Print Head Control Circuit Signal Segmentation

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Solution Overview

Problem

Existing liquid discharge apparatuses, such as ink jet printers, face issues with discharge abnormality due to waveform distortion in signals used for self-diagnosis, leading to decreased ink discharge accuracy and image quality.

Innovation Solution

A print head control circuit that includes a driving signal selection circuit and a temperature abnormality detection circuit, which selects and generates driving signals based on print data signals, clock signals, and latch signals to reduce waveform distortion and ensure normal discharge operations, while also detecting temperature abnormalities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a self-diagnosis function is implemented in the print head, then the ability to detect discharge abnormalities is improved, but waveform distortion in the signal may occur leading to decreased discharge accuracy

Engineering Contradiction:
Improveself-diagnosis functionVSAvoiddischarge accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent divides the signal transmission path into separate channels: one for the self-diagnosis signal and another for the driving signal to the piezoelectric element. This segmentation prevents waveform distortion in the self-diagnosis signal from affecting the discharge accuracy of the driving signal, allowing both functions to operate independently without interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a signal separation mechanism that acts as an intermediary between the self-diagnosis function and the driving function. By routing the self-diagnosis signal through a dedicated path with separate wiring, the system prevents the diagnostic signal from distorting the driving signal waveform, thus maintaining discharge accuracy while enabling reliable self-diagnosis.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the waveform of the self-diagnosis signal is distorted, then the self-diagnosis function cannot be normally performed, but the cause of distortion is not identified

Engineering Contradiction:
Improveself-diagnosis functionVSAvoidwaveform distortion detection
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent implements a feedback mechanism where the print head control circuit monitors the self-diagnosis signal waveform and compares it against expected characteristics. When distortion is detected in the self-diagnosis signal, the system identifies the specific abnormality and provides feedback to the control circuit, enabling automatic detection and reporting of the distortion cause without requiring complex manual measurement.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If separate wiring is used for the self-diagnosis signal, then waveform distortion is reduced, but the device complexity increases

Engineering Contradiction:
Improvesignal waveform qualityVSAvoidwiring structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent merges the signal separation function into the existing print head control circuit architecture rather than adding completely independent wiring systems. The control circuit integrates the self-diagnosis signal routing and driving signal routing through a unified circuit design, allowing separate signal paths to be achieved while minimizing overall device complexity and sharing common control resources.

Inventive Principle:
Principle #5Merging (Combining)

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 solution effectively reduces the likelihood of waveform distortion, thereby improving ink discharge accuracy and ensuring the normal operation of the self-diagnosis function in the print head, enhancing the overall quality of images formed on the recording medium.

Implementation Method 1

drives a piezoelectric element provided in a print head by a driving signal and thus discharges a liquid such as an ink

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3693171B1Print head control circuit
Publication Date: 2022.11.02 SEIKO EPSON CORP
  • EP3693171B1 patent drawingFigure 1
  • EP3693171B1 patent drawingFigure 2
  • EP3693171B1 patent drawingFigure 3~4

AI summary

A print head control circuit includes 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, a fifth diagnosis signal propagation wiring for propagating a fifth diagnosis signal indicating a diagnosis result, a first voltage signal propagation wiring for propagating a first voltage signal supplied to a driving signal selection circuit, and a second voltage signal propagation wiring for propagating a second voltage signal. The fifth diagnosis signal propagation wiring and the second voltage signal propagation wiring are electrically coupled to each other via a fifth terminal and a seventh terminal, and the first diagnosis signal propagation wiring and the second diagnosis signal propagation wiring are located to be aligned. The first diagnosis signal propagation wiring and the second voltage signal propagation wiring are located to be adjacent to each other in a direction in which the first diagnosis signal propagation wiring and the second diagnosis signal propagation wiring are aligned.