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JP-7855948-B2 - Liquid dispensing head, liquid dispensing unit, and device for dispensing liquid

JP7855948B2JP 7855948 B2JP7855948 B2JP 7855948B2JP-7855948-B2

Inventors

  • 坂東 佳憲

Assignees

  • 株式会社リコー

Dates

Publication Date
20260511
Application Date
20220704

Claims (9)

  1. A flow path through which liquid flows from the liquid inlet towards the nozzle, A heating member that heats the liquid at a predetermined heating point in the flow path, A pressure measuring member for measuring the pressure difference between two points in the aforementioned flow path, It includes a temperature measuring member provided downstream of the heating member in the flow path for measuring the temperature of the liquid in the flow path, The pressure difference between the two points measured by the pressure measuring member is used to calculate the flow rate. The heating element is controlled so that the temperature measured by the temperature measuring element reaches a predetermined value. A liquid dispensing head characterized in that the predetermined value is changed based on the calculated flow rate.
  2. The liquid discharge head according to claim 1, characterized in that two points for measuring the pressure difference are provided on the side surface of the straight portion of the flow path.
  3. The liquid discharge head according to claim 1, characterized in that the pressure measuring member is a differential pressure gauge.
  4. The liquid discharge head according to claim 1, characterized in that the pressure measuring member is provided upstream of the heating member in the flow path.
  5. The heating element is If a change occurs that increases the calculated flow rate, the temperature measured by the temperature measuring member is controlled to increase. The liquid discharge head according to claim 1, characterized in that if a change occurs that causes the calculated flow rate to decrease, the temperature measured by the temperature measuring means is controlled to decrease.
  6. The liquid discharge head according to claim 1, characterized in that the flow path has a liquid resistance section between the two points.
  7. The liquid discharge head according to claim 6, characterized in that the liquid resistance section consists of a plurality of holes, and the size of the holes is smaller than the diameter of the nozzle.
  8. A liquid dispensing unit characterized by comprising a liquid dispensing head as described in any one of claims 1 to 7.
  9. A liquid dispensing device characterized by comprising a liquid dispensing head according to any one of claims 1 to 7.

Description

This invention relates to a liquid dispensing head, a liquid dispensing unit, and a device for dispensing liquid. In image forming apparatuses using inkjet technology, it is known that the liquid (e.g., ink) ejected from the nozzle is heated using a heat source such as a heater to reach a desired state. In such apparatuses, techniques have been proposed to control the amount of heating by determining the ink flow rate in order to heat the ink to the desired temperature. Patent Document 1 discloses a liquid viscosity control device that controls the viscosity of a liquid discharged from a nozzle. Patent Document 1 discloses a liquid viscosity control device that controls the viscosity of a liquid by controlling the output of a heater so that the measured flow rate measured by a flow rate measuring device approaches the ideal flow rate. According to Patent Document 1, viscosity control to obtain the ideal flow rate can be performed directly based on the actual flow rate, and the responsiveness of viscosity control can be improved. Furthermore, Patent Document 1 discloses that a temperature sensor is provided downstream of the heating point where the heater heats the liquid in the flow path, and the flow rate of the liquid flowing through the flow path is measured using the output of the temperature sensor, and the output of the heater is controlled so that the measured flow rate approaches the ideal flow rate for discharging the liquid from the nozzle. This is a schematic perspective view showing an example of a liquid dispensing head according to the present invention.This is an exploded perspective schematic diagram showing an example of a liquid dispensing head according to the present invention.This is a schematic front view showing an example of a liquid dispensing head according to the present invention.This is a schematic diagram illustrating an example of a flow path.This is another schematic diagram illustrating an example of a flow path.Figure 5 is a schematic cross-sectional view of AA'.This is a schematic diagram illustrating an example of a heated area.This is a schematic diagram illustrating an example of ink temperature distribution.This is a schematic diagram (A) illustrating an example of a method for measuring a pressure difference (Example 1), and a diagram (B) illustrating an example of a pressure measurement area.This diagram illustrates an example of measuring P1 and P2 when Q = 0.This diagram illustrates an example of measuring P1 and P2 when Q = Q1.This diagram illustrates an example of measuring P1 and P2 when Q = Q2.This figure shows the discharge droplet temperature in Comparative Example 1.This figure shows the discharge droplet temperature in Example 1.This is a schematic diagram illustrating another example (Example 2) of a method for measuring pressure difference.This is a schematic diagram (A) illustrating another example of a method for measuring a pressure difference (Example 3), and a diagram (B) illustrating another example of a pressure measurement area.This is a schematic diagram (A) illustrating another example of a method for measuring a pressure difference (Example 4), and a diagram (B) illustrating another example of a pressure measurement area.This is a schematic diagram illustrating another example (Example 5) of a method for measuring pressure difference.This is a schematic diagram illustrating another example (Example 6) of a method for measuring pressure difference.This is a schematic diagram illustrating another example (Example 7) of a method for measuring pressure difference.This is a schematic diagram illustrating another example (Example 8) of a method for measuring pressure difference.This is a schematic diagram of an example of a device that dispenses liquid.This is a schematic diagram of another example of a device for dispensing liquid.This is a schematic diagram of an example of a liquid dispensing unit. The liquid dispensing head, liquid dispensing unit, and liquid dispensing device according to the present invention will be described below with reference to the drawings. It should be noted that the present invention is not limited to the embodiments shown below, and other embodiments, additions, modifications, and deletions may be made within the scope of what a person skilled in the art can conceive. Any embodiment that achieves the function and effects of the present invention is included within the scope of the present invention. The liquid discharge head of the present invention comprises a flow path through which liquid flows from a liquid inlet toward a nozzle, a heating element that heats the liquid at a predetermined heating point in the flow path, a pressure measuring element that measures the pressure difference between two points in the flow path, and a temperature measuring element provided downstream of the heating element in the flow path that measures the temperature of the liquid in the flow path. The pressure difference between the tw