Movable Scan Sensor for Liquid Discharging Apparatus

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Solution Overview

Problem

Existing liquid discharging apparatuses face challenges in accurately forming images on a medium when it is deviated from its intended position, as existing edge sensors and detection methods may not detect significant deviations, leading to misalignment of the image on the medium.

Innovation Solution

A liquid discharging apparatus with a line head and a scan sensor that can detect the end portion of the medium in the intersecting direction, allowing for real-time adjustment of the ink discharge position and movement of the line head to ensure accurate alignment, even when the medium is significantly deviated from its original position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a fixed edge sensor is used to detect medium position, then the device structure is simple, but the medium position detection accuracy deteriorates when the medium is greatly deviated from the original position

Engineering Contradiction:
Improvedevice structureVSAvoidmedium position detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The sensor is made movable along the medium width direction, transforming from a fixed detection point to a dynamic scanning detection system. This allows the sensor to actively search for and track the medium's actual position, solving the contradiction between simple structure and accurate detection under large deviations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The detection approach transitions from a single fixed point detection to a two-dimensional scanning detection by adding movement capability in the width direction. This dimensional expansion enables comprehensive position detection across the entire medium width, maintaining detection accuracy even when the medium is greatly deviated.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If the sensor position is fixed, then the detection system is simple, but the image formation accuracy deteriorates when medium deviation exceeds sensor detection range

Engineering Contradiction:
Improvedetection systemVSAvoidimage formation accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The sensor's ability to move dynamically along the medium width allows it to adapt to various deviation scenarios. This dynamic adjustment ensures that the sensor can always detect the medium's actual position, enabling accurate image formation even when deviations exceed the range of fixed sensors.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The movable sensor provides real-time feedback on the medium's actual position, which is then used to adjust the head unit's discharge position. This feedback loop ensures that image formation accuracy is maintained by continuously adapting to the medium's position, solving the contradiction between system simplicity and precision under varying conditions.

Inventive Principle:
Principle #23Feedback

3Device complexity

If the line head discharges liquid based on original position without real-time detection, then the discharging system is simple, but the liquid discharge position accuracy deteriorates when medium position deviates

Engineering Contradiction:
Improvedischarging systemVSAvoidliquid discharge position accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The system implements real-time feedback by using the movable sensor to detect the medium's actual position and then adjusting the head unit's discharge position accordingly. This feedback mechanism ensures that liquid discharge position accuracy is maintained despite medium position deviations, resolving the contradiction between system simplicity and positioning precision.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system replaces fixed mechanical positioning with a combination of optical/electronic detection (sensor) and controlled mechanical adjustment (movable sensor and adjustable head unit). This substitution enables dynamic adaptation to position changes, maintaining discharge accuracy without requiring complex mechanical positioning systems.

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

Data Source

PatentEP3109052B1Liquid discharging apparatus
Publication Date: 2020.02.12 SEIKO EPSON CORP
  • EP3109052B1 patent drawingFigure 1
  • EP3109052B1 patent drawingFigure 2
  • EP3109052B1 patent drawingFigure 3

AI summary

A liquid discharging apparatus (1) includes a transport section (10) for a medium (P), a line head (19) in which nozzles discharging liquid in an intersecting direction (B) that intersects a direction of transporting the medium are arrayed, a scan sensor (20) which is moved in the intersecting direction (B) and is capable of detecting an end portion (25) of the medium (P) in the intersecting direction (B), and a controller that controls movement in the intersecting direction (B) of the scan sensor (20), and controls discharging of the liquid based on a detection result of the scan sensor (20).