Inkjet Driver Circuit Reducing Power Dissipation via Switch Tuning

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Solution Overview

Problem

High power dissipation in electronic circuits driving multiple inkjet print elements due to the need for individually tunable waveforms for each piezo actuator, which increases with the density of print elements in a printhead.

Innovation Solution

An electronic circuit with a common waveform generator and switch-based tuning mechanism that limits power dissipation by using a fixed voltage source for tuning, allowing switches to operate in saturation or blocking states to minimize energy loss, and compensating for neighboring print elements' actuation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If individual waveform generators are used for each print element to achieve tunable waveforms, then droplet uniformity and print quality are improved, but power dissipation increases significantly with print element density

Engineering Contradiction:
Improvedroplet uniformityVSAvoidpower dissipation
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent merges multiple individual waveform generators into a single common waveform generator that serves all print elements. This common generator produces a base waveform that is then distributed to multiple print elements, eliminating the need for separate generators and thereby reducing power dissipation while maintaining individual tunability through switch-based selection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the waveform generation function into two parts: a common base waveform generated by a shared generator, and individual tuning components achieved through switch-based selection. This segmentation allows the system to maintain individualized waveform control for each print element while using a single power-efficient generator.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If voltage adjustment methods are used to tune waveforms for each print element, then individual waveform optimization is achieved, but power dissipation increases due to continuous voltage variation

Engineering Contradiction:
Improvewaveform tunabilityVSAvoidpower dissipation
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent uses periodic switching action to select from pre-defined waveform segments stored in memory. Instead of continuously adjusting voltage, the system periodically switches between discrete waveform segments that are optimized for different print element characteristics. This periodic switching minimizes power dissipation by avoiding continuous voltage adjustment while maintaining waveform adaptability.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent uses switches that operate in saturation or blocking states, which are energy-efficient switching elements. The switches act as simple on/off components rather than continuous control elements, dissipating minimal energy during operation. This approach replaces expensive and energy-intensive continuous voltage adjustment with simple, energy-efficient switching between pre-optimized waveform segments.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Power

If switches operate in conducting state to deliver required voltage to actuators, then sufficient power delivery is achieved, but dissipation increases in the switching circuits

Engineering Contradiction:
Improvepower deliveryVSAvoidcircuit dissipation
Core Design Contradiction:
PowerVSLoss of energy

Solution Approach 1:

The patent dynamically switches between different operational states of the switching elements (saturation and blocking states) depending on the specific requirements of each print element. This dynamic switching allows the circuit to deliver full power when needed while minimizing dissipation during waveform selection and tuning, optimizing the balance between power delivery and energy efficiency.

Inventive Principle:
Principle #15Dynamics

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

Reduces power dissipation by half compared to traditional voltage adjustment methods, enabling efficient and uniform ink drop properties across the printhead array with reduced energy consumption.

Implementation Method 1

a piezo transducer for converting the electric waveform in a mechanical displacement

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3313665B1Electronic circuit for driving an array of inkjet print elements
Publication Date: 2020.08.19 CANON PRODUCTION PRINTING NETHERLANDS BV
  • EP3313665B1 patent drawingFigure 1~3
  • EP3313665B1 patent drawingFigure 4

AI summary

An electronic circuit for driving an inkjet print element in an array of print elements with an electric waveform is provided. The print element comprises a piezotransducer for converting the electric waveform in a mechanical displacement. The electric waveform is tunable for an individual print element. The circuit comprises a common waveform generator that is connected to the piezo transducer through a first print data dependent switch for providing an electric waveform independent of the print element. The circuit further comprises a waveform tuning part, dependent on the print element and the print data, for controlling a second switch that adds electric energy from a voltage source to the electric waveform. The switches are operable in either a saturation state or a blocking state to limit an amount of dissipation in the switches.