Printhead Die Temperature Control via Centralized ASIC

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Solution Overview

Problem

Existing printhead devices face challenges in accurately and efficiently measuring and controlling temperature uniformity across multiple printhead dies, leading to issues like ink droplet size variation, light area banding, and striping in printed media due to non-uniform temperatures.

Innovation Solution

Implementing a centralized application-specific integrated circuit (ASIC) connected to multiple printhead dies, which includes temperature sensors and control logic for time-multiplexed measurement and control, allowing for fast and accurate temperature regulation and integrity monitoring of each printhead die.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature control circuitry is integrated within each printhead die, then temperature measurement and control can be performed locally, but manufacturing cost and device complexity increase due to redundant circuitry

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidcontrol circuitry redundancy
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the temperature control circuitry from individual printhead dies and consolidates it into a separate controller. The controller includes temperature sensors that interface with multiple printhead dies through a bus system, eliminating redundant circuitry while maintaining local temperature measurement and control capabilities. This extraction reduces manufacturing costs and device complexity while preserving measurement precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The separate controller is designed to serve multiple printhead dies simultaneously through a time-multiplexed bus interface. A single temperature sensor and control circuit can measure and regulate temperatures across multiple dies by sequentially interfacing with each one, making the controller universal and eliminating the need for dedicated circuitry in each die.

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

2Stability of the object's composition

If multiple temperature sensors and control circuitry are placed in each printhead die, then temperature uniformity can be monitored and controlled, but manufacturing cost increases

Engineering Contradiction:
Improvetemperature uniformityVSAvoidmanufacturing cost
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent extracts temperature sensing and control functions from individual printhead dies and consolidates them into a shared controller. This eliminates the need to manufacture expensive temperature control circuitry in each die, significantly reducing per-unit manufacturing costs while maintaining the ability to monitor and control temperature uniformity across all dies.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges multiple temperature sensing and control functions into a single shared controller that serves multiple printhead dies. By combining these functions and using time-multiplexed communication through a bus interface, the system achieves temperature uniformity control without the high manufacturing cost of duplicating circuitry in each die.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If temperature is rapidly measured and controlled in multiple printhead dies, then print quality improves by preventing defects, but device complexity and cost increase

Engineering Contradiction:
Improveprint quality consistencyVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements periodic temperature measurement and control through time-multiplexed operation. The controller sequentially interfaces with multiple printhead dies in rapid succession, measuring and adjusting temperatures in a periodic cycle. This approach maintains print quality consistency by ensuring temperature uniformity across all dies while using a simpler, shared control system rather than complex distributed control in each die.

Inventive Principle:
Principle #19Periodic action

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 solution reduces manufacturing costs, enhances temperature control precision, and minimizes defects such as light area banding and striping by ensuring uniform temperature across printhead dies, thereby improving print quality.

Implementation Method 1

Each of the printhead die includes a number of sensors to measure properties of a number of elements associated with the printhead die

Methodology Applied
Scientific EffectTemperature sensing:

Implementation Method 2

Examples described herein determine if a printhead die or a number of zones within the printhead die are to be heated, or if is to be deactivated to achieve a uniform temperature throughout the length of the printhead

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3456542B1Printhead die
Publication Date: 2020.04.01 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3456542B1 patent drawingFigure 1A
  • EP3456542B1 patent drawingFigure 1B
  • EP3456542B1 patent drawingFigure 2

AI summary

A printhead die includes a number of sensors to measure properties of a number of property control elements associated with the printhead die, a pass gate to communicate a number of signals to an application specific integrated circuit (ASIC) via an analog bus using control logic associated with the pass gate, and a bi-directional configuration bus coupled to the printhead die to transmit a number of control signals to property control elements located on the printhead die.