Reference Voltage Adjustment for Piezoelectric Inkjet Drivers

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Solution Overview

Problem

Existing liquid discharging apparatuses, such as ink jet printers, face challenges in reducing circuit scale and trimming time due to the need for precise adjustment of reference voltages for piezoelectric elements, with existing methods not considering the characteristics of these elements, leading to increased circuit complexity and adjustment time.

Innovation Solution

A liquid discharging apparatus with a reference voltage generation system that adjusts the first reference voltage to a lower resolution than the second reference voltage, considering the displacement characteristics of the piezoelectric elements, to ensure necessary trimming accuracy while reducing circuit area and adjustment time, and includes a modulation portion, gate driver, and low pass filter to generate and control the driving signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the reference voltage is adjusted with high precision for all voltage ranges, then the trimming accuracy is improved, but the circuit scale and adjustment time increase

Engineering Contradiction:

Improve trimming accuracyVSAvoid adjustment time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies different adjustment resolutions to different voltage ranges: high adjustment resolution for the second reference voltage (affecting minimum driving signal voltage where piezoelectric sensitivity is high) and low adjustment resolution for the first reference voltage (affecting maximum driving signal voltage where piezoelectric sensitivity is low). This local differentiation optimizes trimming accuracy where needed while reducing circuit scale and adjustment time overall.

Inventive Principle:

Principle #3Local quality

2Measurement precision

If the reference voltage is adjusted with high precision for all voltage ranges, then the trimming accuracy is improved, but the circuit scale increases

Engineering Contradiction:

Improve trimming accuracyVSAvoid circuit scale

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements local quality by assigning different adjustment resolutions to different reference voltages based on the piezoelectric element's sensitivity characteristics. The first reference voltage uses low adjustment resolution while the second reference voltage uses high adjustment resolution, thereby reducing the overall circuit scale while maintaining necessary trimming accuracy in critical regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the adjustment resolution parameter differently for first and second reference voltages. By setting the adjustment resolution of the first reference voltage to be lower than that of the second reference voltage, the circuit scale is reduced while the essential trimming accuracy is preserved in the voltage range where the piezoelectric element is most sensitive.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If uniform high adjustment resolution is applied to both reference voltages, then the trimming accuracy is ensured, but the circuit scale and adjustment time increase unnecessarily

Engineering Contradiction:

Improve trimming accuracyVSAvoid trimming efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by differentiating the adjustment resolution for first and second reference voltages according to the piezoelectric element's sensitivity characteristics. This ensures reliable trimming accuracy in the critical low-voltage range while improving overall trimming efficiency by reducing the adjustment resolution requirement in the less critical high-voltage range.

Inventive Principle:

Principle #3Local quality

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 approach allows for a reduced circuit scale and shorter trimming time while maintaining necessary accuracy, improving the efficiency and effectiveness of the liquid discharging process by optimizing the adjustment of driving signals for piezoelectric elements.

Implementation Method 1

a piezoelectric element which is displaced as the driving signal is applied

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS9573366B2Liquid discharging apparatus, head unit, integrated circuit device for capacitive load driving, capacitive load driving circuit, and manufacturing method of liquid discharging apparatus

Publication Date: 2017.02.21 SEIKO EPSON CORP

AI summary

There is provided a liquid discharging apparatus including: an original driving signal generation portion which generates an original driving signal based on a source signal; a driving signal generation portion which generates a driving signal based on the original driving signal; a reference voltage generation portion which generates a first reference voltage and a second reference voltage adjusted based on an adjustment signal, and supplies the voltage to the original driving signal generation portion; a piezoelectric element which is displaced as the driving signal is applied; a cavity; and a nozzle, and discharges the liquid inside the cavity as liquid droplets in accordance with the change in the internal volume of the cavity, in which adjustment resolution of the first reference voltage is lower than adjustment resolution of the second reference voltage.