Print Head Control Circuit Ink Mist Protection

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Solution Overview

Problem

Existing liquid discharge apparatuses, such as inkjet printers, face challenges in self-diagnosing discharge accuracy issues due to ink mist adhering to conductive parts, leading to short-circuits and waveform distortions, which are not effectively addressed by current technologies.

Innovation Solution

A print head control circuit with a specific configuration of coupling points and signal propagation wiring that includes diagnosis signal propagation wiring and driving signal propagation wiring, allowing for self-diagnosis functions based on input signals from multiple coupling points, and a cable configuration that separates high and low voltage signals to prevent interference and adherence of ink mist.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If diagnosis signal propagation wiring is placed close to the nozzle plate for compact design, then device complexity is reduced, but ink mist adherence to conductive parts causes short-circuits and waveform distortions

Engineering Contradiction:
Improvecable configuration complexityVSAvoidsignal propagation reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the signal propagation wiring into multiple separate cables rather than using a single integrated cable. Specifically, it separates the first diagnosis signal propagation wiring from the second diagnosis signal propagation wiring, and positions them in different spatial locations relative to the nozzle plate. This segmentation reduces the risk that ink mist will cause short-circuits between multiple wires in the same cable, thereby improving signal propagation reliability while maintaining manageable device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary spatial arrangement between the nozzle plate and the diagnosis signal propagation wirings. By positioning the first cable at a first distance and the second cable at a second distance from the nozzle plate, it creates a controlled spatial relationship that reduces direct exposure to ink mist while ensuring adequate signal transmission. This intermediary positioning acts as a protective measure against ink mist adherence.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple cables with separate wirings are used for self-diagnosis, then signal propagation reliability is improved, but device complexity increases

Engineering Contradiction:
Improveself-diagnosis reliabilityVSAvoidcable and wiring configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent designs the multiple cables and wirings to serve universal functions within the self-diagnosis system. The first diagnosis signal propagation wiring and second diagnosis signal propagation wiring both transmit diagnostic signals but from different coupling points. This multi-functionality allows the system to perform comprehensive self-diagnosis of different components (nozzle plate, print head, cable connections) using a standardized cable architecture, thereby improving self-diagnosis reliability without proportionally increasing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies local quality by assigning specific functions to specific cables based on their spatial relationships. The first cable, positioned at a specific distance from the nozzle plate, is optimized for receiving signals from certain coupling points, while the second cable at a different distance handles signals from other coupling points. This localized optimization ensures that each cable is suited to its specific diagnostic task, improving overall self-diagnosis reliability while keeping individual cable designs relatively simple.

Inventive Principle:
Principle #3Local quality

3Use of energy by moving object

If power voltage signal propagation wiring is positioned close to the nozzle plate, then energy efficiency is improved, but ink mist adherence causes electrical malfunctions

Engineering Contradiction:
Improvepower voltage signal efficiencyVSAvoidink mist adherence to conductive parts
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the power voltage signal propagation wiring from the immediate vicinity of the nozzle plate by positioning it at a controlled distance. This extraction removes the wiring from the high-risk zone where ink mist concentration is highest, thereby preventing ink mist adherence and electrical malfunctions. The wiring is repositioned to a location where it can still receive power voltage signals efficiently but is less exposed to the harmful ink mist environment.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the potential harm of ink mist exposure into a benefit by using the spatial separation as a protective feature. The distance positioning of the power voltage signal propagation wiring from the nozzle plate, while potentially reducing direct energy coupling, actually protects the wiring from ink mist adherence. This spatial arrangement transforms the distance into a protective barrier, converting what could be a disadvantage (distance) into an advantage (protection from harmful factors).

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

The solution enables stable self-diagnosis and power supply to the print head, reducing the occurrence of short-circuits and ensuring accurate ink discharge by effectively managing ink mist adherence and signal propagation.

Implementation Method 1

driving a piezoelectric element provided in a print head using a driving signal, and forms a letter or an image on a medium

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The ink, which floats on the inside of the liquid discharge apparatus, is extremely small, and, therefore, is charged due to Lenard effect

Methodology Applied
Scientific EffectLenard effect: Lenard Effect

Data Source

PatentEP3626459B1Print head control circuit and liquid discharge apparatus
Publication Date: 2023.05.03 SEIKO EPSON CORP
  • EP3626459B1 patent drawingFigure 1
  • EP3626459B1 patent drawingFigure 2
  • EP3626459B1 patent drawingFigure 3~4

AI summary

A print head control circuit controls an operation of a print head that includes a nozzle plate and has a self-diagnosis function performed based on signals input from a first coupling point, a second coupling point, a third coupling point, and a fourth coupling point. The print head control circuit includes a first cable that includes a first power voltage signal propagation wiring for propagating a first power voltage signal, and a second cable that includes a first diagnosis signal propagation wiring for propagating a first diagnosis signal input to the first coupling point, a second diagnosis signal propagation wiring for propagating a second diagnosis signal input to the second coupling point, a third diagnosis signal propagation wiring for propagating a third diagnosis signal input to the third coupling point, and a fourth diagnosis signal propagation wiring for propagating a fourth diagnosis signal input to the fourth coupling point. A shortest distance between the nozzle plate and the first cable is longer than a shortest distance between the nozzle plate and the second cable.