line AA' in Figure 7. Figure 9 is a plan view of the liquid injection head H and the medium S of a comparative example, viewed in the -Z direction. Figure 10 is a cross-sectional view showing the contact state between the cover 30 and the medium S according to line BB' in Figure 9.

[0026] As shown in Figures 3 to 6, the head holder 11 that constitutes the liquid injection head H has a mounting portion 12 on the surface facing the +Z direction.

[0027] The head holder 11 has a plurality of ink passages 13, one end of which opens to each mounting portion 12 and the other end of which opens to a surface facing the +Z direction. A portion of the +Z direction side of each ink passage 13 is provided inside a tubular flow path forming portion 14 that protrudes in the +Z direction from the surface of the head holder 11 facing the +Z direction.

[0028] On the surface of the head holder 11 facing the -Z direction, a plurality of hollow, needle-shaped flow path connection parts 15 are fixed to the opening of the ink passage 13 of the mounting part 12, via a filter 16 to prevent air bubbles and foreign matter from entering the ink. Note that the flow path connection parts 15 are not limited to a needle shape and may be cylindrical in shape.

[0029] The supply tube may be directly connected to the flow path connection section 15, or it may be connected via other flow path components, such as a pressure adjustment mechanism that adjusts the pressure supplied from upstream and supplies it downstream. Furthermore, a liquid storage unit 3, such as a cartridge, may be directly attached to the mounting section 12. In other words, the flow path connection section 15 may be inserted into the liquid storage unit 3 attached to the mounting section 12.

[0030] The head member 19 is fixed to the surface of the head holder 11 facing the +Z direction, with the sealing member 17 and the circuit board 18 sandwiched between them.

[0031] The head member 19 comprises a head case 21, which is a hollow box-shaped member for housing a piezoelectric actuator unit 20 having a plurality of piezoelectric actuators, and a head body 22 fixed to the side of the head case 21 opposite to the head holder 11, that is, the side facing the +Z direction.

[0032] The head body 22 comprises a nozzle plate 24, a flow path forming substrate 26, and a diaphragm 27.

[0033] The nozzle plate 24 has multiple nozzles 23 formed on it. In this embodiment, eight rows of nozzles 23 arranged in the X-axis direction are provided in the Y-axis direction. The arrangement of the nozzles 23 and the number of nozzle rows are not particularly limited to this. The surface of the nozzle plate 24 facing the +Z direction is the nozzle surface 24a. The outer shape of such a nozzle plate 24, when viewed in the -Z direction, is a rectangle or a substantially rectangle including a pair of sides 24b extending in the Y-axis direction and a pair of sides 24c extending in the X-axis direction. In this embodiment, "substantially rectangle" refers to a shape that is basically a rectangle with corners that are beveled into curved or straight edges when viewed in the -Z direction.

[0034] The channel-forming substrate 26 has a channel including a pressure chamber 25 that communicates with the nozzle 23. The nozzle plate 24 is bonded to the surface of the channel-forming substrate 26 facing the +Z direction.

[0035] The diaphragm 27 is fixed to the surface of the channel forming substrate 26 facing the -Z direction. The nozzle plate 24 and the diaphragm 27 and the channel forming substrate 26 are each joined together by adhesive.

[0036] The piezoelectric actuator constituting the piezoelectric actuator unit 20, although not specifically shown in the figures, is, for example, a longitudinal vibration type actuator device that expands and contracts in the axial direction by alternately stacking piezoelectric material and electrode forming material. Such a piezoelectric actuator serves as a driving element that generates pressure fluctuations in the ink within the pressure chamber 25.

[0037] Furthermore, the head case 21 has an ink supply passage 28, one end of which communicates with the pressure chamber 25 and the other end of which communicates with the ink passage 13 of the head holder 11. The connection between the ink passage 13 and the ink supply passage 28 is liquid-tightly connected by a sealing member 17 made of rubber or the like.

[0038] Furthermore, the liquid spray head H has a cover 30. The cover 30 comprises a frame portion 40 provided along the XY plane defined by the X axis and the Y axis, and a side wall portion 50 extending from the frame portion 40 so as to bend along the side surface of the head body 22.

[0039] The frame portion 40 has a rectangular or substantially rectangular shape when viewed in the -Z direction. The frame portion 40 has one opening 41 that exposes the nozzles 23 of the nozzle plate 24 in the +Z direction. In this embodiment, the opening 41 is sized to expose the nozzles 23 of all nozzle rows in the +Z direction.

[0040] Furthermore, the frame portion 40 has a first edge portion 42 that covers the portion of the outer periphery of the nozzle surface 24a that extends in the X-axis direction. The frame portion 40 also has a second edge portion 43 that covers the portion of the outer periphery of the nozzle surface 24a that extends in the Y-axis direction. In other words, when viewed in the -Z direction, the cover 30 has the first edge portion 42 covering the portion of the outer periphery of the nozzle plate 24 that has a pair of sides 24c extending in the X-axis direction, and the second edge portion 43 covering the portion of the outer periphery of the nozzle plate 24 that has a pair of sides 24b extending in the Y-axis direction. In short, the cover 30 has a box shape that covers the entire outer periphery of the nozzle plate 24.

[0041] The opening 41 is defined by the first edge 42 and the second edge 43. Specifically, the first edge 42 has a first inner edge 44 that defines the inner edge of the opening 41. The second edge 43 has a second inner edge 45 that defines the inner edge of the opening 41. The first inner edge 44 is a portion having a vector along the X-axis direction and is the inner edge on both sides of the opening 41 in the Y-axis direction. Furthermore, the first inner edge 44 refers only to the portion located in the +Z direction from the nozzle surface 24a. The second inner edge 45 is a portion provided along the Y-axis direction and is the inner edge on both sides of the opening 41 in the X-axis direction. In this embodiment, the second inner edge 45 is also located in the +Z direction from the nozzle surface 24a, similar to the first inner edge 44. The opening 41 is defined by this pair of first inner edges 44 and pair of second inner edges 45.

[0042] The first inner edge 44 comprises a straight portion 46 extending substantially parallel to the X-axis direction, two inclined portions 47 that are inclined with respect to the straight portion extending parallel to the X-axis direction, and two curved portions 48.

[0043] In this embodiment, the straight section 46 is positioned at the center of the first inner edge 44 in the X-axis direction. In this invention, "center" includes the central portion when the first inner edge 44 is divided into three parts in the X-axis direction, and more preferably, the central portion when the first inner edge 44 is divided into five parts in the X-axis direction. Furthermore, being positioned at the center of the first inner edge 44 in the X-axis direction means that a part or all of the straight section 46 is located in the central portion in the X-axis direction.

[0044] The inclined sections 47 are provided adjacent to both sides of the straight section 46 in the X-axis direction, that is, they are provided continuously so as to be connected to the straight section 46 in the +X direction and the -X direction, respectively.

[0045] The curved sections 48 are provided on each of the two inclined sections 47 on the opposite side from the straight sections 46 in the X-axis direction. In other words, the curved sections 48 are provided continuously in the +X direction of the inclined section 47 located in the +X direction of the straight section 46, and in the -X direction of the inclined section 47 located in the -X direction of the straight section 46. Furthermore, both ends of the curved sections 48 in the X-axis direction are connected to the second inner edge 45. In other words, the curved sections 48 are provided on each of the ends of the first inner edge 44 in the X-axis direction.

[0046] Here, "approximately parallel" in this invention means less than 5 degrees with respect to the X-axis direction. In other words, the straight section 46 is provided at an inclination angle of less than 5 degrees with respect to the X-axis direction. Furthermore, when the inclined section 47 is said to be inclined with respect to a straight line parallel to the X-axis direction, it means that it is provided at an inclination angle of 5 degrees or more with respect to the X-axis direction.

[0047] The inclination angle of the inclined portion 47 is preferably 5 degrees or more and 15 degrees or less with respect to the X-axis direction, and more preferably 5 degrees or more and 10 degrees or less. In this embodiment, the inclination angle of the inclined portion 47 is 8 degrees.

[0048] Furthermore, the straight section 46 is positioned furthest outward in the Y-axis direction of the first inner edge 44. In other words, with respect to the center of the nozzle plate 24 as viewed in the Z-axis direction, the straight section 46 is positioned furthest outward in the Y-axis direction, the inclined section 47 is positioned inward of the straight section 46 in the Y-axis direction, and the curved section 48 is positioned inward of the inclined section 47 in the Y-axis direction. That is, each inclined section 47 is inclined toward the center in the X-axis direction to widen the width of the opening 41 in the Y-axis direction.

[0049] Furthermore, the combined length of the inclined portion 47 and the curved portion 48 in the X-axis direction is longer than 50% of the length L of the first inner edge 44 in the X-axis direction. In other words, the proportion of the first inner edge 44 in the X-axis direction occupied by the two inclined portions 47 and the two curved portions 48, i.e., the sum of the lengths of the two inclined portions 47 in the X-axis direction (2 × L2) and the lengths of the two curved portions 48 in the X-axis direction (2 × L3), is longer than 50% of the length L of the first inner edge 44 in the X-axis direction. In other words, the combined length of the inclined portion 47 and the curved portion 48 in the X-axis direction is longer than the length of the straight portion 46 in the X-axis direction. That is, the sum of the lengths L2 of the two inclined portions 47 in the X-axis direction and the lengths L3 of the curved portion 48 in the X-axis direction (2 × L2 + 2 × L3) is longer than the length L1 of the straight portion 46. In other words, the length L1 of the straight section 46, the length L2 of the inclined section 47, and the length L3 of the curved section 48 satisfy the relationship (2 × L2 + 2 × L3) > L1.

[0050] Furthermore, it is preferable that the length L2 in the X-axis direction of one inclined portion 47 is 25% or more and 40% or less of the length L in the X-axis direction of the first inner edge 44. In this embodiment, the length L2 of one inclined portion 47 is 32% of the length L.

[0051] Furthermore, the ratio of the length in the X-axis direction of one or more straight sections 46 located at the same position in the Y-axis direction to the length L in the X-axis direction of the first inner edge 44 is less than 50%, more preferably 30% or less, and even more preferably 10% or less. In this embodiment, the ratio of the length L1 of the straight section 46 to the length L of the first inner edge 44 is approximately 13%. The ratio occupied by the straight section 46 refers to the ratio of the length L1 of the straight section 46 in the X-axis direction, and in the case of a single straight section 46 as in this embodiment, it is the ratio of the length L1 of the straight section 46 to the length L of the first inner edge 44. Although not illustrated in this embodiment, if multiple straight sections 46 are provided, the ratio occupied by the straight sections 46 located at the same position in the Y-axis direction is the ratio of the total length of the multiple straight sections 46 located at the same position in the Y-axis direction to the length L of the first inner edge 44.

[0052] The side wall portion 50 extends from the frame portion 40, bending outwards along the outer peripheral edge of the nozzle surface 24a of the liquid spray head H, on the side surface of the nozzle surface 24a. The side wall portion 50 has a flange portion 51 provided with fixing holes 51a for fixing the cover 30 to the head case 21. The flange portion 51 is provided by bending outwards in the Y-axis direction in the same direction as the surface direction of the nozzle surface 24a.

[0053] Then, the sealing member 17, the circuit board 18, the head case 21 and head body 22 constituting the head member 19 are arranged in that order on the surface of the head holder 11 facing the +Z direction, and the cover 30 is positioned to cover the +Z direction ends of the head body 22 and the head case 21. In this state, the liquid spray head H is formed by fixing the cover 30 to the head holder 11 with screws 52. In other words, in this embodiment, the components constituting the liquid spray head H are fixed to each other by inserting the screws 52 through the fixing holes 51a of the cover 30, the first insertion holes 21a of the head case 21 and the second insertion holes 18a of the circuit board 18 and screwing them into the head holder 11. Of course, in addition to fixing the cover 30 to the head case 21 with screws 52, another screw or the like may be provided to fix the head case 21 to the head holder 11. Thus, in this embodiment, the cover 30 and the head case 21 and head body 22 are fixed without the use of adhesive. Therefore, when the cover 30 and the components constituting the head case 21 and head body 22, such as the nozzle plate 24 and the flow path forming substrate 26, change temperature, warping due to differences in their coefficients of thermal expansion and subsequent destruction due to warping can be suppressed. In other words, if materials with different coefficients of thermal expansion, such as the cover 30 and the head case 21 and head body 22, are bonded together, warping and destruction will occur when they expand or contract due to temperature changes. Furthermore, if the cover 30 and the head case 21 and head body 22 are bonded together with adhesive, problems such as the nozzle plate 24 peeling off can occur due to the stress when the medium S collides with the cover 30. In this embodiment, by fixing the cover 30 and the head case 21 and head body 22 without using adhesive, it is possible to suppress destruction such as peeling of the nozzle plate 24 due to differences in coefficients of thermal expansion and collision of the medium S with the cover 30.

[0054] Such a cover 30 is formed by press-forming a thin metal sheet, such as stainless steel. If the cover 30 is too thick, the distance in the X-axis direction between the nozzle surface 24a and the medium S increases, making it easy for the ink droplets ejected from the nozzle 23 to land on the medium S in a misaligned position. Conversely, if the cover 30 is too thin, its rigidity decreases, and it cannot protect the head member 19 from impact with the medium S. For this reason, the thickness of the cover 30 is preferably 0.1 mm to 0.2 mm.

[0055] Here, the medium S may bend and lift away from the support member 8 due to slack between the first transport mechanism 5 and the second transport mechanism 6, or due to twisting caused by ink impact. When the carriage 7a equipped with the liquid spray head H is moved in the Y-axis direction while the medium S is lifted away from the support member 8 in this state, there is a risk that the first edges 42 on both sides of the cover 30 of the liquid spray head H in the Y-axis direction will come into contact with the Y-axis end of the lifted medium S. At this time, as shown in Figure 9, if the proportion occupied by the straight portion 46 of the first inner edge 44 is large, that is, if the straight portion 46 is 50% or more, then, as shown in Figure 10, the Y-axis end face of the curled-up medium S and the straight portion 46 of the first inner edge 44 will come into contact in a parallel state. In addition, the area in which the Y-axis end face of the medium S is simultaneously in contact with the first inner edge 44 will increase. Therefore, the medium S can easily get trapped between the first edge 42 of the cover 30 and the nozzle surface 24a, and paper jams are likely to occur as the medium S gets caught on the first edge 42. Also, if the straight portion is 50% or more, the lifted medium S can collide with the first edge 42 in a line contact manner, and paper jams can occur, which can easily cause the first edge 42 of the cover 30 to curl up. Furthermore, when the first edge 42 of the cover 30 curls up, the medium S becomes even more likely to get caught there, making paper jams more likely.

[0056] In contrast, in this embodiment, as shown in Figures 7 and 8, the proportion occupied by the straight portion 46 of the first inner edge 44 is made less than 50%, and an inclined portion 47 and a curved portion 48 are provided on the first inner edge 44, so that the media S that has lifted away from the support member 8 comes into contact with the inclined portion 47 and the curved portion 48. As a result, the inclined portion 47 and the curved portion 48 of the cover 30 come into contact with the end face of the media S in the Y-axis direction at an angle, and the area in which the end face of the media S simultaneously contacts the first inner edge 44 can be reduced. Therefore, it is difficult for the lifted media S to get stuck between the first edge 42 of the cover 30 and the nozzle surface 24a, and the occurrence of paper jams caused by the media S getting caught on the first edge 42 can be reduced. In addition, since the end face of the media S comes into contact with the first inner edge 44 at an angle, i.e., at a point, the impact at the time of contact can be dissipated. This also reduces the likelihood of the first edge 42 being damaged by curling up. Furthermore, since the lifted media S can suppress the curling of the first edge 42, the occurrence of paper jams caused by the media S getting caught on the curled first edge 42 can be reduced.

[0057] Furthermore, in this embodiment, by providing the straight section 46, the angle between the inclined section 47 and the straight section 46 can be reduced compared to the case where the two inclined sections 47 are directly connected when viewed in the -Z direction. In other words, for example, if the inclined section 47 is provided at an angle of 8 degrees with respect to the X-axis direction, in this embodiment the angle between the straight section 46 and the inclined section 47 will be 8 degrees, whereas if the straight section 46 is not provided, the inclined sections 47 will be directly connected, and the angle between the two inclined sections 47 will be a larger 16 degrees. As described above, the cover 30 is formed by press-forming a metal plate, so if the angle of the corners is large during press-forming, stress will concentrate at the corners and the flatness of the frame section 40 will decrease. In this embodiment, by providing the straight section 46, the angle between the straight section 46 and the inclined section 47 can be reduced during press-forming, making it less likely for stress to concentrate at the corners and improving the flatness of the frame section 40. Furthermore, in this embodiment, by providing a straight section 46 and dividing the inclined section 47 into two, the maximum width of the first edge 42 in the Y-axis direction can be reduced compared to the case where one inclined section 47 is provided on one first inner edge 44.

[0058] Furthermore, since the straight section 46 is positioned furthest outward in the X-axis direction of the first inner edge 44, the medium S is less likely to enter the gap between the straight section 46 and the nozzle surface 24a compared to when the straight section 46 is positioned furthest inward in the X-axis direction. In other words, for example, if the straight section 46 is positioned furthest inward in the X-axis direction, the first inner edge 44 is formed in a convex shape toward the inward direction in the X-axis direction when viewed in the -Z direction. When the first inner edge 44 is provided in a convex shape in this way, the medium S is more likely to get caught on this convex tip portion, i.e., the straight section 46, and the medium S is more likely to enter the gap between the straight section 46 and the nozzle surface 24a. In this embodiment, by positioning the straight section 46 furthest outward in the X-axis direction, the first inner edge 44 is formed in a concave shape. For this reason, in this embodiment, the first inner edge 44 is less likely to enter the gap between the straight section 46 and the nozzle surface 24a compared to when it is formed in a convex shape.

[0059] Furthermore, the cover 30 of this embodiment is provided so as to contact the outer peripheral edge of the nozzle plate 24. Specifically, as shown in Figure 6, the first edge 42 of the frame portion 40 of the cover 30 has a contact portion 42a on the side wall portion 50 of the face facing the -Z direction opposite to the nozzle surface 24a that contacts the outer peripheral edge of the nozzle plate 24. The frame portion 40 extends away from the nozzle plate 24 from the contact portion 42a toward the first inner edge 44. In other words, the frame portion 40 is provided inclined in the +Z direction with respect to the nozzle surface 24a toward the first inner edge 44 from the contact portion 42a. By extending the first edge 42 away from the nozzle plate 24 toward the first inner edge 44 from the contact portion 42a in this way, the contact portion 42a can be reliably brought into contact with the nozzle plate 24, and the nozzle plate 24 and the cover 30 can be stably connected electrically, allowing the nozzle plate 24 to be grounded via the cover 30. By grounding the nozzle plate 24 in this way, the influence of the charged medium S on the liquid spray head H, especially damage due to static charge, can be suppressed. In this way, even if the distance in the Z-axis direction between the first inner edge 44 and the nozzle surface 24a is relatively wide because the nozzle plate 24 is grounded via the cover 30, by providing the straight portion 46, inclined portion 47, and curved portion 48 on the first inner edge 44 in the above proportions, it is difficult for the medium S to get between the first edge 42 of the cover 30 and the nozzle surface 24a, and the curling of the first edge 42 due to paper jams or the medium S can be suppressed. In other words, an increase in the number of parts and a large-scale configuration are unnecessary in order to connect the cover 30 and the nozzle plate 24.

[0060] Furthermore, in the case where the first edge portion 42 extends from the contact portion 42a toward the first inner edge 44 so as to move away from the nozzle surface 24a, as described above, the maximum width of the first edge portion 42 in the Y-axis direction can be reduced by providing a straight portion 46 to divide the inclined portion 47 into two. In other words, by providing a straight portion 46 to divide the inclined portion 47 into two and making the inclination directions of the two inclined portions 47 different, the maximum width of the first edge portion 42 in the Y-axis direction can be reduced. And by reducing the maximum width of the first edge portion 42 in the Y-axis direction, the gap in the Z-axis direction between the first inner edge 44 and the nozzle surface 24a can be reduced. Therefore, it is difficult for the medium S to enter between the first edge portion 42 and the nozzle surface 24a.

[0061] In this embodiment, the second inner edge 45 extends substantially parallel to the Y-axis direction. Of course, the second inner edge 45 may have a straight portion 46, an inclined portion 47, and a curved portion 48, similar to the first inner edge 44.

[0062] Furthermore, in this embodiment, the Y-axis direction is an example of the "first direction," and the X-axis direction is an example of the "second direction." Also, the inclined portion 47 and the curved portion 48 are examples of the "first portion that does not extend substantially parallel to the second direction," and the straight portion 46 is an example of the "second portion." In other words, the "first portion" is the portion that defines the first inner edge 44, and is not a straight portion that extends substantially parallel to the "second direction" (corresponding to the "second portion" in this embodiment).

[0063] Furthermore, the first inner edge 44 does not necessarily have to have a curved portion 48, in which case the "first part" consists only of the inclined portion 47. Similarly, the first inner edge 44 does not necessarily have to have an inclined portion 47, in which case the "first part" consists only of the curved portion 48.

[0064] In this embodiment, the proportion of the straight portion 46 to the length L of the first inner edge 44 is approximately 13%, but it is not limited to this, and the proportion of the straight portion 46 may be less than 50%. Here, Figure 11 shows the case where the proportion of the straight portion 46 to the length L of the first inner edge 44 is 46%. Figure 11 is a plan view of a modified liquid injection head H of Embodiment 1 as seen from the -Z direction.

[0065] As shown in Figure 11, the first inner edge 44 comprises a straight portion 46 positioned in the center in the X-axis direction, inclined portions 47 provided on both sides of the straight portion 46 in the X-axis direction, and a curved portion 48 provided on the side of each inclined portion 47 opposite to the straight portion 46 in the X-axis direction.

[0066] The length L1 of the straight section 46 is set to be 46% of the length L of the first inner edge 44. In other words, the sum of the lengths in the X-axis direction of the two inclined sections 47 and the two curved sections 48 is approximately 54% of the length L of the first inner edge 44.

[0067] Even with this configuration, since more than 50% of the first inner edge 44 is composed of the inclined portion 47 and the curved portion 48, similar to Embodiment 1 described above, the medium S is less likely to enter between the cover 30 and the nozzle surface 24a, thereby suppressing the occurrence of paper jams and preventing the first edge 42 of the cover 30 from curling up.

[0068] In addition, in the modified embodiment of Embodiment 1, the Y-axis direction is an example of the "first direction," and the X-axis direction is an example of the "second direction," similar to Embodiment 1. Furthermore, the inclined portion 47 and the curved portion 48 are examples of the "first portion that does not extend substantially parallel to the second direction," and the straight portion 46 is an example of the "second portion."

[0069] (Embodiment 2) Figure 12 is a plan view of the liquid injection head H according to Embodiment 2, viewed in the -Z direction. Note that components similar to those in Embodiment 1 described above are denoted by the same reference numerals, and redundant explanations are omitted.

[0070] As shown in Figure 12, the liquid injection head H of this embodiment has the same configuration as the first embodiment described above, except for the shape of the opening 41 of the cover 30. The first inner edge 44 of the first edge 42 of the cover 30 of this embodiment comprises two inclined portions 47 with different inclination angles and two curved portions 48 provided on both sides of the two inclined portions 47 in the X-axis direction.

[0071] The ends of the two inclined portions 47 are connected to each other. In other words, the first inner edge 44 of this embodiment does not have the straight portion 46 of Embodiment 1 described above. That is, the proportion of the straight portion 46 to the length L in the X-axis direction of the first inner edge 44 of this embodiment is less than 50%. That is, the proportion of the straight portion 46 to the length L in the X-axis direction of the first inner edge 44 being less than 50% includes 0%. And, in this embodiment, since the straight portion 46 of Embodiment 1 is not provided, the sum of the lengths of the two inclined portions 47 and the two curved portions 48 in the X-axis direction (2 × L2 + 2 × L3) is longer than 50% of the length L in the X-axis direction of the first inner edge 44, or in other words, it is longer than the length of the straight portion in the X-axis direction, which is 0 (zero) in this embodiment.

[0072] The two inclined portions 47 are inclined so as to widen the width of the opening 41 in the Y-axis direction toward the center in the X-axis direction, that is, so that the first inner edge 44 becomes concave. The inclination angle and length of these inclined portions 47, and the length of the curved portion 48 are the same as in Embodiment 1 described above.

[0073] Even with this configuration, similar to Embodiment 1 described above, even if the medium S lifts up from the support member 8, the medium S is less likely to get stuck between the nozzle surface 24a and the first edge 42, thereby suppressing paper jams and preventing the first edge 42 from curling up due to the medium S.

[0074] In Embodiment 2, the Y-axis direction is an example of the "first direction," and the X-axis direction is an example of the "second direction." Also, the inclined portion 47 and the curved portion 48 are examples of the "first portion that does not extend substantially parallel to the second direction."

[0075] (Embodiment 3) Figure 13 is a plan view of the liquid injection head H according to Embodiment 3, viewed in the -Z direction. Note that components similar to those in Embodiment 1 described above are denoted by the same reference numerals, and redundant explanations are omitted.

[0076] As shown in Figure 13, the liquid injection head H of this embodiment has the same configuration as Embodiment 1 described above, except for the shape of the opening 41 of the cover 30. The first inner edge 44 of the first edge 42 of the cover 30 of this embodiment has only one curved portion 48. That is, the first inner edge 44 does not have the straight portion 46 and inclined portion 47 of Embodiment 1 described above.

[0077] The curved portion 48 is formed to be a concave surface when viewed in the -Z direction toward the nozzle 23.

[0078] The length L3 of the curved portion 48 in the X-axis direction is longer than 50% of the length L of the first inner edge 44 in the X-axis direction. In other words, the ratio of the length L3 of the curved portion 48 in the X-axis direction to the length L of the first inner edge 44 in the X-axis direction is greater than 50%. This ratio is more preferably 70% or more, and even more preferably 90% or more. Also, the ratio of the length L1 of the straight portion 46 in the X-axis direction to the length L of the first inner edge 44 in the X-axis direction is less than 50%, more preferably 30% or less, and even more preferably 10% or less. Note that, as in this embodiment, the length of the straight portion 46 may be 0 (zero), and the ratio of the length L3 of the curved portion 48 in the X-axis direction to the length L of the first inner edge 44 in the X-axis direction may be 100%. In other words, in this embodiment, the length L3 of the curved portion 48 in the X-axis direction is equal to the length L of the first inner edge 44 in the X-axis direction.

[0079] Even with this configuration, similar to Embodiment 1 described above, even if the medium S lifts up from the support member 8, the medium S is less likely to get stuck between the nozzle surface 24a and the first edge 42, thereby suppressing paper jams and preventing the first edge 42 from curling up due to the medium S.

[0080] In Embodiment 3, the Y-axis direction is an example of the "first direction," and the X-axis direction is an example of the "second direction." Also, the curved portion 48 is an example of the "first portion that does not extend substantially parallel to the second direction."

[0081] (Embodiment 4) Figure 14 is a plan view of the liquid injection head H according to Embodiment 4, viewed in the -Z direction. Note that components similar to those in Embodiment 1 described above are denoted by the same reference numerals, and redundant explanations are omitted.

[0082] As shown in Figure 14, the liquid injection head H of this embodiment has the same configuration as Embodiment 1 described above, except for the shape of the opening 41 of the cover 30. The first inner edge 44 of the first edge 42 of the cover 30 of this embodiment comprises one inclined portion 47 provided in the center in the X-axis direction and two curved portions 48 provided on both sides of the inclined portion 47 in the X-axis direction. In other words, the first inner edge 44 does not have the straight portion 46 of Embodiment 1 described above. That is, the proportion of the straight portion 46 to the length L in the X-axis direction of the first inner edge of this embodiment is less than 50%. That is, the proportion of the straight portion 46 to the length L in the X-axis direction of the first inner edge 44 being less than 50% includes 0%. Furthermore, in this embodiment, since the straight section 46 of Embodiment 1 is not provided, the sum of the lengths of the one inclined section 47 and the two curved sections 48 in the X-axis direction (L2 + 2 × L3) is longer than 50% of the length L of the first inner edge 44 in the X-axis direction, or in other words, longer than the length of the straight section in the X-axis direction, which is 0 (zero) in this embodiment.

[0083] The inclination angle and total length of these inclined portions 47, and the length of the curved portion 48 are the same as in Embodiment 1 described above.

[0084] The inclined portions 47 provided on each of the first inner edges 44 on both sides in the Y-axis direction are inclined in different directions from each other so that the width of the opening 41 in the Y-axis direction widens as it moves toward the +X direction. Of course, the inclined portions 47 provided on each of the first inner edges 44 on both sides in the X-axis direction may be parallel to each other so that the width of the opening 41 in the Y-axis direction is approximately the same along the X-axis direction. That is, the opening 41 may be provided in the shape of a parallelogram when viewed in the -Z direction. However, even if the opening 41 of the cover 30 is a parallelogram, the outer shape of the nozzle plate 24 is rectangular or approximately rectangular as described above.

[0085] Even with this configuration, similar to Embodiment 1 described above, even if the medium S lifts up from the support member 8, the medium S is less likely to get stuck between the nozzle surface 24a and the first edge 42, thereby suppressing paper jams and preventing the first edge 42 from curling up due to the medium S.

[0086] In Embodiment 4, the Y-axis direction is an example of the "first direction," and the X-axis direction is an example of the "second direction." Also, the inclined portion 47 and the curved portion 48 are examples of the "first portion that does not extend substantially parallel to the second direction."

[0087] (Embodiment 5) Figure 15 is a plan view of the liquid injection head H according to Embodiment 5, viewed in the -Z direction. Note that components similar to those in Embodiment 1 described above are denoted by the same reference numerals, and redundant explanations are omitted.

[0088] As shown in Figure 15, the liquid injection head H of this embodiment has the same configuration as the first embodiment described above, except for the shape of the opening 41 of the cover 30. The first inner edge 44 of the first edge 42 of the cover 30 of this embodiment comprises a plurality of straight sections 46, in this embodiment three straight sections 46, which are offset in the X-axis direction, two inclined sections 47 that connect two straight sections 46, and two curved sections 48 provided at both ends of the first inner edge 44 in the X-axis direction.

[0089] The three straight sections 46 extend substantially parallel to the X-axis direction. The three straight sections 46 comprise a first straight section 46a provided at the center of the first inner edge 44 in the X-axis direction, and two second straight sections 46b provided on both sides of the first straight section 46a in the X-axis direction via inclined sections 47. The second straight sections 46b are provided at the same position in the Y-axis direction and with the same length in the X-axis direction. Hereafter, when the first straight section 46a and the second straight sections 46b are not distinguished, they will be referred to as the straight section 46.

[0090] The curved section 48 is provided continuously with the second straight section 46b on the side opposite to the inclined section 47 in the X-axis direction.

[0091] The inclined portion 47 is provided at an inclination with respect to a straight line extending parallel to the X-axis direction.

[0092] The inclination angles of the straight section 46 and the inclined section 47 with respect to the X-axis direction are the same as those specified in Embodiment 1 described above.

[0093] The ratio of the length of the straight section 46 located at the same position in the Y-axis direction to the length L of the first inner edge 44 in the X-axis direction is less than 50%, more preferably 30% or less, and even more preferably 10% or less. In this embodiment, the straight section 46 located at the same position in the Y-axis direction refers to the first straight section 46a or the two second straight sections 46b. In other words, the length L4 of the first straight section 46a should be less than 50% of the length L of the first inner edge 44. Also, the sum of the lengths of the two second straight sections 46b in the X-axis direction, (2 × L5), should be less than 50% of the length L of the first inner edge 44.

[0094] Even with this configuration, similar to Embodiment 1 described above, even if the medium S lifts up from the support member 8, the medium S is less likely to get stuck between the nozzle surface 24a and the first edge 42, thereby suppressing paper jams and preventing the first edge 42 from curling up due to the medium S.

[0095] In Embodiment 5, the Y-axis direction is an example of the "first direction," and the X-axis direction is an example of the "second direction."

[0096] (Embodiment 6) Figure 16 is a plan view of the liquid injection head H according to Embodiment 6, viewed in the -Z direction. Note that components similar to those in Embodiment 1 described above are denoted by the same reference numerals, and redundant explanations are omitted.

[0097] As shown in Figure 16, the liquid injection head H of this embodiment has the same configuration as the first embodiment described above, except for the shape of the opening 41 of the cover 30. The first inner edge 44 of the first edge 42 of the cover 30 of this embodiment comprises two inclined portions 47 that are inclined with respect to the X-axis direction in different directions and are located in the central part in the X-axis direction, two straight portions 46 provided on both sides of the inclined portions 47 in the X-axis direction, and two curved portions 48 provided on the side of the straight portions 46 opposite to the inclined portions 47 in the X-axis direction.

[0098] Here, the "central portion" in this invention refers to the central portion obtained by dividing the first inner edge 44 into three parts, more preferably the central portion obtained by dividing it into five parts.

[0099] The inclined portion 47 is provided at an angle to a straight line extending parallel to the X-axis direction. In this embodiment, two inclined portions 47 are provided on one first inner edge 44 such that their ends connect to each other to form a recess.

[0100] The straight sections 46 are provided continuously adjacent to both sides of the two inclined sections 47 in the X-axis direction, that is, connected to the inclined sections 47 in the +X direction and the -X direction, respectively.

[0101] The curved sections 48 are provided on the opposite side of the inclined sections 47 of the two straight sections 46. The inclined sections 47 are provided at an angle to a straight line parallel to the X-axis direction, similar to Embodiment 1 described above.

[0102] In this embodiment, two inclined portions 47 are provided in the central part of each first inner edge 44, but the embodiment is not limited to this, and a curved portion forming a single concave curved surface may be provided instead.

[0103] Here, the medium S that has lifted from the support member 8 is likely to come into contact with the central portion of the first inner edge 44 in the X-axis direction, and the central portion of the first edge 42 in the X-axis direction is relatively less rigid because it is far from the second edge 43. Therefore, by providing the inclined portion 47 in the central portion of the first inner edge 44 in the X-axis direction, the medium S that has lifted from the support member 8 is less likely to get stuck between the nozzle surface 24a and the first edge 42, thereby suppressing paper jams and preventing the first edge 42 from curling up due to the medium S. In Embodiment 6, the Y-axis direction is an example of the "first direction," and the X-axis direction is an example of the "second direction."

[0104] (Other embodiments) Although various embodiments of the present invention have been described above, the basic configuration of the present invention is not limited to those described above.

[0105] For example, in the embodiments described above, the cover 30 is exemplified as covering the entire outer edge of the nozzle plate 24, but it is not limited to this, and the cover 30 may cover at least a part of it. For example, the second inner edge of the cover 30 may be located outward in the X-axis direction from one side 24c of the nozzle surface 24a, and the second inner edge may be located in the -Z direction from the nozzle surface 24a. In such a configuration, a portion of the inner edges on both sides in the Y-axis direction of the opening 41 connected to the second inner edge is also located in the -Z direction from the nozzle surface 24a, but the first inner edge 44 refers to the portion of the inner edges on both sides in the Y-axis direction that is located in the +Z direction from the nozzle surface 24a. In other words, the collision of the medium S with the cover 30 occurs in the portion of the cover 30 that is located in the +Z direction from the nozzle surface 24a, so by configuring the first inner edge 44 as in the embodiments described above, deformation of the cover 30 and the occurrence of paper jams due to collisions with the medium S can be suppressed.

[0106] Furthermore, although a serial printer was used as an example of the liquid ejection device 1 in the embodiments described above, the device is not limited to this, and may also be a so-called line printer in which the liquid ejection head H is fixed during printing, and ink is ejected and deposited onto the medium S from the liquid ejection head H while the medium S is being transported. Figure 17 is a diagram showing the schematic configuration of the liquid ejection device 1 according to another embodiment. An example of a liquid ejection device 1 that is a line printer will be described with reference to Figure 17. Note that the same reference numerals are used for components similar to those in Embodiment 1 described above, and redundant explanations are omitted.

[0107] As shown in Figure 17, the liquid injection device 1 comprises a line head LH on which at least one liquid injection head H is mounted, a liquid storage unit 3, a control unit 4, a first transport mechanism 5 for transporting the medium S, and a device body 9.

[0108] The line head LH extends along the X-axis. In this embodiment, it comprises one liquid injection head H and a support 100 that supports the liquid injection head H.

[0109] Each liquid spray head H is supported by a support 100. Of course, the number of liquid spray heads H constituting the line head LH is not limited to one, but may be two or more. Furthermore, multiple liquid spray heads H may be arranged in a staggered pattern along the X-axis. Here, arranging multiple liquid spray heads H in a staggered pattern means arranging liquid spray heads H that are arranged side by side along the X-axis with alternating shifts in the Y-axis direction. In other words, two rows of liquid spray heads H arranged side by side along the X-axis are arranged side by side along the Y-axis, and these two rows of liquid spray heads H are shifted in the X-axis direction. By arranging the liquid spray heads H in a staggered pattern along the X-axis in this way, the nozzles of two liquid spray heads H can be partially overlapped in the X-axis direction, forming a continuous row of nozzles along the X-axis. Of course, multiple liquid spray heads H may also be arranged in a matrix pattern.

[0110] The support 100 that supports the liquid injection head H is fixed to the main body 9 of the apparatus. Here, the liquid injection head H is positioned such that the direction in which the nozzles constituting the nozzle row are arranged coincides with the X-axis direction. In other words, the liquid injection head H is positioned such that the first edge 42 constitutes both sides of the opening 41 in the Y-axis direction, and the second edge 43 constitutes both sides of the opening 41 in the X-axis direction.

[0111] In this line head LH, nozzles are arranged across the entire width of the medium S in the X-axis direction. In other words, in this embodiment, the multiple nozzles of the liquid injection head H are provided over a width greater than the width of the medium S in the X-axis direction. As described above, by arranging the liquid injection heads H in a staggered pattern in the X-axis direction, nozzles can be arranged across the entire width of the medium S, which has a relatively wide width in the X-axis direction.

[0112] The first conveying mechanism 5 conveys the medium S along the Y-axis relative to the line head LH. When the medium S is conveyed in the +Y direction by the first conveying mechanism 5, the +Y end of the medium S contacts the first inner edge 44. Also, when the medium S is conveyed in the -Y direction by the first conveying mechanism 5, the -Y end of the medium S contacts the first inner edge 44. At this time, by configuring the first inner edge 44 as described in embodiments 1 to 6 above, it is possible to suppress the floating medium S from getting into the gap between the first edge 42 and the nozzle surface 24a, thereby reducing the occurrence of paper jams, and the contact of the medium S with the first inner edge 44 reduces damage to the first inner edge 44 due to curling up. Note that in the example shown in Figure 17, the Y-axis direction is an example of the "first direction", and the X-axis direction is an example of the "second direction".

[0113] Furthermore, in the embodiments described above, a longitudinal vibration type actuator device was used as the driving element for generating a pressure change in the pressure chamber 25, which involves alternately stacking piezoelectric material and electrode-forming material to expand and contract in the axial direction. However, the driving element is not particularly limited to this. As a driving element, for example, a thin-film type actuator device can be used, such as a thin-film type formed by stacking electrodes and piezoelectric material by film deposition and lithography, or a thick-film type formed by methods such as attaching a green sheet. In addition, as a driving element, a so-called electrostatic actuator can be used, such as one in which a heating element is placed in the pressure chamber 25 and droplets are discharged from the nozzle 23 by bubbles generated by the heat generated by the heating element, or one that generates static electricity between a diaphragm and an electrode, deforming the diaphragm with electrostatic force and discharging droplets from the nozzle 23.

[0114] Furthermore, the present invention broadly applies to liquid spraying devices in general that are equipped with liquid spraying heads. Examples of liquid spraying heads include recording heads such as various inkjet recording heads used in image recording devices such as printers, and colorant spraying heads used in the manufacture of color filters for liquid crystal displays. Other examples of liquid spraying heads include electrode material spraying heads used in electrode formation for organic EL displays and FEDs (field emission displays), and bio-organic material spraying heads used in biochip manufacturing, and the invention can also be applied to liquid spraying devices equipped with these liquid spraying heads.

[0115] (Note) From the forms exemplified above, the following configuration can be understood, for example.

[0116] A liquid spray head according to Embodiment 1, which is a preferred embodiment, comprises a nozzle plate having a nozzle surface having a plurality of nozzles for spraying liquid in the spraying direction, and a cover having one opening that exposes a part of the nozzle surface when viewed in the direction opposite to the spraying direction, and covering at least a part of the outer edge of the nozzle surface, wherein the outer shape of the nozzle plate is rectangular or substantially rectangular when viewed in the spraying direction, including a pair of sides extending in a first direction and a pair of sides extending in a second direction perpendicular to the first direction, the cover has a first edge portion that covers the portion of the outer edge of the nozzle surface that extends in the second direction, the first edge portion has a first inner edge that defines the inner edge of the opening, the first inner edge has a first portion that does not extend substantially parallel to the second direction, and the length of the first portion in the second direction is longer than 50% of the length of the first inner edge in the second direction. According to this design, because the straight section provided on the first inner edge is short, the medium contacts the first portion that does not extend substantially parallel to the second direction, i.e., the first portion having at least one of an inclined portion or a curved portion, making it less likely for the medium to get caught in the gap between the first edge and the nozzle surface. Therefore, paper jams caused by the medium getting into the gap and damage to the first edge that causes it to curl up can be reduced.

[0117] In Embodiment 2, which is a specific example of Embodiment 1, the first inner edge has a linear second portion that is positioned in the center of the first inner edge in the second direction and extends substantially parallel to the second direction when viewed in the direction opposite to the spray direction, and the first portion has two inclined portions adjacent to both sides of the second portion, each inclined with respect to the second direction. Compared to connecting the ends of the two inclined portions together, connecting the two inclined portions via a linear portion reduces the angle of the formed corner, suppresses the occurrence of warping due to stress concentration at the corner during manufacturing, and improves the flatness of the cover. Furthermore, by dividing the inclined portion into two, the maximum width of the first edge in the first direction can be reduced compared to when the first inner edge is composed of a single inclined portion. This shortens the gap between the first inner edge and the nozzle surface, suppressing the entry of the medium into this gap.

[0118] In embodiment 3, which is a specific example of embodiment 2, the first portion has two curved portions arranged at each of the two ends of the first inner edge in the second direction. With this, by providing curved portions, it is possible to suppress the occurrence of warping due to stress concentration at the corners during manufacturing without forming sharp corners, and the flatness of the cover can be improved.

[0119] In Embodiment 4, which is a specific example of Embodiment 1, the first inner edge has a linear second portion that extends substantially parallel to the second direction, and the second portion is positioned on the outermost side of the first inner edge in the first direction. With this configuration, by positioning the second portion on the outermost side of the first inner edge in the first direction, it is possible to make it more difficult for the medium S to enter the gap between the second portion and the nozzle surface compared to the case where the second portion is positioned on the innermost side in the first direction.

[0120] In embodiment 5, which is a specific example of embodiment 2, the inclination angle of the inclined portion with respect to the second direction is 5 to 10 degrees, and the ratio of the length of one of the inclined portions in the second direction to the length of the first inner edge in the second direction is 25% to 40%. According to this, by providing the first portion within this range, paper jams and curling of the first edge caused by the medium S entering between the first inner edge and the nozzle surface can be reduced.

[0121] In embodiment 6, which is a specific example of embodiment 1, the liquid is sprayed in the spray direction while moving relative to the medium in the first direction.

[0122] In Embodiment 7, which is a specific example of Embodiment 1, the side of the nozzle plate extending in the second direction and the contact portion of the first edge of the cover are in contact, and when viewed in the second direction, the first edge extends away from the nozzle plate from the contact portion toward the first inner edge of the cover. This allows the nozzle plate and the cover to be electrically connected, and the nozzle plate to be grounded through the cover. Furthermore, even if the gap between the first inner edge and the nozzle surface is widened by inclining the first edge for grounding the nozzle plate, it is difficult for the medium to enter between the cover and the nozzle surface, thereby suppressing the occurrence of paper jams and the curling of the first edge.

[0123] A liquid spray head according to Embodiment 8, a preferred embodiment, is a liquid spray head that sprays liquid in a spraying direction while moving relative to a medium in a first direction, comprising: a nozzle plate having a nozzle surface having a plurality of nozzles for spraying liquid; and a cover having one opening that exposes a part of the nozzle surface when viewed in the direction opposite to the spraying direction, and covering at least a part of the outer peripheral edge of the nozzle surface, wherein the cover has a first edge portion that covers the portion of the outer peripheral edge of the nozzle surface that extends in a second direction perpendicular to the first direction, the first edge portion has a first inner edge that defines the inner edge of the opening, and the ratio of one or more straight portions that are located at the same position in the first direction, define the first inner edge, and extend substantially parallel to the second direction to the length of the first inner edge in the second direction is less than 50%. The ratio is more preferably 30% or less, and even more preferably 10% or less. The ratio may be 0%. According to this design, because the straight section provided on the first inner edge is short, the media is less likely to get caught in the gap between the first edge and the nozzle surface. Therefore, paper jams caused by the media getting stuck in the gap and damage to the first edge that causes it to curl up can be reduced.

[0124] In embodiment 9, which is a specific example of embodiment 8, the first inner edge has at least one of an inclined portion that is inclined with respect to a straight line parallel to the second direction, and a curved portion that is curved. With this, the medium comes into contact with the inclined portion and the curved portion, making it difficult for the medium to enter between the first edge and the nozzle surface.

[0125] In embodiment 10, which is a specific example of embodiment 8, the first inner edge has a first portion that does not extend substantially parallel to the second direction, and the ratio of the length of the first portion in the second direction to the length of the first inner edge in the second direction is greater than 50%. With this, by providing the first portion, which consists of at least one of the inclined portion and the curved portion, within the above range, the medium is less likely to enter the gap between the first edge and the nozzle surface, and paper jams and curling of the first edge can be suppressed. The ratio is preferably 70% or more, and more preferably 90% or more. The ratio is also not limited to 100%, meaning that no straight portion is provided on the first inner edge.

[0126] In embodiment 11, which is a specific example of embodiment 8, the outer shape of the nozzle plate is a rectangle or substantially rectangle, when viewed in the direction opposite to the spraying direction, and includes a pair of sides extending in the first direction and a pair of sides extending in the second direction.

[0127] In embodiment 12, which is a specific example of embodiment 8, the first inner edge has a plurality of linear portions that are offset in the first direction, define the first inner edge, and extend substantially parallel to the second direction.

[0128] A liquid spray head according to embodiment 13, which is a preferred embodiment, is a liquid spray head that sprays liquid in a spraying direction while moving relative to a medium in a first direction, comprising: a nozzle plate having a nozzle surface having a plurality of nozzles for spraying liquid; and a cover having an opening that exposes a part of the nozzle surface when viewed in the direction opposite to the spraying direction, and covering at least a part of the outer peripheral edge of the nozzle surface, wherein the cover has a first edge portion that covers the portion of the outer peripheral edge of the nozzle surface that extends in a second direction perpendicular to the first direction, the first edge portion has a first inner edge that defines the inner edge of the opening, and the first inner edge has an inclined portion or a curved portion that is inclined with respect to a straight line parallel to the second direction, or at least in the central portion in the second direction. With this, by providing an inclined portion or a curved portion in the central part of the first inner edge, which is most likely to come into contact with the medium and has relatively low rigidity, the medium is less likely to get caught between the first inner edge and the nozzle surface, and the occurrence of paper jams and curling up of the first edge portion can be suppressed.

[0129] A liquid injection device according to Embodiment 14, which is a preferred embodiment, comprises a liquid injection head as described in the above embodiment, a carriage that holds the liquid injection head and moves back and forth in the first direction, and a transport mechanism that transports the medium in the second direction at a position facing the nozzle surface. With this, when the first end of the bent medium in the first direction comes into contact with the liquid injection head due to the reciprocating movement of the carriage in the first direction, it is possible to suppress the medium from getting caught or getting stuck between the cover and the nozzle surface, and the first edge from curling up.

[0130] A liquid injection device according to embodiment 15, which is a preferred embodiment, comprises a line head configured with the liquid injection head described in the above embodiment, and a conveying mechanism that conveys the medium in the first direction at a position facing the nozzle surface. With this, when the first end of the bent medium comes into contact with the liquid injection head as the medium is conveyed, it is possible to suppress the medium from getting caught or getting stuck between the cover and the nozzle surface, and the first edge from curling up. [Explanation of Symbols]

[0131] H...Liquid spray head, LH...Line head, S...Media, 1...Liquid spray device, 3...Liquid reservoir, 4...Control unit, 5...First transport mechanism, 5a...First transport roller, 5b...First driven roller, 6...Second transport mechanism, 6a...Second transport roller, 6b...Second driven roller, 7...Moving mechanism, 7a...Carriage, 7b...Conveyor belt, 8...Support member, 9...Device body, 11...Head holder, 12...Mounting part, 13...Ink passage, 14...Flow path forming part, 15...Flow path connection part, 16...Filter, 17...Sealing member, 18...Circuit board, 19...Head member, 20 ...piezoelectric actuator unit, 21...head case, 22...head body, 23...nozzle, 24...nozzle plate, 24a...nozzle surface, 24b, 24c...edges, 25...pressure chamber, 26...flow channel forming substrate, 27...diaphragm, 28...ink supply path, 30...cover, 40...frame part, 41...opening, 42...first edge part, 42a...contact part, 43...second edge part, 44...first inner edge, 45...second inner edge, 46...straight part, 46a...first straight part, 46b...second straight part, 47...inclined part, 48...curved part, 50...side wall part, 51...flange part, 52...screw, 100...support.

Claims

1. A nozzle plate having a nozzle surface with multiple nozzles that spray liquid in the direction of injection, A cover having one opening that exposes a portion of the nozzle surface when viewed in the direction opposite to the injection direction, and covering at least a portion of the outer edge of the nozzle surface, Equipped with, The outer shape of the nozzle plate is rectangular or substantially rectangular, as viewed in the spraying direction, and includes a pair of sides extending in a first direction and a pair of sides extending in a second direction perpendicular to the first direction. The cover has a first edge portion that covers the portion of the outer periphery of the nozzle surface that extends in the second direction, The first edge portion has a first inner edge that defines the inner edge of the opening, The first inner edge has a first portion that does not extend substantially parallel to the second direction, The length of the first portion in the second direction is longer than 50% of the length of the first inner edge in the second direction. A liquid spray head characterized by the following features.

2. The first inner edge has a linear second portion that, when viewed in the direction opposite to the injection direction, is positioned at the center of the first inner edge in the second direction and extends substantially parallel to the second direction. The first portion has two inclined portions adjacent to the second portion on both sides, each inclined with respect to the second direction. The liquid spray head according to feature 1.

3. The first portion has two curved portions, each of which is positioned at both ends of the first inner edge in the second direction, The liquid spray head according to feature 2.

4. The first inner edge has a linear second portion that extends substantially parallel to the second direction, The second portion is the outermost part of the first inner edge in the first direction. The liquid spray head according to feature 1.

5. The inclination angle of the inclined portion with respect to the second direction is 5 to 10 degrees. The ratio of the length of one of the inclined portions in the second direction to the length of the first inner edge in the second direction is 25% to 40%. The liquid spray head according to feature 2.

6. The liquid is sprayed in the spray direction while moving relative to the medium in the first direction. The liquid spray head according to feature 1.

7. The side of the nozzle plate extending in the second direction and the contact portion of the first edge of the cover come into contact, Viewed in the second direction, the first edge extends away from the nozzle plate toward the first inner edge of the cover from the contact portion. The liquid spray head according to feature 1.

8. A liquid spray head that sprays liquid in the spraying direction while moving relative to a medium in a first direction, A nozzle plate having a nozzle surface with multiple nozzles for spraying liquid, A cover having one opening that exposes a portion of the nozzle surface when viewed in the direction opposite to the injection direction, and covering at least a portion of the outer edge of the nozzle surface, Equipped with, The cover has a first edge portion that covers the portion of the outer peripheral edge of the nozzle surface that extends in a second direction perpendicular to the first direction, The first edge portion has a first inner edge that defines the inner edge of the opening, The proportion of the length of the first inner edge in the second direction occupied by one or more straight sections that are located at the same position in the first direction, define the first inner edge, and extend substantially parallel to the second direction is less than 50%. A liquid spray head characterized by the following features.

9. The first inner edge has at least one of an inclined portion that is inclined with respect to a straight line parallel to the second direction, and a curved portion that is curved. The liquid spray head according to feature 8.

10. The first inner edge has a first portion that does not extend substantially parallel to the second direction, The ratio of the length of the first portion in the second direction to the length of the first inner edge in the second direction is greater than 50%. The liquid spray head according to feature 8.

11. The outer shape of the nozzle plate, when viewed in the direction opposite to the spraying direction, is a rectangle or substantially rectangle including a pair of sides extending in the first direction and a pair of sides extending in the second direction. The liquid spray head according to feature 8.

12. The first inner edge has a plurality of straight sections that are offset in the first direction, define the first inner edge, and extend substantially parallel to the second direction. The liquid spray head according to feature 8.

13. A liquid spray head that sprays liquid in the spraying direction while moving relative to a medium in a first direction, A nozzle plate having a nozzle surface with multiple nozzles for spraying liquid, A cover having an opening that exposes a portion of the nozzle surface when viewed in the direction opposite to the injection direction, and covering at least a portion of the outer edge of the nozzle surface, Equipped with, The cover has a first edge portion that covers the portion of the outer peripheral edge of the nozzle surface that extends in a second direction perpendicular to the first direction, The first edge portion has a first inner edge that defines the inner edge of the opening, The first inner edge has, at least in its central portion in the second direction, an inclined portion that is inclined with respect to a straight line parallel to the second direction, or a curved portion that is curved. A liquid spray head characterized by the following features.

14. A liquid spray head according to any one of claims 1 to 13, A carriage that holds the liquid injection head and moves back and forth in the first direction, A conveying mechanism for conveying the medium in the second direction at a position opposite the nozzle surface, A liquid injection device characterized by being equipped with the following features.

15. A line head comprising a liquid injection head according to any one of claims 1 to 13, A conveying mechanism that conveys the medium in the first direction at a position opposite the nozzle surface, A liquid injection device characterized by being equipped with the following features.

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