Inkjet Printhead Shield Plate and Manifold Design

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Solution Overview

Problem

Current Memjet printheads face issues with de-priming due to labyrinthine ink pathways at high speeds, susceptibility to air bubbles, and alignment challenges in pagewide printing, particularly for longer printheads, and high manufacturing costs of flex PCBs.

Innovation Solution

A robust inkjet printhead design featuring a rigid elongate manifold with parallel ink supply channels and rows of printhead chips, using a metal alloy shim with low thermal expansion for attachment, and a shield plate to minimize condensation, allowing for efficient ink delivery and alignment without the need for precise registration in the field.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If labyrinthine ink pathways are used in LCP manifold, then multi-color ink delivery is achieved, but de-priming occurs at high print speeds

Engineering Contradiction:

Improvemulti-color ink deliveryVSAvoidde-priming resistance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The ink delivery system is segmented into separate straight pathways for each color channel, eliminating the shared labyrinthine structure. Each color (CMYK) has its own dedicated ink pathway from the manifold to the printhead chip, preventing ink starvation and de-priming events while maintaining multi-color capability.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If labyrinthine ink pathways are used, then ink distribution is achieved, but air bubble trapping occurs

Engineering Contradiction:

Improveink distributionVSAvoidair bubble trapping

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

3Reliability

If LCP manifold is used, then CTE matching with silicon is achieved, but rigidity for longer printheads is insufficient

Engineering Contradiction:

ImproveCTE matchingVSAvoidrigidity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The manifold is constructed from aluminum alloy, a material that provides the necessary rigidity and structural strength for longer printhead configurations (A3 size and beyond). While aluminum has different CTE properties than LCP, the design accepts this trade-off to achieve the required mechanical integrity for extended printhead lengths.

Inventive Principle:

Principle #40Composite materials

4Ease of manufacture

If flex PCB is used for electrical connections, then wiring is achieved, but manufacturing cost increases

Engineering Contradiction:

Improveelectrical wiringVSAvoidmanufacturing cost

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The flex PCB component is extracted and replaced with a simpler, more cost-effective solution. Electrical connections are achieved through alternative methods such as direct bonding or rigid PCB integration, eliminating the need for expensive flex PCB materials and complex bending operations while maintaining electrical connectivity functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

5Productivity

If multiple printheads are stacked for pagewide printing, then printing speed is improved, but alignment precision is compromised

Engineering Contradiction:

Improveprinting speedVSAvoidalignment precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

Multiple color channels (CMYK) are merged into a single integrated printhead unit rather than requiring separate stacked printheads. This consolidation eliminates alignment and registration issues between multiple printheads while maintaining high-speed pagewide printing capability through the unified multi-color architecture.

Inventive Principle:

Principle #5Merging (Combining)

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 design enhances print speed, minimizes print artifacts, and reduces the risk of de-priming and air bubble trapping, while enabling the construction of longer printheads and reducing manufacturing costs through simplified alignment and robust electrical connections.

Implementation Method 1

The printhead chips are mounted to the manifold surface via an adhe-sive; a rigid PCB is attached to the lower surface of the manifold, offset from the ink outlets; the PCB is electrically connected to the printhead chips; a shield plate covers the PCB, wherein the shield plate has one face in thermal contact with the PCB

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

using a metal alloy shim with low thermal expansion for attachment

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10870278B2Inkjet printhead with sealed shield plate

Publication Date: 2020.12.22 MEMJET TECH LTD

AI summary

An inkjet printhead includes: a support structure having a plurality of printhead chips mounted thereto; and a shield plate bonded to the support structure, the shield plate having a slot aligned with the printhead chips, the slot having a perimeter edge. A sealant is disposed on all exposed portions of the support structure adjacent the perimeter edge of each slot.