Printhead Die Crack Sensing via Time-Multiplexed ASIC

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Solution Overview

Problem

Printhead dies in wide array printing devices are prone to hairline cracks, which can propagate and cause circuit malfunctions, and existing measurement and control circuitry is costly and space-intensive.

Innovation Solution

Implementing an application-specific circuit (ASIC) separate from the printhead dies to perform time-multiplexed crack sensing using crack sense resistors, reducing the need for individual circuitry on each die and consolidating measurement and control functions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If individual measurement and control circuitry is provided on each printhead die, then crack detection capability is improved, but cost and space requirements increase significantly

Engineering Contradiction:
Improvecrack detection capabilityVSAvoidcircuitry space requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The measurement and control circuitry is extracted from the printhead die and placed on a separate substrate. This allows the printhead die to maintain crack detection capability through externally connected circuitry, while reducing the space requirements on the die itself. The circuitry is taken out and repositioned to resolve the contradiction between detection capability and space constraints.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A single set of measurement and control circuitry on the separate substrate serves multiple printhead dies simultaneously. This universal circuitry provides crack detection capability for all connected dies without requiring individual circuitry on each die, thereby reducing overall device complexity and space requirements while maintaining reliability.

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

2Reliability

If individual measurement and control circuitry is provided on each printhead die, then crack detection capability is improved, but manufacturing cost increases

Engineering Contradiction:
Improvecrack detection capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple printhead dies are merged with a single set of measurement and control circuitry on a shared substrate. This consolidation reduces the total number of circuitry units required, lowering manufacturing costs while maintaining crack detection capability across all dies through the shared circuitry resource.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The universal circuitry on the separate substrate serves multiple printhead dies, reducing the overall component count and manufacturing complexity. This multi-functional approach lowers production costs compared to providing individual circuitry on each die, while still enabling crack detection for all dies.

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

3Reliability

If multiple crack detectors are provided on a printhead, then crack detection coverage is improved, but device complexity increases

Engineering Contradiction:
Improvecrack detection coverageVSAvoidcircuitry quantity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Crack detectors are extracted from individual printhead dies and consolidated on a separate substrate. This allows multiple detection points to be maintained for comprehensive coverage, while the external placement reduces the complexity burden on each individual die and enables shared circuitry resources.

Inventive Principle:
Principle #2Taking out (Extraction)

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 approach significantly reduces cost and space requirements for circuitry while effectively monitoring printhead dies for cracks, enhancing the reliability and efficiency of the printing system.

Implementation Method 1

a crack sense resistor for each printhead die of the plurality of printhead dies

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3293009B1Crack sensing for printhead having multiple printhead dies
Publication Date: 2021.09.08 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3293009B1 patent drawingFigure 1
  • EP3293009B1 patent drawingFigure 2
  • EP3293009B1 patent drawingFigure 3

AI summary

In an example, a printhead (102) comprises a plurality of printhead dies (114), each printhead die including at least one crack sense element (120); and at least one analog bus (150) connected to each printhead die, the at least one analog bus to deliver a known current to at least one crack sense element and to output a voltage to allow a controller to determine whether at least one of the printhead dies is cracked based on the voltage.