Print Head Adjustment Device for Thermal Expansion Compensation
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Solution Overview
Problem
Single-pass inkjet printers face challenges in maintaining print head alignment due to thermal cycling, leading to visible deviations in the printed image as the print heads change position relative to the module, affecting print quality.
Innovation Solution
A print head adjustment device with an adjustable receiving means in the X-Y plane, where a fixed end of the print head is secured and a loose end can rotate and move in the X direction, creating a defined floating bearing that allows the print head to return to its original position after temperature changes, preventing positional shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the print head is fixed rigidly in the print head module, then the manufacturing precision is improved, but the reliability deteriorates due to thermal cycling causing permanent position changes
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a rigid fixed connection to a dynamic floating bearing mechanism. The print head is mounted on floating bearings that allow controlled movement in the running direction (Y direction) while maintaining precise positioning in the transverse direction (X direction). This dynamic mounting allows the print head to accommodate thermal expansion and contraction during thermal cycling, preventing permanent position shifts while maintaining manufacturing precision.
Solution Approach 2:
The patent applies parameter changes by allowing the print head position to vary dynamically in the Y direction through the floating bearing mechanism. The system permits controlled parameter changes (position in running direction) in response to thermal conditions, while maintaining critical parameters (transverse position and orientation) within required tolerances. This selective parameter control resolves the contradiction between rigid fixation and thermal adaptability.
2Reliability
If the print head is allowed to move freely to accommodate thermal expansion, then the reliability is improved, but the manufacturing precision deteriorates due to positional deviations
Solution Approach 1:
The floating bearing mechanism creates a dynamic system that selectively permits movement. The print head can move freely in the Y direction (running direction) to accommodate thermal expansion, while the bearing structure constrains movement in the X direction (transverse direction) to maintain positioning precision. This anisotropic freedom of movement resolves the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The patent segments the degrees of freedom of the print head mounting. The floating bearing mechanism divides the movement capabilities into independent components: free movement in the Y direction for thermal accommodation, and constrained movement in the X direction for precision maintenance. This segmentation allows simultaneous achievement of reliability and manufacturing precision.
3Manufacturing precision
If manual adjustment under light microscope is used, then the manufacturing precision is improved, but the device complexity and construction time increase
Solution Approach 1:
The floating bearing mechanism provides self-adjusting capabilities that reduce the need for complex manual adjustment equipment. The mechanism automatically compensates for thermal effects and maintains positioning through its inherent mechanical design, rather than requiring external microscopy and manual intervention. This self-service approach maintains precision while reducing device complexity.
Solution Approach 2:
The patent replaces the complex mechanical adjustment system (requiring light microscopes and manual positioning) with a simpler floating bearing mechanism that achieves positioning through mechanical self-adjustment. The floating bearings provide automatic compensation for thermal effects, substituting complex measurement and adjustment equipment with a straightforward mechanical solution.
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 ensures precise alignment and stability of the print heads, maintaining print quality by absorbing thermal expansion differences and preventing wandering of the print heads during temperature fluctuations, thus ensuring consistent image output.
Implementation Method 1
the position of the print heads relative to the respective print head module is fixed due to the prestressed stop... Manufacturing tolerances in the printhead or frame dimensions cannot be corrected in this way
Implementation Method 2
it has been found to be disadvantageous that a print head installed in a fixed position relative to the print head module is able to change its position relative to the print head module in the event of thermal cycling
Data Source
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AI summary
Disclosed is a print head adjustment device (1) for an ink-jet printer, comprising an adjustment adapter (4) and a print head (3) that has a printing side (6) extending on an X-Y plane. The adjustment adapter (4) comprises a holding means (20) which is adjustable in the X-Y plane and in which a stationary end (9) of the print head (3) is accommodated. A movable end (8) of the print head (3) is mounted on the adjustment adapter (4) so as to be slidable in the X direction and rotatable about an axis of rotation that is perpendicular to the X-Y plane.