Recording Device Working Gap Determination via Test Pattern Imaging

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Solution Overview

Problem

Existing recording devices cannot accurately determine the working gap between the recording head and the recording medium when the medium's thickness is unknown, as they rely on known medium thickness for calculations.

Innovation Solution

A method and device that use a test pattern recorded on a known thickness medium to calculate a function correlating pixel number with working gap, allowing determination of the working gap on mediums of unknown thickness by capturing and analyzing the test pattern at different distances using an imaging unit with a zoom lens.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the working gap is calculated based on known medium thickness, then the calculation is simple and direct, but the method cannot be applied to recording mediums with unknown thickness

Engineering Contradiction:
Improveapplicability to unknown thickness mediumsVSAvoidmeasurement system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces a test pattern as an intermediary element that can be captured by an imaging unit. By recording a known test pattern on the recording medium and analyzing its captured image, the system indirectly determines the working gap without requiring direct physical measurement or knowing the medium thickness in advance. The test pattern serves as a mediator between the recording head and the imaging unit, enabling gap determination through image analysis rather than direct measurement.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical thickness measurement methods with an optical imaging and analysis system. Instead of using physical probes or mechanical gauges to measure medium thickness and calculate working gap, the system uses an imaging unit to capture the test pattern and employs image processing algorithms to determine the working gap based on the captured pixel dimensions and known test pattern specifications.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If the working gap is determined without using a test pattern, then the process is faster, but the accuracy cannot be ensured for unknown thickness mediums

Engineering Contradiction:
Improveworking gap determination accuracyVSAvoiddetermination process time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent employs preliminary action by pre-defining test patterns with known dimensions and characteristics before the actual recording process. These test patterns are recorded on the recording medium in advance, and their captured images are analyzed to establish the relationship between pixel dimensions and actual physical dimensions. This preliminary setup enables accurate working gap determination without requiring complex real-time measurements during the main recording operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by capturing the test pattern image, analyzing its pixel dimensions, and using this information to calculate and adjust the working gap. The captured test pattern serves as feedback that provides actual measurement data about the relationship between the imaging unit and the recording medium, allowing the system to determine and optimize the working gap based on real captured data rather than theoretical calculations.

Inventive Principle:
Principle #23Feedback

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

Enables accurate determination of the working gap for recording mediums of unknown thickness by establishing a correlation between pixel numbers and working gap distances, improving accuracy and applicability across various medium thicknesses.

Implementation Method 1

an imaging unit with a zoom lens... capturing and analyzing the test pattern

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3689627B1Method for determining working gap, and recording device
Publication Date: 2023.05.10 SEIKO EPSON CORP
  • EP3689627B1 patent drawingFigure 1
  • EP3689627B1 patent drawingFigure 2
  • EP3689627B1 patent drawingFigure 3

AI summary

A method for determining a working gap includes a first recording step for ejecting ink from a recording head onto a first recording medium having a known medium thickness to record a test pattern, a first imaging step for capturing the test pattern recorded on the first recording medium in each of a state where a distance between the recording head and the first recording medium is a first distance, and a state where a distance between the recording head and the first recording medium is a second distance, a function calculating step for calculating a function to determine the distance based on the number of pixels of the captured test pattern, a second recording step for recording the test pattern on a second recording medium, a second imaging step for capturing the test pattern recorded on the second recording medium, and a working gap determining step for determining, based on the number of pixels of the captured test pattern and the function, a distance between the recording head and the second recording medium.