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EP-4431291-B1 - LIQUID DISCHARGE MODULE AND LIQUID DISCHARGE APPARATUS

EP4431291B1EP 4431291 B1EP4431291 B1EP 4431291B1EP-4431291-B1

Inventors

  • NAKANO, TORU
  • HANADA, Takaya
  • MATSUFUJI, RYOHTA

Dates

Publication Date
20260506
Application Date
20240311

Claims (13)

  1. A liquid discharge module (30) comprising: a nozzle plate (15) having: a first face; a second face opposite to the first face; and a nozzle hole (14) through which a liquid is discharged from the second face, the nozzle hole (14) having at least two different inner diameters between the first face and the second face; a housing (11) having a liquid chamber: facing the first face of the nozzle plate (15); and communicating with the nozzle hole (14), the housing (11) supporting the nozzle plate (15); a valve (17) in the liquid chamber, the valve (17) to contact the first face of the nozzle plate (15) to form a sealed portion (17b) between the valve (17) and the nozzle plate (15) to close the nozzle hole (14), wherein the valve includes an elastic seal (17a, 17c, 17d, 17e) to elastically contact the first face of the nozzle plate (15) to form the sealed portion (17b), wherein the valve (17) includes a needle supporting the elastic seal (17a, 17c, 17d, 17e) at a leading end of the needle adjacent to the nozzle hole (14); and a mover (18) to move the valve (17) in a contact-separation direction between: a contact position at which the valve (17) contacts the nozzle plate (15); and a separation position at which the valve (17) is separated from the nozzle plate (15), characterized in that the elastic seal (17c, 17d) has a recess facing the nozzle plate (15).
  2. The liquid discharge module (30) according to claim 1, wherein the sealed portion (17b) is formed outside a largest inner diameter of the nozzle hole (14).
  3. The liquid discharge module (30) according to any one of claims 1 to 2, wherein the nozzle hole (14) has: a first inner wall having: a first inner diameter (R2); and a first length (T2) in the contact-separation direction; and a second inner wall having: a second inner diameter (R1) larger than the first inner diameter (R2); and a second length (T1) longer than the first length (T2) in the contact-separation direction.
  4. The liquid discharge module (30) according to claim 3, wherein the first inner wall extends in a direction parallel to the contact-separation direction, and the second inner wall is inclined toward the first inner wall at a predetermined angle and connected to the first inner wall.
  5. The liquid discharge module (30) according to claim 3 or 4, wherein the first inner wall is closer to the second face than the second inner wall, and the second inner diameter (R1) increases toward the first face.
  6. The liquid discharge module (30) according to claim 3, wherein the first inner wall and the second inner wall extend in a direction parallel to the contact-separation direction.
  7. The liquid discharge module (30) according to claim 3, wherein the second inner wall is closer to the first face than the first inner wall.
  8. The liquid discharge module (30) according to claim 3, wherein the second inner wall is closer to the second face than the first inner wall, and the second inner diameter (R1) decreases toward the first face.
  9. The liquid discharge module (30) according to any one of claims 3 to 8, wherein the nozzle plate (15) includes: a first component (15b, 15i) having the first inner wall; and a second component (15c, 15f, 15h, 15k) joined to the first component (15b, 15i) in the contact-separation direction and having the second inner wall.
  10. The liquid discharge module (30) according to claim 9, wherein the first component (15b, 15i) and the second component (15c, 15f, 15h, 15k) are joined to each other to form a single unit.
  11. The liquid discharge module (30) according to any one of claims 4 to 10, wherein the sealed portion (17b) on the first face is disposed away from the nozzle hole (14) on the second face for a predetermined distance equal to a sum of the first length of the first inner wall and the second length of the second inner wall.
  12. The liquid discharge module (30) according to any one of claims 1 to 11, wherein the housing (11) has: a side wall defining the liquid chamber; and an end face joined to the first face of the nozzle plate around the liquid chamber, the side wall has a projection adjacent to the end face of the housing, and the projection projects toward an interior of the liquid chamber.
  13. A liquid discharge apparatus (800, 830,850, 870) comprising a liquid discharge head (10, 100) including multiple liquid discharge modules (30) including the liquid discharge module (30) according to any one of claims 1 to 12.

Description

BACKGROUND Technical Field Embodiments of the present disclosure relate to a liquid discharge module and a liquid discharge apparatus. Related Art In the related art, a liquid discharge head discharges droplets of liquid (e.g., ink) from a nozzle. The liquid discharge head includes a nozzle opening-closing valve (i.e., a needle valve), a nozzle opening-closing driver (i.e., a piezoelectric element or an actuator), and a nozzle opening-closing controller. The needle valve is provided for the nozzle. The nozzle opening-closing driver moves the needle valve toward and away from the nozzle. The nozzle opening-closing controller controls the nozzle opening-closing driver to open and close the nozzle to discharge the droplets of the liquid from the nozzle. Such a liquid discharge head supplies liquid to be discharged to the nozzle under pressure. In this condition, the liquid discharge head causes the nozzle opening-closing valve to contact or separate from the nozzle. By so doing, the liquid that is supplied under pressure is discharged from the nozzle as liquid droplets only while the nozzle opening-closing valve is separated from the nozzle. The liquid is discharged in accordance with the pressure applied to the liquid and the gap distance between the nozzle and the nozzle opening-closing valve that separates from the nozzle, i.e., the fluid resistance in supply and the duration of opening-closing of the nozzle opening-closing valve. In the liquid discharge head of such a type, the opening-closing valve is pressed against a nozzle plate in which the nozzle is formed to close (seal) the nozzle. As a result, the liquid is prevented from being accidentally discharged. For example, Japanese Unexamined Patent Application Publication No. 2022-064482 discloses a paint jet nozzle including: a base; a nozzle hole through which paint is jetted; a paint chamber for supplying the paint to the nozzle hole; a needle valve in the paint chamber; and a drive mechanism that reciprocates the needle valve relative to the nozzle hole. The needle valve has a leading end that opens and closes the nozzle hole. The leading end of the needle valve is covered with a synthetic resin layer. In such a type of liquid discharge head described above, the pressing force of the opening-closing valve acts on the nozzle plate. In a liquid discharge head without high durability, the nozzle plate may be deformed, causing the deterioration in sealing performance to seal liquid in the chamber. US 2019/336990 A1 discloses applying a coating agent to a component, in particular for applying a paint to a motor vehicle body component, having a nozzle plate, a nozzle in the nozzle plate for dispensing the coating agent, and a valve element movable relative to the nozzle plate for controlling the release of coating agent through the nozzle, the movable valve element closing the nozzle in a closed position, whereas the movable valve element releases the nozzle in an opened position, and having a seal for sealing the nozzle with respect to the movable valve element in the closed position of the valve element. The disclosure provides that the seal is not designed as an elastomer insert on the valve element. US 4 628 330 A discloses an inkjet recording apparatus having a recording head including a nozzle for jetting ink droplets. A valve is disposed between the pressurized supply and the nozzle in order to control the ink flow to the nozzle. WO 2022/259063 A1 discloses a liquid discharge head including a nozzle member having a nozzle, a valve to open and close the nozzle, a driver to drive the valve, diaphragm between the valve and the driver, and a housing. WO 01/42024 discloses a printer having an inkjet head for pressurizing pressurization regions provided in a plurality of pressure chambers to discharge the ink from nozzles in the pressure chambers. A nozzle plate in which the nozzles are perforated is formed by micropress working of metal such as stainless steel. The nozzle plate is to be joined to a stainless steel plate. SUMMARY The present disclosure has an object to provide a liquid discharge head having high durability. The invention is defined by the subject-matter of claim 1. The dependent claims relate to preferred embodiments of the invention. As a result, according to one aspect of the present disclosure, a liquid discharge head having high durability can be provided. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS A more complete appreciation of the disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings, wherein: FIG. 1 is a perspective view of a liquid discharge head according to an embodiment of the present disclosure;FIG. 2 is a cross-sectional view of a head unit of the liquid discharge head of FIG. 1;FIGS. 3A and 3B are cross-sectional views of a liquid discharge module of the liquid discharge head