Liquid discharge head and liquid discharge apparatus

Abstract

The present disclosure provides a liquid discharge head and a liquid discharge apparatus. The liquid discharge head includes a channel member and a recording element substrate. The channel member includes a discharge port configured to discharge a liquid and at least one channel configured to supply the liquid to the discharge port. The recording element substrate includes a supply path and an energy generating element. The supply path is connected to the at least one channel with a connection portion, and is configured to supply the liquid to the at least one channel. The energy generating element is configured to discharge the liquid from the discharge port. The channel member further includes a plurality of spaces at a position of the channel member facing the connection portion, the spaces being formed by covering a portion of a groove of the channel member with a covering portion, each of the spaces including an opening communicating with the at least one channel.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a liquid discharge head and a liquid discharge apparatus. BACKGROUND

[0002] An inkjet printer as a liquid discharge apparatus includes a liquid discharge head that discharges a liquid such as ink. The liquid discharge head includes an energy generating element that generates discharge energy for discharging the liquid. Droplets discharged from the liquid discharge head land on a recording medium to perform recording.

[0003] In an inkjet printer, liquid vibration causes meniscus vibration in a discharge port. In particular, a liquid discharge head having a plurality of nozzles densely arranged and a high liquid flow rate per unit time tends to generate such meniscus vibration. For example, when discharging a liquid from a plurality of discharge ports is simultaneously stopped, an inertial force of the liquid moving forward increases. The inertial force pushes the liquid in the nozzle out, causing the meniscus to protrude from the discharge port. A liquid tank as a liquid supply source is generally configured to maintain a negative pressure to prevent the liquid from dripping from a supply port. For this reason, the liquid supplied from the liquid tank is subjected to a force to pull it back upstream (toward the liquid tank). As described above, this causes the liquid that has the meniscus protruding in the discharge port to move back to the opposite side.

[0004] Therefore, after stopping the discharge, meniscus vibration is induced in the discharge port, in which the meniscus protrudes forward and retracts backward. Such vibration increases as the ink flow rate per unit time increases. If the next discharge is performed in a state where the meniscus protrudes forward or retracts backward, in the former state, small droplets are splattered, and in the latter state, the discharge speed and volume are reduced, both of which can cause a printing failure such as unstable discharge.

[0005] To address the above problem, Japanese Patent Application Publication No. 2006-240150 discloses a technique that uses a buffer chamber to attenuate meniscus vibration in a discharge port, the buffer chamber being used to accommodate a bubble in an intermediate point of a surface of the liquid discharge head and an ink passage in a common liquid chamber away from the discharge port.

[0006] Japanese Patent Application Publication No. 2002-166553 discloses a technique that uses a dummy passage having no discharge port in an outermost nozzle row of a liquid discharge head to attenuate meniscus vibration, a bubble remaining in the dummy passage so that the dummy passage functions as a buffer.

[0007] The liquid discharge head disclosed in Japanese Patent Application Publication No. 2006-240150 can not be able to produce sufficient effects of reducing meniscus vibration because the distance from the discharge port to the buffer chamber is large. In contrast, the liquid discharge head disclosed in Japanese Patent Application Publication No. 2002-166553 has sufficient effects of reducing meniscus vibration when recording is performed at a normal flow rate because the distance from the dummy passage serving as a buffer to the discharge port is small. However, when recording is performed at a high ink flow rate per unit time, air bubbles in the dummy passage can flow to the discharge port together with the ink, thus degrading the ink discharge performance.

[0008] SUMMARY

[0009] The present disclosure provides a liquid discharge head that can stably reduce or eliminate meniscus vibration in a discharge port even when recording is performed at a high ink flow rate per unit time.

[0010] In one aspect of the present disclosure, a liquid discharge head includes a channel member including a discharge port configured to discharge a liquid and at least one channel configured to supply the liquid to the discharge port; and a recording element substrate including a supply path connected to the at least one channel with a connection portion, the supply path being configured to supply the liquid to the at least one channel, and an energy generating element configured to discharge the liquid from the discharge port, wherein the channel member further includes a plurality of spaces at a position of the channel member facing the connection portion, the spaces being formed by covering a portion of a groove of the channel member with a covering portion, each of the spaces including an opening communicating with the at least one channel.

[0011] Further features of the present disclosure will become apparent from the following description of embodiments with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a schematic view showing an example of a recording apparatus of the present disclosure.

[0013] Figure 2 is a perspective view of an example of a liquid discharge head of the present disclosure.

[0014] Figure 3 is an exploded view showing an example of a liquid discharge head of the present disclosure.

[0015] Figure 4A is a perspective view of an example of an internal structure of a liquid discharge head of the present disclosure.

[0016] Figure 4B is a cross-sectional view of an example of an internal structure of a liquid discharge head of the present disclosure.

[0017] Figure 5 is an exploded view showing an example of a recording element of the present disclosure.

[0018] Figure 6 is a cross-sectional view of an example of a recording element of the present disclosure.

[0019] Figure 7 is a cross-sectional view of an example of a recording element of the present disclosure.

[0020] Figure 8 is a cross-sectional view of an example of a recording element of the present disclosure.

[0021] Figure 9A is a graph showing behavior of a bubble in a recording element of the present disclosure.

[0022] Figure 9B is a graph showing behavior of a bubble in a recording element of the present disclosure.

[0023] Figure 9C is a graph showing behavior of a bubble in a recording element of the present disclosure.

[0024] Figure 10A is a cross-sectional view of an example of a recording element of a comparative example.

[0025] Figure 10B is a cross-sectional view of an example of a recording element of a comparative example.

[0026] Figure 11A is a cross-sectional view of a recording element according to a second embodiment of the present disclosure.

[0027] Figure 11B is a cross-sectional view of a recording element according to a second embodiment of the present disclosure.

[0028] Figure 12 is a cross-sectional view of a recording element according to a third embodiment of the present disclosure.

[0029] Figure 13A is a cross-sectional view of a recording element according to a fourth embodiment of the present disclosure.

[0030] Figure 13B is a cross-sectional view of a recording element according to a fourth embodiment of the present disclosure.

[0031] Figure 13C is a cross-sectional view of a recording element according to a fourth embodiment of the present disclosure. DETAILED DESCRIPTION

[0032] Embodiments of the present disclosure will be described below. The following embodiments describe a liquid discharge head that discharges ink or liquid, and an inkjet recording device as a liquid discharge apparatus.

[0033] Recording device and liquid discharge head

[0034] Figure 1 is a schematic view showing a recording device according to an embodiment of the present disclosure. The recording device 1, which is a liquid discharge device, includes a guide rail 2 on which a carriage 3 is arranged to scan a recording medium. The carriage 3 is loaded with a liquid discharge head 5, which discharges liquid for printing (recording). The recording device according to an embodiment of the present disclosure can be a recording device configured to move the recording medium while discharging liquid from the liquid discharge head without moving the carriage.

[0035] Ink is supplied from an ink supply source 6 to the liquid discharge head 5 through an ink supply tube 4. The liquid discharge head 5 includes a number of nozzles through which ink is discharged when an energy generating element such as a heater or a piezoelectric element is driven. The ink supply source 6 includes ink reservoirs 7 for individual inks, here four colors of ink, black, yellow, magenta, and cyan. Each ink reservoir 7 includes a connection port to the outside and is configured to supply ink directly in an external ink bottle or the like. The ink supply tube 4 is individual to the individual inks and connects the ink supply source 6 (ink reservoir 7) to the liquid discharge head 5.

[0036] The ink supply source 6 can be a replaceable ink tank or ink cartridge. The ink supply source 6 can be arranged on the carriage 3 or integrated with the liquid discharge head 5.

[0037] Figure 2 is a schematic view of the liquid discharge head 5. Figure 3 is an exploded perspective view of the liquid discharge head 5. As Figure 3 indicated, the liquid discharge head 5 includes a sub-tank unit 10, a head body 12, and a recording element unit 14. The head body 12 and the sub-tank unit 10 are screwed together, holding a first elastic member 11 therebetween, for fixation and sealing. The head body 12 and the recording element unit 14 are screwed together, holding a second elastic member 13 therebetween, for fixation and sealing and connection to the ink passage. The recording element unit 14 includes recording elements 30, a support member 31, an electric substrate 32, and an electric wire board 33.

[0038] Next, the ink supply path will be described. Figure 4A and Figure 4B is a view showing an example of the internal structure of the liquid discharge head 5 according to an embodiment of the present disclosure. Figure 4B is a cross-sectional view of the liquid discharge head 5 taken along the Figure 4A midline IVB-IVB. The liquid discharge head 5 is supplied with ink from the ink supply source 6 (see Figure 1) The ink is supplied through the joint 20 into the ink chamber 21 in the sub-tank unit 10. The ink supplied to each ink chamber 21 passes through the filter 22 of the head body 12 and is supplied to the recording element unit 14 through the first internal passage 23. The supply port 24 and the second internal passage 25 of the recording element unit 14 are formed by the support member 31. In the present embodiment, the second internal passage 25 expands toward the recording element 30.

[0039] Next, the structure of the recording element 30 will be described. Figure 5 is an exploded view showing the structure of the recording element 30. The recording element 30 includes a recording element substrate 40 made of silicon and a passage member 41 formed on the recording element substrate 40 using a photolithography technique.

[0040] The passage member 41 includes a passage forming member 42 and an adhesion enhancing member 43 that enhances adhesion between the passage forming member 42 and the recording element substrate 40.

[0041] The process for manufacturing the recording element 30 will be described below. However, this is merely illustrative, and the present disclosure is not limited to this process. First, a layer of the adhesion enhancing member 43 is formed on the recording element substrate 40. Thereafter, the layer is patterned using an exposure apparatus and a photomask to form the adhesion enhancing member 43 in which an opening of a desired shape is formed. An example of the forming method is a method of patterning the adhesion enhancing member 43 made of a photosensitive material into a desired shape using an exposure apparatus and a photomask. This method hardens only the portion of the light irradiation from the exposure apparatus, and the portion masked by the photomask is not hardened. This allows the desired shape to be given by rinsing off the unhardened portion after the light irradiation. Examples of the material for the adhesion enhancing member include a material that hardens only in the region that is not irradiated with light.

[0042] Next, a passage mold (not shown) is formed on the adhesion enhancing member 43. The passage forming member 42 is formed on the passage mold, and the discharge port 52 is formed using an exposure apparatus and a photomask. Thereafter, the supply path 50 is formed in the recording element substrate 40. Next, the passage mold is removed with a reagent or the like to form the passage member 41.

[0043] First Embodiment

[0044] The first embodiment of the present disclosure will be described below.

[0045] Figure 6 is a view taken along the line VI-VI and Figure 5 in Fig. 6B, and Figure 7The image shows a cross-sectional view of the recording element 30 of the first embodiment, taken from line VI-VI. In the following description, depth refers to length in the liquid discharge direction. The recording element substrate 40 includes a supply path 50 and a plurality of energy generating elements 51. In this embodiment, the energy generating elements 51 are electrothermal conversion elements, but may also be other pressure generating units, such as piezoelectric elements. The channel forming member 42 includes a plurality of outlets 52 and channels 53 corresponding to each outlet 52. The positions of the outlets 52 correspond to the positions of the energy generating elements 51. In this embodiment, the plurality of energy generating elements 51 are arranged alternately at densities of 600 dpi on one side and 1200 dpi on both sides. Ink is supplied from the supply path 50 to the channels 53 and is driven by the energy generating elements 51 to be discharged to the outside through the outlets 52. The channel forming member 42 also includes ribs 54 located on the same side as the outlets 52 and facing the connection portion 44 between the supply path 50 and the channels 53 of the recording element substrate 40. The ribs 54 extend in the longitudinal direction of the supply path 50. The connection portion 44 is formed by… Figure 6 The dashed lines in the diagram represent the area. In this embodiment, the rib 54 has a width of 60 μm and a depth of 16 μm. The area represented by the dashed lines in the rib 54 is space 55, which will be described later.

[0046] Figure 7 It is along Figure 6 A cross-sectional view of the recording element 30 taken from line VII-VII. Figure 8 It is along Figure 7 A cross-sectional view of the recording element 30 taken along line VIII-VIII. The portion of the adhesive reinforcement member 43 shown is only provided on the rib 54. The rib 54, extending in the longitudinal direction of the supply path 50, includes a plurality of spaces 55. Each space 55 is formed by covering a portion of the groove of the rib 54 of the recording element substrate 40 with a cover 57 of the adhesive reinforcement member 43 and includes an opening 56 communicating with a channel 53. The spaces 55 extend in a plane direction parallel to the recording element substrate 40 (i.e., in a plane direction perpendicular to the liquid discharge direction). Even when ink is supplied to the liquid discharge head 5, air or bubbles 58 remain in the spaces 55 to exhibit a function of attenuating the vibration of the meniscus in the discharge outlet 52 (hereinafter also referred to as "buffering function"). Because the construction of the embodiments of this disclosure has a buffering function near the discharge outlet 52, it is contemplated to have a more efficient function compared to the function of existing constructions. This disclosure allows the space 55 used as a buffer to be formed using only existing components and manufacturing processes, without the use of other components.

[0047] In the present embodiment, the spaces 55 are arranged at intervals of every four discharge ports 52 in the longitudinal direction of the channel member 41. Each space 55 has a width of 15 μm and a length of 75 μm in the longitudinal direction. The opening 56 has a length of 30 μm in the longitudinal direction. The cover portion 57 has a length of 45 μm in the longitudinal direction. The length of the opening 56 in the longitudinal direction can be about twice the depth of the space 55 in the liquid discharge direction. This is to reliably remove the channel mold by using a reagent to prevent the channel mold from remaining. If the channel mold remains in the channel member 41, the channel mold can expand due to heat during the hardening process after the channel member 41 is formed, resulting in manufacturing failure, such as cracking of the channel member 41.

[0048] In the configuration of the present embodiment, the spaces 55 are located at positions corresponding to the connection portions between the supply paths 50 and the channels 53. These positions are offset from the ink flow path from the supply paths 50 to the channels 53. For this reason, even when ink is filled into the liquid discharge head 5, or when a recovery operation of sucking ink from the discharge ports 52 is performed to recover from a printing failure, the bubbles 58 are held in the spaces 55. The bubbles 58 function as a damper that absorbs liquid vibrations, preventing a decrease in printing quality even if meniscus vibrations occur.

[0049] Figure 9A to Figure 9C The behavior of the bubbles 58 in the spaces 55 is shown. In the spaces 55, the openings 56 are opened in a direction opposite the liquid discharge direction, and the supply paths 50 are connected to the upper side of the spaces 55. Therefore, when the bubbles 58 grow due to a change in temperature Figure 9B , air is discharged from the openings 56 to the upstream of the channels Figure 9C . This configuration eliminates the risk of the bubbles 58 flowing toward the discharge ports 52 during printing, resulting in a printing failure.

[0050] In the embodiment shown in Figure 7 , one space 55 is provided every four discharge ports 52, so that all of the discharge ports 52 have the same buffering function. The interval between the spaces 55 can be reduced. This configuration reduces the distance between each discharge port 52 and the damper (opening 56), but reduces the volume of the bubbles 58 in each space 55, thereby reducing the buffering effect in the spaces 55. The structure of the spaces 55 can be such that the openings 56 are located at the center of the spaces 55. However, this structure makes it possible for the bubbles 58 to be released, and a bubble having a large volume can absorb vibrations. Therefore, each cover portion 57 can be provided on one side of each space 55, as shown in Figure 8 .

[0051] Figure 10A and Figure 10BA cross-sectional view of the recording element 30 of the comparative example is shown, in which one space 55 includes a plurality of openings 56. Figure 10A corresponding to the cross-sectional view of the recording element 30 taken along the line XA-XA in Figure 6 Figure 10B is a cross-sectional view of the recording element 30 taken along the line XB-XB in Figure 10A

[0052] Figure 10A corresponding to the cross-sectional view of the recording element 30 taken along the line XA-XA in Figure 7 Figure 10B corresponding to the cross-sectional view of the recording element 30 taken along the line XA-XA in Figure 8 Figure 10A A portion of the adhesion-enhancing member 43 provided only on the ribs 54 is shown. As shown in Figure 10A and Figure 10B Even in the structure in which the space 55 includes a plurality of openings 56, the air bubbles 58 between the adhesion-enhancing member 43 (covering portion 57) and the channel-forming member 42 function as a buffer. However, the presence of the plurality of openings 56 that allow the air bubbles 58 to escape reduces the air bubble retention performance, thus eliminating the buffering function. In contrast, the embodiment of the present disclosure includes only one opening 56 in each space 55, thus providing a constant buffering function.

[0053] Second Embodiment

[0054] The description of the commonalities with the first embodiment will be omitted.

[0055] Figure 11A and Figure 11B are cross-sectional views of the recording element 30 according to the second embodiment. Figure 11A corresponding to the cross-sectional view of the recording element 30 taken along the line XIA-XIA in Figure 6 Figure 11B is a cross-sectional view of the recording element 30 taken along the line XIB-XIB in Figure 11A Figure 11A A portion of the adhesion-enhancing member 43 provided only on the ribs 54 is shown. As shown in Figure 4B The second internal channel 25 of the recording element unit 14 expands from the supply port 24 toward the recording element 30. In this case, the farther the discharge port 52 in the recording element 30 is from the supply port 24, the more the temporary ink supply shortage at the start of printing is noticeable. To address this problem, in the present embodiment, as shown in Figure 11A the space 55 at the end portion away from the supply port 24 has a longer covering portion 57 than the others. This allows the space 55 at the end portion to accommodate a larger air bubble 58 away from the discharge port 52 that functions as a buffer area, and a high buffering effect can be expected even at the discharge port 52 away from the supply port 24. On the other hand, where the discharge port 52 is away from the opening 56, the buffering function can be obtained only in the vicinity of the opening 56. ​​​​​​

[0056] Third Embodiment

[0057] Figure 12 is a cross-sectional view of the recording element 30 according to the third embodiment. Figure 12 is a cross-sectional view of the recording element 30 taken along the line XII-XII in Figure 6 Figure 12 shows only the portion of the adhesion-enhancing member 43 provided on the ribs 54. The spaces 55 can be arranged in two or more rows in the longitudinal direction of the passage member 41. Figure 12 shows an example in which the thickness of the ribs 54 is increased and the spaces 55 are arranged in two or more rows in the longitudinal direction. This increases the cross-sectional area and volume of each air bubble 58, providing a higher cushioning effect. On the other hand, the increase in the thickness of the ribs 54 narrows the ink flow path from the supply path 50 to the passage 53, leading to the risk of interference with the supply.

[0058] Fourth Embodiment

[0059] Figure 13A to Figure 13C is a schematic view of the fourth embodiment. In this embodiment, two supply paths 50 are connected to one discharge port 52 in the recording element 30. Figure 13A to Figure 13C is a cross-sectional view of the recording element 30 viewed from the side. This configuration also provides a high cushioning effect by providing spaces 55 at positions facing the connecting portions 44 between the supply paths 50 and the passages 53. In this case, the cover portions 57 of the spaces 55 can be formed by the passage-forming member 42, as shown in Figure 13B , or by other layers in the passage-forming member 42, as shown in Figure 13C .

[0060] According to an embodiment of the present disclosure, a liquid discharge head can stably reduce or eliminate meniscus vibration in a discharge port even when recording is performed at a high ink flow rate per unit time.

[0061] While the present disclosure has been described with reference to embodiments, it is to be understood that the present disclosure is not limited to the disclosed embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.​

Claims

1. A liquid discharge head, comprising: A channel component, the channel component including an outlet and at least one channel, the outlet being configured to discharge liquid, and the at least one channel being configured to supply liquid to the outlet; as well as A recording element substrate includes a supply path and an energy generating element. The supply path is connected to the at least one channel via a connector and is configured to supply liquid to the at least one channel. The energy generating element is configured to discharge the liquid from the outlet. The channel component further includes a plurality of spaces located at the position of the channel component facing the connection portion. The spaces are formed by covering a portion of the groove of the channel component with a cover portion, and each space includes only one opening communicating with the at least one channel.

2. The liquid discharge head according to claim 1, wherein, The space extends in a plane that is substantially perpendicular to the direction of liquid discharge.

3. The liquid discharge head according to claim 1, wherein, The space is configured to contain gas.

4. The liquid discharge head according to claim 1, in, The channel component includes a channel forming component and an adhesion enhancement component between the channel forming component and the recording element substrate. The space is surrounded by the adhesive reinforcement member and the channel forming member.

5. The liquid discharge head according to claim 1, wherein, The opening is in the direction opposite to the direction of liquid discharge.

6. The liquid discharge head according to claim 1, wherein, In each of the grooves, a partially covered space is provided on one side of the groove.

7. The liquid discharge head according to claim 1, wherein, The plurality of spaces are arranged in a row in the longitudinal direction of the channel member.

8. The liquid discharge head according to claim 1, wherein, The plurality of spaces are arranged in rows in the longitudinal direction of the channel member and in two or more rows in the transverse direction of the channel member.

9. The liquid discharge head according to claim 1, wherein, The plurality of spaces arranged along the longitudinal direction of the channel member, In the longitudinal direction, the covering portion is longer in the space farther from the supply port than in the space closer to the supply port, and the liquid is supplied from the supply port to the channel member.

10. A liquid discharge device, comprising: Liquid discharge head, the liquid discharge head comprising: A channel component, the channel component including an outlet and at least one channel, the outlet being configured to discharge liquid, and the at least one channel being configured to supply liquid to the outlet; and A recording element substrate includes a supply path and an energy generating element. The supply path is connected to the at least one channel via a connector and is configured to supply liquid to the at least one channel. The energy generating element is configured to discharge the liquid from the outlet. The channel component further includes a plurality of spaces located at the position of the channel component facing the connection portion. The spaces are formed by covering a portion of the groove of the channel component with a cover portion, and each space includes only one opening communicating with the at least one channel.

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