Solenoid Valve Ink Overflow Prevention in Printers

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Solution Overview

Problem

In printers, when the circulation pump stops due to a power failure, ink can overflow from the recovery tank into the negative pressure tank due to a pressure difference between the supply tank and the recovery tank, leading to ink overflow into the negative pressure applying part.

Innovation Solution

A solenoid valve is provided between the supply tank and the recovery tank to cut off communication when energized, preventing the pressure difference from inhibiting ink flow, and allowing communication when not energized to cancel the pressure difference and prevent ink overflow during a power failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a circulation pump is used to transfer ink from the recovery tank to the supply tank, then ink can be circulated continuously, but ink may overflow into the negative pressure tank when the pump stops due to power failure

Engineering Contradiction:
Improveink circulation efficiencyVSAvoidink overflow prevention
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

A solenoid valve is installed between the supply tank and recovery tank to preemptively control ink flow paths. When power failure is detected, the solenoid valve switches states to open a communication path between tanks, allowing pressure equalization before overflow can occur into the negative pressure tank

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The solenoid valve acts as an intermediary device between the supply tank and recovery tank, controlling the communication state between them. By switching the valve state upon power failure detection, it mediates the pressure difference cancellation and prevents direct overflow into the negative pressure tank

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a solenoid valve is added between the supply tank and recovery tank, then ink overflow can be prevented during power failure, but the device complexity increases

Engineering Contradiction:
Improveink overflow preventionVSAvoidvalve control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The solenoid valve is integrated into the existing control circuitry of the circulation pump system. It utilizes the same power supply monitoring mechanism to detect power failures and automatically switches states without requiring separate control logic or additional sensors, allowing the system to protect itself

Inventive Principle:
Principle #25Self-service

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

This solution effectively suppresses ink overflow into the negative pressure applying parts by quickly canceling the pressure difference between the supply tank and the recovery tank, reducing the risk of ink backflow and simplifying the recovery process during power failures.

Implementation Method 1

a solenoid valve configured to cut off the supply tank and the recovery tank from each other when being energized

Methodology Applied
Scientific EffectSolenoid: Solenoid

Implementation Method 2

a circulation pump that transfers the ink from the recovered tank to the supply tank with supply electric power

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 3

a first negative pressure applying part configured to apply a negative pressure to the inside of the supply tank, a second negative pressure applying part configured to apply a negative pressure to the inside of the recovery tank

Methodology Applied
Scientific EffectNegative pressure: Pressure Gradient

Data Source

PatentEP3628495B1Printing apparatus, printing system, printing method
Publication Date: 2022.05.18 SCREEN HOLDINGS CO LTD
  • EP3628495B1 patent drawingFigure 1
  • EP3628495B1 patent drawingFigure 2
  • EP3628495B1 patent drawingFigure 3

AI summary

A printing apparatus, comprises: a discharge head that discharges ink from a nozzle; a recovery tank that stores ink recovered from the discharge head; a supply tank that stores ink to be supplied to the discharge head; a circulation pump that transfers the ink from the recovery tank to the supply tank with supplied electric power to perform an ink circulation operation of circulating ink in a circulation path that returns to the recovery tank after reaching the discharge head from the recovery tank via the supply tank; a first negative pressure applying part configured to apply a negative pressure to the inside of the supply tank; a second negative pressure applying part configured to apply a negative pressure to the inside of the recovery tank; a first solenoid valve provided between the supply tank and the recovery tank, to cut off the supply tank and the recovery tank from each other when being energized and cause the supply tank and the recovery tank to communicate with each other when not being energized; and a power supply part configured to supply electric power to the circulation pump and the first solenoid valve.