Discharge Head Bypass Channel Flow Control

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Solution Overview

Problem

Existing liquid discharge heads face challenges in adequately discharging bubbles during initial filling and maintenance, leading to unstable liquid discharge during printing operations due to inadequate bubble removal and flow rate control in the bypass channel system.

Innovation Solution

A discharge head design featuring multiple nozzles, pressure chambers, supply and collection branch channels, and a first bypass channel with a first open-close unit that adjusts flow rate in response to pressure differences between the upstream and downstream sides, enhancing bubble dischargeability and discharge stability by controlling the flow rate through the bypass channel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If a bypass channel is provided to enhance bubble dischargeability, then bubble dischargeability is improved, but flow rate control stability deteriorates

Engineering Contradiction:
Improvebubble dischargeabilityVSAvoidflow rate control stability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The bypass channel includes a flow rate controller that dynamically adjusts the flow rate based on operational conditions. The controller can change the degree of opening of the bypass channel to balance between bubble discharge during maintenance and stable flow control during printing operations, resolving the contradiction between these two requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The flow rate controller changes the flow rate parameter of the bypass channel according to different operational states. By adjusting parameters such as the opening degree or cross-sectional area of the bypass channel, the system can optimize performance for either bubble discharge or stable flow control as needed.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If the bypass channel flow rate is increased to discharge bubbles, then bubble dischargeability is improved, but liquid discharge stability deteriorates

Engineering Contradiction:
Improvebubble dischargeabilityVSAvoidliquid discharge stability
Core Design Contradiction:
Object-generated harmful factorsVSStability of the object's composition

Solution Approach 1:

The system employs periodic switching between different operational modes: during maintenance periods, the bypass channel flow rate is increased to discharge bubbles; during printing periods, the flow rate is reduced to ensure stable liquid discharge. This periodic action allows the system to achieve both bubble dischargeability and liquid discharge stability at different times.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The flow rate controller dynamically adjusts the bypass channel flow rate based on real-time operational requirements. When bubble discharge is needed, the controller increases the flow rate; when stable printing is required, it reduces the flow rate, thus resolving the contradiction between these opposing requirements.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If a flow rate controller is added to the bypass channel, then flow rate adjustability is improved, but device complexity increases

Engineering Contradiction:
Improveflow rate adjustabilityVSAvoidbypass channel structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The flow rate controller is designed to automatically adjust the bypass channel flow rate based on pre-set conditions or feedback signals, reducing the need for manual intervention. This self-service capability provides flow rate adaptability while minimizing the complexity of control mechanisms required.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The flow rate controller acts as an intermediary component between the bypass channel and the control system. By introducing this intermediate element, the system achieves flow rate adjustability while keeping the overall structural complexity manageable through modular design.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design effectively enhances bubble dischargeability during initial filling and maintenance, and ensures stable liquid discharge during printing operations by adjusting the flow rate through the bypass channel in response to pressure differences, preventing bubbles from entering the pressure chamber and maintaining consistent liquid flow.

Implementation Method 1

decrease a flow rate of the liquid flowing through the first bypass channel with an increase in a first pressure difference between an upstream side and a downstream side of the first open-close unit

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Data Source

PatentEP4303017B1Discharge head and discharge apparatus
Publication Date: 2025.01.15 RICOH CO LTD
  • EP4303017B1 patent drawingFigure 1A~2
  • EP4303017B1 patent drawingFigure 3~4
  • EP4303017B1 patent drawingFigure 5A~5B

AI summary

A discharge head (100) includes: multiple nozzles (111) from each of which a liquid is discharged; multiple pressure chambers (121) respectively communicating with the multiple nozzles (111); multiple supply branch channels (152) each communicating with two or more of the multiple pressure chambers (121) to supply the liquid to the two or more of the pressure chambers (121); multiple collection branch channels (153) each communicating with two or more of the multiple pressure chambers (121) to collect the liquid from the two or more of the pressure chambers (121); a supply main channel (156) communicating with each of the multiple supply branch channels (152) to supply the liquid to the multiple supply branch channels (152); and a collection main channel (157) communicating with each of the multiple collection branch channels (153) to collect the liquid from the multiple collection branch channels (153).