Wiper Two-Layer Structure for Nozzle Cleaning

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Solution Overview

Problem

Conventional wiper methods struggle to effectively remove dried, fixedly-adhered matter from nozzle surfaces of liquid discharge heads, leading to unstable or non-discharging issues after cleaning, affecting discharge reliability.

Innovation Solution

A wiper with a two-layer nonwoven fabric structure, where the first layer has a specific waviness and roughness to scrape off dried ink, and the second layer absorbs excess liquid, combined with a cleaning fluid containing a compound and glycol ether to dissolve and permeate dried ink, improving the wiping process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional single-layer wiper is used to clean the nozzle surface, then the structure is simple and easy to manufacture, but it cannot effectively remove fixedly-adhered dried matter from the nozzle surface

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidwiper structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The wiper is divided into two distinct layers: a first layer with voids and capillary action for guiding and capturing dispersed particles, and a second layer for absorbing the dispersion medium. This segmentation allows each layer to perform its specific function optimally, enabling effective removal of fixedly-adhered matter while maintaining a manageable structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The wiper combines two different material structures in a composite configuration - the first layer uses a porous structure with specific void ratios for capillary action and particle capture, while the second layer uses an absorbent material for liquid absorption. This composite approach leverages the complementary properties of different materials to achieve superior cleaning performance that neither layer could accomplish alone.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a conventional wiper is used to wipe the nozzle surface, then the wiping process is simple, but unstable discharging or non-discharging occurs after cleaning, affecting discharge reliability

Engineering Contradiction:
Improvedischarge reliabilityVSAvoidwiping process
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The two-layer structure separates the cleaning functions into distinct stages: the first layer captures and holds dispersed particles through capillary action in its voids, while the second layer absorbs excess dispersion medium. This segmentation prevents residual liquid from interfering with nozzle discharge, thereby improving discharge reliability without complicating the wiping operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first layer is designed with specific voids and porosity to enable capillary action, which automatically draws the dispersion liquid into the layer and traps dispersed particles. This porous structure provides self-regulating liquid management that ensures reliable nozzle discharge after cleaning without requiring complex operational controls.

Inventive Principle:
Principle #31Porous materials

3Reliability

If multiple wiping cycles are performed to remove fixedly-adhered matter, then cleaning effectiveness improves, but the time and number of operations increase

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidwiping time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The composite two-layer structure performs multiple cleaning functions simultaneously in a single wiping action: the first layer captures dispersed particles through capillary action while the second layer absorbs excess liquid. This multi-functional composite design achieves thorough removal of fixedly-adhered matter in one pass, eliminating the need for repeated wiping cycles and reducing time consumption.

Inventive Principle:
Principle #40Composite materials

4Reliability

If the first layer has high void ratio for capillary action, then droplet guidance and particle capture improve, but liquid absorption capacity decreases

Engineering Contradiction:
Improvedroplet guidance and particle captureVSAvoidliquid absorption capacity
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The wiper structure segments the liquid management functions between two layers: the first layer with high void ratio is dedicated to capillary action, droplet guidance, and particle capture, while the second layer is dedicated to bulk liquid absorption. This segmentation allows the first layer to maintain high porosity for effective capillary action without compromising overall liquid absorption capacity, as the second layer compensates for this.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The composite structure combines a porous first layer optimized for capillary action with an absorbent second layer optimized for liquid absorption. This material combination allows the system to simultaneously achieve effective droplet guidance and particle capture in the first layer while maintaining sufficient overall liquid absorption capacity through the second layer.

Inventive Principle:
Principle #40Composite materials

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 wiper efficiently removes fixedly-adhered matter and enhances discharge reliability by effectively cleaning the nozzle surface, reducing the number of wiping cycles required and minimizing post-cleaning discharge issues.

Implementation Method 1

The first layer has voids capable of guiding droplets, which are the dispersion medium of the dispersion liquid adhered to the nozzle surface, to the second layer by capillary action

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

The second layer absorbs the dispersion medium

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP3902682B1Wiper, wiping device, liquid discharge apparatus, and wiping method
Publication Date: 2024.05.22 RICOH CO LTD
  • EP3902682B1 patent drawingFigure 1
  • EP3902682B1 patent drawingFigure 2
  • EP3902682B1 patent drawingFigure 3

AI summary

A wiper for wiping a nozzle surface of a liquid discharge head that discharges liquid from the nozzle is provided. The wiper comprises a plurality of layers including at least a first layer, and the first layer has a surface that contacts the nozzle surface. The surface that contacts the nozzle surface has a maximum height of waviness Wz of from 100 to 600 μm.