Carriage Air Curtain for Inkjet Printers

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Solution Overview

Problem

Scanning type inkjet printers face significant air flow issues under the carriage due to higher speeds and closer printhead-to-substrate spacing, leading to lower print quality and limitations in using higher carriage speeds and smaller ink drops.

Innovation Solution

A carriage is designed to form an air curtain across the print zone by actively or passively directing air, either through pressurized air ducting or air redirection, to inhibit airflow during printing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If higher carriage speeds are used, then productivity is improved, but air flow under the carriage increases causing ink drop placement errors

Engineering Contradiction:

Improvecarriage speedVSAvoidink drop placement precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

An air curtain is introduced as an intermediary substance between the carriage and print substrate to block air flow. The air curtain acts as a mediator that prevents the harmful air current from affecting ink drop placement while allowing the carriage to move at high speeds, thus resolving the contradiction between productivity and manufacturing precision.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful air flow under the carriage into a beneficial force by using it to generate the air curtain. The same air that causes problems at high speeds is redirected and pressurized to form a protective barrier, turning the harmful effect into a useful function that maintains ink drop placement precision.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Manufacturing precision

If printhead-to-substrate spacing is reduced, then manufacturing precision is improved, but air flow under the carriage increases

Engineering Contradiction:

Improveprint qualityVSAvoidair flow under carriage

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The air curtain serves as an intermediary layer between the printhead and substrate, allowing closer spacing while preventing harmful air flow. This mediator enables the system to achieve both close spacing for high precision and protection from air currents that would otherwise disrupt printing.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If active air curtain formation is used, then air flow inhibition is improved, but device complexity increases

Engineering Contradiction:

Improveair flow under carriageVSAvoidair ducting system

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The system uses the existing air flow that moves the carriage to serve the dual purpose of propulsion and air curtain generation. By positioning the air curtain to utilize the same air current, the system reduces the need for separate pressurization mechanisms, thereby lowering device complexity while maintaining effective air flow inhibition.

Inventive Principle:

Principle #25Self-service

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 air curtain effectively reduces air flow under the carriage, improving ink drop placement and allowing for higher carriage speeds and smaller ink drops without compromising print quality.

Implementation Method 1

actively by ducting pressurized air down toward the substrate at the upstream part of the carriage

Methodology Applied

Scientific EffectPressurized air flow: Pressure Gradient

Implementation Method 2

passively by redirecting oncoming air at the upstream part of the carriage down toward the substrate

Methodology Applied

Scientific EffectAir redirection: Fluid Spray

Data Source

PatentUS10099496B2Inhibiting air flow

Publication Date: 2018.10.16 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

In one example, a carriage to carry a printhead back and forth over a print substrate includes an inboard part to hold the printhead and an outboard part to inhibit the flow of air under the carriage when the carriage is moving back and forth over the print substrate.