Test Pattern Creation for Print Head Alignment Measurement

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Solution Overview

Problem

Existing test patterns struggle to accurately measure impact displacement when tightly packed, making it difficult to determine alignment issues between print heads and print tips due to the challenge of measuring displacement in a cost-effective manner.

Innovation Solution

A test pattern creation method that includes a reference ruled line set and a measurement ruled line set, where the spacings between the ruled lines increase in the secondary scan direction, facilitating the measurement of impact displacement by aligning specified ruled lines, and utilizing different ink colors and print tips to measure head and tip misalignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If the test pattern is printed tightly packed to reduce the area, then the area occupied by the test pattern is reduced, but the measurement of impact displacement becomes difficult

Engineering Contradiction:

Improvearea of test patternVSAvoidimpact displacement measurement

Core Design Contradiction:

Area of moving objectVSMeasurement precision

Solution Approach 1:

The patent applies local quality by creating two distinct sets of ruled lines with different spacing characteristics: reference ruled lines with uniform spacing and measurement ruled lines with progressively increasing spacing. This local differentiation in spacing quality enables both compact overall layout and accurate displacement measurement in specific regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a second dimension to the measurement system by using multiple sets of ruled lines oriented in different directions (primary scan direction and secondary scan direction). This dimensional approach allows impact displacement to be measured in both directions simultaneously, maintaining measurement capability even when the test pattern is tightly packed.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If the spacings between ruled lines are increased to facilitate measurement, then the measurement precision is improved, but the area occupied by the test pattern increases

Engineering Contradiction:

Improveimpact displacement measurementVSAvoidarea of test pattern

Core Design Contradiction:

Measurement precisionVSArea of moving object

Solution Approach 1:

The patent segments the test pattern into multiple functional regions: reference ruled line sets for establishing baseline positions, measurement ruled line sets for detecting displacement, and cross-section marks for verification. This segmentation allows each region to be optimized for its specific function while maintaining overall compactness through efficient arrangement.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the spacing parameter of the measurement ruled lines progressively in the secondary scan direction, creating a gradient spacing pattern. This parameter variation allows the measurement region to expand only where needed for accurate displacement detection, while other regions remain compact.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If multiple print tips are used to create different ruled line sets, then the measurement capability for head and tip misalignment is improved, but the device complexity increases

Engineering Contradiction:

Improvemeasurement capabilityVSAvoidprint head configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes the print head system multi-functional by using the same carriage and scan mechanism to create multiple types of ruled lines (reference and measurement sets) and cross-section marks. Different print tips within the same print head are utilized to create different ink color patterns, enabling comprehensive measurement of both head-to-head and tip-to-tip alignment without requiring separate measurement devices.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10661587B2Test pattern creation method, test pattern, printing apparatus, and program

Publication Date: 2020.05.26 SEIKO EPSON CORP

AI summary

A method for creating a test pattern includes creating a reference ruled line set by ejecting ink from a nozzle formed in a first print tip among a plurality of print tips, and creating a measurement ruled line set by ejecting ink from a nozzle formed in a second print tip among the plurality of print tips. A ruled line in the reference ruled line set and a ruled line in the measurement ruled line set whose positions align in a secondary scan direction when no impact displacement is present in the secondary scan direction are designated as specified ruled lines. The test pattern is created such that spacings between the ruled lines within the reference ruled line set and spacings between the ruled lines within the measurement ruled line set increase on progression in the secondary scan direction away from the specified ruled lines.