Inkjet Drying Device Airflow Management Prevents Condensation

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Solution Overview

Problem

Existing drying devices for inkjet printers face issues with condensation of moisture-laden air outside the device, leading to droplet formation and adhesion problems, which are not effectively addressed by previous solutions like heat discharging fins and restricted heat sources.

Innovation Solution

The drying device incorporates a duct with a serpentine path made of solvent-resistant materials like stainless steel, where the air is gradually cooled by increasing the contact area and using a combination of heating and cooling sections to reduce temperature, preventing condensation and collecting droplets efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the air inside the drying section is exhausted outside the device, then the moisture and solvent are removed from the drying section, but the air condenses outside the device and forms liquid droplets

Engineering Contradiction:
Improvedrying effectivenessVSAvoidcondensation and droplet formation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A condensation prevention section is introduced as an intermediary component between the drying section and the external environment. This section includes a condensation prevention heater that heats the air before it is exhausted outside, preventing condensation. The condensation prevention section acts as a mediator that transforms the harmful cold, moisture-laden air into a safe, warm, condensed vapor stream that can be safely discharged without forming droplets.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The temperature parameter of the air is changed by heating it in the condensation prevention section before discharge. By increasing the temperature of the air from the drying section, the dew point is raised above the external ambient temperature, preventing condensation. This parameter change transforms the air from a condensation-prone state to a stable, non-condensing state.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a heater is provided to supply heat to coated paper, then the solvent medium is eliminated and the image is fixed, but the heat becomes excessive for normal paper and requires an extra appliance

Engineering Contradiction:
Improveimage fixation on coated paperVSAvoidnumber of heating appliances
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The drying section with the heat roller is designed to serve multiple functions: it can dry coated paper by eliminating solvent medium, and it can also gently warm normal paper without excessive heat. The heating capability is made universal to handle different paper types, eliminating the need for separate heating appliances for different paper kinds.

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

Solution Approach 2:

The heating function is merged into the drying section that is already present in the inkjet printer system. By integrating the heat roller and drying capabilities into the existing printer architecture, the need for separate external heating appliances is eliminated, reducing device complexity while maintaining image fixation capability.

Inventive Principle:
Principle #5Merging (Combining)

3Object-generated harmful factors

If the recording medium is cooled to prevent blocking, then adhesion between stacked recording media is reduced, but the ink image may be affected by temperature changes

Engineering Contradiction:
Improveblocking phenomenonVSAvoidimage quality
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

Cooling is applied locally and selectively to prevent blocking, while the drying section maintains appropriate temperature for image fixation. The cooling section is positioned downstream after the drying section, so that the image is first fixed by heat, then the recorded medium is cooled to prevent blocking. This local quality approach ensures that each section performs its specific function without interfering with the other.

Inventive Principle:
Principle #3Local quality

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 effectively prevents condensation and droplet formation outside the device, ensuring efficient heat absorption and collection of moisture, thereby maintaining device integrity and preventing adhesion issues.

Implementation Method 1

the air is gradually cooled by increasing the contact area

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

the heating section or the drying section heated by the heat roller heats the recording medium to eliminate solvent inside the ink

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 3

the air outside the device is taken in and is blown to the recording medium, and the air inside the cooler is sucked and is exhausted outside the device, so that a flow of air is formed and the heat is absorbed from the recording medium

Methodology Applied
Scientific EffectHeat absorption: Conduction (thermal)

Implementation Method 4

the air containing a great deal of moisture contacts other parts in the drying section, the air is cooled and condensed to thereby adhere the other parts as liquid droplets

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3189974B1Drying device, and inkjet printer system including drying device
Publication Date: 2020.04.29 RICOH CO LTD
  • EP3189974B1 patent drawingFigure 1
  • EP3189974B1 patent drawingFigure 2
  • EP3189974B1 patent drawingFigure 3

AI summary

A drying device includes a drying section (3) to dry a recording medium (W); a cooling section (5) to cool the recording medium (W) conveyed from the drying section (3); and a duct (10) to expel air inside the drying section (3) to outside the drying device. The duct (10) includes a joint section (18) where the air from the drying section (3) meets air from the cooling section (5). The air from the drying section (3) containing moisture and solvent medium is cooled in the duct (10).