WO2024247612A1 - Inkjet head and image formation device - Google Patents

Abstract

The present invention provides an inkjet head and an image formation device that make it possible to discharge ink of a plurality of colors without an increase in head size. This inkjet head comprises: a head chip that has formed therein a plurality of individual supply flow paths which individually supply ink to a plurality of nozzles and that has a shear-mode type piezoelectric element which changes the pressure in the individual supply flow paths; and a partition member that has a damper function and that has formed therein a common supply flow path which communicates with the plurality of individual supply flow paths and through which ink flows and a division unit which divides the plurality of individual supply flow paths and the plurality of nozzles into a plurality of regions.

Description

Inkjet head and image forming apparatus

This disclosure relates to an inkjet head and an image forming device.

In the past, inkjet image forming devices have been known that eject ink from multiple nozzles arranged in an inkjet head onto a recording medium such as paper to form an image on the recording medium. Some of these inkjet image forming devices are capable of handling multiple colors of ink with a single inkjet head (see, for example, Patent Document 1). In an inkjet head that handles multiple colors of ink, multiple colors of ink are ejected by arranging multiple head chips that eject ink of a single color.

JP 2012-061719 A

Incidentally, when arranging multiple head chips that eject ink of a single color in a single inkjet head to be able to eject ink of multiple colors, it is necessary to align the nozzles so that the nozzles of each head chip are properly positioned. However, in order to align the nozzle positions, it is necessary to perform position adjustment with high precision, and an adjustment margin is required for the head chips. In other words, in this case, there is a problem in that the size of the inkjet head becomes large.

The present disclosure aims to provide an inkjet head and an image forming device that can eject ink of multiple colors without increasing the head size.

The inkjet head according to the present disclosure comprises:
a head chip in which a plurality of individual supply flow paths are formed to supply ink to a plurality of nozzles individually, the head chip having a shear mode type piezoelectric element that varies the pressure within the individual supply flow paths;
The inkjet head is provided with a partition member having a damper function, the partition member having a common supply flow path that communicates with the individual supply flow paths and through which the ink flows, and a dividing portion that divides the individual supply flow paths and the nozzles into a plurality of regions.

In addition, the image forming apparatus according to the present disclosure includes:
The inkjet head is provided as described above.

According to this disclosure, it is possible to eject multiple colors of ink without increasing the head size.

FIG. 1 is a schematic diagram showing an example of the configuration of an inkjet printer according to the present embodiment. FIG. 2 is a block diagram showing the main components of a control system of the inkjet printer according to this embodiment. FIG. 3 is a perspective view showing an example of the appearance of the ink-jet head of FIG. FIG. 4 is a cross-sectional view showing a schematic example of the configuration of the head shown in FIG. 3 taken along a plane perpendicular to the X-axis. FIG. 5 is an exploded perspective view for explaining the internal configuration of the head in FIG. FIG. 6 is a perspective view showing an example of the appearance of the partition member of FIG. FIG. 7 is an exploded perspective view showing an example of the configuration of the partition member of FIG. FIG. 8 is a cross-sectional view that typically shows a cross section of the partition member of FIG. 6 taken along line segment AA (a plane perpendicular to the X-axis). 9 is a perspective view of the cross section of the partition member shown in FIG. 8 as viewed from the X-axis direction. FIG. 10 is a bottom view of the partition member as viewed from the bottom side. FIG. 11 is an enlarged view of a portion indicated by reference character C in FIG. FIG. 12 is a perspective view of the vicinity of the portion indicated by the symbol C in FIG. 10 as viewed from the Z-axis direction. FIG. 13 is a partial cross-sectional view showing a schematic cross section of the partition member of FIG. 6 taken along line segment AA (a plane perpendicular to the X-axis) and line segment BB (a plane perpendicular to the Y-axis). FIG. 14 is a cross-sectional view that typically shows a cross section of the partition member of FIG. 6 taken along line segment BB (a plane perpendicular to the Y-axis). FIG. 15 is a front view of the partition member of FIG. 6 . FIG. 16 is an enlarged view of a portion indicated by the symbol D in FIG.

Below, an embodiment of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiment, and various modifications are possible without departing from the spirit of the present disclosure. In addition, in each drawing, the same reference numerals are used to denote the same or equivalent parts, and this is common throughout the entire specification.

An embodiment of the present disclosure will be described with reference to the drawings. The image forming device according to this embodiment is, for example, an inkjet printer, which forms an image by ejecting droplets of ink onto a recording medium such as paper. The following description will be given using an inkjet printer as an example of an image forming device.

[Configuration of Inkjet Printer 100]
Fig. 1 is a schematic diagram showing an example of the configuration of an inkjet printer 100 according to this embodiment. Fig. 2 is a block diagram showing the main parts of a control system of the inkjet printer 100 according to this embodiment. As shown in Figs. 1 and 2, the inkjet printer 100 includes a transport unit 10, a supply unit 20, a discharge unit 30, an ink supply unit 40, an image forming unit 50, an image reading unit 60, an operation display unit 70, an input/output interface 80, and a control unit 90.

The transport unit 10 has multiple components related to transport, such as a transport belt 11, a drive roller 12, and a driven roller 13. The transport unit 10 transports the recording medium M by the transport operation of multiple components such as the transport belt 11. Specifically, in the transport unit 10, the transport belt 11 is stretched across the drive roller 12 and the driven roller 13, and is driven by driving the drive roller 12 to rotate. As a result, the recording medium M supplied from the supply unit 20 is transported to the image forming unit 50 while placed on the transport surface 11a of the transport belt 11, and after an image is formed (printed) in the image forming unit 50, it is transported to the discharge unit 30.

The recording medium M can be any of a variety of media capable of fixing the ink ejected from the inkjet head 55 described below. The recording medium M is, for example, a medium such as sheet-shaped paper, cloth (woven fabric), or resin. Note that the recording medium M is not limited to a sheet-shaped medium, and may also be a medium such as roll-shaped paper, cloth, or resin.

In addition, as an example, the conveying unit 10 is shown here as conveying the recording medium M with a conveying belt 11, but the conveying unit 10 is not limited to the conveying belt 11 and may be configured to convey the recording medium M with a drum or roller.

The supply unit 20 has a supply stacking unit 21 and a supply transport unit 22. The supply stacking unit 21 stacks and stores multiple recording media M. The supply transport unit 22 transports and supplies the recording media M from the supply stacking unit 21 to the transport unit 10. The supply stacking unit 21 is configured to be able to rise and fall, and when the topmost recording medium M is transported to the transport unit 10 by the supply transport unit 22, the supply stacking unit 21 rises so that the recording medium M that has become the topmost after the transport can be transported to the supply transport unit 22.

The discharge section 30 has a discharge stacking section 31 and a discharge transport section 32. The discharge stacking section 31 stacks and stores a plurality of recording media M. The discharge transport section 32 transports the recording media M discharged from the transport section 10 to the discharge stacking section 31. The discharge stacking section 31 is configured to be capable of rising and lowering, and when the recording media M is transported from the discharge transport section 32 to the discharge stacking section 31, the discharge stacking section 31 descends.

The supply conveying unit 22 and the discharge conveying unit 32 have, for example, multiple rollers, and convey the recording medium M by rotating the rollers. The supply conveying unit 22 and the discharge conveying unit 32 are not limited to rollers, and may be configured as belts, or may be configured as a combination of rollers and belts.

When a roll-shaped medium is used as the recording medium M, an unwinding roller on which the roll-shaped medium is stored in a wound state is used instead of the supply stacking section 21. Also, a take-up roller that takes up the roll-shaped medium is used instead of the discharge stacking section 31. The roll-shaped medium is transported to the transport section 10 by rotating the unwinding roller, and is wound up onto the take-up roller by rotating the take-up roller.

A post-processing device may be provided between the conveying section 10 and the discharging section 30 to perform post-processing on the recording medium M on which an image has been formed by the image forming section 50. One example of the post-processing device is a fixing device that fixes the ink to the recording medium M. When, for example, an ultraviolet-curable ink is used as the ink, a fixing device is used that irradiates the recording medium M with ultraviolet light to fix the ink to the recording medium M. When, for example, an aqueous ink or a solvent ink is used as the ink, a fixing device is used that fixes the ink to the recording medium M by a method such as drying. Furthermore, the post-processing device may be a device other than a fixing device, such as a cutting device that cuts the recording medium M to a desired length.

The ink supply unit 40 is connected to the image forming unit 50 via a flow path 42, which is an ink supply path, and is a device that supplies ink to the image forming unit 50. In this embodiment, the ink supply unit 40 is configured to supply ink of multiple colors to the image forming unit 50. In particular, in this example, the ink supply unit 40 is configured to supply ink of two colors to the image forming unit 50.

The ink supply unit 40 has main tanks 41a and 41b, as well as components related to ink supply (e.g., pumps and valves, etc.) not shown. The main tank 41a stores ink at room temperature to be supplied to the first sub-tank 52a-1. The main tank 41b stores ink at room temperature to be supplied to the first sub-tank 52a-2. The ink supply unit 40 uses a pump or the like not shown to supply ink from the main tanks 41a and 41b, respectively, via the flow paths 42a and 42b to the first sub-tanks 52a-1 and 52a-2.

The image forming unit 50 includes a carriage 51, first sub-tanks 52a-1 and 52a-2, second sub-tanks 52b-1 and 52b-2, flow paths 53a-1, 53a-2, 53b-1, 53b-2, 53c-1 and 53c-2, a head drive unit 54, and an inkjet head (hereinafter referred to as "head") 55.

The inkjet printer 100 according to this embodiment ejects two colors of ink from a single image forming unit 50. Therefore, in FIG. 1, for the sake of simplicity, ink supply units 40 and image forming units 50 for two colors are shown, but the ink supply units 40 and image forming units 50 are arranged according to the number of colors used. For example, when using four colors, yellow (Y), magenta (M), cyan (C), and black (K), ink supply units 40 and image forming units 50 corresponding to the four colors are arranged, and the image forming units 50 are arranged so that they are lined up at a predetermined interval along the transport direction T.

In this embodiment, when multiple ink supply units 40 and image forming units 50 are arranged, at least one ink supply unit 40 and one image forming unit 50 for two colors may be arranged. In this case, for the remaining colors, for example, an ink supply unit 40 and one image forming unit 50 for one color may be arranged.

Specifically, for example, when the four colors YMCK described above are used, two ink supply units 40 and two image forming units 50 corresponding to any two colors may be arranged. Also, for example, one ink supply unit 40 and one image forming unit 50 corresponding to two colors, and two ink supply units 40 and two image forming units 50 corresponding to one color may be arranged.

Although not shown, the second sub-tanks 52b-1 and 52b-2 and the inkjet head 55 are connected in a tree-like arrangement downstream of the first sub-tanks 52a-1 and 52a-2, but in FIG. 1, only one of each is shown for the sake of simplicity.

The carriage 51 is a housing that holds the first sub-tanks 52a-1 and 52a-2, the second sub-tanks 52b-1 and 52b-2, the flow paths 53a-1, 53a-2, 53b-1, 53b-2, 53c-1 and 53c-2, the head drive unit 54, the head 55, and the devices and members required for image formation.

The first sub-tanks 52a-1 and 52a-2 are connected to the downstream side of the main tank 41. The first sub-tank 52a-1 stores ink supplied from the main tank 41a in the carriage 51. The ink in the first sub-tank 52a-1 is supplied to the second sub-tank 52b-1 via a flow path 53a-1, which is an ink supply path, using a pump (not shown) or the like in the carriage 51.

The first sub-tank 52a-2 stores ink supplied from the main tank 41b inside the carriage 51. The ink in the first sub-tank 52a-2 is supplied to the second sub-tank 52b-2 via the flow path 53a-2, which is an ink supply path, using a pump (not shown) or the like inside the carriage 51.

Although not shown, multiple second sub-tanks 52b-1 are connected downstream of the first sub-tank 52a-1. The second sub-tank 52b-1 stores ink supplied from the first sub-tank 52a-1 in the carriage 51. The ink in the second sub-tank 52b-1 is supplied to the manifold 56a of the head 55, which will be described later, via a flow path 53b-1, which is an ink supply path, using a pump (not shown) or the like in the carriage 51. The ink supplied to the manifold 56a is returned to the second sub-tank 52b-1 via flow path 53c-1. In other words, the flow paths 53b-1 and 53c-1 form a circulation flow path that circulates the ink between the second sub-tank 52b-1 and the manifold 56a.

Although not shown, multiple second sub-tanks 52b-2 are connected downstream of the first sub-tank 52a-2. The second sub-tank 52b-2 stores ink supplied from the first sub-tank 52a-2 in the carriage 51. The ink in the second sub-tank 52b-2 is supplied to the manifold 56b of the head 55, which will be described later, via a flow path 53b-2, which is an ink supply path, using a pump (not shown) or the like in the carriage 51. The ink supplied to the manifold 56b is returned to the second sub-tank 52b-2 via a flow path 53c-2. In other words, the flow paths 53b-2 and 53c-2 form a circulation flow path that circulates ink between the second sub-tank 52b-2 and the manifold 56b.

Based on the control of the control unit 90 (described later), the head drive unit 54 outputs a drive voltage corresponding to the image data of the image to be formed to the piezoelectric element 58 of the head 55 (described later). The drive voltage from the head drive unit 54 drives the piezoelectric element 58, causing it to eject an amount of ink corresponding to the image data from the nozzles 59a and 59b of the head 55 (described later).

The head 55 is connected to the downstream side of each of the second sub-tanks 52b-1 and 52b-2. In other words, although not shown, the second sub-tanks 52b-1 and 52b-2 and the head 55 are connected in a tree-like configuration to the downstream side of the first sub-tanks 52a-1 and 52a-2.

The head 55 has manifolds 56a and 56b, individual supply flow paths 57a and 57b as pressure chambers, a piezoelectric element 58, and nozzles 59a and 59b. The head 55 has a plurality of nozzles 59a and 59b, and the individual supply flow paths 57a and 57b and the piezoelectric elements 58 are provided according to the number of nozzles 59a and 59b.

In the following description, when there is no need to distinguish between the individual supply flow paths 57a and 57b, they may simply be referred to as "individual supply flow paths 57." Similarly, when there is no need to distinguish between the nozzles 59a and 59b, they may simply be referred to as "nozzle 59."

Manifold 56a communicates with a plurality of individual supply flow paths 57a, and ink supplied to manifold 56a is supplied to individual supply flow paths 57a. Manifold 56b communicates with a plurality of individual supply flow paths 57b, and ink supplied to manifold 56b is supplied to individual supply flow paths 57b.

Individual supply flow paths 57a and 57b are each a space in which the ink to be ejected is stored, and a piezoelectric element 58 is provided on the wall surface. One end of nozzle 59a is connected to individual supply flow path 57a, and the other end is an open end. Furthermore, one end of nozzle 59b is connected to individual supply flow path 57b, and the other end is an open end.

A driving voltage is applied to the piezoelectric element 58 from the head driving unit 54. When the driving voltage from the head driving unit 54 is applied to the piezoelectric element 58, the piezoelectric element 58 deforms in response to the applied driving voltage, and the individual supply flow path 57 deforms. Then, due to the deformation of the individual supply flow path 57, the pressure on the ink in the individual supply flow path 57 that is supplied to the nozzle 59 changes.

Therefore, when a drive voltage from the head drive unit 54 is applied to the piezoelectric element 58, the piezoelectric element 58 and the individual supply flow path 57 are deformed, causing a pressure change in the ink in the individual supply flow path 57. As a result, the ink in the individual supply flow path 57 is ejected from the nozzle 59. In this way, an image is formed on the recording medium M being transported by ejecting droplets of ink from the nozzle 59.

In the carriage 51, the heads 55 may be configured to use a single pass (one-pass) method in which an image is formed in one scan, or a scan (multi-pass) method in which an image is formed in multiple scans. In the case of a single pass method, the carriage 51 is arranged with heads 55 in the number equal to the image formation width in the width direction of the recording medium M (direction perpendicular to the transport direction T of the recording medium M).

The image reading unit 60 is disposed downstream of the image forming unit 50 in the transport direction T of the recording medium M, and reads images such as a predetermined pattern image formed on the recording medium M transported by the transport belt 11. The image reading unit 60 outputs the results of reading the predetermined pattern image to the control unit 90. The control unit 90 changes the image formation conditions, such as the image formation position and the drive conditions of the head 55, based on the results of reading.

Although not shown, the inkjet printer 100 also includes a maintenance unit that performs maintenance such as cleaning the head 55.

The operation display unit 70 is, for example, a flat panel display such as a liquid crystal display or an organic EL (Electro Luminescence) display with a touch panel. The operation display unit 70 displays operation menus for the user, information related to image data, and various states of the inkjet printer 100. The operation display unit 70 also has a number of keys and accepts various input operations from the user.

The input/output interface 80 mediates the transmission and reception of data between the external device 200 and the control unit 90. The input/output interface 80 is, for example, composed of any one of various serial interfaces, various parallel interfaces, or a combination of these.

The external device 200 is, for example, a personal computer or a facsimile machine, and supplies print jobs, image data, etc. to the control unit 90 via the input/output interface 80.

The control unit 90 has a CPU (Central Processing Unit) 91, a RAM (Random Access Memory) 92, a ROM (Read Only Memory) 93, and a memory unit 94, etc.

The CPU 91 reads out various control programs and setting data stored in the ROM 93, stores them in the RAM 92, and executes the programs to perform various calculation processes. For example, the control unit 90 generates a drive signal for the image to be formed based on image data received from the input/output interface 80, and outputs the signal to the head 55.

RAM 92 provides working memory space for CPU 91 and stores temporary data. Note that RAM 92 may also include non-volatile memory.

The ROM 93 stores various control programs and setting data executed by the CPU 91. Note that instead of the ROM 93, a rewritable non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used.

The storage unit 94 stores print jobs and image data related to print jobs input from the external device 200 via the input/output interface 80. As the storage unit 94, for example, a non-volatile semiconductor memory (so-called flash memory) or a HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may also be used in combination.

The storage unit 94 stores print jobs and image data related to print jobs input from the external device 200 via the input/output interface 80. As the storage unit 94, for example, a non-volatile semiconductor memory (so-called flash memory) or a HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may also be used in combination.

The control unit 90 is connected to the transport unit 10, supply unit 20, discharge unit 30, ink supply unit 40, image forming unit 50, image reading unit 60, operation display unit 70, input/output interface 80, etc. The control unit 90 controls the overall operation of the inkjet printer 100. The transport unit 10, supply unit 20, discharge unit 30, ink supply unit 40, image forming unit 50, image reading unit 60, operation display unit 70, input/output interface 80, etc. are controlled by the control unit 90 to execute predetermined processes.

The inkjet printer 100 having the above configuration supplies the recording medium M from the supply unit 20 to the transport unit 10 under the control of the control unit 90, draws on the recording medium M transported to the transport unit 10 in the image forming unit 50, and transports the recording medium M with the image formed thereon to the discharge unit 30.

[Configuration of Inkjet Head 55]
Next, the configuration of the head 55 will be described. The configuration described here is the configuration of a single head 55. Note that all heads 55 in the inkjet printer 100 may have the same configuration, or the inkjet printer 100 may include heads 55 with a different configuration from the configuration described below.

FIG. 3 is a perspective view showing an example of the appearance of the inkjet head 55 of FIG. 1. In FIG. 3, hidden components are shown with dashed lines to facilitate understanding of the configuration of the head 55. In the following description, the longitudinal direction of the head 55 is defined as the X-axis direction, the lateral direction of the head 55 as the Y-axis direction, and the height direction of the head as the Z-axis direction. In addition, for each part constituting the head 55, the upper surface of the paper in the Z-axis direction may be referred to as the "upper surface," and the lower surface of the paper in the Z-axis direction as the "lower surface." The X-axis direction, Z-axis direction, and Y-axis direction correspond to the "first direction," "second direction," and "third direction" of this disclosure, respectively.

As shown in FIG. 3, the head 55 includes a housing 101 and an exterior member 102 that is fitted to the housing 101 on the underside of the housing 101. The main components of the head 55 are housed inside the housing 101 and the exterior member 102.

Inlet 103 and outlet 104 are arranged on exterior member 102. In this embodiment, since a single head 55 handles two colors of ink, in this example, inlet 103 includes inlets 103a and 103b, and outlet 104 includes outlets 104a and 104b.

Inlets 103a and 103b are ink supply ports through which ink is supplied from the outside. Inlets 103a and 103b are each supplied with ink of a different color. Outlets 104a and 104b are ink discharge ports through which ink is discharged to the outside. Outlets 104a and 104b are each discharged with ink of a different color.

Inside the exterior member 102, a manifold 56a connected to the inlet 103a and a manifold 56b connected to the inlet 103b are provided. Furthermore, the exterior member 102 is provided with a number of mounting holes 105 for mounting the inkjet head 55 to the base of the carriage 51.

(Internal configuration of inkjet head 55)
Fig. 4 is a cross-sectional view showing a schematic example of the configuration of the head 55 in Fig. 3 cut along a plane perpendicular to the X-axis. Fig. 5 is an exploded perspective view for explaining the internal configuration of the head 55 in Fig. 3. As shown in Figs. 4 and 5, the head 55 includes manifolds 56a and 56b, a head chip 110, a nozzle plate 120, a partition member 130, and the like.

(Nozzle plate 120)
Nozzle plate 120 is formed, for example, in a flat plate shape, and is disposed on the lower surface side of head chip 110 so that the plate surface is perpendicular to the Z axis. Nozzle plate 120 has a plurality of nozzles 59, which are holes penetrating in the Z axis direction, formed in a row along the X axis. Ink droplets are ejected to the outside in the Z axis direction via nozzles 59.

(Head chip 110)
The head chip 110 includes an insulating member 111 and a piezoelectric element 58. The insulating member 111 is formed, for example, in a flat plate shape, and is disposed so that the plate surface is perpendicular to the Z axis. The piezoelectric element 58 is disposed on the lower surface of the insulating member 111. The nozzle plate 120 described above is disposed on the lower surface side of the piezoelectric element 58 of the head chip 110 thus formed.

The insulating member 111 is a wiring board, and is connected to a flexible wiring 112. The insulating member 111 is electrically connected to the head driving unit 54 via the flexible wiring 112, and receives a driving voltage signal from the head driving unit 54. The insulating member 111 has flow paths formed therethrough in the Z-axis direction. For example, glass is used as the insulating member 111.

The piezoelectric element 58 has a number of individual supply flow paths 57 formed in a row along the X axis, each of which penetrates in the Z axis direction and communicates with a corresponding nozzle 59. The piezoelectric element 58 is electrically connected to the head drive unit 54 by electrodes, an insulating member 111, and flexible wiring 112 (not shown).

The piezoelectric element 58 is driven in response to a drive voltage signal applied from the head drive unit 54 via the electrodes, the insulating member 111, and the flexible wiring, thereby repeatedly generating shear-mode type displacements in the partitions of the individual supply channels 57. This causes the pressure of the ink in the individual supply channels 57 to fluctuate, and ink is ejected from the nozzles 59 in response to this pressure fluctuation. In other words, the head 55 in this embodiment is an inkjet head that ejects shear-mode type ink.

The piezoelectric element 58 is, for example, a ceramic piezoelectric body (a member that deforms in response to the application of voltage). Examples of the piezoelectric body that can be used include PZT (lead zirconate titanate), lithium niobate, barium titanate, lead titanate, and lead metaniobate.

(Partition member 130)
Partition member 130 is arranged to divide a plurality of individual supply channels 57 in head chip 110 into a plurality of regions in order to eject a plurality of colors of ink from head 55. Partition member 130 is attached to head chip 110 by, for example, an adhesive or welding. When partition member 130 and head chip 110 are attached by an adhesive, for example, an adhesive that hardens at a temperature of about 40° C. to 60° C. is used as the adhesive.

FIG. 6 is a perspective view showing an example of the appearance of the partition member 130 in FIG. 4. FIG. 7 is an exploded perspective view showing an example of the configuration of the partition member 130 in FIG. 6. FIG. 8 is a cross-sectional view showing a schematic cross section of the partition member 130 in FIG. 6 taken along line segment A-A (a plane perpendicular to the X-axis). Note that in FIG. 8, in order to make it easier to explain the partition member 130, the partition member 130 is shown stacked on the head chip 110.

As shown in FIG. 6, the partition member 130 is formed, for example, in a flat plate shape. The partition member 130 has common supply flow paths 131a and 131b. The common supply flow paths 131a and 131b are provided to connect the manifolds 56a and 56b to the individual supply flow paths of the head chip 110. Different colors of ink flow through the common supply flow path 131a and the common supply flow path 131b.

As shown in FIG. 7, the partition member 130 is formed by stacking a plurality of plate-like members formed, for example, in a flat plate shape. Specifically, the partition member 130 is configured by stacking a first plate-like member 133, a damper member 134, a second plate-like member 135, and a third plate-like member 136 in this order. The first plate-like member 133, the damper member 134, the second plate-like member 135, and the third plate-like member 136 are bonded, for example, by diffusion bonding or with an adhesive.

The first plate-like member 133 is formed with first flow paths 1301a and 1301b, second flow paths 1302a and 1302b, and a dividing section 1330.

The first flow paths 1301a and 1301b each penetrate in the Z-axis direction and are formed along both ends of the first plate-like member 133 that are parallel to the X-axis. The second flow paths 1302a and 1302b each penetrate in the Z-axis direction and are formed parallel to the X-axis of the first plate-like member 133 so as to be aligned with the first flow paths 1301a and 1301b.

The dividing unit 1330 is provided to divide the flow paths through which the multiple colors of ink handled by one head 55 flow. That is, the dividing unit 1330 divides the multiple nozzles 59 and the multiple individual supply flow paths 57 that communicate with the multiple nozzles 59 and supply ink individually into multiple regions. In this embodiment, the dividing unit 1330 divides the region including the multiple nozzles 59 and the multiple individual supply flow paths 57 into a first nozzle region including nozzles 59a and individual supply flow paths 57a, and a second nozzle region including nozzles 59b and individual supply flow paths 57b.

The dividing section 1330 is formed between the second flow paths 1302a and 1302b by forming the second flow paths 1302a and 1302b. The dividing section 1330 is formed over the entire first plate-like member 133 in the X-axis direction.

The damper member 134 is a plate-like member that functions as a damper to attenuate the ink pressure fluctuations that occur when ink is ejected and suppress adverse effects on ink ejection from other nozzles 59. Third flow paths 1303a and 1303b are formed in the damper member 134. The third flow paths 1303a and 1303b each penetrate in the Z-axis direction and are formed along both ends of the damper member 134 that are parallel to the X-axis. When the damper member 134 is stacked on the first plate-like member 133, it blocks the openings on the upper surface side of the second flow paths 1302a and 1302b of the first plate-like member 133.

The second plate-like member 135 is formed with fourth flow paths 1304a and 1304b and fifth flow paths 1305a and 1305b. The fourth flow paths 1304a and 1304b each penetrate in the Z-axis direction and are formed along both ends of the second plate-like member 135 that are parallel to the X-axis. The fifth flow paths 1305a and 1305b each penetrate in the Z-axis direction and are formed parallel to the X-axis of the second plate-like member 135 so as to be aligned with the fourth flow paths 1304a and 1304b.

When the second plate-like member 135 is stacked on the damper member 134, the openings on the lower side of the fifth flow paths 1305a and 1305b are blocked by the damper member 134. This forms air chambers 1350a and 1350b, which are sealed spaces, between the second plate-like member 135 and the damper member 134.

Sixth flow paths 1306a and 1306b are formed in the third plate-like member 136. The sixth flow paths 1306a and 1306b each penetrate in the Z-axis direction and are formed along both ends of the third plate-like member 136 that are parallel to the X-axis.

When the components of the partition member 130 are stacked, the first flow path 1301a, the third flow path 1303a, the fourth flow path 1304a, and the sixth flow path 1306a are connected and communicated with each other, forming a common supply flow path 131a in the partition member 130. Also, the first flow path 1301b, the third flow path 1303b, the fourth flow path 1304b, and the sixth flow path 1306b are connected and communicated with each other in the partition member 130, forming a common supply flow path 131b in the partition member 130.

Here, in the head 55 having the above configuration, the center-to-center distance between the nozzles 59a and 59b (see FIG. 4) is 5 mm or less. The center-to-center distance is the distance between the nozzles 59a and 59b that are located on the innermost side in the Y-axis direction, with the dividing portion 1330 of the partition member 130 at the center.

[Structure of partition member 130]
Next, a specific structure of the partition member 130 will be described.

(Step portion 1331)
Fig. 9 is a perspective view of the cross section of the partition member 130 shown in Fig. 8 as viewed from the X-axis direction. As shown in Fig. 9, a dividing portion 1330 formed in the first plate-like member 133 of the partition member 130 is formed with a step portion 1331 including a first step portion 1331a and a second step portion 1331b.

The first step 1331a is a step formed on the upper surface side of the first plate-like member 133 in the dividing section 1330. The second step 1331b is a step formed so as to protrude from the first step 1331a to the lower surface side of the first plate-like member 133. The second step 1331b is formed so that the length of the side in the Y-axis direction in the cross-sectional shape when the dividing section 1330 is cut along a plane perpendicular to the X-axis is shorter than the length of the side in the Y-axis direction of the first step 1331a.

In other words, the step portion 1331 is formed so that the length of the side in the Y-axis direction in the cross-sectional shape when the dividing portion 1330 is cut on a plane perpendicular to the X-axis becomes shorter in stages from the upper surface side to the lower surface side of the first plate-like member 133. By forming the step portion 1331 in the dividing portion 1330 in this way, when the partition member 130 and the head chip 110 are bonded with an adhesive, the surface tension of the step portion 1331 can be used to prevent the adhesive from spreading toward the flow path side.

In this example, the second step 1331b has its vertical sides in a cross section cut along a plane perpendicular to the X-axis formed in a direction parallel to the Z-axis, but this is not limited thereto, and it may be formed, for example, in a tapered shape from the top surface side to the bottom surface side.

(Outflow control section 1332)
Fig. 10 is a bottom view of the partition member 130 as viewed from the bottom side. Fig. 11 is an enlarged view of a portion indicated by reference character C in Fig. 10. Fig. 12 is an enlarged view of a portion indicated by reference character C in Fig. 10. 10 to 12, an outflow suppression portion 1332 is formed on the bottom surface of the partition member 130 (first plate-shaped member 133). It has been done.

The outflow suppression portion 1332 is a partition that prevents the adhesive from flowing into the flow path on the bonding surface when the head chip 110 and the partition member 130 are bonded. The outflow suppression portion 1332 is formed with a predetermined gap on the outer periphery of the dividing portion 1330 in the region of the first plate-like member 133 in the X-axis direction where the first flow paths 1301a and 1301b and the second flow paths 1302a and 1302b are not formed. The outflow suppression portion 1332 is also formed with a predetermined gap on the inside in the Y-axis direction from both ends of the first plate-like member 133 that are parallel to the X-axis direction.

When bonding the head chip 110 and the partition member 130, adhesive is applied to this gap, but by forming the outflow suppression section 1332 in this manner, it is possible to prevent the adhesive from leaking into the space that serves as the ink flow path.

(Beam 1333 and pillar 1334)
Fig. 13 is a partial cross-sectional view showing a schematic cross section of the partition member 130 shown in Fig. 6 taken along line segment A-A (a plane perpendicular to the X-axis) and line segment B-B (a plane perpendicular to the Y-axis). As shown in Figs. 10 and 13, a beam 1333 and a support pillar 1334 are formed on the bottom surface of the partition member 130 (first plate-like member 133).

The beams 1333 are formed to extend in the X-axis direction between the first flow path 1301a and the second flow path 1302a in the first plate-like member 133, and between the first flow path 1301b and the second flow path 1302b. That is, the beams 1333 are formed on the inside of the common supply flow paths 131a and 131b in the Y-axis direction. The beams 1333 are also formed to protrude entirely downward in the Z-axis direction. The height of the beams 1333 (the length in the Z-axis direction) is shorter than the length between the bottom surface of the first plate-like member 133 and the top surface of the head chip 110 (insulating member 111) when the head chip 110 and the partition member 130 are bonded together.

The pillars 1334 are arranged at a predetermined interval in the X-axis direction so as to protrude downward in the Z-axis direction from the beam 1333. The height of the pillars 1334 (the length in the Z-axis direction) is the height at which they come into contact with the head chip 110 when the partition member 130 and the head chip 110 are bonded together.

By forming the beams 1333 and the supports 1334 in this manner, the partition member 130 can be properly supported when the head chip 110 and the partition member 130 are bonded together. Also, by forming the beams 1333 and the supports 1334 on the inside in the Y-axis direction of the common supply flow paths 131a and 131b, the damper member 134 sandwiched between the first plate-like member 133 and the second plate-like member 135 can be properly supported when the respective members are joined to fabricate the partition member 130.

(Adhesion of each member in the partition member 130)
Fig. 14 is a cross-sectional view showing a schematic cross section of the partition member 130 shown in Fig. 6 taken along line segment B-B (a plane perpendicular to the Y-axis). As shown in Fig. 14, an adhesive is applied to the inner circumferential surfaces of the common supply channels 131a and 131b in the partition member 130. In this case, it is preferable that the adhesive is applied to the inner circumferential surfaces of the common supply channels 131a and 131b that extend in the X-axis direction, and to the inner surface of the partition member 130 in the Y-axis direction.

In this way, by applying adhesive to the inner circumferential surfaces of the common supply flow paths 131a and 131b, the bonding of each component that constitutes the partition member 130 is reinforced. This allows each component to be bonded more reliably.

(Hole portions 132a and 132b)
Fig. 15 is a front view of the partition member 130 of Fig. 6 when viewed from the front. Fig. 16 is an enlarged view of the portion indicated by the reference symbol D in Fig. 15. As shown in Figs. 6, 15 and 16, the partition member 130 (third plate-like member 136) is formed with holes 132a and 132b penetrating in the Z-axis direction. The hole 132a is provided to communicate an air chamber 1350a formed inside the partition member 130 with the outside. The hole 132b is provided to communicate an air chamber 1350b with the outside.

The holes 132a and 132b are filled, for example, by gluing, welding, or taping, when the head 55 is manufactured. This forms sealed air chambers 1350a and 1350b in the partition member 130.

When filling holes 132a and 132b, it is necessary to prevent adhesive or the like from falling into air chambers 1350a and 1350b. Therefore, holes 132a and 132b are preferably formed to have a diameter (hole diameter) of, for example, 0.6 mm or less, taking into account the viscosity of the adhesive, etc.

Furthermore, if the height (length in the Z-axis direction) of air chambers 1350a and 1350b in the nozzle region, which is the region in which nozzles 59a and 59b are formed, is not constant, the damping function of damper sheet 134 will not function properly. Therefore, it is preferable to form holes 132a and 132b at a position outside the nozzle region in the X-axis direction so that the damping function functions properly even if the height of air chambers 1350a and 1350b when holes 132a and 132b are filled is not constant.

As described above, the head 55 according to this embodiment includes a head chip 110 having a shear mode type piezoelectric element 58, and a partition member 130 having a damping function and formed with a dividing section 1330 that divides the multiple nozzles 59 into multiple regions. In such a head 55, the ink flow path in the head chip 110 is divided into multiple regions by the partition member 130. Therefore, multiple colors of ink can be handled with one head chip 110. Therefore, the head 55 according to this embodiment can eject multiple colors of ink without increasing the head size.

The entire disclosures of the specification, drawings and abstract contained in the Japanese application for Patent Application No. 2023-088571, filed on May 30, 2023, are incorporated herein by reference.

10 Transport section 20 Supply section 30 Discharge section 40 Ink supply section 50 Image forming section 55 Inkjet head 56a, 56b Manifold 57, 57a, 57b Individual supply flow path 58 Piezoelectric element 59, 59a, 59b Nozzle 100 Inkjet printer 101 Housing 102 Exterior member 103, 103a, 103b Inlet 104, 104a, 104b Outlet 105 Mounting hole 110 Head chip 111 Insulating member 112 Flexible wiring 120 Nozzle plate 130 Partition member 131a, 131b Common supply flow path 132a, 132b Hole 133 First plate member 134 Damper member 135 Second plate member 136 Third plate member 1301a, 1301b First flow path 1302a, 1302b Second flow path 1303a, 1303b Third flow path 1304a, 1304b Fourth flow path 1305a, 1305b Fifth flow path 1306a, 1306b Sixth flow path 1330 Dividing portion 1331 Step portion 1331a First step portion 1331b Second step portion 1332 Outflow suppression portion 1333 Beam 1334 Support 1350a, 1350b Air chamber

Claims (16)

a head chip in which a plurality of individual supply flow paths are formed to supply ink to a plurality of nozzles individually, the head chip having a shear mode type piezoelectric element that varies the pressure within the individual supply flow paths;
a partition member having a damper function, the partition member including a common supply flow path communicating with the individual supply flow paths and through which the ink flows, and a dividing portion dividing the individual supply flow paths and the nozzles into a plurality of regions;
An inkjet head comprising: The division unit is
a step portion in which the length of a side in a third direction perpendicular to the first direction and the second direction is shortened stepwise from the upper side to the lower side in a second direction which is a vertical direction perpendicular to the first direction, in a cross-sectional shape when cut along a plane perpendicular to a first direction;
2. The ink-jet head according to claim 1. The step portion is
The second direction is tapered from the upper side to the lower side.
3. The ink-jet head according to claim 2. The partition member is
An outflow suppression portion that suppresses outflow of the adhesive into the flow path is formed on the adhesive surface when the adhesive is adhered to the head chip.
2. The ink-jet head according to claim 1. The outflow suppression portion is
A predetermined gap is provided around the outer periphery of the divided portion.
5. The ink-jet head according to claim 4. The partition member is
A beam extending in a first direction and protruding downward in a second direction that is a vertical direction perpendicular to the first direction;
A support pillar protruding downward in the second direction from the beam;
is formed,
2. The ink-jet head according to claim 1. The beam is
the common supply flow path is formed on the inside in a third direction perpendicular to the first direction and the second direction;
7. The ink-jet head according to claim 6. an adhesive is applied to an inner circumferential surface of the common supply flow path of the partition member;
2. The ink-jet head according to claim 1. The partition member is
A plurality of plate-like members and a damper member disposed so as to be sandwiched between the plurality of plate-like members are stacked,
a hole portion communicating with an air chamber formed by the damper member and the plate-like member is formed on an upper surface in a second direction, which is a vertical direction;
2. The ink-jet head according to claim 1. The hole portion is
In a third direction perpendicular to the second direction, the nozzle is formed at a position outside the region where the nozzle is formed.
10. The ink-jet head according to claim 9. The hole portion is
The diameter is 0.6 mm or less.
10. The ink-jet head according to claim 9. The partition member is
A plurality of plate-shaped members;
A damper member disposed so as to be sandwiched between the plurality of plate-like members;
are laminated to form a
The plurality of plate-like members and the damper member are joined by diffusion bonding.
2. The ink-jet head according to claim 1. The partition member is
A plurality of plate-shaped members;
A damper member disposed so as to be sandwiched between the plurality of plate-like members;
are laminated to form a
The plurality of plate-like members and the damper member are joined together by an adhesive.
2. The ink-jet head according to claim 1. a distance between a nozzle in one of the plurality of nozzles that is closest to the other divided region and a nozzle in the other divided region that is closest to the one region is 5 mm or less in a third direction that is perpendicular to the first direction and a second direction that is a vertical direction perpendicular to the first direction;
2. The ink-jet head according to claim 1. The head chip and the partition member are bonded with an adhesive that hardens at 40°C to 60°C.
2. The ink-jet head according to claim 1. The inkjet head according to claim 1,
Image forming device.

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