Printhead Alignment Assembly Using Kinematic Locating Elements
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Solution Overview
Problem
Conventional techniques for aligning components of inkjet printheads are inefficient due to high assembly times, sensitivity to heat and humidity, and difficulties in field replacement, particularly in achieving precise multi-dimensional tolerances for locating elements, which increases manufacturing complexity and cost.
Innovation Solution
A printhead assembly that includes a base plate, a locator plate with through holes, and a coupling member with kinematic locating elements, allowing for precise alignment of the printhead module and frame using interference fits and kinematic mounts, reducing the need for precise machining and enhancing field replaceability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive is used to affix printhead components together, then assembly is simplified, but assembly time increases due to curing requirements
Solution Approach 1:
The patent removes the adhesive curing step from the assembly process by using mechanical interference fits and locating elements. The components are joined through precise mechanical engagement rather than chemical bonding, eliminating the time-consuming curing phase while maintaining assembly simplicity.
Solution Approach 2:
The patent replaces the chemical adhesive system with a mechanical joining system using interference fits, locating elements, and precision-machined surfaces. This mechanical substitution eliminates the need for curing time while achieving secure component attachment.
2Strength
If epoxy is used to affix printhead components, then strong bonding is achieved, but sensitivity to heat and humidity increases
Solution Approach 1:
The patent extracts the epoxy adhesive material from the assembly system, replacing it with mechanical joining methods. This eliminates the inherent sensitivity of epoxy to heat and humidity while maintaining strong bonding through precision mechanical fits and locating elements.
Solution Approach 2:
The patent uses field-replaceable locating elements that can be easily installed or removed as needed, replacing the permanent and sensitive epoxy bonds. This allows for maintenance and replacement without concern for heat and humidity sensitivity.
3Strength
If adhesives or epoxies are used to affix components, then components are securely bonded, but field replaceability is hindered
Solution Approach 1:
The patent segments the printhead into modular components that can be independently replaced. The locating elements and precision-machined interfaces enable individual components to be removed and replaced in the field without requiring complete disassembly or special tools, while maintaining secure bonding through interference fits.
Solution Approach 2:
The patent incorporates self-aligning locating elements that guide components into proper alignment during assembly or replacement. This self-service feature allows field technicians to replace components without requiring complex alignment procedures or specialized equipment.
4Manufacturing precision
If dedicated assembly fixtures are used for alignment, then precise alignment is achieved, but field repair capability is reduced
Solution Approach 1:
The patent creates universal locating elements and precision-machined surfaces that serve both manufacturing assembly and field repair functions. The same locating features used during factory assembly with fixtures are replicated in the field-replaceable components, allowing precise alignment without dedicated fixtures during maintenance.
Solution Approach 2:
The patent incorporates self-aligning locating elements that automatically guide components into precise alignment during assembly or replacement. This eliminates the need for dedicated assembly fixtures during field repairs, as the components themselves provide the alignment function.
5Manufacturing precision
If precision ground balls or cylindrical pins are used as locating elements, then high alignment accuracy is achieved, but multi-dimensional tolerance requirements increase manufacturing complexity
Solution Approach 1:
The patent extracts the complex precision machining requirements for multiple-dimensional tolerances by using simplified locating element geometries. Instead of requiring precision ground balls or cylindrical pins with tight tolerances, the patent uses straightforward interference fit features that are easier to manufacture while achieving comparable alignment accuracy.
Solution Approach 2:
The patent changes the geometric parameters of the locating elements from complex spherical or cylindrical forms to simplified interference fit features. This parameter change reduces manufacturing complexity while maintaining the necessary alignment accuracy through precise interference fit design.
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 enables reproducible, high-precision alignment of printhead components with reduced manufacturing costs and improved field replaceability, ensuring consistent performance across various printing applications.
Implementation Method 1
Each of the locating elements of the first set are positioned with an interference fit in a respective one of the pockets
Data Source
AI summary
A printhead includes a printhead module and frame, and an alignment assembly including a base plate, locator plate, first set of locating elements, and coupling member. The locator plate, including through holes, is affixed with the base plate such that pockets are formed having a wall corresponding to a wall of one of the through holes and a base corresponding to a surface of the base plate. The first set of locating elements is positioned with an interference fit in one of the pockets. The walls of the pockets define positions of the first set of locating elements in a plane of the locator plate surface. The bases of the pockets define positions of the first set of locating elements in a direction normal to the base plate surface. The coupling member includes a second set of locating elements that contact the first set of locating elements.