Liquid dispensing head, head unit, and liquid dispensing device

Abstract

Effectively suppresses deviations in the point of impact of liquids. [Solution] A liquid discharge head 20 has a plurality of nozzles 30 for discharging liquid 10 to a moving object S that is moving relative to it, and a nozzle surface 31 through which the plurality of nozzles 30 open, and has an air passage 21 through which air passes, and both an inlet 21a through which air flows in and an outlet 21b through which air flows out of the air passage 21 are provided on the nozzle surface 31.

Description

Technical Field

[0007] ,

[0001] The present invention relates to a liquid ejection head, a head unit, and a liquid ejection device.

Background Art

[0002] As an example of a liquid ejection device that ejects liquid onto a moving object that moves relatively, an inkjet type image forming device that ejects liquid ink onto a sheet such as paper being conveyed to form an image is known.

[0003] Generally, an inkjet type image forming device includes a liquid ejection head having a plurality of nozzles for ejecting liquid (ink).

[0004] By the way, in such a liquid ejection head, there has been pointed out a problem that the liquid deviates from the target position and lands due to the influence of negative pressure generated when the liquid is ejected from the nozzle. Regarding such a problem, in Patent Document 1 (Japanese Patent Laid-Open No. 2008-173939), an air communication passage that opens to the nozzle surface side where the nozzles of the liquid ejection head are provided and the surface side other than the nozzle surface is provided, and air is supplied to the nozzle surface side through the air communication passage to avoid becoming negative pressure. A technology has been proposed.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, the problem of deviation of the landing position caused by a cause other than the negative pressure generated with the ejection of the liquid has not been studied.

[0006] Therefore, an object of the present invention is to effectively suppress the deviation of the landing position of the liquid. <00岁00026>

Means for Solving the Problems

[0008] According to the present invention, deviations in the point of impact of a liquid can be effectively suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram showing the overall configuration of an inkjet-type image forming apparatus, which is an example of a liquid ejection device to which the present invention is applied. [Figure 2] This is a block diagram showing a control system for an image forming apparatus according to the first embodiment of the present invention. [Figure 3] This is a plan view of a head unit according to the first embodiment of the present invention. [Figure 4] This is a side view of a liquid discharge head according to the first embodiment of the present invention, viewed from the horizontal direction. [Figure 5] This is a plan view of a liquid discharge head according to the first embodiment of the present invention, as seen from the nozzle side. [Figure 6] This is a cross-sectional view of the liquid dispensing head according to the first embodiment of the present invention, cut along line AA in Figure 5. [Figure 7] This is a cross-sectional view of the liquid discharge head according to the first embodiment of the present invention, cut along the line BB in Figure 5. [Figure 8] This is a plan view of the nozzle plate, the first flow path plate, and the second flow path plate as superimposed according to the first embodiment of the present invention. [Figure 9] This is a plan view of the nozzle plate, the first flow path plate, and the second flow path plate in a state where they are superimposed according to the second embodiment of the present invention. [Figure 10] This is a plan view of the nozzle plate, the first flow path plate, and the second flow path plate in a state where they are superimposed according to the third embodiment of the present invention. [Figure 11] It is a plan view showing an example of a serial type head unit. [Figure 12] It is a side view showing an example in which the present invention is applied to a liquid ejection head mounted on a serial type head unit. [Figure 13] It is a diagram showing the flow of air current when the liquid ejection head moves in one direction. [Figure 14] It is a diagram showing the flow of air current when the liquid ejection head moves in the opposite direction. [Figure 15] It is a schematic diagram showing the overall configuration of an electrode manufacturing apparatus to which the present invention can be applied. [Figure 16] It is a side view of a liquid ejection head according to a comparative example as viewed from the horizontal direction.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described based on the accompanying drawings. In each of the drawings for explaining the present invention, components such as members and constituent parts having the same function or shape are denoted by the same reference numerals as far as possible to be distinguishable, and the description thereof will be omitted after being explained once.

[0011] <Overall Configuration of Image Forming Apparatus> FIG. 1 is a schematic diagram showing the overall configuration of an inkjet type image forming apparatus which is an example of a liquid ejection apparatus to which the present invention is applied.

[0012] First, while referring to FIG. 1, the overall configuration of the inkjet type image forming apparatus according to the first embodiment of the present invention will be described.

[0013] As shown in FIG. 1, an image forming apparatus 100 according to the first embodiment of the present invention includes a sheet supply unit 1 that supplies a sheet S on which an image is to be formed, a conveyance unit 2 that conveys the sheet S supplied from the sheet supply unit 1, an image forming unit 3 that forms an image on the sheet S, a drying unit 4 that dries the sheet S, and a sheet collection unit 5 that collects the sheet S on which the image has been formed.

[0014] The sheet supply unit 1 is provided with a supply roller 11 around which a long sheet S is wound in a roll shape, and a tension adjustment mechanism 12 for adjusting the tension applied to the sheet S. The supply roller 11 is configured to be rotatable in the direction of the arrow in FIG. 1, and when the supply roller 11 rotates, the sheet S is fed out. The tension adjustment mechanism 12 has a plurality of adjustment rollers that span the sheet S and apply tension. By changing the distance between the adjustment rollers, the tension of the sheet S is adjusted, and the sheet S is supplied with a constant tension.

[0015] The conveyance unit 2 is provided with a plurality of conveyance rollers 15 as conveyance means for conveying the sheet S. When the sheet S is supplied from the sheet supply unit 1 to the conveyance unit 2, the sheet S is conveyed to the image forming unit 3 by the plurality of conveyance rollers 15.

[0016] The image forming unit 3 is provided with a head unit 13 having a plurality of liquid ejection heads that eject liquid ink onto the sheet S, and a platen 14 as a sheet support member that supports the conveyed sheet S. The sheet S conveyed by the conveyance roller 15 passes under the head unit 13 while being supported by the platen 14. At this time, ink is ejected from the head unit 13 onto the sheet S, and an image is formed on the sheet S.

[0017] The drying unit 4 is provided with a heating drum 16 as heating means for heating the sheet S. The heating drum 16 is a cylindrical heating member that houses a heating source such as a halogen heater inside. When the sheet S on which an image has been formed in the image forming unit 3 is conveyed to the drying unit 4, the sheet S is heated by contacting the outer peripheral surface of the heating drum 16, and the sheet S is dried. Note that as heating means for heating the sheet S, in addition to contact-type heating means such as the heating drum 16, non-contact-type heating means such as a hot air generator that blows hot air onto the sheet S may also be used.

[0018] The sheet retrieval unit 5 is equipped with a retrieval roller 17 for winding up and retrieving the sheet S, and a tension adjustment mechanism 18 for adjusting the tension applied to the sheet S. The retrieval roller 17 is configured to rotate in the direction of the arrow in Figure 1, and as the retrieval roller 17 rotates, the sheet S is wound up into a roll and retrieved. The tension adjustment mechanism 18 has multiple adjustment rollers, similar to the tension adjustment mechanism 12 of the sheet supply unit 1. By changing the distance between the adjustment rollers, the tension of the sheet S is adjusted, and the sheet S is wound up with a constant tension and retrieved by the retrieval roller 17.

[0019] Figure 2 is a block diagram showing the control system of an image forming apparatus according to the first embodiment of the present invention.

[0020] As shown in Figure 2, the image forming apparatus 100 according to the first embodiment of the present invention includes a sheet supply unit 1, a transport unit 2, an image forming unit 3, a drying unit 4, and a sheet recovery unit 5, as well as a control unit 6 that controls these units.

[0021] The control unit 6 is composed of an information processing device such as a PC (Personal Computer). The control unit 6 generates image data of the image to be formed on the sheet S, and also controls various operations of the sheet supply unit 1, transport unit 2, image forming unit 3, drying unit 4, and sheet recovery unit 5. For example, the control unit 6 controls the ink ejection operation of the head unit 13, the rotation speed of the supply roller 11, recovery roller 17, and each transport roller 15, and the heating temperature of the heating drum 16. Furthermore, an image is formed on the sheet S by ejecting ink from the head unit 13 onto the sheet S based on the image data generated by the control unit 6.

[0022] <Head unit configuration> Next, the configuration of the head unit 13 according to the first embodiment of the present invention will be described based on Figure 3.

[0023] Figure 3 is a plan view of the head unit 13 according to the first embodiment of the present invention.

[0024] As shown in Figure 3, the head unit 13 according to the first embodiment of the present invention comprises a plurality of liquid ejection heads 20. Each liquid ejection head 20 is provided with a plurality of nozzles 30 that eject ink in droplet form. In this case, the plurality of nozzles 30 are arranged in a direction perpendicular to or intersecting the sheet transport direction Y in which the sheet S is transported. Note that the arrangement of the nozzles 30 is not limited to the arrangement in Figure 3.

[0025] In the first embodiment of the present invention, a so-called line-type head unit that ejects ink without moving relative to the sheet S is used as the head unit 13. Therefore, in this case, the sheet S is transported in the direction of arrow Y in Figure 3, and when the sheet S reaches a position facing the head unit 13 (image formation position), ink is ejected from the nozzles 30 of each head unit 13 onto the transported sheet S, and an image is formed on the sheet S.

[0026] <Challenges related to deviations in the impact point of liquids> Here, we will explain the problem of misalignment of the liquid's landing position in a liquid dispensing head, based on a comparative example different from the present invention.

[0027] Figure 16 is a side view of the liquid discharge head 200 according to the comparative example, viewed from the horizontal direction (a direction perpendicular to the liquid discharge direction).

[0028] The liquid discharge head 200 in the comparative example is a line-type liquid discharge head, the same as the liquid discharge head 20 in the first embodiment of the present invention. Therefore, as shown in Figure 16, when the sheet S is transported in the direction of arrow Y and reaches a position facing the liquid discharge head 200, ink is discharged from multiple nozzles 201 onto the transported sheet S.

[0029] At this time, as the ink 10 (liquid) is ejected as a droplet, the air around the nozzle 201 moves in the direction of ink ejection. As a result, the amount of air decreases between adjacent nozzles 201 (the area enclosed by the dashed line 90 in Figure 16), creating a negative pressure state. To compensate for the lost air, the surrounding air moves into the area between the nozzles 201 (the negative pressure area), generating an airflow 9A that flows from the surroundings towards the area between the nozzles 201. The ejected ink 10 is then affected by this airflow 9A, causing the ink 10 to curve as shown by the dotted arrow in Figure 16, resulting in a shift in the landing position of the ink 10.

[0030] On the other hand, on the sheet S side facing the liquid ejection head 200, the air that moves toward the sheet S side as the ink 10 is ejected hits the sheet S, generating an airflow 9B that spreads along the sheet S. In addition, as the sheet S is transported, the surrounding air moves, generating an airflow 9C directed toward the sheet transport direction Y. Therefore, especially upstream of the nozzle 201 in the sheet transport direction Y, the airflow 9C directed toward the sheet transport direction Y and the airflow 9B directed toward the opposite direction (upstream) collide, generating an upward airflow 9D from the sheet S side toward the liquid ejection head 200 side. When this upward airflow 9D hits the nozzle surface 202 of the liquid ejection head 200, some of the airflow 9E moves toward the nozzle 201 side along the nozzle surface 202. Therefore, especially at the nozzle 201, which is the uppermost nozzle in the sheet transport direction Y, the ejected ink 10 is affected by the airflow 9E directed toward the nozzle 201 side and curves in the direction of the dotted arrow in Figure 16. Therefore, the deviation in the point of impact becomes more pronounced.

[0031] Thus, in the comparative example liquid discharge head 200, a shift in the ink's landing position occurs due to the influence of the negative pressure generated when the ink 10 is discharged and the upward airflow generated on the upstream side in the sheet transport direction.

[0032] Furthermore, regarding the problem of deviation in the point of impact, Patent Document 1 proposes a measure to suppress deviation in the point of impact due to the effect of negative pressure by providing atmospheric communication passages that open on both the nozzle side and the non-nozzle side of the liquid discharge head, and supplying air to areas where negative pressure is likely to occur. However, the deviation in the point of impact due to the effect of updrafts accompanying the transport of the sheet has not been considered.

[0033] Therefore, the present invention aims to effectively suppress not only the displacement of the impact point due to the effect of negative pressure, but also the displacement of the impact point due to the effect of rising air currents. The following describes the characteristic parts of the liquid discharge head according to the first embodiment of the present invention.

[0034] <Configuration of the liquid dispensing head> Figure 4 is a side view of the liquid discharge head 20 according to the first embodiment of the present invention, viewed from the horizontal direction (a direction perpendicular to the liquid discharge direction).

[0035] As shown in Figure 4, the liquid discharge head 20 according to the first embodiment of the present invention has a ventilation passage 21 that penetrates the inside of the liquid discharge head 20. Both ends of the ventilation passage 21 open to the outside from the liquid discharge head 20, and of the openings 21a and 21b at both ends, one opening 21a functions as an "inlet" for bringing in air from the outside. In contrast, the other opening 21b functions as an "outlet" for letting air out to the outside. Both the inlet 21a and the outlet 21b are provided on the nozzle surface 31 through which the nozzle 30 opens.

[0036] The inlet 21a is positioned at a location corresponding to the point where the rising airflow 9D is generated upstream of the sheet conveying direction Y. In the first embodiment of the present invention, as in the comparative example above, an rising airflow 9D is generated upstream of the uppermost nozzle 30A in the sheet conveying direction Y when the airflow 9C directed toward the sheet conveying direction Y collides with the airflow 9B directed toward the opposite direction (upstream) of the sheet conveying direction Y. Therefore, the inlet 21a is positioned upstream of the uppermost nozzle 30A where this rising airflow 9D is generated.

[0037] On the other hand, the outlet 21b is positioned at a location corresponding to a place where negative pressure may be generated as a result of the ejection of ink 10 (the area enclosed by the dashed line 90 in Figure 4). That is, since negative pressure is generated between adjacent nozzles, the outlet 21b is positioned here between adjacent nozzles 30A and 30B in the sheet transport direction Y.

[0038] Thus, in the liquid discharge head 20 according to the first embodiment of the present invention, an inlet 21a is provided corresponding to a location where an upward airflow 9D is generated, and an outlet 21b is provided corresponding to a location where negative pressure may be generated, thereby effectively suppressing the shift in the point of impact caused by the upward airflow and negative pressure.

[0039] To explain in more detail, as shown in Figure 4, when ink 10 is ejected from each nozzle 30A, 30B onto the conveyed sheet S, upstream of the uppermost nozzle 30A, the airflow 9B generated by the ejection of ink 10 and the airflow 9C in the sheet conveying direction Y generated by the conveying of the sheet S collide, generating an upward airflow 9D. This upward airflow 9D is directed towards the liquid ejection head 20, but since an inlet 21a is provided at the destination of the upward airflow 9D, the upward airflow 9D flows into the liquid ejection head 20 through the inlet 21a. As a result, the upward airflow 9D does not hit the nozzle surface 31, and the airflow generated by the upward airflow 9D hitting the nozzle surface 31 (airflow 9E directed towards nozzle 201 in Figure 16) is suppressed. Therefore, the deflection of the ejected ink 10 due to the influence of the airflow directed towards nozzle 30A is suppressed, and the deviation of the landing position is suppressed.

[0040] Furthermore, as shown in Figure 4, the rising airflow 9D that flows into the ventilation passage 21 is discharged through the ventilation passage 21 from the outlet 21b. This replenishes air in areas where negative pressure may occur between adjacent nozzles 30A and 30B (areas enclosed by dashed lines in Figure 4, area 90). This suppresses the generation of negative pressure, and therefore also suppresses the shift in the landing position of the ink 10 caused by negative pressure.

[0041] As described above, in the first embodiment of the present invention, not only the deviation of the impact position due to the effect of negative pressure but also the deviation of the impact position due to the effect of rising airflow is effectively suppressed, thereby improving the accuracy of ink impact. This makes it possible to provide high-resolution images. Furthermore, in the first embodiment of the present invention, by simply providing a ventilation passage 21 in the liquid discharge head 20, both the effect of rising airflow and the effect of negative pressure can be effectively suppressed, thus improving impact accuracy with a simple configuration.

[0042] Next, a more specific configuration of the liquid discharge head 20 according to the first embodiment of the present invention will be described.

[0043] Figure 5 is a plan view of the liquid discharge head 20 according to the first embodiment of the present invention, as seen from the nozzle surface 31 side.

[0044] As shown in Figure 5, the liquid discharge head 20 according to the first embodiment of the present invention has multiple nozzle rows 32 (32A, 32B) in which multiple nozzles 30 are arranged in a direction perpendicular to the sheet conveying direction Y. In this case, there are two (two rows) of nozzle rows 32A and 32B, and the nozzles 30 constituting one nozzle row 32A and the nozzles 30 constituting the other nozzle row 32B are offset from each other in a direction perpendicular to the sheet conveying direction Y (the vertical direction in Figure 5). Note that the number of nozzle rows 32 and the arrangement of the nozzles 30 are not limited to the example in Figure 5 and can be changed as appropriate.

[0045] Furthermore, in the liquid discharge head 20 according to the first embodiment of the present invention, multiple inlets 21a and outlets 21b are provided along the nozzle arrangement direction of the nozzle row 32 (vertical direction in Figure 5). The multiple inlets 21a are located upstream of the uppermost nozzle 30 (nozzle row 32A) in the sheet transport direction Y. On the other hand, the multiple outlets 21b are located between adjacent nozzles 30 (nozzle rows 32A, 32B) in the sheet transport direction Y. Note that "between nozzles 30" here does not necessarily mean a position on a line segment connecting adjacent nozzles 30. "Between nozzles 30" means any position within a range R that is downstream of the upstream nozzle 30 and upstream of the downstream nozzle 30 among adjacent nozzles 30 in the sheet transport direction Y. Specifically, in the example in Figure 5, each outlet 21b is not located on a line segment connecting adjacent nozzles 30, but is located upstream of the downstream nozzle 30 in the sheet transport direction.

[0046] Figure 6 is a cross-sectional view of the liquid discharge head 20 according to the first embodiment of the present invention, cut along line AA in Figure 5.

[0047] As shown in Figure 6, the liquid discharge head 20 according to the first embodiment of the present invention comprises a nozzle plate 40 having a nozzle 30, a first flow path plate 41, a second flow path plate 42, a diaphragm member 43, a common flow path member 44, a piezoelectric element 45, and the like. The nozzle plate 40, the first flow path plate 41, the second flow path plate 42, the diaphragm member 43, and the common flow path member 44 are stacked in this order from the sheet side (lower side in Figure 6).

[0048] The first flow channel plate 41 has a plurality of pressure chambers 33 that communicate individually with a plurality of nozzles 30. On the other hand, the second flow channel plate 42 has a plurality of individual supply channels 34 that communicate individually with the plurality of pressure chambers 33.

[0049] The diaphragm member 43 is made of a deformable sheet member. A piezoelectric element 45 is provided in the area of ​​the diaphragm member 43 corresponding to the pressure chamber 33. The piezoelectric element 45 is, for example, a member made of alternating layers of piezoelectric layers and internal electrodes, and a wiring board or the like is connected to the internal electrodes via external electrodes. When a driving voltage is applied to the piezoelectric element 45 via the wiring board, the piezoelectric element 45 expands and contracts, causing the diaphragm member 43 to deform, pressurizing the liquid (ink) in the pressure chamber 33 and causing the liquid to be discharged from the nozzle 30.

[0050] The common flow channel member 44 has a common supply channel 35 that communicates with all of the individual supply channels 34. When liquid is supplied to the common supply channel 35, the liquid is supplied to each individual supply channel 34 via a supply port 36 provided in the diaphragm member 43, and further supplied from each individual supply channel 34 into each pressure chamber 33. Then, the expansion and contraction of the piezoelectric element 45 deforms the diaphragm member 43, pressurizing the liquid in the pressure chamber 33, which is then discharged from the nozzle 30.

[0051] Figure 7 is a cross-sectional view of the liquid discharge head 20 according to the first embodiment of the present invention, cut along the line BB in Figure 5. In other words, Figure 7 is a cross-sectional view of the liquid discharge head 20 cut at the location where the ventilation passage 21 is provided.

[0052] As shown in Figure 7, in the first embodiment of the present invention, the ventilation passage 21 is provided across both the nozzle plate 40 and the first flow path plate 41. In this case, the nozzle plate 40 has a plurality of through holes 40a, 40b that form an inlet 21a and an outlet 21b, and the first flow path plate 41 has a longitudinal connecting hole 41a that connects the through holes 40a, 40b (inlet 21a and outlet 21b) of the nozzle plate 40.

[0053] In this way, by forming the ventilation passage 21 across multiple members, such as the nozzle plate 40 and the first flow path plate 41, the formation of the ventilation passage 21 becomes easier compared to the case where the ventilation passage 21 is formed in a single member. That is, when forming the ventilation passage 21 in a single member, it is necessary to form the ventilation passage 21 by hollowing out the single member, but when forming the ventilation passage 21 across multiple members, it is only necessary to form predetermined through-holes (flow paths) by punching out each member, thus making the formation of the ventilation passage 21 easier.

[0054] Figure 8 is a plan view of the nozzle plate 40, the first flow path plate 41, and the second flow path plate 42 superimposed according to the first embodiment of the present invention. In Figure 8, the ventilation passage 21 (connecting hole 41a) and pressure chamber 33 provided in the first flow path plate 41 are shown by solid lines, the nozzle 30, inlet 21a (through hole 40a) and outlet 21b (through hole 40b) provided in the nozzle plate 40, and the individual supply passage 34 provided in the second flow path plate 42 are shown by dotted lines.

[0055] As shown in Figure 8, the ventilation passage 21 (connecting hole 41a) provided in the first flow path plate 41 is provided so as to pass between the pressure chambers 33.

[0056] In this configuration, as in the first embodiment of the present invention, where the ventilation passage 21 is provided to pass between the pressure chambers 33, it is necessary to secure space between the pressure chambers 33 to form the ventilation passage 21. Therefore, in this case, it becomes difficult to narrow the spacing between the nozzles 30 constituting the nozzle row (spacing in the nozzle arrangement direction) and arrange the nozzles 30 at high density. Also, because it is necessary to secure space for the ventilation passage 21, it becomes difficult to miniaturize the liquid discharge head in the nozzle arrangement direction. In particular, as in the first embodiment of the present invention, when a plurality of inlets 21a and a plurality of outlets 21b are configured to communicate individually via a plurality of independently provided ventilation passages 21 (connecting holes 41a), a ventilation passage 21 is required for each inlet 21a and outlet 21b, making it difficult to increase the density of the nozzles and miniaturize the head.

[0057] Therefore, in other embodiments of the present invention described below, a configuration is proposed that enables higher nozzle density and miniaturization of the head. In the following description, mainly the parts that differ from the first embodiment of the present invention will be described, and the same parts will be omitted as appropriate.

[0058] <Second Embodiment of the Present Invention> Figure 9 is a plan view of the nozzle plate 40, the first flow path plate 41, and the second flow path plate 42 superimposed according to the second embodiment of the present invention. In Figure 9, as in Figure 8, the solid lines indicate the portion provided on the first flow path plate 41, and the dotted lines indicate the portion provided on the nozzle plate 40 or the second flow path plate 42.

[0059] As shown in Figure 9, in the second embodiment of the present invention, a plurality of inlets 21a and a plurality of outlets 21b are connected via a common ventilation passage 21. In this case, the common ventilation passage 21 is composed of an inlet-side common passage 22 and an outlet-side common passage 23 provided in the first flow channel plate 41, and a connecting common passage 24 provided in the second flow channel plate 42.

[0060] The inlet-side common passage 22 is a common ventilation passage that communicates with all of the multiple inlets 21a, and is provided to extend in the direction of the nozzle arrangement (vertical direction in Figure 9) so as to overlap with each inlet 21a. On the other hand, the outlet-side common passage 23 is a common ventilation passage that communicates with all of the multiple outlets 21b, and is provided to extend in the direction of the nozzle arrangement (vertical direction in Figure 9) so as to overlap with each outlet 21b. The connecting common passage 24 is provided to extend in a direction perpendicular or intersecting the nozzle arrangement direction (horizontal direction in Figure 9), and connects the inlet-side common passage 22 and the outlet-side common passage 23 so as to communicate with each other.

[0061] In the second embodiment of the present invention configured as described above, when the above-mentioned rising airflow 9D (see Figure 4) is generated during ink ejection, the rising airflow 9D flows in from each inlet 21a, passes through the common ventilation passage 21, and flows out from each outlet 21b. As a result, in the second embodiment of the present invention, just as in the first embodiment of the present invention, the generation of airflow 9E (see Figure 16) caused by the rising airflow 9D hitting the nozzle surface 31 can be suppressed, and the generation of negative pressure can also be suppressed, so that deviations in the point of impact caused by these effects can be effectively suppressed.

[0062] Furthermore, in the second embodiment of the present invention, since multiple inlets 21a and multiple outlets 21b are connected via a common ventilation passage 21, the number of ventilation passages 21 can be reduced compared to the configuration in the first embodiment of the present invention, where multiple inlets 21a and multiple outlets 21b are individually connected via multiple ventilation passages 21. This reduces the space required to form the ventilation passages 21, thus enabling a smaller head. Note that the common ventilation passage 21 is not limited to being consolidated into a single common flow path; it may be composed of multiple flow paths as long as the number of ventilation passages 21 can be reduced.

[0063] Furthermore, as shown in Figure 9, in the second embodiment of the present invention, the common ventilation passage 21 (inlet-side common passage 22, outlet-side common passage 23, and connecting common passage 24) is arranged so as not to pass between the multiple pressure chambers 33 that communicate with the multiple nozzles 30 forming the nozzle row, and between the multiple individual supply passages 34 that communicate with these pressure chambers 33. In this way, by not passing between the pressure chambers 33 and between the individual supply passages 34, the spacing between the nozzles 30 forming the nozzle row (spacing in the nozzle arrangement direction) can be narrowed. As a result, it becomes possible to increase the density of the nozzles and miniaturize the head.

[0064] Furthermore, as shown in Figure 9, in the second embodiment of the present invention, of the inlet-side common passage 22, outlet-side common passage 23, and connecting common passage 24 that constitute the common ventilation passage 21, the inlet-side common passage 22 and the outlet-side common passage 23 are provided on the first flow path plate 41, but the connecting common passage 24 is not provided on the first flow path plate 41, but is provided on the second flow path plate 42. In this way, by providing the connecting common passage 24 on a separate member (second flow path plate 42) from the member (first flow path plate 41) on which the inlet-side common passage 22 and the outlet-side common passage 23 are provided, the reduction in strength of the first flow path plate 41 can be suppressed and rigidity can be ensured compared to a configuration in which these common passages 22, 23, and 24 are provided together on the first flow path plate 41. This makes it possible to make the liquid discharge head 20 less susceptible to damage. It should be noted that if the necessary rigidity can be obtained, it is also possible to provide the inlet-side common passage 22, the outlet-side common passage 23, and the connecting common passage 24 on a single member.

[0065] <Third Embodiment of the Invention> Next, a third embodiment of the present invention will be described.

[0066] Figure 10 is a plan view of the nozzle plate 40, the first flow path plate 41, and the second flow path plate 42 superimposed according to the third embodiment of the present invention. In Figure 10, as in Figures 8 and 9, the solid lines indicate the portion provided on the first flow path plate 41, and the dotted lines indicate the portion provided on the nozzle plate 40 or the second flow path plate 42.

[0067] As shown in Figure 10, in the third embodiment of the present invention, both the inlet 21a and the outlet 21b are composed of a single, consolidated through-hole 40a, 40b, rather than multiple through-holes 40a, 40b. That is, the inlet 21a and outlet 21b according to the third embodiment of the present invention are composed of longitudinal through-holes 40a, 40b extending along the nozzle arrangement direction (up and down direction in Figure 10). Otherwise, the configuration is the same as that of the second embodiment of the present invention described above.

[0068] Thus, the inlet 21a and outlet 21b may be composed of a single combined through-hole 40a, 40b. In this case as well, just as in each of the embodiments described above, the rising airflow 9D can be introduced through the inlet 21a and exited through the outlet 21b, making it possible to effectively suppress the shift in the impact position due to the effects of the rising airflow and negative pressure.

[0069] Furthermore, in the third embodiment of the present invention, as in the second embodiment described above, the common ventilation passage 21 connecting the inlets 21a does not pass between the pressure chambers 33 that communicate with the plurality of nozzles 30 forming a nozzle row, and between the individual supply passages 34 that communicate with these pressure chambers 33. As a result, the spacing between the nozzles 30 can be narrowed, enabling higher nozzle density and a smaller head.

[0070] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified as appropriate without departing from the spirit of the invention.

[0071] In the above embodiments, the liquid ejection head according to the present invention was described as being mounted on a line-type head unit as an example. However, the present invention is not limited to line-type head units, but can also be applied to so-called serial-type head units that eject ink while moving the liquid ejection head in the main scanning direction (sheet width direction). An example of a serial-type head unit will be described below.

[0072] <Configuration of a serial-type head unit> As shown in Figure 11, the serial head unit includes a carriage 62 on which multiple liquid discharge heads 20 are mounted, a guide member (guide rod) 63 for guiding the carriage 62 in the main scanning direction X, which is the sheet width direction (a direction perpendicular to the transport direction Y), and a drive device 64 for moving the carriage 62.

[0073] The drive unit 64 includes, for example, a motor 65 which is a drive source, and a timing belt 68 wrapped around a drive pulley 66 and a driven pulley 67. When the motor 65 is driven and the drive pulley 66 rotates, the timing belt 68 rotates, causing the carriage 62 to move along the guide member 63 in the main scanning direction X. Also, by switching the rotation direction of the motor 65 between one direction and the opposite direction, the carriage 62 moves back and forth in the main scanning direction X.

[0074] As shown in Figure 11, the sheet S is transported in the direction of arrow Y, and when the sheet S reaches a predetermined image formation position, the transport of the sheet S is temporarily stopped. Then, as the carriage 62 moves in the main scanning direction X, liquid (ink) is ejected from the liquid ejection head 20. This forms an image of a predetermined width on the stationary sheet S. Subsequently, the intermittent transport (transport and stop) of the sheet S in the direction of arrow Y and the liquid ejection operation accompanying the reciprocating movement of the carriage 62 in the main scanning direction X are repeated, and images are sequentially formed on the sheet S.

[0075] At this time, the sheet S and the liquid discharge head 20 move relative to each other, and between the sheet S and the liquid discharge head 20, an airflow is generated in the direction of that relative movement. For this reason, especially upstream of the nozzle located at the uppermost point in the direction of relative movement of the sheet S relative to the liquid discharge head 20, an upward airflow toward the nozzle surface is generated when the airflow moving in the direction of relative movement collides with the airflow moving in the opposite direction. Therefore, even in serial-type head units, the problem of displacement of the impact position due to the upward airflow can occur, just as in line-type head units. In addition, displacement of the impact position also occurs due to the effect of negative pressure associated with the discharge of liquid.

[0076] Therefore, it is preferable to apply the present invention to serial-type head units as well, in order to effectively suppress the shift in the point of impact caused by the effects of rising airflow and negative pressure. However, in the case of serial-type head units, since the head unit moves back and forth in one direction and the opposite direction, the positions of the upstream and downstream sides in the relative direction of movement are reversed depending on the direction of movement of the head unit.

[0077] Therefore, as shown in Figure 12, in a liquid discharge head 20 mounted on a serial-type head unit, it is preferable to provide the inlet 21a on both outer sides in the relative movement direction Y of the sheet S, relative to the plurality of nozzles 30.

[0078] As a result, for example, as shown in Figure 13, when the liquid discharge head 20 moves in one direction X1 of the main scanning direction, an upward airflow 9D flows in from the upstream inlet 21a (the left inlet 21a in Figure 13) in the relative movement direction Y1 of the sheet S at that time, and the airflow can be discharged from the outlet 21b through the ventilation passage 21. As a result, as in each embodiment of the present invention described above, the generation of airflow 9E (see Figure 16) due to the upward airflow 9D hitting the nozzle surface 31 and the generation of negative pressure between the nozzles 30 (the area enclosed by the dashed line 90 in Figure 13) can be suppressed, and thus it is possible to effectively suppress the deviation of the impact position caused by these effects.

[0079] Furthermore, as shown in Figure 14, if the liquid discharge head 20 moves in the opposite direction X2 to the one direction X1 described above, the relative movement direction of the sheet S will also be the opposite direction Y2. In this case, the rising airflow 9D flows in from the upstream inlet 21a (the right inlet 21a in Figure 14) in the relative movement direction Y2 of the sheet S at that time, and the airflow can be discharged from the outlet 21b through the ventilation passage 21. This suppresses the generation of airflow 9E (see Figure 16) caused by the rising airflow 9D hitting the nozzle surface 31, and the generation of negative pressure between the nozzles 30 (the area enclosed by the dashed line 90 in Figure 14), thereby effectively suppressing deviations in the point of impact caused by these effects.

[0080] Thus, by applying the present invention to the liquid discharge head 20 mounted on a serial-type head unit, it is possible to effectively suppress not only the deviation of the impact position due to the effect of negative pressure, but also the deviation of the impact position caused by the effect of rising airflow, thereby enabling the provision of high-quality images. Furthermore, since the deviation of the impact position can be effectively suppressed simply by providing the ventilation passage 21, it is possible to improve the accuracy of the impact with a simple configuration.

[0081] Furthermore, in order to increase the density of the nozzles and reduce the size of the head, in the liquid discharge head mounted on the serial type head unit, multiple inlets 21a and multiple outlets 21b may be connected via a common ventilation passage 21, or the common ventilation passage 21 may be configured so that it does not pass between pressure chambers 33 and between individual supply passages 34, similar to the second or third embodiment of the present invention.

[0082] In a serial-type head unit, it is preferable that the inlet 21a be provided at least at locations where the upward airflow 9D is mainly generated. That is, it is preferable that the inlet 21a be positioned at least upstream of the uppermost nozzle 30 in the relative movement direction of the seat S. If upward airflow is generated at other locations as well, the inlet 21a may be provided at locations other than upstream of the uppermost nozzle 30 (downstream locations where upward airflow is generated).

[0083] On the other hand, it is preferable that the outlet 21b be provided at least in locations where negative pressure is mainly generated. Therefore, it is preferable that the outlet 21b be located at least within a range that is downstream of the upstreammost nozzle 30 in the relative movement direction of the sheet S, and upstream of the downstreammost nozzle 30 in the conveying direction of the sheet S or in the relative movement direction of the sheet S. Here, "within a range" is not limited to the position between the upstreammost nozzle 30 and the downstreammost nozzle 30 (position on the line segment connecting them), but means within the range in the relative movement direction of the sheet S from the upstreammost nozzle 30 to the downstreammost nozzle 30.

[0084] Furthermore, the liquid discharge head and head unit according to the present invention can be applied not only to the image forming apparatus described above, but also to other liquid discharge devices. In other words, any liquid discharge device that discharges liquid onto a moving object that moves relative to the liquid discharge head may experience the same problem of misalignment of the impact position, and by applying the present invention, it is possible to effectively suppress misalignment of the impact position.

[0085] For example, the liquid dispensing head and head unit according to the present invention can also be applied to an electrode manufacturing apparatus that dispenses a liquid composition to manufacture electrodes. An example of an electrode manufacturing apparatus to which the present invention can be applied will be described below.

[0086] <Configuration of electrode manufacturing equipment> Figure 15 is a schematic diagram showing the overall configuration of an electrode manufacturing apparatus 700 to which the present invention can be applied.

[0087] Here, as an example of an electrode manufacturing apparatus 700, a manufacturing apparatus for forming an electrode composite layer containing an active material on an electrode substrate (current collector) will be described. The electrode composite layer is used, for example, as part of the configuration of an electrochemical element. There are no particular restrictions on the components of the electrochemical element other than the electrode composite layer, and known components can be appropriately selected. For example, components other than the electrode composite layer include a positive electrode, a negative electrode, and a separator.

[0088] The electrode manufacturing apparatus 700 shown in Figure 15 includes an ejection process section 110 which includes a step of applying a liquid composition for manufacturing electrodes onto a printing substrate 704 having an object to be ejected to form a liquid composition layer, and a heating process section 130 which includes a heating step of heating the liquid composition layer to obtain an electrode composite layer.

[0089] Furthermore, the electrode manufacturing apparatus 700 includes a transport unit 705 for transporting the printing substrate 704. The transport unit 705 transports the printing substrate 704 at a preset speed in the order of the discharge process unit 110 and the heating process unit 130. There are no particular restrictions on the method for manufacturing the printing substrate 704 having an object to be discharged, such as an active material layer, and known methods can be appropriately selected. The discharge process unit 110 includes a liquid discharge head 281a that realizes a dispensing process for applying a liquid composition onto the printing substrate 704, a container 281b that contains the liquid composition 707, and a supply tube 281c that supplies the liquid composition 707 contained in the container 281b to the liquid discharge head 281a.

[0090] In the discharge process section 110, the liquid composition 707 is discharged from the liquid discharge head 281a and applied to the printing substrate 704, forming a thin film layer of the liquid composition. The containment container 281b may be integrated with the electrode manufacturing apparatus or may be detachable from the electrode manufacturing apparatus. Alternatively, the containment container 281b may be a container used for adding to a containment container integrated with the electrode manufacturing apparatus or a containment container detachable from the electrode manufacturing apparatus.

[0091] The containment container 281b and the supply tube 281c can be arbitrarily selected as long as they are capable of stably containing and supplying the liquid composition 707.

[0092] In the heating section 130, a solvent removal step is performed in which the solvent remaining in the liquid composition layer is heated and removed. Specifically, the solvent remaining in the liquid composition layer is heated and dried by the heating device 703 of the heating section 130, thereby removing the solvent from the liquid composition layer. This forms the electrode composite layer. Furthermore, the solvent removal step in the heating section 130 may be performed under reduced pressure.

[0093] There are no particular restrictions on the heating device 703, and it can be appropriately selected according to the purpose. For example, the heating device 703 can be a substrate heater, an IR heater, or a hot air heater. Alternatively, the heating device 703 may be a combination of at least two of the substrate heater, IR heater, and hot air heater. Furthermore, the heating temperature and heating time can be appropriately selected according to the boiling point of the solvent contained in the liquid composition 707 or the film thickness to be formed.

[0094] The object onto which the liquid composition is discharged (hereinafter sometimes referred to as the "discharge target") is not particularly limited as long as it is an object on which a layer containing electrode material is formed, and can be appropriately selected according to the purpose. For example, the target object may be an electrode substrate (current collector), an active material layer, or a layer containing solid electrode material. The target object may also be an electrode composite layer containing active material on an electrode substrate (current collector). Furthermore, the discharge means and discharge process may be means and processes for forming a layer containing electrode material by directly discharging the liquid composition, as long as it is possible to form a layer containing electrode material on the discharge target. Alternatively, the discharge means and discharge process may be means and processes for forming a layer containing electrode material by indirectly discharging the liquid composition.

[0095] By applying the present invention to the electrode manufacturing apparatus 700 described above, deviations in the impact position of the liquid (liquid composition) can be effectively suppressed, and impact accuracy can be improved. As a result, the liquid composition can be discharged to the target location of the object to be discharged.

[0096] Furthermore, the present invention is broadly applicable not only to liquid dispensing devices that dispense liquid onto moving objects such as sheets or electrode substrates that move relative to a liquid dispensing head, but also to liquid dispensing devices that dispense liquid onto objects (moving objects) to which liquid can at least temporarily adhere. Examples of objects (moving objects) to which liquid is dispensed include paper, resin films, wallpaper, and electronic circuit boards. Examples of materials for objects (moving objects) to which liquid is dispensed include paper, leather, metal, plastic, glass, wood, and ceramics.

[0097] Furthermore, the liquid discharged by the liquid dispensing device according to the present invention is not particularly limited, but may include solutions, suspensions, emulsions, etc., containing water, solvents such as organic solvents, colorants such as dyes and pigments, functional materials such as polymerizable compounds, resins, and surfactants, biocompatible materials such as DNA, amino acids and proteins, and calcium, and edible materials such as natural pigments. These are used, for example, in inkjet inks, surface treatment liquids, components of electronic elements and light-emitting elements, liquids for forming electronic circuit resist patterns, and material liquids for 3D molding.

[0098] To summarize the embodiments of the present invention described above, the present invention includes at least the following embodiments.

[0099] [First aspect] The first embodiment is a liquid discharge head having a plurality of nozzles for discharging liquid to a moving object that is moving relative to it, and a nozzle surface through which the plurality of nozzles open, wherein the liquid discharge head has an air passage through which air passes, and both the inlet for air entering the air passage and the outlet for air exiting the air passage are provided on the nozzle surface.

[0100] [Second aspect] In a second embodiment, the inlet is positioned outward from the plurality of nozzles in the relative direction of movement of the moving object, in the first embodiment.

[0101] [Third aspect] In a third embodiment, the inlet is positioned at least upstream of the nozzle furthest upstream in the relative direction of movement of the moving object, as in the first or second embodiment.

[0102] [Fourth aspect] A fourth embodiment is one of the first to third embodiments wherein the outlet is located at least downstream of the upstream nozzle in the relative direction of movement of the moving object, and within a range upstream of the downstream nozzle in the relative direction of movement of the moving object.

[0103] [Fifth aspect] The fifth embodiment is one of the first to fourth embodiments, wherein a plurality of inlets and outlets are provided, and the plurality of inlets and outlets are individually connected via a plurality of independently provided ventilation passages.

[0104] [Sixth aspect] The sixth embodiment is one of the first to fourth embodiments, wherein a plurality of inlets and outlets are provided, and the plurality of inlets and outlets are in communication through a common ventilation passage.

[0105] [Seventh aspect] The seventh aspect is the arrangement in the sixth aspect in which the common ventilation passage is not located between pressure chambers communicating with the plurality of nozzles forming a nozzle row, and between individual supply passages communicating with the pressure chambers.

[0106] [Eighth aspect] The eighth embodiment is a head unit comprising a plurality of liquid dispensing heads according to any one embodiment of the first to seventh embodiments.

[0107] [Ninth aspect] The ninth embodiment is a liquid dispensing device comprising a liquid dispensing head according to any one of the first to seventh embodiments, or a head unit according to the eighth embodiment. [Explanation of Symbols]

[0108] 13 Head Unit 20 liquid dispensing heads 21 Ventilation channel 21a Inlet 21b Outlet 30 nozzles 31 Nozzle surface 33 Pressure Chamber 34 Individual supply channels 100 Image forming device (liquid ejection device) S Sheet (movable object) Y: Sheet transport direction (relative movement direction of the sheet) Y1 Relative movement direction of the sheet Y2 Sheet relative movement direction [Prior art documents] [Patent Documents]

[0109] [Patent Document 1] Japanese Patent Publication No. 2008-173939

Claims

1. Multiple nozzles that discharge liquid onto a moving object that is moving relative to them, The nozzle surface through which the plurality of nozzles open, In a liquid dispensing head having, It has a ventilation channel through which air passes, A liquid dispensing head characterized in that both the inlet through which air flows in and the outlet through which air flows out of the aforementioned ventilation passage are provided on the nozzle surface.

2. The liquid discharge head according to claim 1, wherein the inlet is positioned outward from the plurality of nozzles in the relative direction of movement of the moving object.

3. The liquid discharge head according to claim 1, wherein the inlet is positioned at least upstream of the nozzle furthest upstream in the relative direction of movement of the moving object.

4. The liquid discharge head according to claim 1, wherein the outlet is located downstream of the upstream nozzle in the relative direction of movement of the moving object, and is positioned at least within the range upstream of the downstream nozzle in the relative direction of movement of the moving object.

5. Multiple inlets and outlets are provided, The liquid discharge head according to claim 1, wherein the plurality of inlets and the plurality of outlets are individually connected via a plurality of independently provided ventilation passages.

6. Multiple inlets and outlets are provided, The liquid discharge head according to claim 1, wherein the plurality of inlets and the plurality of outlets are in communication via a common ventilation passage.

7. The liquid discharge head according to claim 6, wherein the common vent is arranged so as not to pass between pressure chambers communicating with the plurality of nozzles forming a nozzle row, and between individual supply channels communicating with the pressure chambers.

8. A head unit characterized by comprising a plurality of liquid discharge heads as described in claim 1.

9. A liquid dispensing device characterized by comprising the liquid dispensing head described in claim 1.

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