Thermal Printer Spring Mechanism for Platen Roller Stress Reduction

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Solution Overview

Problem

Existing thermal printers face issues with the biasing mechanism, where a coil spring on a back support plate presses the thermal head toward the platen roller, leading to stress on the thermal head during attachment and detachment of the platen roller, potentially causing deformation and reducing the printer's durability and reliability.

Innovation Solution

The implementation of a dual bias spring system, where a first bias spring presses the thermal head toward the platen roller, and a second bias spring biases the open-close arm to support the platen roller, allowing for stable contact without excessive stress on the thermal head, and enabling easy detachment and attachment without deforming the components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a coil spring on a back support plate presses the thermal head toward the platen roller, then the contact between thermal head and platen roller is improved, but stress on the thermal head increases during attachment and detachment of the platen roller

Engineering Contradiction:
Improvecontact stabilityVSAvoidthermal head durability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The biasing function is segmented into two independent spring systems: one spring system supports the platen roller assembly, and another spring system maintains contact between the thermal head and platen roller. This segmentation allows each spring to operate independently, preventing stress concentration on the thermal head during platen roller attachment and detachment while maintaining stable contact during printing.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a single bias spring presses the thermal head toward the platen roller, then printing contact is maintained, but the platen roller cannot be easily detached and attached

Engineering Contradiction:
Improveprinting contactVSAvoidplaten roller detachment
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The support structure is segmented into a fixed back support plate and a movable open-close arm with independent spring biasing. This allows the platen roller to be easily detached and attached by moving the open-close arm, while the thermal head contact is maintained by the independent spring system on the back support plate.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The open-close arm is designed to be movable rather than fixed, allowing dynamic adjustment for platen roller detachment and attachment. The spring biasing system compensates for position changes, maintaining reliable thermal head contact regardless of the open-close arm's position during operation or maintenance.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the back support plate moves during platen roller detachment, then the platen roller can be removed, but the coil spring stress increases and may deform the thermal head

Engineering Contradiction:
Improveplaten roller removalVSAvoidspring stress
Core Design Contradiction:
Ease of operationVSStress or pressure

Solution Approach 1:

The support system is divided into a fixed back support plate carrying the coil spring and thermal head, and a separate movable open-close arm carrying the platen roller. This segmentation ensures the back support plate and coil spring remain stationary during platen roller detachment, eliminating stress increases and preventing thermal head deformation while still allowing easy platen roller removal through open-close arm movement.

Inventive Principle:
Principle #1Segmentation

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

This configuration enhances the durability and reliability of the thermal head and platen roller by reducing stress during attachment and detachment, ensuring stable printing performance and extending the lifespan of the printer components.

Implementation Method 1

a first bias spring that presses the thermal head toward the platen roller

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a second bias spring that biases the open-close arm in a direction in which the platen roller is brought into contact with the thermal head

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3278997B1printer
Publication Date: 2020.06.10 FCL COMPONENTS LTD
  • EP3278997B1 patent drawingFigure 1~2
  • EP3278997B1 patent drawingFigure 3~4
  • EP3278997B1 patent drawingFigure 5~6

AI summary

A printer, comprises a frame, an arm that is rotatably supported by the frame, a platen roller that is rotatably supported by the arm or the frame, a print head that performs printing on recording paper placed between the platen roller and the print head, and a spring that is connected to the arm, wherein the spring presses the print head toward the platen roller.