Printhead Drive Voltage Trimming Using Comparator Feedback
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Solution Overview
Problem
Existing printhead circuits for inkjet printers face challenges in accurately controlling drive voltages for actuating elements, often requiring complex timing signals and high-resolution digital circuitry, which increases costs and power dissipation.
Innovation Solution
A printhead circuit with a trim generating circuit that uses feedback to adjust drive voltages, eliminating the need for precise timing references and reducing circuit complexity, incorporating a comparator and digital-to-analog converter for accurate voltage trimming, and a switch control circuit for efficient voltage adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex timing signals and high-resolution digital circuitry are used for voltage control, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex digital timing circuits and high-resolution digital-to-analog converters with an analog comparator-based feedback system. The comparator continuously compares the actual drive voltage with a reference voltage and generates trim signals to correct deviations, eliminating the need for precise digital timing references and complex digital circuitry while maintaining high voltage control accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where the actual drive voltage is monitored and compared with a reference voltage. The comparator uses this feedback to generate trim signals that adjust the drive voltage to the desired level. This closed-loop feedback system achieves high precision voltage control without requiring complex forward-path digital circuitry or timing signals.
2Manufacturing precision
If complex digital circuitry is used for voltage trimming, then manufacturing precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent substitutes complex digital trimming circuits with a simpler analog comparator-based system. The comparator naturally provides high-precision voltage comparison and trim signal generation using basic analog components, which are easier to manufacture and integrate than high-resolution digital circuitry, thereby improving both manufacturing precision and ease of manufacture.
3Measurement precision
If high-resolution digital circuitry is used for timing references, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The patent replaces energy-intensive high-resolution digital timing circuits and digital-to-analog converters with a low-power analog comparator system. The comparator continuously monitors voltage levels and generates trim signals with minimal power consumption, eliminating the need for high-resolution digital timing references while maintaining measurement precision.
Solution Approach 2:
The analog comparator system is inherently self-regulating, continuously comparing voltages and generating corrective trim signals without requiring external timing references or complex control logic. This self-service mechanism achieves high precision voltage control with minimal power consumption by using only the essential feedback comparison function.
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 allows for more accurate and cost-effective voltage trimming, reducing power dissipation and circuit complexity, while maintaining high accuracy, especially in cold switch arrangements.
Implementation Method 1
the trim generating circuit having a comparator coupled to receive and compare feedback indicative of a present level of a drive voltage, with a configurable reference voltage value
Implementation Method 2
the comparator comprising an analog comparator circuit arranged to receive the feedback as an analog signal and having a digital to analog converter for converting the reference voltage value into an analog signal
Data Source
AI summary
A printhead circuit or driving at least two actuating elements has a trim generating circuit for generating a trim signal using a comparator coupled to receive and compare feedback indicative of a present level of a drive voltage, with a configurable reference voltage value. The trim being based on a drive voltage feedback can give a more direct indication of actuating element output than given by timing references. Hence the trim can be more accurate, can be simpler, without accurate digital timing references, and thus costs can be reduced. It can be combined with a cold switch arrangement.