Printing Apparatus Detecting Medium Displacement via Optical Imaging

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Solution Overview

Problem

Existing printing apparatuses face issues with print quality due to medium displacement in directions intersecting the printing surface, leading to defects like ink droplet deviation, printing head scratches, and medium jams, which are not effectively detected or addressed by current technologies.

Innovation Solution

A printing apparatus equipped with sensors that image the medium at different times to detect displacement amounts in intersecting directions, controlling the transporting and printing units to correct for these displacements, thereby preventing or alleviating defects such as ink deviation, printing head scratches, and medium jams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the medium is transported without detection of displacement, then the transporting unit operates continuously, but printing defects occur due to medium displacement in the intersecting direction

Engineering Contradiction:

Improvetransporting unit operation continuityVSAvoidprinting position accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The sensor images the medium at multiple positions along the transporting path to detect displacement in the intersecting direction. The control unit receives this displacement information and adjusts the printing unit's operation accordingly, creating a feedback loop that maintains printing accuracy despite medium displacement during continuous transport

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces mechanical displacement sensors with an optical imaging system. The sensor captures images of the medium at different positions, and the control unit calculates displacement from these images, substituting direct mechanical measurement with optical field-based detection

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If photo interrupters are used to detect medium position, then the system can detect medium presence, but it cannot detect displacement in the direction intersecting the printing surface

Engineering Contradiction:

Improvemedium presence detectionVSAvoiddisplacement detection capability

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent transitions from one-dimensional detection (photo interrupters detecting presence/absence) to two-dimensional detection (sensor imaging the medium surface). By capturing spatial information across the medium width and analyzing positional changes in the intersecting direction, the system gains the ability to detect displacements that photo interrupters cannot perceive

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If the transporting unit stops immediately upon jam detection, then the jam is prevented from worsening, but the response time is delayed until oblique movement amounts become significantly different

Engineering Contradiction:

Improvejam prevention effectivenessVSAvoidresponse time delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The sensor images the medium at multiple positions along the transporting path, enabling the control unit to detect displacement trends before they develop into significant oblique movements. This preliminary detection allows the system to stop the transporting unit earlier, preventing jams before they worsen and reducing the response time delay

Inventive Principle:

Principle #10Preliminary action

4Device complexity

If the printing head operates with a fixed gap from the medium, then the printing system is simple, but any medium displacement causes ink droplet deviation from target position

Engineering Contradiction:

Improveprinting system structureVSAvoidink landing position accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent makes the printing system dynamic by allowing the gap between the printing head and medium to be adjusted based on detected displacement. The control unit modifies the printing head position or discharge timing in response to sensor feedback about medium position changes, maintaining ink landing accuracy despite medium displacement while keeping the overall system structure relatively simple

Inventive Principle:

Principle #15Dynamics

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 effectively restricts or alleviates printing defects by accurately detecting medium displacement and adjusting the printing and transporting units, ensuring proper ink landing and preventing medium jams, thus maintaining print quality.

Implementation Method 1

a sensor that images the medium

Methodology Applied

Scientific EffectImage sensing: Photography

Data Source

PatentUS10336106B2Printing apparatus and printing method

Publication Date: 2019.07.02 SEIKO EPSON CORP

AI summary

A printing apparatus includes a transporting device that transports a medium and a printing unit that prints onto the medium. In addition, the printing apparatus includes an image sensor that images the medium and a controller that detects a displacement amount of the medium in an intersecting direction which intersects a surface to be printed of the medium based on a plurality of images obtained by imaging the medium by the sensor at different times and that controls the transporting device and the printing unit according to the displacement amount.