Rotating Paper Guides for Thermal Printer Skew Reduction

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Solution Overview

Problem

Existing thermal printers face issues with paper skew during conveyance due to imbalance in components, leading to misalignment, corner folding, and increased friction, which results in load loss and potential abrasion of paper guides, hindering printing speed and accuracy.

Innovation Solution

The implementation of circular paper guides at both ends of the idle roller support shaft and a semi-circular printing paper guide curved surface on the platen roller frame to minimize friction load and stabilize paper conveyance, preventing skew by ensuring surface contact without sliding motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If fixed fence form paper guides are used to prevent paper skew, then paper alignment is improved, but friction load increases and printing speed decreases

Engineering Contradiction:
Improvepaper alignmentVSAvoidprinting speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The paper guide is changed from a fixed structure to a rotatable structure that rotates together with the idle roller during paper conveyance. This dynamic adaptation allows the paper guide to maintain proper alignment with the paper while reducing friction, as the rotating surface moves with the paper rather than creating sliding friction against a stationary guide.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The fixed mechanical fence structure is replaced with a rotatable guide structure that eliminates sliding friction. By substituting the stationary mechanical constraint with a rotating guide surface that moves synchronously with the paper, the system reduces frictional resistance while maintaining alignment functionality.

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

2Reliability

If fixed paper guides are used to guide paper conveyance, then paper skew is prevented, but friction causes load loss and paper guide abrasion

Engineering Contradiction:
Improveskew preventionVSAvoidfriction load
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The paper guide structure is made dynamic by connecting it to the idle roller rotation. The guide rotates together with the roller, creating a moving contact surface that reduces sliding friction. This dynamic configuration maintains reliable skew prevention while significantly reducing frictional energy loss and wear on the guide structure.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If paper guides contact printing paper to prevent skew, then alignment is maintained, but friction increases conveyance load

Engineering Contradiction:
Improvepaper alignmentVSAvoidconveyance load
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The paper guide is transformed from a static contact surface to a dynamic rotating surface that moves with the paper conveyance. By rotating together with the idle roller, the guide surface eliminates sliding friction, thereby maintaining alignment precision while reducing the force required for paper conveyance.

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

This solution effectively reduces the occurrence of paper skew, minimizes load during conveyance, and enhances printing speed by maintaining paper alignment and reducing friction-related wear, thereby improving the overall performance and longevity of the printer mechanism.

Implementation Method 1

circular paper guides are additionally installed at both ends of a support shaft of an idle roller to convey the printing paper while rotating the idle roller and the circular paper guide together, thereby minimizing a load due to a friction of the printing paper with the circular paper guides

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2946936B1Apparatus for protecting paper skew of printer
Publication Date: 2017.07.12 SHIN HEUNG PRECISION
  • EP2946936B1 patent drawingFigure 1
  • EP2946936B1 patent drawingFigure 2
  • EP2946936B1 patent drawingFigure 3

AI summary

In one aspect of the present disclosure, an apparatus for protecting a paper skew of a printer comprises a printer head unit (30) comprising a support shaft (34) installed on a support frame (31) and a thermal printer head (32) installed on the support frame to print printing paper (P), a platen roller unit (40) comprising a roller frame (41) and a platen roller (42), and paper guides (37) formed at both sides of the support shaft (34).