Separator With Projecting Portion for Thermal Stress Resistance

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Solution Overview

Problem

Conventional separators in fixing devices for image forming apparatuses face issues with durability and image quality due to thermal expansion and contraction, leading to adhesive failure and deformation, which results in faulty medium conveyance and reduced lifespan.

Innovation Solution

A separator design featuring a base with a tapered shape and a resin sheet attached via a silicone adhesive, where the sheet's length is equal to or greater than the base's length, with a projecting portion to prevent peeling and ensure stable attachment, enhancing durability and image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separator is used in contact with the fixing rotator or pressure rotator, then medium separation is improved, but thermal expansion and contraction cause adhesive failure and deformation

Engineering Contradiction:

Improvemedium separationVSAvoidadhesive attachment

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the physical parameters of the separator by introducing a projecting portion that extends beyond the end of the base in the longitudinal direction. This structural parameter change allows the adhesive to be applied in a manner that accommodates thermal expansion and contraction, preventing adhesive failure while maintaining reliable medium separation functionality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent adds a dimensional feature by creating a projecting portion that extends in the longitudinal direction beyond the base. This dimensional change provides additional surface area for adhesive attachment and creates a structural configuration that resists thermal deformation, thereby improving adhesive stability without compromising separation performance.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Temperature

If the separator is subjected to thermal stress from heat and pressure, then fixing function is maintained, but adhesive peeling and deformation occur

Engineering Contradiction:

Improveheat resistanceVSAvoidadhesive bond strength

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

The patent modifies the geometric parameters of the separator by adding a projecting portion that extends beyond the base. This parameter change increases the effective adhesive attachment area and creates a structural configuration that better distributes thermal stress, preventing adhesive peeling while maintaining the necessary heat resistance for fixing operation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The projecting portion acts as a preemptive structural feature that cushions against thermal stress before adhesive failure can occur. By providing additional adhesive attachment surface and structural flexibility in advance, the design prevents thermal shock from causing adhesive peeling during heat and pressure cycles.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If the separator structure is simplified, then manufacturing is easier, but durability against thermal stress is reduced

Engineering Contradiction:

Improveseparator fabricationVSAvoidthermal stress resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent segments the separator structure into a base and a projecting portion, where the projecting portion is a distinct structural element that can be independently formed or attached. This segmentation allows for simplified manufacturing of each component while the combined structure provides enhanced thermal stress resistance through increased adhesive attachment area and improved stress distribution.

Inventive Principle:

Principle #1Segmentation

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 separator effectively withstands thermal stress, maintaining adhesion and preventing peeling, thus ensuring reliable medium separation and extended device lifespan while maintaining image quality.

Implementation Method 1

The sheet is attached to the first face and the second face via a silicone adhesive

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

Conventional separators in fixing devices for image forming apparatuses face issues with durability and image quality due to thermal expansion and contraction

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10295938B2Separator, fixing device, and image forming apparatus

Publication Date: 2019.05.21 RICOH CO LTD

AI summary

A separator includes a base and a sheet. The base includes a first face to face a medium, a second face being opposite to the first face, and a third face being an end face in a longitudinal direction of the base. The sheet is disposed on a portion of each of the first and second faces that contacts or is adjacent to a rotator. The sheet has a length in a longitudinal direction thereof substantially equal to a length of the base in the longitudinal direction thereof. The sheet includes a projecting portion outboard from the length of the sheet in the longitudinal direction thereof. A combined length of the sheet and the projecting portion in the longitudinal direction of the sheet is greater than the length of the base in the longitudinal direction thereof. The projecting portion is attached to the second and third faces of the base.