Piezoelectric Print Head Clock Distribution for Heat Management

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Solution Overview

Problem

High-density piezoelectric ink jet printers face challenges with heat generation due to increased electric current, leading to temperature rises that can alter ink properties and reduce print quality, especially when using heat-sensitive inks with solvents having boiling points between 70°C and 100°C.

Innovation Solution

The implementation of a clock distribution circuit that distributes clock signals in a staggered manner to selectively stop heat-generating discharge section groups, reducing overall heat generation and maintaining ink quality by refilling the print head with cooler ink during non-discharge states, and incorporating a micro vibration waveform to manage temperature without discharging ink.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the number of nozzles is increased to achieve high-density printing, then the nozzle density is improved, but the heat generation increases due to increased electric current

Engineering Contradiction:
Improvenozzle densityVSAvoidheat generation
Core Design Contradiction:
Manufacturing precisionVSTemperature

Solution Approach 1:

The discharge sections are divided into multiple groups, and the clock signals are distributed to different groups in a staggered manner. This segmentation allows heat-generating sections to be separated by non-heat-generating sections, reducing overall heat accumulation while maintaining high nozzle density.

Inventive Principle:
Principle #1Segmentation

2Temperature

If the transfer operation is stopped in certain discharge section groups, then the heat generation is reduced, but the printing productivity decreases

Engineering Contradiction:
Improveheat generationVSAvoidprinting speed
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The clock signals are distributed periodically to different discharge section groups in a staggered fashion. While some groups are active and generating heat, other groups are inactive and cooling down. This periodic alternation maintains continuous printing capability while allowing heat dissipation cycles.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically alternates the active state between different discharge section groups. By making the heat generation dynamic and distributed across time and space, the system maintains high productivity while preventing excessive heat accumulation in any single group.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the temperature of the ink increases, then the ink can be discharged, but the physical properties of the ink change which degrades print quality

Engineering Contradiction:
Improveink dischargeVSAvoidink physical properties
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent converts the harmful effect of heat generation into a beneficial cooling effect by using the inactive discharge section groups as heat sinks. The non-operating groups absorb heat from the operating groups, preventing excessive temperature rise that would degrade ink properties, while still allowing continuous ink discharge from active groups.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 configuration effectively suppresses heat generation in the piezoelectric print head, stabilizes ink properties, and maintains high-quality printing by reducing temperature-related viscosity increases and ink quality degradation.

Implementation Method 1

piezoelectric ink jet printers that use piezoelectric elements. These piezoelectric elements are provided to correspond to a plurality of discharge sections

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the heat-generating discharge section groups are separated by the non-heat-generating discharge section group. Accordingly, the heat dispersibility can be increased

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP3505349B1Piezoelectric print head and piezoelectric ink jet printer
Publication Date: 2020.10.14 SEIKO EPSON CORP
  • EP3505349B1 patent drawingFigure 1
  • EP3505349B1 patent drawingFigure 2
  • EP3505349B1 patent drawingFigure 3

AI summary

A piezoelectric print head includes a first discharge section, a second discharge section, a third discharge section, a first switch corresponding to the first discharge section, a second switch corresponding to the second discharge section, and a third switch corresponding to the third discharge section. The second discharge section is located between the first discharge section and the third discharge section, the first switch and the third switch are switched in accordance with a print signal in synchronization with a first clock, the second switch is switched in accordance with a print signal in synchronization with a second clock, in a first period, the print signal synchronized with the second clock is transferred and the print signal synchronized with the first clock is not transferred, and in a second period, the print signal synchronized with the second clock is not transferred and the print signal synchronized with the first clock is transferred.