Print Head Control Circuit Signal Path Separation

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Solution Overview

Problem

In liquid discharge apparatuses like ink jet printers, discharge abnormalities due to signal interference in the print head's self-diagnosis function can lead to decreased ink discharge accuracy and image quality, as multiple high-voltage signals are propagated through a single cable, causing interference and disrupting normal operation.

Innovation Solution

The implementation of a driving signal selection circuit and temperature abnormality detection circuit within the print head, which utilize separate signal pathways and amplification to reduce signal interference, allowing for accurate diagnosis and operation of the print head.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple high-voltage driving signals and self-diagnosis signals are propagated through a single cable, then the print head can receive both driving signals for operation and signals for self-diagnosis, but signal interference occurs between the driving signals and self-diagnosis signals, causing the self-diagnosis function to fail

Engineering Contradiction:
Improvesignal transmission capabilityVSAvoidself-diagnosis function reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent segments the signal transmission by providing separate cable connections: one cable for transmitting high-voltage driving signals and another cable for transmitting self-diagnosis signals. This physical separation eliminates signal interference between the two signal types, allowing the self-diagnosis function to operate reliably while maintaining full driving capability.

Inventive Principle:
Principle #1Segmentation

2Reliability

If separate cables are used for driving signals and self-diagnosis signals, then signal interference is eliminated and self-diagnosis function operates normally, but the device complexity and connection requirements increase

Engineering Contradiction:
Improveself-diagnosis function reliabilityVSAvoidcable and connector configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements multi-functionality by enabling the print head to operate normally with standard single-cable connections while adding optional separate cable connections for enhanced self-diagnosis capability. The system can function with either configuration, making the solution adaptable to different application requirements without mandating increased complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enhances the print head's self-diagnosis capability, reducing signal interference and maintaining discharge accuracy, thereby improving the quality of images formed on the recording medium.

Implementation Method 1

A liquid discharge apparatus such as an ink jet printer forms characters or an image on a recording medium in a manner that the liquid discharge apparatus drives a piezoelectric element provided in a print head by a driving signal and thus discharges a liquid such as an ink with which a cavity is filled, from a nozzle.

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3686013B1Print head control circuit
Publication Date: 2022.11.02 SEIKO EPSON CORP
  • EP3686013B1 patent drawingFigure 1
  • EP3686013B1 patent drawingFigure 2
  • EP3686013B1 patent drawingFigure 3~4

AI summary

A print head control circuit controls an operation of a print head including a diagnosis circuit that diagnoses whether or not normal discharge of a liquid is possible. The print head control circuit includes a first cable including a first diagnosis signal propagation wiring for propagating a first diagnosis signal, a second diagnosis signal propagation wiring for propagating a second diagnosis signal, a third diagnosis signal propagation wiring for propagating a third diagnosis signal, a fourth diagnosis signal propagation wiring for propagating a fourth diagnosis signal, and a first driving signal propagation wiring for propagating a driving signal. A shortest distance between the first driving signal propagation wiring and the diagnosis circuit is longer than a shortest distance between the first diagnosis signal propagation wiring and the diagnosis circuit, longer than a shortest distance between the second diagnosis signal propagation wiring and the diagnosis circuit, longer than a shortest distance between the third diagnosis signal propagation wiring and the diagnosis circuit, and longer than a shortest distance between the fourth diagnosis signal propagation wiring and the diagnosis circuit.