Liquid dispensing head, image forming apparatus

Abstract

The objective of this invention is to improve the discharge stability of liquids. [Solution] A liquid discharge head 100 comprising a nozzle plate 1 having a nozzle hole 4 for discharging liquid, a flow path plate 2 having a pressure chamber 6, fluid resistance sections 7A and 7B leading to the pressure chamber 6, and individual supply liquid chambers 66 and 68 on the opposite side from the pressure chamber 6 leading to the fluid resistance sections 7A and 7B, and a piezoelectric element 12 for generating pressure in the pressure chamber 6, wherein the liquid is supplied from the individual supply liquid chambers 66 and 68 to the pressure chamber 6 via the fluid resistance sections 7A and 7B, and the flow path plate 2 has a plurality of fluid resistance sections 7A and 7B with equal longitudinal lengths formed thereon overlapping in the liquid discharge direction, and the plurality of fluid resistance sections 7A and 7B lead to a common pressure chamber 6.

Description

Technical Field

[0001] The present invention relates to a liquid ejection head and an image forming apparatus.

Background Art

[0002] There exists a liquid ejection head configured such that liquid supplied from a common liquid chamber to a pressure chamber via a fluid resistance portion or the like is ejected from a nozzle by pressurizing the pressure chamber with a pressure generating means.

[0003] In such a liquid ejection head, it is important to appropriately set the resistance value and inertia in the fluid resistance portion to achieve excellent refill characteristics, high stability of the liquid ejection speed, and the liquid ejection amount.

[0004] Due to restrictions on the arrangement space of the liquid ejection head within the liquid ejection device, the height of the fluid resistance portion has a greater degree of freedom compared to the width and length of the fluid resistance portion, and it was relatively easy to change the height of the fluid resistance portion. However, when changing the resistance value by changing the height of the fluid resistance portion, the value of inertia also changes simultaneously, so it was difficult to set both the resistance value and inertia to appropriate values only by changing the height of the fluid resistance portion.

[0005] For example, in the liquid ejection head of Patent Document 1 (Japanese Patent Application Laid-Open No. 2018-154067), a configuration is disclosed in which a plurality of fluid resistance portions communicate with one pressure chamber in order to suppress variations in ejection characteristics. The lengths of the respective fluid resistance portions are different.

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the configuration of Patent Document 1, since the supply speeds of liquid from the respective fluid resistance portions to the pressure chamber are different, there is a problem that the liquid ejection property by the liquid ejection head is not stable.

[0007] An object of the present invention is to improve the ejection stability of liquid. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a liquid discharge head comprising: a nozzle plate having a nozzle hole for discharging liquid; a flow path member having a pressure chamber, a fluid resistance section leading to the pressure chamber, and an individual supply liquid chamber on the opposite side of the pressure chamber that leads to the fluid resistance section; and a pressure generating means for generating pressure in the pressure chamber, wherein the liquid is supplied from the individual supply liquid chamber to the pressure chamber via the fluid resistance section, and the flow path member is formed with a plurality of fluid resistance sections having equal longitudinal lengths, overlapping in the liquid discharge direction, and the plurality of fluid resistance sections leading to a common pressure chamber. [Effects of the Invention]

[0009] According to the present invention, the liquid discharge stability can be improved. [Brief explanation of the drawing]

[0010] [Figure 1] This is an external perspective view illustrating a liquid discharge head according to one embodiment of the present invention. [Figure 2] This is a cross-sectional diagram illustrating the liquid discharge head along a direction perpendicular to the nozzle arrangement direction. [Figure 3] This is a cross-sectional view along line AA in Figure 2. [Figure 4] This is a plan view of the nozzle plate, the flow path plate, and the diaphragm plate, as seen from the ink discharge direction. [Figure 5] This is a perspective view showing a simplified flow path for calculating the resistance value of the ink flow path. [Figure 6] This is a cross-sectional diagram illustrating a liquid discharge head that differs from the above embodiment, along a direction perpendicular to the nozzle arrangement direction. [Figure 7] This is a plan view of the first and second restrictors as seen from the ink ejection direction. [Figure 8]The figure shows embodiments with different lengths of fluid resistance sections and slit spacings. Figure (a) is a cross-sectional explanatory view along a direction perpendicular to the nozzle arrangement direction, and Figure (b) is a plan view of each plate-shaped member constituting the flow path plate as seen from the ink discharge direction. [Figure 9] This is a plan view illustrating the main parts of a liquid dispensing device according to one embodiment. [Figure 10] This is a side view illustrating the main part of a liquid dispensing device according to one embodiment. [Figure 11] These are plan views illustrating the main parts of liquid dispensing units according to different embodiments. [Figure 12] This is a front view illustrating the main parts of a liquid dispensing unit in a different embodiment. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will now be described with reference to the accompanying drawings. The first embodiment of the present invention will be described with reference to Figures 1 to 3. Figure 1 is an external perspective view of the liquid discharge head according to the first embodiment, Figure 2 is a cross-sectional view of the pressure chamber of the liquid discharge head according to the same embodiment along the longitudinal direction X, and Figure 3 is a cross-sectional view of the same embodiment along the nozzle arrangement direction Y. Direction X is also the longitudinal direction of the fluid resistance section 7. Direction Y is the arrangement direction of the plurality of nozzle holes 4, and will hereinafter be simply referred to as the nozzle arrangement direction. Direction Z is the height direction of the pressure chamber 6, and is the opening direction of the nozzle holes or the liquid discharge direction and the opposite direction. Direction Z is also the up and down direction. This up and down direction is the direction parallel to the direction of gravity when the liquid discharge head is in use, and the direction when the liquid discharge head is in use is the direction when the liquid discharge head is mounted on a device such as a liquid discharge device. The directions X, Y, and Z shown in Figure 1 are mutually orthogonal directions. Direction X is one of these mutually orthogonal directions, different from the nozzle arrangement direction and the up and down direction. However, the longitudinal direction X of the pressure chamber 6, the nozzle arrangement direction Y, and the liquid discharge direction Z do not need to be strictly perpendicular, and some error is acceptable. Also, direction Z does not necessarily need to be parallel to the direction of gravity.

[0012] The liquid ejection head 100 of the present embodiment includes a nozzle plate 1, a flow path plate 2 that is a flow path member, a diaphragm member 3 as a wall surface member, a piezoelectric actuator 11, a common liquid chamber member 20, and a head cover 29. The nozzle plate 1, the flow path plate 2, and the diaphragm member 3 are laminated and joined. The piezoelectric actuator 11 displaces the deformation part 30 of the diaphragm member 3. The head cover 29 also serves as a frame member of the liquid ejection head 100.

[0013] A piezoelectric element 12 and the like are disposed inside the common liquid chamber member 20. As shown in FIG. 1, the head cover 29 is mounted on the upper part of the common liquid chamber member 20 and covers the piezoelectric element 12 and the like.

[0014] The supply port 28 supplies ink as a liquid to the common supply flow path inside the common liquid chamber member 20.

[0015] As shown in FIGS. 2 and 3, the nozzle plate 1 has a plurality of nozzle holes 4 for ejecting ink.

[0016] Inside the flow path plate 2, a first fluid resistance part 7A, a second fluid resistance part 7B, and an intermediate supply part 8 are defined. Further, a plurality of pressure chambers 6 are defined by the nozzle plate 1, the flow path plate 2, and the diaphragm member 3. The pressure chamber 6 communicates with the nozzle hole 4. The fluid resistance parts 7A and 7B are individual flow paths that lead to the pressure chamber 6. In the present embodiment, two fluid resistance parts 7A and 7B lead to one pressure chamber 6. The intermediate supply part 8 is a liquid introduction part that leads to the fluid resistance parts 7A and 7B.

[0017] The flow path plate 2 of the present embodiment is formed by laminating a plurality of laminated members including a first pressure chamber member 21, a first restrictor 22, a second pressure chamber member 23, and a second restrictor 24. The fluid resistance parts 7A and 7B are formed by these plate materials that constitute the flow path plate 2. The fluid resistance parts 7A and 7B are arranged in the vertical direction in FIG. 2. Hereinafter, the fluid resistance parts 7A and 7B are also referred to as fluid resistance part 7. However, the flow path plate 2 may be formed by five or more plate materials, and a configuration may be adopted in which three or more fluid resistance parts 7 lead to one pressure chamber 6.

[0018] The diaphragm member 3 is formed by laminating a plurality of plate materials. In this embodiment, two metal plates are laminated. The diaphragm member 3 also has a deformation portion 30 facing the piezoelectric actuator 11.

[0019] The deformation portion 30 forms a part of the wall surface of the pressure chamber 6 and is a portion that can be elastically deformed by the piezoelectric actuator 11. The piezoelectric actuator 11 includes a piezoelectric element 12, which is an electromechanical conversion element as a pressure generating means (driving means, actuator means) for generating pressure in the pressure chamber 6. The deformation portion 30 of this embodiment has a smaller number of laminated plate materials and a smaller length in the thickness direction than other portions of the diaphragm member 3. Specifically, the deformation portion 30 is formed by one metal plate. Also, a cut may be made in the diaphragm member 3 to make it partially deformable, and a portion that forms the wall surface of the pressure chamber 6 among this deformable portion may be used as the deformation portion 30.

[0020] This piezoelectric actuator 11 is formed by grooving a piezoelectric member joined on the base member 13 by half-cut dicing, and forming a required number of columnar piezoelectric elements 12 in a comb shape at a predetermined interval in the nozzle arrangement direction.

[0021] A support member 27 for supporting the deformation portion 30 is provided above the deformation portion 30. The piezoelectric element 12 is joined to the support member 27.

[0022] This piezoelectric element 12 is formed by alternately laminating a piezoelectric layer and internal electrodes. For the piezoelectric element 12, the internal electrodes are respectively drawn out to the end faces and connected to external electrodes (end face electrodes), and a flexible wiring member 15 is connected to the external electrodes.

[0023] The common liquid chamber member 20 forms a common liquid chamber 10 communicating with a plurality of pressure chambers 6. The common liquid chamber 10 communicates with the intermediate supply portion 8 through an opening 9 provided in the diaphragm member 3, and communicates with the fluid resistance portions 7A and 7B through the intermediate supply portion 8.

[0024] The ink in the common liquid chamber 10 is supplied to the pressure chamber 6 via the intermediate supply unit 8 and the fluid resistance units 7A and 7B. The ink in the pressure chamber 6 is ejected from the nozzle hole 4 to the outside of the liquid discharge head 100. In the pressure chamber 6, the direction of ink supply is from the fluid resistance units 7A and 7B in the X direction towards the nozzle hole 4.

[0025] In this liquid dispensing head 100, for example, the piezoelectric element 12 contracts by lowering the voltage applied to it from a reference potential (intermediate potential). This contraction of the piezoelectric element 12 causes the deformation portion 30 to deform toward the piezoelectric element 12, expanding the volume of the pressure chamber 6, and allowing ink to flow into the pressure chamber 6.

[0026] Subsequently, the voltage applied to the piezoelectric element 12 is increased, causing the piezoelectric element 12 to stretch in the stacking direction, thereby deforming the deformed portion 30 toward the nozzle hole 4 and contracting the volume of the pressure chamber 6. As a result, the ink in the pressure chamber 6 is pressurized, and the ink is ejected from the nozzle hole 4.

[0027] Figure 4 is a plan view of the plate-shaped members and diaphragm member 3 that make up the nozzle plate 1 and flow path plate 2, as seen from the ink discharge direction.

[0028] As shown in Figure 4, the first pressure chamber member 21, the first restrictor 22, the second pressure chamber member 23, and the second restrictor 24 each have holes (recesses) that constitute part of the pressure chamber. Specifically, holes 61, 62, 63, and 64 that form each pressure chamber are formed in the first pressure chamber member 21, the first restrictor 22, the second pressure chamber member 23, and the second restrictor 24, respectively. These holes 61 to 64 are stacked in the height direction to form a plurality of pressure chambers 6 (see Figure 2) corresponding to each nozzle hole 4.

[0029] Furthermore, a first fluid resistance section 7A is formed in the first restrictor 22, and a second fluid resistance section 7B is formed in the second restrictor 24. The first restrictor 22 is the first laminated member of this embodiment that forms the fluid resistance section 7A. The second restrictor 24 is the third laminated member of this embodiment that forms the fluid resistance section 7B. The second pressure chamber member 23 is the second laminated member of this embodiment that separates the fluid resistance section 7A and the fluid resistance section 7B. The longitudinal length of the first fluid resistance section 7A is set to L1a, and the longitudinal length of the fluid resistance section 7B is set to L1b. The longitudinal direction of the fluid resistance section is the left-right direction in Figure 4, and is the direction in which the liquid mainly flows in the fluid resistance section. In this embodiment, it is also the direction from the individual liquid chamber to the pressure chamber. The recesses formed in the first restrictor 22 and the second restrictor 24 define the fluid resistance section 7A and the first individual supply fluid chamber 66, or the fluid resistance section 7B and the second individual supply fluid chamber 68, side by side in the longitudinal direction.

[0030] The first pressure chamber member 21 has a first intermediate supply liquid chamber 65 that leads to the common liquid chamber 10 (see Figure 2) via an opening 9 formed in the diaphragm member 3. The first restrictor 22 has first individual supply liquid chambers 66 that lead to each first fluid resistance section 7A. The second pressure chamber member 23 has a second intermediate supply liquid chamber 67. The second restrictor 24 has second individual supply liquid chambers 68 that lead to each second fluid resistance section 7B. The first intermediate supply liquid chamber 65 leads to each first individual supply liquid chamber 66. The second intermediate supply liquid chamber 67 leads to each first individual supply liquid chamber 66 on one side and to each second individual supply liquid chamber 68 on the other side. The first intermediate supply liquid chamber 65, each first individual supply liquid chamber 66, the second intermediate supply liquid chamber 67, and each second individual supply liquid chamber 68 form an intermediate supply section 8 (see Figure 2). The intermediate supply section 8 is the part that supplies ink from the common liquid chamber 10 to each fluid resistance section 7A and 7B. Thus, the intermediate supply liquid chamber is a part that leads to each individual liquid chamber or to the common liquid chamber.

[0031] Incidentally, it is important to appropriately set the resistance value R and inertance L in the fluid resistance section 7 to achieve excellent refill characteristics and high stability of liquid discharge speed and liquid discharge volume in the liquid discharge head.

[0032] Here, the resistance value R of the fluid resistance section 7 changes depending on the width w, length l, and height h of the fluid resistance section 7. However, due to the constraints on the space for arranging the liquid discharge head within the liquid discharge device, the width w and length l are heavily constrained, while the degree of freedom in setting the height h is relatively large. However, since both the resistance value R and the inertance L change with respect to the height h, it was difficult to set both the resistance value R and the inertance L to appropriate values ​​by changing only the height h. For example, reducing the resistance value R is desirable from the viewpoint of refill characteristics, but it leads to a large change in the liquid discharge amount during frequency fluctuations.

[0033] Figure 5 is a perspective view showing a simplified flow path for calculating the resistance value of the ink flow path.

[0034] Assuming the viscosity μ and density ρ of the ink flowing through the channel in Figure 5, and the speed of sound c, the resistance R and inertance L in the channel in Figure 5 can be calculated using the following formulas (1) and (2), respectively, along with the width w, length l, and height h of the channel shown in Figure 5.

number

[0035] In this embodiment, as shown in Figure 2, a first fluid resistance section 7A and a second fluid resistance section 7B are provided, each connected to a common pressure chamber 6. This allows the height h of each fluid resistance section 7A and 7B to be kept small, and the respective resistance values ​​R and inertance L can be adjusted to appropriate values. Although reducing the height h tends to worsen the refill characteristics, the configuration of supplying ink from multiple fluid resistance sections to the common pressure chamber 6 can improve the refill characteristics. Therefore, excellent refill characteristics can be achieved, and fluctuations in liquid ejection speed and liquid ejection volume can be suppressed. In particular, by keeping the inertance L small in this embodiment, deterioration of refill characteristics during high-frequency operation can be prevented.

[0036] Furthermore, in this embodiment, the fluid resistance sections 7A and 7B are arranged in an overlapping configuration in the liquid discharge direction. In other words, when viewed in the liquid discharge direction, part or all of the fluid resistance sections 7A and 7B overlap. This "overlapping" may include other components sandwiched in between, as in this embodiment. By arranging the fluid resistance sections 7A and 7B in an overlapping configuration in the liquid discharge direction, it becomes possible to realize a liquid discharge head with the fluid resistance sections 7A and 7B arranged without increasing the size of the liquid discharge device, thereby miniaturizing the liquid discharge device. In addition, in a configuration where the fluid resistance sections 7A and 7B are arranged side by side in a direction perpendicular to the liquid discharge direction, if each fluid resistance section is not formed to cleanly penetrate the stacked first pressure chamber member 21, first restrictor 22, second pressure chamber member 23, and second restrictor 24, irregularities will be created at the joints between the layers. These irregularities can cause errors in resistance, leading to variations in resistance values. However, by arranging the fluid resistance sections 7A and 7B side-by-side in the liquid discharge direction, as in this embodiment, such variations can be suppressed. In this embodiment, in particular, the fluid resistance section 7A and the fluid resistance section 7B are provided at the same position on a plane perpendicular to the liquid discharge direction.

[0037] Furthermore, as in this embodiment, a configuration in which two fluid resistance sections 7 pass through a single pressure chamber 6 is preferable. Compared to a configuration in which three or more fluid resistance sections 7 pass through a single pressure chamber 6, the number of plate members constituting the flow path plate 2 can be reduced, making it easier to align each plate member and reducing the likelihood of resonance due to misalignment. In addition, it becomes easier to stably supply liquid when supplying a small amount of liquid to the pressure chamber 6. These effects can be obtained while simultaneously achieving the above-mentioned excellent refill characteristics and suppressing fluctuations in liquid discharge speed and liquid discharge volume.

[0038] Figure 6 is a cross-sectional diagram showing a liquid ejection head different from that of this embodiment, along a direction perpendicular to the nozzle arrangement direction, and Figure 7 is a plan view of the first restrictor and the second restrictor as seen from the ink ejection direction.

[0039] In the liquid discharge head 200 shown in Figure 6, the configuration of the flow path plate 202, particularly the first fluid resistance section 207A and the second fluid resistance section 207B formed on the flow path plate 202, differs from that of the liquid discharge head 100 shown in Figure 2, although the configuration of the other parts is basically the same. Specifically, as shown in Figure 7, the longitudinal length L1a of the first fluid resistance section 207A formed on the first restrictor 222 and the longitudinal length L1b of the second fluid resistance section 207B formed on the second restrictor 224 are different. As a result, the liquid supply speed from each fluid resistance section 207A and 207B to the pressure chamber 6 is different. In other words, the liquid supply speed is relatively faster in the second fluid resistance section 207B, which is longer than the first fluid resistance section 207A. The liquid velocity after passing through the fluid resistance section 207 changes depending on the discharge frequency. Furthermore, if the liquid supply speed from each fluid resistance section 207 to the pressure chamber 6 is different, turbulence and bends occur in the ink flow within the pressure chamber 6 each time a frequency fluctuation occurs. Consequently, turbulence and vortices, as indicated by the arrows in Figure 6, are more likely to occur within the pressure chamber 6, worsening the liquid discharge stability in the liquid discharge head, such as increasing ink failure.

[0040] In contrast, in this embodiment, as shown in Figure 4, the longitudinal length L1a of the first fluid resistance section 7A and the longitudinal length L1b of the second fluid resistance section 7B are set to the same length. This makes it possible to equalize the liquid supply speed at which ink is supplied from each fluid resistance section 7A and 7B to the pressure chamber 6, even when frequency fluctuations occur. Therefore, it is possible to suppress the generation of turbulence and vortices in the pressure chamber 6 as shown in Figure 6 and improve the liquid discharge stability. However, it is not necessary for lengths L1a and L1b to be exactly the same. In other words, as long as there is a difference in ink supply speed that does not cause turbulence or vortices in the ink within the pressure chamber 6 that would hinder discharge stability, as shown in Figure 6 above, it is acceptable. Therefore, if the difference between lengths L1a and L1b is such that it causes this difference in ink supply speed, the same effect as when lengths L1a and L1b are exactly the same can be obtained. Specifically, regarding this difference in ink supply speed, if the difference between the lengths L1a and L1b of the fluid resistance section is within 10%, preferably within 5%, then the same effect as when lengths L1a and L1b are exactly the same can be obtained.

[0041] Furthermore, in this embodiment, the width (width w) in direction Y and the width (height h) in direction Z of the fluid resistance sections 7A and 7B are made smaller than the first individual supply liquid chamber 66 or the second individual supply liquid chamber 68 (or pressure chamber 6). This allows the flow path in the fluid resistance section 7 to be narrowed in both directions Y and Z, and the resistance value R can be made larger. Therefore, by combining this with a configuration that provides multiple fluid resistance sections as in this embodiment, it is possible to prevent deterioration of refill characteristics and to further suppress fluctuations in the liquid discharge amount, especially at high frequencies, which is preferable.

[0042] Furthermore, as shown in Figures 8(a) and 8(b), it is preferable that the length L1a of the first fluid resistance section 7A (or the length L1b of the second fluid resistance section 7B) be larger than the slit spacing L2a of the first fluid resistance section 7A (or the slit spacing L2b of the second fluid resistance section 7B). This allows the flow path width in direction Y to be narrowed first at the inlets of the fluid resistance sections 7A and 7B (the right ends of L1a and L1b), and then the flow path width in direction Z to be narrowed beyond the first intermediate supply liquid chamber 65 or the second intermediate supply liquid chamber 67 (the right ends of L2a and L2b). Therefore, the flow path resistance can be increased in stages to stabilize the liquid flow and suppress turbulence in the liquid flow. In this embodiment, the flow path resistance can also be similarly reduced in stages on the outlet side. The slit spacings L2a and L2b are the distances between the pressure chamber 6 and the first intermediate supply liquid chamber 65 or the second intermediate supply liquid chamber 67.

[0043] Next, an example of an image forming apparatus according to the present invention will be described with reference to Figures 9 and 10. Figure 9 is a plan view illustrating the main parts of the apparatus, and Figure 10 is a side view illustrating the main parts of the apparatus.

[0044] The liquid ejection device 500, as an image forming apparatus, is a serial type apparatus, and the carriage 403 reciprocates in the main scanning direction K by the main scanning movement mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, etc. The guide member 401 is stretched across the left and right side plates 491A and 491B and holds the carriage 403 in a movable position. The carriage 403 is then reciprocated in the main scanning direction K by the main scanning motor 405 via the timing belt 408 stretched between the drive pulley 406 and the driven pulley 407.

[0045] The carriage 403 is equipped with a liquid discharge unit 300 that integrates a liquid discharge head 100 and a head tank 441 according to the present invention. The liquid discharge head 100 of the liquid discharge unit 300 discharges liquids of various colors, such as yellow (Y), cyan (C), magenta (M), and black (K). The liquid discharge head 100 has a nozzle row consisting of multiple nozzles arranged in a sub-scanning direction L perpendicular to the main scanning direction K, and is mounted with the discharge direction facing downward. The main scanning direction K is the direction X in the liquid discharge head described above, and the sub-scanning direction L is the direction Y in the liquid discharge head described above.

[0046] The liquid dispensing device 500 includes a transport mechanism 495 for transporting paper 410. The transport mechanism 495 includes a transport belt 412, which is a transport means, and a sub-scanning motor 416 for driving the transport belt 412.

[0047] The conveyor belt 412 attracts the paper 410 and transports it to a position opposite the liquid discharge head 100. This conveyor belt 412 is an endless belt and is stretched between the conveyor roller 413 and the tension roller 414. Attraction can be performed by electrostatic attraction or air suction.

[0048] Then, the conveyor belt 412 moves in a circular motion in the sub-scanning direction L as the conveyor rollers 413 are rotated by the sub-scanning motor 416 via the timing belt 417 and timing pulley 418.

[0049] Furthermore, a maintenance and recovery mechanism 420 for maintaining and recovering the liquid discharge head 100 is positioned on one side of the carriage 403 in the main scanning direction K, next to the conveyor belt 412.

[0050] The maintenance and recovery mechanism 420 consists of, for example, a cap member 421 that caps the nozzle surface (the surface on which the nozzle is formed) of the liquid discharge head 100, and a wiper member 422 that wipes the nozzle surface.

[0051] The main scanning movement mechanism 493, the maintenance and recovery mechanism 420, and the transport mechanism 495 are mounted on a housing that includes side plates 491A, 491B, and a back plate 491C.

[0052] In the liquid dispensing device 500 configured in this way, the paper 410 is fed onto the conveyor belt 412 and picked up, and the paper 410 is transported in the sub-scanning direction L by the circumferential movement of the conveyor belt 412.

[0053] Therefore, by moving the carriage 403 in the main scanning direction K and driving the liquid ejection head 100 in accordance with the image signal, liquid is ejected onto the stationary paper 410 to form an image.

[0054] Next, another example of the liquid dispensing unit according to the present invention will be described with reference to Figure 11. Figure 11 is a plan view illustrating the main parts of the unit.

[0055] The liquid discharge unit 300 comprises a housing portion consisting of side plates 491A, 491B and a back plate 491C, a main scanning movement mechanism 493, a carriage 403, and a liquid discharge head 100, which are components of the liquid discharge device.

[0056] Furthermore, a liquid dispensing unit can also be constructed by attaching the aforementioned maintenance and recovery mechanism 420 to, for example, the side plate 491B of the liquid dispensing unit 300.

[0057] Next, yet another example of the liquid dispensing unit according to the present invention will be described with reference to Figure 12. Figure 12 is a front view of the unit.

[0058] This liquid discharge unit 300 consists of a liquid discharge head 100 to which a flow path component 444 is attached, and a tube 456 connected to the flow path component 444.

[0059] The flow path component 444 is located inside the cover 442. A head tank 441 (see Figure 10) can be included instead of the flow path component 444. Furthermore, a connector 443 for electrical connection to the liquid discharge head 100 is provided on the upper part of the flow path component 444.

[0060] The aforementioned liquid dispensing units and liquid dispensing devices can also be equipped with the aforementioned liquid dispensing head 100. This improves the stability of liquid dispensing.

[0061] In this application, the discharged liquid is not particularly limited as long as it has a viscosity and surface tension that can be discharged from the head, but it is preferable that its viscosity becomes 30 mPa·s or less at room temperature and atmospheric pressure, or when heated or cooled. More specifically, it is a solution, suspension, emulsion, etc. containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a polymerizable compound, a resin, a functional material such as a surfactant, a biocompatible material such as DNA, amino acids or proteins, calcium, or an edible material such as a natural pigment. These can be used, for example, as inkjet inks, surface treatment liquids, liquids for forming components of electronic elements and light-emitting elements or electronic circuit resist patterns, and material liquids for 3D molding.

[0062] The energy source for discharging liquid includes piezoelectric actuators (multilayer piezoelectric elements and thin-film piezoelectric elements), thermal actuators using electrothermal conversion elements such as heating resistors, and electrostatic actuators consisting of a diaphragm and a counter electrode.

[0063] A "liquid dispensing unit" is a liquid dispensing head with integrated functional components and mechanisms, and includes an assembly of parts related to liquid dispensing. For example, a "liquid dispensing unit" may include a combination of a liquid dispensing head with at least one of the following components: a head tank, carriage, supply mechanism, maintenance and recovery mechanism, and main scanning and moving mechanism.

[0064] Here, integration includes, for example, cases where the liquid dispensing head and functional components or mechanisms are fixed to each other by fastening, bonding, engaging, etc., or where one is held movably relative to the other. Furthermore, the liquid dispensing head and functional components or mechanisms may be configured to be detachable from each other.

[0065] For example, some liquid dispensing units have a liquid dispensing head and head tank integrated into one unit. Others have a liquid dispensing head and head tank integrated into one unit, connected to each other by tubes or similar means. In these liquid dispensing units, a unit including a filter can also be added between the head tank and the liquid dispensing head.

[0066] Additionally, some liquid dispensing units have an integrated liquid dispensing head and carriage.

[0067] Furthermore, some liquid dispensing units integrate the liquid dispensing head and the scanning mechanism by movably holding the liquid dispensing head in a guide member that constitutes part of the scanning mechanism. Others integrate the liquid dispensing head, carriage, and main scanning mechanism.

[0068] Furthermore, some liquid dispensing units integrate the liquid dispensing head, carriage, and maintenance / recovery mechanism by fixing a cap component, which is part of the maintenance / recovery mechanism, to a carriage to which the liquid dispensing head is attached.

[0069] Furthermore, some liquid discharge units have a head tank or a liquid discharge head to which flow path components are attached, to which a tube is connected, integrating the liquid discharge head and the supply mechanism.

[0070] The main scanning movement mechanism shall include the guide member alone. The supply mechanism shall also include the tube alone and the loading section alone.

[0071] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention.

[0072] The term "liquid" includes not only ink but also paint.

[0073] In this application, "liquid dispensing device" refers to a device that includes a liquid dispensing head or a liquid dispensing unit and drives the liquid dispensing head to dispense liquid. A liquid dispensing device includes not only devices that can dispense liquid onto objects to which liquid can adhere, but also devices that dispense liquid into air or into liquid.

[0074] This "liquid dispensing device" may also include means for feeding, transporting, and dispensing paper onto materials to which liquid can adhere, as well as pre-treatment devices, post-treatment devices, etc.

[0075] For example, "liquid ejection devices" include image forming devices that eject ink to form images on paper, and three-dimensional molding devices that eject molding liquid into a powder layer formed in layers to create three-dimensional objects.

[0076] Furthermore, the term "liquid dispensing device" is not limited to those that visualize meaningful images such as letters or figures through the dispensed liquid. For example, it also includes devices that form patterns that do not have meaning in themselves, or devices that create three-dimensional images.

[0077] The term "materials to which liquid can adhere" above refers to materials to which liquid can adhere, at least temporarily, including materials that adhere and solidify, or materials that adhere and penetrate. Specific examples include recording media such as paper, recording paper, film, and cloth; electronic components such as electronic circuit boards and piezoelectric elements; powder layers; organ models; and inspection cells. Unless otherwise specified, it includes all materials to which liquid can adhere.

[0078] The materials referred to as "materials to which liquid can adhere" above include paper, thread, fibers, fabrics, leather, metal, plastic, glass, wood, ceramics, etc., as long as liquid can adhere to them, even temporarily.

[0079] Furthermore, while "liquid dispensing device" includes devices in which the liquid dispensing head and the object to which the liquid can adhere move relative to each other, it is not limited to these. Specific examples include serial-type devices in which the liquid dispensing head moves, and line-type devices in which the liquid dispensing head does not move.

[0080] Other examples of "liquid dispensing devices" include processing liquid coating devices that dispense processing liquid onto the surface of paper for purposes such as modifying the paper surface, and injection granulation devices that granulate fine particles of raw materials by spraying a compositional liquid, in which raw materials are dispersed in a solution, through a nozzle.

[0081] In this application, the terms image formation, recording, printing, copying, printing, and shaping are all considered synonymous.

[0082] Examples of the present invention are as follows: <1> A nozzle plate having nozzle holes for discharging liquid, A flow path member having a pressure chamber, a fluid resistance section connected to the pressure chamber, and an individual supply liquid chamber connected to the fluid resistance section on the side opposite to the pressure chamber, A liquid discharge head comprising a pressure generating means for generating pressure in the pressure chamber, The liquid is supplied from the individual supply liquid chamber to the pressure chamber via the fluid resistance section. A liquid discharge head characterized in that the flow path member has a plurality of fluid resistance portions, each having the same longitudinal length, that overlap in the liquid discharge direction, and the plurality of fluid resistance portions are connected to a common pressure chamber. <2> Multiple fluid resistance components are provided at the same position on a plane perpendicular to the liquid discharge direction. <1> The liquid dispensing head described. <3> The flow channel member includes a plurality of stacked members, The recess formed within the laminated member defines the fluid resistance portion and the individual supply liquid chambers, which are aligned in the longitudinal direction. <1> or <2> The liquid dispensing head described. <4> Multiple fluid resistance sections are formed on different laminated members. <3> The liquid dispensing head described. <5> The laminated member includes a first laminated member, a second laminated member, and a third laminated member. The second laminated member is provided between the first laminated member and the third laminated member, The fluid resistance portion is formed by recesses formed in the first laminated member and the third laminated member, respectively, and these fluid resistance portions are separated by the second laminated member. <4> The liquid dispensing head described. <6> The fluid resistance section has a width smaller than the width of the individual supply liquid chamber in both the nozzle arrangement direction and the liquid discharge direction. <1> from <5> One of the liquid dispensing heads listed. <7> The flow channel member has an intermediate supply liquid chamber formed inside it that leads to a plurality of individual supply liquid chambers, In the longitudinal direction of the fluid resistance section, the length of the fluid resistance section is longer than the distance between the intermediate supply liquid chamber and the pressure chamber. <1> from <6> One of the liquid dispensing heads listed. <8> Two fluid resistance sections pass through one pressure chamber. <1> from <7> One of the liquid dispensing heads listed. <9> <1> from <8> An image forming apparatus equipped with one of the liquid dispensing heads described above. [Explanation of Symbols]

[0083] 1 Nozzle plate 2. Flow channel plate (flow channel member) 4 nozzle holes 6. Pressure Chamber 7A 1st fluid resistance section 7B 2nd fluid resistance section 10 Common liquid chamber 12. Piezoelectric element (pressure generating means) 20 Common liquid chamber member 21. First pressure chamber member (laminated member) 22 First restrictor (first laminated member) 23. Second pressure chamber member (second laminated member) 24. Second restrictor (third laminated member) 65 1st intermediate supply liquid chamber (intermediate supply liquid chamber) 66 1st individual supply liquid chamber (individual supply liquid chamber) 67 2nd intermediate supply liquid chamber (intermediate supply liquid chamber) 68 2nd individual supply liquid chamber (individual supply liquid chamber) 100 liquid dispensing heads 500 Liquid ejection device (image forming device) L1a, L1b: Longitudinal length of the fluid resistance section L2a, L2b: Distance between the intermediate supply liquid chamber and the pressure chamber. X Longitudinal direction of the fluid resistance section Y nozzle arrangement direction Z Liquid discharge direction [Prior art documents] [Patent Documents]

[0084] [Patent Document 1] Japanese Patent Publication No. 2018-154067

Claims

1. A nozzle plate having nozzle holes for discharging liquid, A flow path member having a pressure chamber, a fluid resistance section connected to the pressure chamber, and an individual supply liquid chamber connected to the fluid resistance section on the side opposite to the pressure chamber, A liquid discharge head comprising a pressure generating means for generating pressure in the pressure chamber, The liquid is supplied from the individual supply liquid chamber to the pressure chamber via the fluid resistance section. A liquid discharge head characterized in that the flow path member has a plurality of fluid resistance portions, each having the same longitudinal length, that overlap in the liquid discharge direction, and the plurality of fluid resistance portions are connected to a common pressure chamber.

2. The liquid discharge head according to claim 1, wherein the plurality of fluid resistance portions are provided at the same position on a plane perpendicular to the liquid discharge direction.

3. The flow channel member includes a plurality of stacked members, The liquid discharge head according to claim 1, wherein the fluid resistance portion and the individual liquid supply chambers are defined in the longitudinal direction by recesses formed within the laminated member.

4. The liquid discharge head according to claim 3, wherein a plurality of fluid resistance portions are each formed on different laminated members.

5. The laminated member includes a first laminated member, a second laminated member, and a third laminated member. The second laminated member is provided between the first laminated member and the third laminated member, The liquid discharge head according to claim 4, wherein the fluid resistance portion is formed by recesses formed in the first laminated member and the third laminated member, and these fluid resistance portions are separated by the second laminated member.

6. The liquid discharge head according to claim 1, wherein the width of the fluid resistance portion is smaller than the width of the individual supply liquid chamber in both the nozzle arrangement direction and the liquid discharge direction.

7. The flow channel member has an intermediate supply liquid chamber formed inside it that leads to a plurality of individual supply liquid chambers, The liquid discharge head according to claim 1, wherein the length of the fluid resistance portion in the longitudinal direction is longer than the distance between the intermediate supply liquid chamber and the pressure chamber.

8. The liquid discharge head according to claim 1, wherein two fluid resistance sections pass through one pressure chamber.

9. An image forming apparatus comprising a liquid dispensing head according to any one of claims 1 to 8.

Images