JP4938604B2 - Liquid ejection head and image forming apparatus - Google Patents

Description

  The present invention relates to a liquid discharge head and an image forming apparatus.

  In general, a printer, a fax machine, a copier, a plotter, or an image forming apparatus that combines a plurality of these functions includes, for example, a recording head composed of a liquid ejection head that ejects ink droplets, It is also referred to as “paper”, but the material is not limited, and a recording medium, recording medium, transfer material, recording paper, etc. are also used synonymously.) Some perform formation (recording, printing, printing, and printing are also used synonymously).

  The “image forming apparatus” means an apparatus that forms an image by discharging liquid onto a medium such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc. “Formation” means not only giving an image having a meaning such as a character or a figure to a medium but also giving an image having no meaning such as a pattern to the medium (simply ejecting a droplet). means. Further, “ink” is not limited to ink in a narrow sense, and is not particularly limited as long as it becomes liquid when ejected, and includes, for example, a DNA sample, a resist, a pattern material, and the like. .

  Examples of the liquid discharge head include a nozzle that discharges droplets having a size of several μm to several tens of μm, a liquid chamber that communicates with the nozzle, a vibration plate that forms a wall surface of the liquid chamber, and a liquid via the vibration plate. A piezoelectric actuator such as a piezoelectric element that pressurizes the recording liquid in the chamber, a nozzle that discharges droplets, a liquid chamber that communicates with the nozzle, and an electrothermal conversion element such as a heating resistor for recording liquid in the liquid chamber Using a thermal actuator that pressurizes using phase change caused by film boiling, a nozzle that discharges droplets, a liquid chamber that communicates with the nozzle, a diaphragm that forms the wall of the liquid chamber, and a diaphragm There are known devices including an electrostatic actuator that pressurizes a recording liquid in a liquid chamber by displacing a diaphragm with an electrostatic force generated between opposing electrodes.

  By the way, a flow path plate (flow path member, flow path forming member, liquid chamber) that forms a flow path such as a liquid chamber or a fluid resistance section having a narrower width than the liquid chamber serving as a liquid supply path for supplying liquid to the liquid chamber. The forming member, the liquid chamber member, etc. are also used synonymously. For example, a metal plate extracted with a punch press or the like is bonded and laminated, a silicon single crystal substrate is formed by anisotropic etching, SUS or the like. Examples include a metal plate formed by etching and an electroformed method.

  For example, when a member is formed by an electroforming method, a pattern is formed with a non-conductive resist on an electroforming support substrate (electrode substrate) to deposit an electroformed plating film. The larger the electric field, the more concentrated the electric field of the portion is on the electrode portion at the end of the resist and the thicker the plating film thickness, that is, there is a tendency that the film thickness is biased (this is referred to as “uneven thickness”).

  In this case, if the member has a relatively small shielding pattern such as a nozzle plate, these uneven thicknesses will not be a big problem, but if the member is a member having a fine shielding pattern such as a diaphragm, Unevenness of film thickness due to patterns increases. Such uneven thickness becomes a serious problem when the diaphragm and the flow path plate are joined, and when the diaphragm and the piezoelectric element as an actuator are joined. That is, in the case where uneven thickness has occurred, the film thickness of the adhesive is required to be equal to or greater than the uneven thickness (difference between the lowest portion and the thick portion) in order to perform complete joining. Specifically, if there is an uneven thickness of 10 μm, the film thickness of the adhesive must be 10 μm or more. However, the increase in the amount of adhesive means that the adhesive protrudes from the thick part of the diaphragm, and if it is a fine pattern, it may come into contact with the adjacent pattern, or the deformable part of the diaphragm (diaphragm part) Is buried with adhesive.

  On the other hand, the fluid resistance portion of the flow path is formed by reducing the cross-sectional area of the flow path in the height direction or the width direction. However, if the flow resistance is reduced in the width direction of the flow path, the width of the flow path is reduced. Therefore, many flow path patterns have been used which inevitably increase the partition wall width between the fluid resistance portions. Therefore, the amount of adhesive applied to the partition between the fluid resistance portions increases, and the amount of adhesive sticking out to the fluid resistance portions increases due to pressurization during the adhesive curing operation, which causes discharge failure. It was. Conventionally, the adhesive application amount is reduced, the uneven thickness (film thickness) of the fluid resistance part is slightly reduced, or a thinning pattern is inserted between the fluid resistance parts so that this adhesive is not affected by the protrusion. In other words, an adhesive relief has been provided.

Conventionally, in Patent Document 1, a flow path member having a liquid chamber and a fluid resistance portion is formed so that the fluid resistance portion side is thin and the liquid chamber side is thick in order to reduce the protrusion of the adhesive to the fluid resistance portion. It is described.
JP 2002-052723 A

Patent Document 2 describes that a fluid resistance portion is formed by a plurality of plate members, and a fluid resistance value is obtained by adjusting a channel height and a channel width.
Japanese Patent Laid-Open No. 2001-030483

Patent Document 3 discloses a fluid resistance portion having a shape in which the fluid resistance portion is not brought into the middle of the flow path but is brought close to the end of the flow path and gradually expanded from the pressurized liquid chamber to the ink supply port. It is described to provide.
Japanese Patent No. 3679863

  As shown in FIG. 32, a conventional general flow path pattern includes a liquid chamber (pressurized liquid chamber) 501, a fluid resistance portion 502 serving as a supply path for supplying liquid to the liquid chamber 501, and a fluid resistance portion 502. The liquid introduction path 503 that faces each other forms one flow path 500, and the respective flow paths 500 are arranged at predetermined intervals along the nozzle arrangement direction.

  In the case of such a flow path configuration, between the adjacent flow paths 500 and 500, the width of the partition wall (liquid chamber interval wall) 511 between the liquid chambers 501 and 501 (the width in the direction in which the flow paths are arranged) and the fluid resistance portion 502. , 502 has a different width from the partition wall (fluid resistance portion spacing wall) 512. Therefore, when the flow path member is formed by electroforming, the current density in the outer peripheral portion of the liquid chamber 501 and the outer peripheral portion of the fluid resistance portion 502 is large. In contrast, the film thickness distribution formed by the electroforming method becomes large, and the height of the liquid chamber interval wall 511 and the height of the fluid resistance portion interval wall 512 are different.

  Further, even when the flow path member is formed by the press method or the etching method instead of the electroforming method, the fluid resistance portion interval wall 512 is wider than the liquid chamber interval wall 511, so that the fluid resistance The amount of the adhesive protruding to the portion 502 is increased, which causes discharge failure.

  In view of this, it is conceivable to provide a hollow portion (concave portion) that serves as an escape place for the adhesive in the fluid resistance portion interval wall 512. However, in the flow path pattern as shown in FIG. The width of the part interval wall 512 is narrowed, and due to construction restrictions, in fact, forming a thinned part in the fluid resistance part interval wall requires a highly accurate construction method, and the yield decreases. Even if the lightening portion can be formed, there is a problem that dimensional restrictions are severe and the target droplet discharge characteristics cannot be obtained.

  In Patent Document 3 described above, the fluid resistance portion has a shape having a plurality of step portions so that the fluid resistance portion expands toward the pressure generation chamber. However, as the arrangement density of the liquid chambers (nozzle arrangement density) increases, the flow path width and the partition wall width between the flow paths become narrower, and a plurality of steps or minute recesses are formed. In order to form a thin groove, high-precision processing is required, which increases labor and cost.

  The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to arrange a fluid resistance portion having a necessary fluid resistance value in a smaller region.

In order to solve the above-described problem, a liquid discharge head according to the present invention includes:
Each individual liquid chamber that communicates with a plurality of nozzles that discharge droplets, and a flow path that includes a fluid resistance portion that is narrower than the liquid chamber that supplies liquid to the individual liquid chamber,
The individual liquid chamber and the fluid resistance portion are provided so that the longitudinal center axis of the fluid resistance portion obliquely intersects the longitudinal center axis of the individual liquid chamber, and the flow paths have the same pitch. Arranged along the direction in which the nozzles are arranged ,
The width of the partition between the adjacent individual liquid chambers is the same as the width of the partition between the adjacent fluid resistance portions .

  An image forming apparatus according to the present invention includes the liquid ejection head according to the present invention.

According to the liquid ejection head according to the present invention, it becomes possible to place the fluid resistance portion having a fluid resistance required for good Ri small area.

  According to the image forming apparatus of the present invention, since the liquid ejection head according to the present invention is provided, a high-quality image can be formed by increasing the density.

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, the basic configuration principle of the present invention will be described with reference to FIG.
As shown in FIG. 1A, a plurality of channels 1001 having a width x, a channel length z, and a partition wall width y are arranged in a vertical a and a horizontal b area, separated by a partition wall 1002 having a width y. Yes.

  As shown in FIG. 1B, the flow path 1001 is a flow path 1001 inclined at an angle θ, so that the width x1 is relatively narrow (x1 <x) even if the flow path area is the same. The flow path length z1 becomes longer (z1> z). That is, by providing an angle to the flow path 1001, it is possible to form a flow path width and a flow path length for obtaining a target fluid resistance value and reactance value within a smaller area.

  In addition, the items that greatly affect the film growth rate in the electroforming method (electroforming method) are the current density per unit area (proportional to the plating area per unit area) and the edge ratio of the plating area (the edge of the charge distribution). Effect). When the influence of the current density per unit area is large, when the pressurized liquid chamber width x and the partition wall width y are set, the fluid resistance portion is bent by an angle θ, and the flow path width of the fluid resistance portion is x1 = x.・ If cos θ and the partition width of the fluid resistance portion are y1 = y · cos θ, the fluid resistance value (R) according to the angle θ while the plating area per unit area remains the same pattern in the pressurized liquid chamber portion and the fluid resistance portion. And the fluid reactance value (L) can be adjusted.

  Further, when the influence of the edge ratio of the plated portion (the edge effect of the charge distribution) is large, as shown in 1 (c), the partition wall width y on the outer periphery of the pressurized liquid chamber and the partition wall width y1 of the fluid resistance portion are The flow width of the fluid resistance unit may be designed as x1 = x · cos θ + y · (1−cos θ) by adjusting the same value (y = y1). That is, the flow path width of the fluid resistance portion is within the range of x · cos θ + y · (1−cos θ) ≦ x1 ≦ x · cos θ (where 0 ° <θ <90 °), depending on the design value and formation conditions. design.

  Thus, by forming the fluid resistance portion at an angle inclined with respect to the longitudinal central axis of the pressurized liquid chamber, it becomes possible to form the fluid resistance portion having the desired flow path width and partition wall width in a smaller area. Therefore, it is possible to reduce the size of the flow path plate. Further, by adjusting the angle of the fluid resistance portion, the partition wall area ratio on the outer periphery of the pressurized liquid chamber and the partition wall area ratio on the outer periphery of the fluid resistance portion can be set to substantially the same value. As a result, it is possible to reduce variations in the amount of protrusion of the adhesive between the outer periphery of the pressurized liquid chamber and the outer periphery of the fluid resistance portion. In addition, when the flow path is formed by the electroforming method (electroforming method), the pressure is adjusted by adjusting the angle and the partition wall width so that the current densities of the outer periphery of the pressurized liquid chamber and the outer periphery of the fluid resistance portion are equal. Variations in the partition wall height on the outer periphery of the liquid chamber and the partition wall height on the outer periphery of the fluid resistance portion can be reduced.

Therefore, a first embodiment of the present invention will be described with reference to FIG. FIG. 2 is an explanatory plan view of the flow path pattern in the same embodiment.
Here, the pressurized liquid chamber 1 communicated with the nozzle 6, the ink is supplied to the pressurized liquid chamber 1, and the width is narrower than the liquid chamber 1, with respect to the longitudinal central axis of the pressurized liquid chamber 1. A fluid resistance portion 2 whose longitudinal central axis is inclined at an angle θ, an ink supply portion 3 for supplying ink to the fluid resistance portion 2, a partition wall 4 between the pressurized liquid chambers 1 and 1, a fluid A flow path is constituted by the partition wall 5 between the resistance portions 2 and 2, and the plurality of pressurized liquid chambers 1 and the fluid resistance portions 2 have the same interval (pitch), here, the same interval as the pitch of the nozzles 6 (nozzle pitch). The nozzles 6 are arranged along the arrangement direction (nozzle arrangement direction).

  Here, the fluid resistance part 2 has a shape as shown in FIGS. 1A and 1B, and the flow path width x1 of the fluid resistance part 2 and the width (partition wall width) y1 of the partition wall 5 are: X · cos θ + y · (1−cos θ) ≦ x1 ≦ x · cos θ (where 0 ° <θ <90 °) with respect to the flow path width x of the pressurized liquid chamber 1 and the width (partition wall width) y of the partition wall 4 It is formed within the range.

  With this configuration, the fluid resistance portion 2 having a desired shape (a shape satisfying a target fluid characteristic value) is relatively compared with the case where the longitudinal central axes of the pressurized liquid chamber 1 and the fluid resistance portion 2 coincide with each other. Therefore, it is possible to reduce the size of the flow path plate (flow path forming member).

  In addition, when the flow path is formed by the electroforming method (electroforming method), a pattern with uniform current distribution can be obtained by adjusting the angle θ and the partition wall width y1 of the fluid resistance partition wall 5. The height variation of the partition wall 4 on the outer periphery of the pressurized liquid chamber 1 and the height of the partition wall 4 on the outer periphery of the fluid resistance portion 2 can be reduced. Also, the adhesive curing operation is performed by adjusting the area ratio of the partition wall 4 around the pressurized liquid chamber 1 and the area ratio of the partition wall 5 around the fluid resistance portion 2 by adjusting the angle θ and the partition wall width y1 of the fluid resistance portion 2. At the time of pressurization at this time, it becomes possible to adjust the amount of the adhesive that protrudes to the fluid resistance portion 2, and it is possible to improve the yield and secure the discharge stability.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is an explanatory plan view of the flow path pattern in the same embodiment.
The ink supply unit 3 in the first embodiment is independent between the adjacent flow paths, but here, the ink supply unit 3 communicates between the adjacent flow paths. Thereby, the fluid resistance value in the ink supply unit 3 can be greatly reduced, and high-speed printing by high-frequency driving becomes possible.

Next, a third embodiment of the present invention will be described with reference to FIGS. 4 is an explanatory plan view of the flow path pattern in the embodiment, and FIG. 5 is an explanatory cross-sectional view taken along the line AA of FIG.
Here, the first, second, and third substrates 11, 12, and 13 are joined to form the pressurized liquid chamber 1, the fluid resistance unit 2, and the ink supply unit 3, and the nozzle 6 is provided on the third substrate 13. In addition, the ink supply unit 3 is configured to be independent between the flow paths. Further, the first substrate 11 is formed with an opening 14 that communicates with each ink supply unit 3 independently.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 6 is an explanatory plan view of the flow path pattern in the same embodiment, and FIG. 7 is an explanatory sectional view taken along line BB in FIG.
Here, the first, second, and third substrates 11, 12, and 13 are joined to form the pressurized liquid chamber 1, the fluid resistance unit 2, and the ink supply unit 3, and the nozzle 6 is provided on the third substrate 13. In addition, the ink supply unit 3 is configured to communicate with each flow path. Further, the second substrate 12 has openings 15 communicating with all the ink supply units 3. Thereby, the fluid resistance value in the ink supply unit 3 can be reduced, and high-frequency printing and printing with a large number of droplets are possible.

Next, a fifth embodiment of the present invention will be described with reference to FIG. FIG. 8 is an explanatory plan view of the flow path pattern in the same embodiment.
Here, there are two nozzle rows in which a plurality of nozzles 6 are arranged (one nozzle row 6A and the other nozzle row 6B), and the other between adjacent nozzles 6 and 6 in one nozzle row 6A. A part of the flow path of the nozzle row 6B (here, the pressurized liquid chambers 1A and 1B) is arranged, and corresponds to the fluid resistance portion 2A of the flow passage corresponding to one nozzle row 6A and the other nozzle row 6B. The fluid resistance part 2B of the flow path is pulled out in the opposite direction, and the inclination directions of the fluid resistance parts 2A and 2B corresponding to the nozzle arrays 6A and 6B are opposite to each other.

  In addition, the ink supply units 3A and 3B communicating with the fluid resistance units 2A and 2B are configured independently of each flow path.

  This makes it possible to eject ink droplets of different colors from the nozzles 6 in the nozzle row 6A and the nozzle row 6B. In addition, the fluid resistance portions 2A and 2B here are formed within the configuration range as shown in FIGS. 1B and 1C, and the flow path width x1 between the pressurized liquid chamber 1 and the fluid resistance portion 2 is as follows. The relationship between the partition wall width y1 and the angle θ is such that x · cos θ + y · (1−cos θ) ≦ x1 ≦ x · cos θ (where 0 ° < It is configured within the range of θ <90 °.

Next, a sixth embodiment of the present invention will be described with reference to FIG. FIG. 9 is an explanatory plan view of the flow path pattern in the same embodiment.
Here, the ink supply units 3A and 3B in each column are common ink supply units that communicate with a plurality of flow paths. Thereby, the fluid resistance value in the ink supply unit can be reduced, and high-frequency printing and printing with a large number of droplets are possible.

Next, a seventh embodiment of the present invention will be described with reference to FIGS. 10 is an explanatory plan view of the flow path pattern in the embodiment, and FIG. 11 is an explanatory cross-sectional view taken along the line CC of FIG.
Here, the first, second, and third substrates 11, 12, and 13 are joined to form the pressurized liquid chambers 1A and 1B, the fluid resistance units 2A and 2B, and the ink supply units 3A and 3B. The nozzles 6 are formed on the substrate 13, and the ink supply unit 3 has an independent configuration between the flow paths. The first substrate 11 has openings 14a and 14b that communicate with the respective ink supply units 3 independently.

Next, an eighth embodiment of the present invention will be described with reference to FIGS. 12 is an explanatory plan view of the flow path pattern in the embodiment, and FIG. 13 is an explanatory sectional view taken along the line DD of FIG.
Here, the first, second, and third substrates 11, 12, and 13 are joined to form the pressurized liquid chambers 1A and 1B, the fluid resistance units 2A and 2B, and the ink supply units 3A and 3B. The nozzles 6 are formed on the substrate 13, and the ink supply units 3A and 3B are configured to communicate with each other. The second substrate 12 has openings 15A and 15B communicating with all the ink supply units 3A and 3B. Thereby, the fluid resistance value in the ink supply unit can be reduced, and high-frequency printing and printing with a large number of droplets are possible.

Next, a ninth embodiment of the present invention will be described with reference to FIG. FIG. 14 is an explanatory plan view of the flow path pattern in the same embodiment.
Here, in the fifth embodiment, the lightening portion 10 is formed by removing all or part of the members forming the flow path in the partition walls 5A and 5B between the adjacent fluid resistance portions 2A and 2B.

  The relationship between the flow paths of the pressurized liquid chambers 1A and 1B and the fluid resistance portions 2A and 2B and the partition walls 4 and 5 has a shape as shown in FIGS. 1B and 1C. The flow path width x1 and the partition wall width y1 of the portions 2A and 2B are set to x · cos θ + y · (1−cos θ) ≦ x1 ≦ x · cos θ (with respect to the flow path width x and the partition wall width y of the pressurized liquid chamber 1) , 0 ° <θ <90 °).

  As a result, when the flow path is formed using the electroforming method (electroforming method), the current density of the fluid resistance portion interval wall can be adjusted, and the variation in the partition wall height can also be reduced. Alternatively, by providing a dummy lightening pattern portion, it is possible to make the amount of protrusion at the time of pressurization during the adhesive curing operation uniform. Further, the adhesive escape effect on the dummy portion can reduce the adhesive protrusion to the fluid resistance portion, thereby improving the yield of components and improving the discharge stability.

Next, a tenth embodiment of the present invention will be described with reference to FIG. FIG. 15 is an explanatory plan view of the flow path pattern in the same embodiment.
Here, in the sixth embodiment, the wall portions 10Aa and 5B between the adjacent fluid resistance portions 2A and 2B are formed with the lightening portions 10 by removing all or part of the members forming the flow path. .

  As described above, in this embodiment, the adjacent fluid resistance portion interval walls 5A and 5B are formed with the lightening portions 10a and 10b having no member that forms the flow path, and further the adjacent ink supply portions 3A and 3B. Since there are multiple connections, when the flow path is formed using the electroforming method (electroforming method), it is possible to adjust the current density of the fluid resistance part interval wall, and also to reduce the height variation of the partition walls. It becomes. Further, by providing the dummy lightening pattern portion, it is possible to make the amount of protrusion at the time of pressurization during the adhesive curing operation uniform. In addition, the adhesive escape effect on the dummy portion can reduce the protrusion of the adhesive to the fluid resistance portion, thereby improving the yield of components and improving the discharge stability. Further, by connecting the ink supply unit, it is possible to improve the ejection stability of high-speed printing by high-frequency driving.

Next, an eleventh embodiment of the present invention will be described with reference to FIG. FIG. 16 is an explanatory plan view of the flow path pattern in the same embodiment.
Here, there are two nozzle rows in which a plurality of nozzles 6 are arranged (one nozzle row 6A and the other nozzle row 6B), and the other between adjacent nozzles 6 and 6 in one nozzle row 6A. A part of the flow path of the nozzle row 6B (here, the pressurized liquid chambers 1A and 1B) is arranged, and corresponds to the fluid resistance portion 2A of the flow passage corresponding to one nozzle row 6A and the other nozzle row 6B. The flow resistance is drawn out in the direction opposite to the fluid resistance part 2B, and the inclination directions of the fluid resistance parts 2A and 2B corresponding to the nozzle rows 6A and 6B are the same.

  In addition, the ink supply units 3A and 3B communicating with the fluid resistance units 2A and 2B are configured independently of each flow path.

  This makes it possible to eject ink droplets of different colors from the nozzles 6 in the nozzle row 6A and the nozzle row 6B. In addition, the fluid resistance portions 2A and 2B here are formed within the configuration range as shown in FIGS. 1B and 1C, and the flow path width x1 between the pressurized liquid chamber 1 and the fluid resistance portion 2 is as follows. The relationship between the partition wall width y1 and the angle θ is such that x · cos θ + y · (1−cos θ) ≦ x1 ≦ x · cos θ (where 0 ° < It is configured within the range of θ <90 °.

Next, a twelfth embodiment of the present invention will be described with reference to FIG. FIG. 17 is an explanatory plan view of the flow path pattern in the same embodiment.
Here, the ink supply units 3A and 3B in each column are common ink supply units that communicate with a plurality of flow paths. Thereby, the fluid resistance value in the ink supply unit can be reduced, and high-frequency printing and printing with a large number of droplets are possible.

Next, a thirteenth embodiment of the present invention will be described with reference to FIGS. 18 is an explanatory plan view of the flow path pattern in the embodiment, and FIG. 19 is an explanatory sectional view taken along the line EE in FIG.
Here, the first, second, and third substrates 11, 12, and 13 are joined to form the pressurized liquid chambers 1A and 1B, the fluid resistance units 2A and 2B, and the ink supply units 3A and 3B. The nozzles 6 are formed on the substrate 13, and the ink supply unit 3 has an independent configuration between the flow paths. The first substrate 11 has openings 14a and 14b that communicate with the respective ink supply units 3 independently.

Next, a fourteenth embodiment of the present invention will be described with reference to FIGS. 20 is an explanatory plan view of the flow path pattern in the embodiment, and FIG. 21 is an explanatory sectional view taken along the line EE of FIG.
Here, the first, second, and third substrates 11, 12, and 13 are joined to form the pressurized liquid chambers 1A and 1B, the fluid resistance units 2A and 2B, and the ink supply units 3A and 3B. The nozzles 6 are formed on the substrate 13, and the ink supply units 3A and 3B are configured to communicate with each other. The second substrate 12 has openings 15A and 15B communicating with all the ink supply units 3A and 3B. Thereby, the fluid resistance value in the ink supply unit can be reduced, and high-frequency printing and printing with a large number of droplets are possible.

Next, a fifteenth embodiment of the present invention is described with reference to FIG. FIG. 22 is an explanatory plan view of the flow path pattern in the same embodiment.
Here, in the eleventh embodiment, the lightening portions 10 are formed in the partition walls 5A and 5B between the adjacent fluid resistance portions 2A and 2B by removing all or part of the members forming the flow path.

  The relationship between the flow paths of the pressurized liquid chambers 1A and 1B and the fluid resistance portions 2A and 2B and the partition walls 4 and 5 has a shape as shown in FIGS. 1B and 1C. The flow path width x1 and the partition wall width y1 of the portions 2A and 2B are set to x · cos θ + y · (1−cos θ) ≦ x1 ≦ x · cos θ (with respect to the flow path width x and the partition wall width y of the pressurized liquid chamber 1) , 0 ° <θ <90 °).

  As a result, when the flow path is formed using the electroforming method (electroforming method), the current density of the fluid resistance portion interval wall can be adjusted, and the variation in the partition wall height can also be reduced. Alternatively, by providing a dummy lightening pattern portion, it is possible to make the amount of protrusion at the time of pressurization during the adhesive curing operation uniform. Further, the adhesive escape effect on the dummy portion can reduce the adhesive protrusion to the fluid resistance portion, thereby improving the yield of components and improving the discharge stability.

Next, a sixteenth embodiment of the present invention will be described with reference to FIG. FIG. 23 is an explanatory plan view of the flow path pattern in the same embodiment.
Here, in the twelfth embodiment, the wall portion 10A is formed by removing all or part of the members forming the flow path in the partition walls 5A and 5B between the adjacent fluid resistance portions 2A and 2B. .

  As described above, in this embodiment, the adjacent fluid resistance portion interval walls 5A and 5B are formed with the lightening portions 10A and 10B having no member that forms the flow path, and further the adjacent ink supply portions 3A and 3B. Since there are multiple connections, when the flow path is formed using the electroforming method (electroforming method), it is possible to adjust the current density of the fluid resistance part interval wall, and also to reduce the height variation of the partition walls. It becomes. Further, by providing the dummy lightening pattern portion, it is possible to make the amount of protrusion at the time of pressurization during the adhesive curing operation uniform. In addition, the adhesive escape effect on the dummy portion can reduce the protrusion of the adhesive to the fluid resistance portion, thereby improving the yield of components and improving the discharge stability. Further, by connecting the ink supply unit, it is possible to improve the ejection stability of high-speed printing by high-frequency driving.

Next, a seventeenth embodiment of the present invention will be described with reference to FIG. FIG. 24 is an explanatory plan view of the flow path pattern in the same embodiment.
Here, the pressurized liquid chamber 1 and the fluid resistance portion 2 have substantially the same configuration as in the first embodiment, but the pressurized liquid chamber 1 and the fluid resistance portion 2 are formed in the same member, and the ink The supply unit 3 is configured as a separate member from the fluid resistance unit 2 and is configured to communicate with the fluid resistance unit 2.

Next, an eighteenth embodiment of the present invention will be described with reference to FIGS. 25 is an explanatory plan view of the flow path pattern in the same embodiment, FIG. 26 is an explanatory sectional view taken along the line GG in FIG. 25, and FIG. 27 is an explanatory sectional view taken along the line HH in FIG. . In FIG. 25, the line types are shown differently in order to distinguish each part.
Here, a plurality of, in this example, two fluid resistance portions 2a and 2b are communicated with one pressurizing fluid chamber 1, and the fluid resistance portion 2a is connected to the pressurizing fluid chamber 1 in each longitudinal central axis. Intersect each other at an angle θa, and the fluid resistance portion 2b intersects the pressurized liquid chamber 1 at each longitudinal central axis at an angle θb.

  Here, the first substrate 21, the second substrate 22, the third substrate 23, and the fourth substrate 24 are sequentially stacked, and the pressurized liquid chamber 1 is a through groove formed in the first to third substrates 21 to 23. 21a, 22a, and 23a, the fluid resistance portion 2a is formed by a through groove 21b formed in the first substrate 21, and the fluid resistance portion 2b is formed by a through groove 22b formed in the second substrate 22, respectively. The common ink supply unit 3 is formed by through grooves 21c, 22c, and 23c formed in the substrates 21 to 23.

  By laminating a plurality of members in this way to form each flow path, the flow path pattern of each member has a simple shape and does not require fine pattern control. In addition, since there are a plurality of fluid resistance parts that supply ink to the pressurized liquid chamber, a smaller reactance value can be obtained even with the same fluid resistance value, and high-speed printing by more stable high-frequency driving is possible. Become.

  Next, an example of the liquid discharge head will be described with reference to FIGS. 28 is a cross-sectional explanatory view along the longitudinal direction of the liquid chamber of the head, and FIG. 29 is a cross-sectional explanatory view of the head along the short direction of the liquid chamber (nozzle arrangement direction).

  This liquid discharge head joins a flow path plate 101, a vibration plate 102 formed by nickel electroforming, for example, joined to the lower surface of the flow path plate 101, and a nozzle plate 103 joined to the upper surface of the flow path plate 101. A fluid communicating with the liquid chamber (individual flow channel) 106, which is a flow path through which the nozzles 104 that discharge the liquid droplets (ink droplets) communicate with each other, a pressure communication chamber 106, and a liquid chamber 106 are stacked. A resistance portion 107 and an ink supply portion (port) 109 are formed. The ink supply portion 109 communicates with the common liquid chamber 108 through an opening 110 formed in the vibration plate 102.

  Further, two rows of stacked piezoelectric elements 121 as electromechanical conversion elements that are pressure generating means (actuator means) for deforming the diaphragm 102 to pressurize the ink in the liquid chamber 106, and the piezoelectric elements 121 And a base substrate 122 to be bonded and fixed. Note that a column portion 123 is provided between the piezoelectric elements 121. This support portion 123 is a portion formed simultaneously with the piezoelectric element 121 by dividing and processing the piezoelectric element member. However, since the drive voltage is not applied, the support portion 123 becomes a simple support. Further, an FPC cable 126 equipped with a drive circuit (drive IC) (not shown) is connected to the piezoelectric element 121.

  The peripheral edge of the diaphragm 102 is joined to a frame member 130, and the frame member 130 serves as a through-hole 131 and a common liquid chamber 108 that house an actuator unit composed of the piezoelectric element 121 and the base substrate 122. A recess and an ink supply hole 132 for supplying ink from the outside to the common liquid chamber 108 are formed.

  The nozzle plate 103 forms a nozzle 104 having a diameter of 10 to 30 μm corresponding to each liquid chamber 106 and is bonded to the flow path plate 101 with an adhesive. The nozzle plate 103 is formed by forming a water repellent layer on the outermost surface of a nozzle forming member made of a metal member via a required layer.

  The piezoelectric element 121 is a stacked piezoelectric element (here, PZT) in which piezoelectric materials 151 and internal electrodes 152 are alternately stacked. An individual electrode 153 and a common electrode 154 are connected to each internal electrode 152 drawn out to different end faces of the piezoelectric element 121 alternately. In this embodiment, the ink in the liquid chamber 106 is pressurized using the displacement in the d33 direction as the piezoelectric direction of the piezoelectric element 121. However, the pressure in the d31 direction is used as the piezoelectric direction of the piezoelectric element 121. The ink in the liquid chamber 106 may be pressurized. Alternatively, a structure in which one row of piezoelectric elements 121 is provided on one substrate 122 may be employed.

  In the liquid discharge head having such a configuration, for example, by lowering the voltage applied to the piezoelectric element 121 from the reference potential, the piezoelectric element 121 contracts, and the diaphragm 102 descends to expand the volume of the liquid chamber 106. Then, the ink flows into the liquid chamber 106, and then the voltage applied to the piezoelectric element 121 is increased to extend the piezoelectric element 121 in the stacking direction, and the diaphragm 102 is deformed in the direction of the nozzle 104, so that the volume / volume of the liquid chamber 106 is increased. By contracting the volume, the recording liquid in the liquid chamber 106 is pressurized, and droplets of the recording liquid are ejected (jetted) from the nozzle 104.

  Then, by returning the voltage applied to the piezoelectric element 121 to the reference potential, the diaphragm 102 is restored to the initial position, and the liquid chamber 106 expands to generate a negative pressure. The recording liquid is filled in 106. Therefore, after the vibration of the meniscus surface of the nozzle 104 is attenuated and stabilized, the operation proceeds to the next droplet discharge.

  Note that the driving method of the head is not limited to the above example (drawing-pushing), and striking or pushing can be performed depending on the direction of the drive waveform.

  Further, here, a liquid discharge head using a piezoelectric actuator as a pressure generating unit has been described. However, as described above, similarly to a head including a thermal actuator, a head including an electrostatic actuator, and the like. Can be applied.

Next, an example of an image forming apparatus including the liquid discharge head according to the present invention will be described with reference to FIGS. FIG. 31 is a schematic configuration diagram for explaining the overall configuration of the mechanism portion of the apparatus, and FIG.
This image forming apparatus is a serial type image forming apparatus, and a carriage 233 is slidably held in the main scanning direction by main and sub guide rods 231 and 232 which are guide members horizontally mounted on the left and right side plates 201A and 201B. The main scanning motor that does not perform moving scanning in the direction indicated by the arrow (carriage main scanning direction) via the timing belt.

  The carriage 233 has recording heads 234a and 234b (which are composed of liquid ejection heads according to the present invention for ejecting ink droplets of each color of yellow (Y), cyan (C), magenta (M), and black (K). When not distinguished, it is referred to as “recording head 234”). A nozzle row composed of a plurality of nozzles is arranged in the sub-scanning direction orthogonal to the main scanning direction, and is mounted with the ink droplet ejection direction facing downward.

  Each of the recording heads 234 has two nozzle rows. One nozzle row of the recording head 234a has black (K) droplets, the other nozzle row has cyan (C) droplets, and the recording head 234b has one nozzle row. One nozzle row ejects magenta (M) droplets, and the other nozzle row ejects yellow (Y) droplets.

  The carriage 233 is equipped with head tanks 235a and 235b (referred to as “head tank 35” when not distinguished) for supplying ink of each color corresponding to the nozzle rows of the recording head 234. The sub-tank 235 is supplementarily supplied with ink of each color from the ink cartridges 210k, 210c, 210m, 210y of each color via the supply tube 36 of each color.

  On the other hand, as a paper feeding unit for feeding the paper 242 stacked on the paper stacking unit (pressure plate) 241 of the paper feed tray 202, a half-moon roller (feeding) that separates and feeds the paper 242 one by one from the paper stacking unit 241. A separation pad 244 made of a material having a large coefficient of friction is provided opposite to the sheet roller 243 and the sheet feeding roller 243, and the separation pad 244 is urged toward the sheet feeding roller 243 side.

  In order to feed the sheet 242 fed from the sheet feeding unit to the lower side of the recording head 234, a guide member 245 for guiding the sheet 242, a counter roller 246, a conveyance guide member 247, and a tip pressure roller. And a conveying belt 251 which is a conveying means for electrostatically attracting the fed paper 242 and conveying it at a position facing the recording head 234.

  The conveyor belt 251 is an endless belt, and is configured to wrap around the conveyor roller 252 and the tension roller 253 so as to circulate in the belt conveyance direction (sub-scanning direction). In addition, a charging roller 256 that is a charging unit for charging the surface of the transport belt 251 is provided. The charging roller 256 is disposed so as to come into contact with the surface layer of the conveyor belt 251 and to rotate following the rotation of the conveyor belt 251. The transport belt 251 rotates in the belt transport direction when the transport roller 252 is rotationally driven through timing by a sub-scanning motor (not shown).

  Further, as a paper discharge unit for discharging the paper 242 recorded by the recording head 234, a separation claw 261 for separating the paper 242 from the transport belt 251, a paper discharge roller 262, and a paper discharge roller 263 are provided. A paper discharge tray 203 is provided below the paper discharge roller 262.

  A double-sided unit 271 is detachably attached to the back surface of the apparatus main body. The duplex unit 271 takes in the paper 242 returned by the reverse rotation of the transport belt 251, reverses it, and feeds it again between the counter roller 246 and the transport belt 251. The upper surface of the duplex unit 271 is a manual feed tray 272.

  Further, a maintenance / recovery mechanism 281 for maintaining and recovering the nozzle state of the recording head 234 is disposed in a non-printing area on one side in the scanning direction of the carriage 233. The maintenance / recovery mechanism 281 includes cap members (hereinafter referred to as “caps”) 282a and 282b (hereinafter referred to as “caps 282” when not distinguished) for capping each nozzle surface of the recording head 234, and nozzle surfaces. A wiper blade 283 that is a blade member for wiping the ink, and an empty discharge receiver 284 that receives liquid droplets for discharging the liquid droplets that do not contribute to recording in order to discharge the thickened recording liquid. ing.

  In addition, in the non-printing area on the other side in the scanning direction of the carriage 233, the liquid that receives liquid droplets when performing idle ejection that ejects liquid droplets that do not contribute to recording in order to discharge the recording liquid thickened during recording or the like. An ink recovery unit (empty discharge receiver) 288 that is a recovery container is disposed, and the ink recovery unit 288 includes an opening 289 along the nozzle row direction of the recording head 234 and the like.

  In this image forming apparatus configured as described above, the sheets 242 are separated and fed one by one from the sheet feeding tray 202, and the sheet 242 fed substantially vertically upward is guided by the guide 245, and is conveyed to the conveyor belt 251 and the counter. It is sandwiched between the rollers 246 and conveyed, and further, the leading end is guided by the conveying guide 237 and pressed against the conveying belt 251 by the leading end pressing roller 249, and the conveying direction is changed by approximately 90 °.

  At this time, a positive output and a negative output are alternately applied to the charging roller 256, that is, an alternating voltage is applied, and a charging voltage pattern in which the conveying belt 251 alternates, that is, in the sub-scanning direction that is the circumferential direction. , Plus and minus are alternately charged in a band shape with a predetermined width. When the sheet 242 is fed onto the conveyance belt 251 charged alternately with plus and minus, the sheet 242 is attracted to the conveyance belt 251, and the sheet 242 is conveyed in the sub scanning direction by the circumferential movement of the conveyance belt 251.

  Therefore, by driving the recording head 234 according to the image signal while moving the carriage 233, ink droplets are ejected onto the stopped paper 242 to record one line, and after the paper 242 is conveyed by a predetermined amount, Record the next line. Upon receiving a recording end signal or a signal that the trailing edge of the paper 242 has reached the recording area, the recording operation is finished and the paper 242 is discharged onto the paper discharge tray 203.

  As described above, since the image forming apparatus includes the liquid discharge head according to the present invention, it is possible to increase the density and stably form a high-quality image.

  In the above embodiment, the present invention has been described with reference to an example in which the present invention is applied to an image forming apparatus having a printer configuration. However, the present invention is not limited to this. For example, the present invention may be applied to an image forming apparatus such as a printer / fax / copier multifunction machine. it can. The present invention can also be applied to an image forming apparatus using a resist, a DNA sample, or the like. Further, the present invention can be applied to a line type liquid discharge head and a line type image forming apparatus.

It is typical explanatory drawing with which it uses for description of the basic composition of the present invention. It is a plane explanatory view of a channel pattern in a 1st embodiment of the present invention. It is a plane explanatory view of a channel pattern in a 2nd embodiment of the present invention. It is a plane explanatory view of a channel pattern in a 3rd embodiment of the present invention. FIG. 5 is a cross-sectional explanatory view taken along line AA in FIG. 4. It is a plane explanatory view of a channel pattern in a 4th embodiment of the present invention. FIG. 7 is a cross-sectional explanatory view taken along line BB in FIG. 6. It is a plane explanatory view of a channel pattern in a 5th embodiment of the present invention. It is a plane explanatory view of a channel pattern in a 6th embodiment of the present invention. It is a plane explanatory view of a channel pattern in a 7th embodiment of the present invention. It is sectional explanatory drawing which follows the CC line of FIG. It is a plane explanatory view of a channel pattern in an 8th embodiment of the present invention. It is sectional explanatory drawing which follows the DD line | wire of FIG. It is a plane explanatory view of a channel pattern in a 9th embodiment of the present invention. It is a plane explanatory view of a channel pattern in a 10th embodiment of the present invention. It is a plane explanatory view of a channel pattern in an 11th embodiment of the present invention. It is a plane explanatory view of a channel pattern in a 12th embodiment of the present invention. It is a plane explanatory view of a channel pattern in a 13th embodiment of the present invention. It is sectional explanatory drawing which follows the EE line | wire of FIG. It is a plane explanatory view of a channel pattern in a 14th embodiment of the present invention. FIG. 21 is an explanatory sectional view taken along line FF in FIG. 20. It is a plane explanatory view of a channel pattern in a 15th embodiment of the present invention. It is a plane explanatory view of a channel pattern in a 16th embodiment of the present invention. It is a plane explanatory view of a channel pattern in a 17th embodiment of the present invention. It is a plane explanatory view of a channel pattern in an 18th embodiment of the present invention. It is sectional explanatory drawing which follows the GG line of FIG. It is sectional explanatory drawing which follows the HH line | wire of FIG. FIG. 6 is an exploded perspective view of an example of a liquid discharge head according to the present invention. It is sectional explanatory drawing along the liquid chamber longitudinal direction of the head. FIG. 5 is an explanatory side view illustrating an example of a mechanism unit of the image forming apparatus according to the present invention including the liquid ejection head according to the present invention. Similarly it is principal part plane explanatory drawing. It is a plane explanatory view showing an example of the conventional channel pattern.

Explanation of symbols

1, 1A, 1B ... pressurized liquid chamber (individual flow path)
2, 2A, 2B ... Fluid resistance part 3, 3A, 3B ... Ink supply part 4 ... Partition wall between liquid chambers 5 ... Partition wall between fluid resistance parts 6 ... Nozzle 6A, 6B ... Nozzle row 10 ... Meat removal part 106 ... Addition Pressure liquid chamber 107 ... Fluid resistance portion 108 ... Common liquid chamber 233 ... Carriage 234 ... Recording head (liquid ejection head)

Claims (2)

Each individual liquid chamber that communicates with a plurality of nozzles that discharge droplets, and a flow path that includes a fluid resistance portion that is narrower than the liquid chamber that supplies liquid to the individual liquid chamber,
The individual liquid chamber and the fluid resistance portion are provided so that the longitudinal center axis of the fluid resistance portion obliquely intersects the longitudinal center axis of the individual liquid chamber, and the flow paths have the same pitch. Arranged along the direction in which the nozzles are arranged ,
The liquid discharge head according to claim 1, wherein a width of a partition wall between adjacent individual liquid chambers is equal to a width of a partition wall between adjacent fluid resistance portions . An image forming apparatus comprising a liquid discharge head for discharging liquid droplets to form an image on a medium, wherein the liquid discharge head is the liquid discharge head according to claim 1 .

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