Overmolded Printhead Slivers for Cost Reduction

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Solution Overview

Problem

The cost and fragility issues associated with shrinking thermal inkjet printhead dies to reduce manufacturing costs and improve print quality are exacerbated by the need for smaller fluid slots, which increase assembly complexity and die failure rates due to structural weakening.

Innovation Solution

The use of an overmolded epoxy mold compound to hold multiple printhead slivers in place, eliminating the need for fluid distribution manifolds and simplifying assembly by extending electrical interconnects to printed circuit boards, thereby reducing costs and enhancing die strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If printhead dies are shrunk to reduce manufacturing costs and improve print quality, then manufacturing cost and print quality are improved, but die fragility increases and assembly complexity increases

Engineering Contradiction:
Improveprint qualityVSAvoiddie strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent uses an overmolded epoxy mold compound that combines the printhead die with a supportive epoxy material. This composite structure reinforces the shrunk die, preventing fragility issues while maintaining the cost and quality benefits of smaller die size.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent separates the die from the fluid distribution manifold by using the overmolded epoxy compound to hold multiple slivers in place. This segmentation eliminates the need for complex slotting processes and reduces die fragility while maintaining manufacturing precision.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If fluid slots are made smaller to accommodate shrunk dies, then manufacturing cost is reduced, but assembly complexity increases and die failure rates increase

Engineering Contradiction:
Improvemanufacturing costVSAvoidassembly complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent extracts the fluid distribution manifold function from the die itself by using the overmolded epoxy compound to provide fluid distribution. This eliminates complex slotting processes and reduces assembly complexity while maintaining ease of manufacture.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The overmolded epoxy mold compound serves multiple functions: it holds multiple slivers in place, provides fluid distribution, and reinforces the die structure. This multi-functionality reduces assembly complexity while maintaining manufacturing cost efficiency.

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

3Ease of manufacture

If electrical interconnections are extended to printed circuit boards, then assembly is simplified and costs are reduced, but device complexity increases

Engineering Contradiction:
Improveassembly costVSAvoidprinthead design complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the electrical interconnection function with the overmolded epoxy mold compound by embedding the printed circuit board within the epoxy structure. This integration simplifies assembly and reduces costs while the epoxy compound manages the complexity of the integrated structure.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3291991B1printhead
Publication Date: 2021.12.01 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3291991B1 patent drawingFigure 1
  • EP3291991B1 patent drawingFigure 2
  • EP3291991B1 patent drawingFigure 3

AI summary

A printhead includes a number of inkjet slivers molded into a moldable substrate. The overmolded inkjet slivers form at least one die. The printhead also includes a number of wire bonds electrically coupling the inkjet slivers to a side connector. The side connector electrically couples the inkjet slivers to a controller of a printing device.