Print Head Uniform Loading via Pivotable Frame
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Solution Overview
Problem
Thermal transfer printers face challenges in maintaining even pressure across the print head and label, especially during edge-justified printing, leading to poor print quality and complications in accommodating various print media widths.
Innovation Solution
A print head assembly with a two-piece frame structure and biasing members that provide differential forces to maintain the print head's alignment and apply uniform pressure, ensuring even ink transfer across the platen roller during edge-justified operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the print media is center justified to avoid uneven pressure, then pressure distribution is improved, but device complexity increases due to moveable edge guides and user adjustment requirements
Solution Approach 1:
The print head is made pivotable about a vertical axis, allowing it to dynamically adjust its angular position. This dynamic capability enables the print head to adapt to different media widths and justification methods (center or edge) without requiring moveable edge guides, thereby maintaining pressure distribution while reducing device complexity
Solution Approach 2:
The system allows the user to simply position the media in the desired justification (center or edge) without requiring manual adjustment of edge guides or pressure skew mechanisms. The pivotable print head automatically adapts to the media placement, making the system self-adjusting and eliminating complex user operations
2Ease of operation
If the print media is edge justified to simplify guiding and sensing, then ease of operation is improved, but print quality deteriorates due to uneven pressure on narrow media
Solution Approach 1:
The pivotable print head can rotate to different angular positions, allowing it to dynamically adjust its pressure distribution pattern. When edge-justified media is detected, the print head pivots to an angle that concentrates pressure on the active printing area, ensuring uniform pressure and high print quality regardless of media width
Solution Approach 2:
The system applies pressure non-uniformly across the print head width by pivoting. The biasing member ensures sufficient pressure is applied locally to the active printing area while reducing pressure on inactive areas, thereby maintaining print quality for edge-justified narrow media without requiring complex pressure adjustment mechanisms
3Manufacturing precision
If a pressure skew adjustment mechanism is added to redistribute pressure uniformly, then print quality is improved, but device complexity and ease of operation worsen
Solution Approach 1:
Instead of a complex pressure skew adjustment mechanism, the invention uses a simple pivotable print head with a biasing member. The pivot angle, controlled by the biasing force, dynamically redistributes pressure uniformly across the media width. This mechanical simplicity maintains pressure uniformity while avoiding complex adjustment mechanisms
Solution Approach 2:
The system changes the angular parameter of the print head by pivoting it to different angles. This parameter change (angular position) automatically adjusts the pressure distribution pattern, achieving uniform pressure across varying media widths without requiring additional pressure adjustment mechanisms
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 achieves consistent print quality by maintaining even pressure across the print face, preventing skewing and faint printing, and simplifies the operation by eliminating the need for user-adjusted pressure skew mechanisms.
Implementation Method 1
a pair of biasing members proximal a pair of opposite ends of the print head to apply a force on the print head that is greater than a force applied by a biasing member proximal the print face
Implementation Method 2
In thermal transfer printing, a layer of print material, such as ink, is heated to be selectively applied to the print media
Implementation Method 3
the thermal print head melts the ink from the ribbon for transfer onto the label
Implementation Method 4
the nip pressure between the thermal print head and the platen roller may help to maintain tension on the ribbon as it is fed past the print head
Data Source
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AI summary
An improved print head assembly is disclosed that provides even pressure over the width of a print face across a platen roller. Accordingly, the print head assembly can perform edge-justified printing operations without portions of the print being faint or skewing due to uneven pressure across the print head.