Variable Thickness Thermal Conductor for Fixing Belt Temperature Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing image forming apparatuses, such as copiers and printers, face challenges in maintaining uniform temperature distribution in fixing belts, leading to overheating and reduced productivity due to uneven thermal conductivity and increased contact resistance in conventional thermal conduction aids.

Innovation Solution

The implementation of a thermal conductor with varying thickness portions and folded portions in the nip former, where a decreased thickness portion in the center span facilitates quick warm-up and increased thickness portions with folded structures in lateral spans enhance thermal capacity, reducing overheating and improving thermal conduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a uniform thickness thermal conductor is used, then the structure is simple, but temperature distribution becomes uneven causing overheating in non-conveyance spans

Engineering Contradiction:

Improvetemperature distribution uniformityVSAvoidthermal conductor structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The thermal conductor is designed with varying thickness where the first span (conveyance span) has a first thickness and the second span (non-conveyance span) has a second thickness greater than the first thickness. This local variation in thickness provides different thermal capacities in different regions, allowing the conveyance span to warm up quickly while the non-conveyance span maintains lower temperature, thus resolving the temperature distribution uniformity issue without requiring complex external control systems.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If thermal conduction aid contact resistance increases, then manufacturing becomes easier, but thermal conduction efficiency decreases leading to temperature unevenness

Engineering Contradiction:

Improvethermal conduction aid assemblyVSAvoidthermal conduction efficiency

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention transitions from relying on improving contact interface quality (two-dimensional surface contact) to utilizing the third dimension of thermal conductor thickness variation. By making the thermal conductor itself thicker in the non-conveyance span region, the patent compensates for contact resistance issues through increased thermal capacity in the bulk material, thereby maintaining thermal conduction efficiency without requiring extremely precise assembly tolerances.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Temperature

If thermal conductor thickness is increased in non-conveyance span, then overheating is suppressed, but manufacturing precision requirements increase

Engineering Contradiction:

Improvenon-conveyance span temperature controlVSAvoidthermal conductor thickness variation

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The patent changes the thickness parameter of the thermal conductor along its length, creating a gradient structure where thickness varies from the first span to the second span. This parameter change approach allows for relatively simple manufacturing methods such as variable thickness extrusion or progressive rolling, where the thickness transition can be achieved through continuous process parameter adjustment rather than requiring precision machining of each section, thus balancing temperature control effectiveness with manufacturing feasibility.

Inventive Principle:

Principle #35Parameter changes

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 configuration effectively suppresses temperature increases in non-conveyance spans of the fixing belt, enhancing productivity by maintaining consistent temperature distribution and reducing thermal resistance, thus improving the overall efficiency of the image forming process.

Implementation Method 1

The thermal conductor includes a first face that contacts the tubular rotator... The thermal conductor has a thermal conductivity that is greater than a thermal conductivity of the support

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a heat source that heats the tubular rotator

Methodology Applied

Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentUS11320767B2Heating device, fixing device, and image forming apparatus

Publication Date: 2022.05.03 RICOH CO LTD

AI summary

A heating device includes a tubular rotator that rotates and a heat source that heats the tubular rotator. A thermal conductor includes a first face that contacts the tubular rotator and a second face that is opposite the first face. A first thickness portion is disposed in a first span of the thermal conductor in a longitudinal direction of the thermal conductor. The first thickness portion has a first thickness. A second thickness portion is disposed in at least a part of a second span of the thermal conductor in the longitudinal direction of the thermal conductor. The second span is different from the first span. The second thickness portion has a second thickness that is greater than the first thickness of the first thickness portion. The second thickness portion includes a folded portion that is disposed on the second face.