Ink Circulation Heater Control to Prevent No-Flow Overheating

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Solution Overview

Problem

Liquid circulation devices face overheating issues when ink is not circulating, leading to potential thermal fuse activation or heater damage, and alterations in ink characteristics due to abrupt temperature rises.

Innovation Solution

A liquid circulation device with a heater and temperature sensors, controlled by a processor that monitors temperature changes and turns off the heater when a predetermined stop condition is met to prevent overheating, ensuring the ink temperature remains within a suitable range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If heating control is performed when ink is not circulating, then the ink temperature can be maintained within the suitable temperature range, but the heater temperature may rise abruptly causing overheating and potential damage

Engineering Contradiction:
Improveink temperatureVSAvoidheater reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The system uses temperature sensors to continuously monitor both the ink temperature and heater temperature, feeding this information back to the control unit. The control unit adjusts the heater operation based on this feedback, comparing sensor readings against reference values and controlling the heater accordingly to prevent overheating while maintaining ink temperature within the suitable range.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The heating control system dynamically adjusts its operation based on real-time temperature conditions. When ink is not circulating, the system detects the stationary state and modifies heater control parameters to prevent abrupt temperature rises. The control unit continuously adapts heater power output based on the relationship between ink temperature and heater temperature, transitioning from standard heating control to protective control modes.

Inventive Principle:
Principle #15Dynamics

2Temperature

If heating control is performed when ink is not circulating, then the ink temperature can be maintained, but the ink characteristics near the heater may be altered due to abrupt temperature rise

Engineering Contradiction:
Improveink temperatureVSAvoidink characteristics
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The control unit receives continuous feedback from temperature sensors monitoring both ink temperature and heater temperature. By comparing these readings against reference values, the system detects when ink is stationary and adjusts heating parameters accordingly, preventing abrupt temperature rises that would alter ink characteristics while still maintaining overall ink temperature within the suitable range.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary detection of ink circulation status using temperature sensors before initiating or continuing heating control. When stationary ink is detected, the control unit preemptively adjusts heater operation to prevent temperature spikes, ensuring ink characteristics remain stable before problematic temperature changes can occur.

Inventive Principle:
Principle #10Preliminary action

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

Prevents overheating, avoids thermal fuse activation, and maintains ink quality by controlling the heater based on real-time temperature measurements, even when ink is not circulating.

Implementation Method 1

a heater configured to heat the liquid circulating in the pipeline

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a first temperature sensor configured to measure a temperature of the heater

Methodology Applied
Scientific EffectThermal radiation detection: Thermal Radiation

Implementation Method 3

a second temperature sensor configured to measure a temperature of the liquid circulating in the pipeline

Methodology Applied
Scientific EffectThermal radiation detection: Thermal Radiation

Implementation Method 4

a controller configured to control the heater based on the temperature of the liquid measured by the second temperature sensor

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4008557B1Liquid circulation device and liquid discharge apparatus
Publication Date: 2025.01.01 RISO TECH CORP
  • EP4008557B1 patent drawingFigure 1
  • EP4008557B1 patent drawingFigure 2
  • EP4008557B1 patent drawingFigure 3

AI summary

A liquid circulation device (30) includes a liquid chamber that stores a liquid that is to be supplied to a liquid discharge head. A pipeline through which the liquid can be circulated between the liquid chamber and the liquid discharge head is provided. A heater (51) heats the liquid circulating in the pipeline. A first temperature sensor (52) measures the temperature of the heater, and a second temperature sensor (53) measures the temperature of the liquid in the pipeline. A controller controls the heating of the heater based on the liquid temperature measured by the second temperature sensor. The controller also monitors a change in the measured temperature of the heater over time and turns off the heating of the heater when the monitored change satisfies a predetermined stop condition.