One-piece printhead support for inkjet cartridges

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Solution Overview

Problem

Conventional inkjet print cartridges face challenges in accurately aligning and adhering components due to their six degrees of freedom in space, leading to orientation inaccuracies and stress-induced cracking of the printhead die caused by different thermal expansion coefficients of materials during thermal cycling.

Innovation Solution

A molded, one-piece printhead support is created using a two-shot molding process that integrates the chiclet and base components, providing a consistently planar surface and a trench around the head-land area to reduce mechanical stress, thus eliminating orientation inaccuracies and preventing cracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If separate chiclet and base components are used, then component modularity is improved, but manufacturing precision deteriorates due to alignment difficulties

Engineering Contradiction:

Improvecomponent modularityVSAvoidalignment precision

Core Design Contradiction:

Weight of moving objectVSManufacturing precision

Solution Approach 1:

The patent merges the separate chiclet and base components into a single monolithic housing structure. This integration eliminates the interface between two separate parts, thereby removing alignment difficulties and ensuring consistent surface planarity while maintaining the functional separation of the printhead support area and the base structure.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of manufacture

If separate chiclet and base components are used, then ease of manufacture is improved, but reliability deteriorates due to stress-induced cracking

Engineering Contradiction:

Improvecomponent assemblyVSAvoidprinthead die integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

By combining the chiclet and base into a monolithic housing, the patent eliminates the interface where thermal expansion differences cause stress concentration. This single-piece construction prevents stress-induced cracking at the junction between different materials, thereby improving reliability while the integrated design simplifies the assembly process.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The monolithic housing is formed from a single material that provides both the structural base functions and the printhead support surface. This eliminates the need to join dissimilar materials (chiclet and base) that have different coefficients of thermal expansion, preventing the stress and cracking issues that arise during thermal cycling.

Inventive Principle:

Principle #40Composite materials

3Adaptability or versatility

If multiple components are assembled, then adaptability is improved, but device complexity increases due to alignment requirements

Engineering Contradiction:

Improvecomponent configurationVSAvoidassembly complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent integrates multiple functional components (chiclet, base, and support structures) into a single monolithic housing. This consolidation reduces the number of parts that need to be aligned and assembled, thereby simplifying the device complexity while maintaining the functional adaptability through the integrated design.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9868309B2Print cartridges with one-piece printhead supports

Publication Date: 2018.01.16 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

In some examples, a print cartridge includes a housing, a one-piece printhead support attached to the housing, a printhead supported on a head-land surface area, and a trench in the printhead support surrounding the head-land surface area on at least two sides.