Printhead Flexure Linkage for Micron Alignment

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Solution Overview

Problem

Achieving precise rotational and translational alignment of inkjet printheads in large-scale printers is challenging due to space restrictions and manufacturing tolerances, especially with higher resolution and smaller drop sizes, which affects print quality and registration between printheads.

Innovation Solution

A printhead support structure that uses translational actuation to provide rotational adjustment, incorporating a flexure arrangement to convert translational movement into rotational movement, allowing for precise alignment without the need for additional locking mechanisms or extra space, and enabling adjustments to be made after printheads are installed in a tightly packed array.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If printheads are arranged in a tightly packed array to improve registration and reduce space, then print quality and space utilization are improved, but the difficulty of making adjustments increases

Engineering Contradiction:
Improveregistration between printheadsVSAvoidadjustment accessibility
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The adjustment mechanism is actuated from the z-direction (perpendicular to the printhead array plane) to produce x-direction (cross-process) translation and rotation. This dimensional transformation allows adjustment access from above or below the tightly packed array, solving the accessibility problem while maintaining tight packing in the x-y plane.

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

Solution Approach 2:

A mechanical intermediary mechanism (bell-crank linkage with flexures) is introduced to convert z-direction actuation into x-direction translation and rotation. This intermediary allows indirect adjustment of printheads in a tightly packed array without requiring direct side access to each printhead.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If standard manufacturing tolerances are used to reduce cost and simplify manufacture, then manufacturing complexity is reduced, but alignment precision deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidazimuthal and cross-process positioning
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The adjustment mechanism is pre-installed on the print carriage during manufacturing, but the actual printhead alignment is performed later during installation or maintenance. This separates the manufacturing phase (using standard tolerances) from the alignment phase (achieving high precision), allowing cost-effective manufacturing without sacrificing final alignment accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system transitions from a static, fixed-tolerance manufacturing approach to a dynamic adjustment approach. The bell-crank mechanism with flexures provides controlled movement capability, allowing printheads to be dynamically adjusted to precise positions after installation, compensating for manufacturing tolerances.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If rotational actuation is provided directly to individual printheads to achieve precise alignment, then alignment precision is improved, but device complexity and space requirements increase

Engineering Contradiction:
Improveprinthead alignment accuracyVSAvoidadjustment mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The mechanism merges translation and rotation functions into a single bell-crank linkage system. A single actuator in the z-direction simultaneously controls both the translational position and rotational angle of the printhead through the coupled flexure mechanism, reducing the number of separate adjustment mechanisms needed.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention replaces complex direct rotational actuators (motors, gears, etc.) with a simpler mechanical linkage system using bell-crank flexures. This substitution achieves the same alignment function with fewer moving parts, reduced complexity, and smaller space requirements.

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

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 enables stable and accurate alignment of printheads to a few microns, improving print quality and reducing the frequency of realignments, as the flexure arrangement is resilient to thermal changes and vibration, and allows for automated adjustment, enhancing the efficiency and accuracy of the printing process.

Implementation Method 1

incorporating a flexure arrangement to convert translational movement into rotational movement

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2979881B1Printhead attachment system
Publication Date: 2021.04.07 INCA DIGITAL PRINTERS
  • EP2979881B1 patent drawingFigure 1~2
  • EP2979881B1 patent drawingFigure 3
  • EP2979881B1 patent drawingFigure 4

AI summary

There is described herein a printhead support structure, comprising: means for receiving a printhead; first and second portions having adjustment means therebetween for converting a translational movement of the first portion to a rotational movement of the second portion; and means for coupling the second portion to said receiving means for adjusting the rotational angle of the printhead. There is also described herein a method for adjusting the position of a printhead coupled to a printhead support, comprising the steps of: applying a force to a first portion of the printhead support to effect a translational movement of the first portion; converting said translational movement of the first portion into a rotational movement of a second portion of the printhead support; and applying said rotational movement of the second portion to the printhead.