Printer Sensor Foreign Matter Detection via Test Pattern

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Solution Overview

Problem

Existing recording/reading systems face challenges in accurately reading recorded materials due to foreign matter adhering to the reading apparatus, which can lead to increased costs from requiring multiple sensors for image reading.

Innovation Solution

A recording/reading system that includes a recording apparatus and a reading apparatus, where the recording apparatus records a density correcting pattern and a comparative pattern on a medium, and the reading apparatus detects foreign matter by comparing the reading results of these patterns, allowing for accurate detection without the need for multiple sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a line sensor is added to clean foreign matter adhering to the colorimeter, then foreign matter detection capability is improved, but device complexity and cost increase due to requiring two sensors for image reading

Engineering Contradiction:
Improveforeign matter detection capabilityVSAvoidnumber of sensors
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The single line sensor performs multiple functions: it reads the test pattern to detect foreign matter on the colorimeter, and also reads the printed material. By making the line sensor multi-functional, the patent eliminates the need for a separate cleaning sensor while maintaining foreign matter detection capability.

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

Solution Approach 2:

The patent uses a test pattern that copies the structure of the printed material (including halftone patterns and color patches) to enable the line sensor to detect foreign matter by comparing reading results with expected values from the test pattern, rather than requiring a separate sensing mechanism.

Inventive Principle:
Principle #26Copying

2Measurement precision

If multiple sensors are used for image reading, then foreign matter detection accuracy is improved, but cost increases

Engineering Contradiction:
Improveforeign matter detection accuracyVSAvoidcost
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent creates a test pattern that replicates the printed material's structure and uses it to generate reference reading results. By comparing actual readings against these copied reference values, the system achieves accurate foreign matter detection using a single sensor, avoiding the cost of multiple sensors.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent changes the parameter being measured by the line sensor from only reading the printed material to reading both the test pattern and printed material, and compares results against reference values. This parameter change enables accurate foreign matter detection with a single sensor.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a test pattern is recorded and read to detect foreign matter, then foreign matter detection is achieved, but reading time increases

Engineering Contradiction:
Improveforeign matter detectionVSAvoidreading time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The test pattern is recorded on the printed material during the normal printing process, and reference reading results are stored in advance. During operation, the line sensor quickly reads the test pattern and compares against pre-stored reference values, enabling rapid foreign matter detection without adding significant time to the reading process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges the test pattern reading function with the normal printed material reading function by using the same line sensor and processing pipeline. The test pattern is integrated into the printed material itself, allowing both functions to be performed in a single reading pass rather than requiring separate reading operations.

Inventive Principle:
Principle #5Merging (Combining)

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 system effectively detects foreign matter adhering to the reading apparatus, ensuring accurate reading results while reducing costs by eliminating the need for multiple image reading sensors.

Implementation Method 1

By optically reading the recorded material output by a printer with a reading apparatus, the color, density, etc. of the recorded material can be obtained and evaluated.

Methodology Applied
Scientific EffectOptical reading: Photoelectric Effect

Data Source

PatentEP4159450B1Recording apparatus, recording/reading system and recording method
Publication Date: 2025.04.30 SEIKO EPSON CORP
  • EP4159450B1 patent drawingFigure 1
  • EP4159450B1 patent drawingFigure 2
  • EP4159450B1 patent drawingFigure 3

AI summary

A recording apparatus includes a first nozzle row and a second nozzle row, and a control unit configured to control ejection of liquid by the first nozzle row and the second nozzle row. The control unit is configured to cause the first nozzle row and the second nozzle row to perform scan of ejecting the liquid while moving forward or backward along a predetermined main scanning direction, and when recording a first pattern including a first overlapping region and a first normal region on the medium by controlling the first nozzle row and recording a second pattern including a second overlapping region and a second normal region on the medium by controlling the second nozzle row, the first overlapping region is formed at a position overlapping the second normal region as viewed in a longitudinal direction, the first overlapping region being an overlapping region where a raster line having a longitudinal direction corresponding to the main scanning direction is formed by performing the scan m times, the first normal region being a normal region where the raster line is formed by performing the scan n times, n being smaller than m, the second overlapping region being the overlapping region, the second normal region being the normal region.