Thermal Printer Platen Eccentric-Shaft Adjustment for Compact Printing

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Solution Overview

Problem

Existing printers require complex and space-consuming structures to adjust the contact position between the thermal head and platen, which are not feasible in low-cost printers.

Innovation Solution

A printer design featuring a thermal head with a bracket and pair of supports that allow the shaft of the platen to be eccentric from the axis of rotation, enabling adjustable contact positions between the thermal head and platen through a rotation stopper mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a structure for adjusting the contact position between the thermal head and platen is provided, then print quality is improved, but device complexity increases

Engineering Contradiction:
Improveprint qualityVSAvoidstructure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The support structure combines multiple functions into a single integrated assembly: the frame provides structural support, the bushings provide rotational support for the shaft, and the support part receives forces from the thermal head. This merging of functions reduces the number of separate components needed for position adjustment while maintaining print quality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The frame serves multiple purposes: it supports the bushings, provides mounting positions for the support structure, and acts as part of the rotation stopper mechanism. The bushings both support the shaft rotation and define the rotational positions through the cooperation with protrusions. This multi-functionality reduces overall device complexity while enabling print quality adjustment.

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

2Manufacturing precision

If a structure for adjusting the contact position between the thermal head and platen is provided, then print quality is improved, but the internal space required increases

Engineering Contradiction:
Improveprint qualityVSAvoidinternal space
Core Design Contradiction:
Manufacturing precisionVSVolume of stationary object

Solution Approach 1:

The support structure is nested within the existing frame structure. The bushings are positioned within the frame, and the support part is integrated into the same space. The shaft rotates within the bushings while the entire assembly fits within the printer's existing internal volume, minimizing space requirements.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The position adjustment is achieved through rotation about an axis rather than linear movement in one dimension. The shaft can be rotated to multiple angular positions within the same compact space, allowing contact position adjustment without requiring additional linear space. The rotation stopper uses angular positioning rather than linear displacement.

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

3Adaptability or versatility

If a rotation stopper mechanism is added to selectively hold supports, then contact position adjustability is improved, but device complexity increases

Engineering Contradiction:
Improvecontact position adjustabilityVSAvoidcomponent count
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The rotation stopper mechanism is merged with the existing frame and support structure. The protrusions are integrated into the support assembly, and the recesses are formed in the frame itself. This integration means no separate rotation stopper components are needed beyond what is already required for support and rotation functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotation stopper uses a simple protrusion-recess engagement system that creates stable equilibrium positions without requiring complex locking mechanisms or additional actuation systems. Each rotational position is equally stable and accessible, providing simple adaptability without increasing complexity.

Inventive Principle:
Principle #12Equipotentiality

Data Source

PatentEP4249272B1printer
Publication Date: 2025.09.10 TOSHIBA TEC KK
  • EP4249272B1 patent drawingFigure 1~2
  • EP4249272B1 patent drawingFigure 3~4
  • EP4249272B1 patent drawingFigure 5

AI summary

A printer (1) including thermal head (41), a platen (42) including a shaft (421), a pair of bushings (6), a bracket (410), a pair of frames (5), and a pair of supports (71). The bushings (6) are positioned proximate opposing ends of the shaft (421). The bracket (410) is configured to support the thermal head (41). The bracket (410) defines a groove (412) at opposing ends thereof. The frames (5) are positioned proximate the opposing ends of the bracket (410). Each of the frames (5) defines an aperture that cooperates with the groove (412) to define a passage through which a portion of the shaft (421) extends. Each of the supports (71) is positioned to engage with the aperture of a respective one of the frames (5). The supports (71) are rotatable within the apertures about an axis of rotation. The supports (71) are positioned to support the opposing ends of the shaft (421) such that the shaft is eccentric from the axis of rotation.