Heater with Segmented Heat Generators for Uniform Temperature

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Solution Overview

Problem

Existing image forming apparatus heaters experience uneven temperature distributions due to heat generation from resistive heat generators and feeders, leading to issues like uneven toner image gloss and degradation in image quality.

Innovation Solution

The heater design incorporates a configuration where primary and secondary connectors connect resistive heat generators differently, adjusting heat generation distribution by dividing each generator into sections and varying connector connections between parts and other generators, ensuring consistent heat delivery across the heating surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If resistive heat generators and feeders are used to heat the image on the recording medium, then heating function is achieved, but uneven temperature distribution occurs

Engineering Contradiction:

Improvetemperature distributionVSAvoidimage quality

Core Design Contradiction:

TemperatureVSManufacturing precision

Solution Approach 1:

The heater is divided into multiple heat generator units arranged in the longitudinal direction, with each unit having independent connectors. This segmentation allows different sections to be controlled independently, enabling compensation for temperature variations across different regions of the heater.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Connectors are positioned at different locations (first connector at one end, second connector at the other end) to create non-uniform current distribution. This local variation in connector placement compensates for heat loss at different positions, ensuring more uniform temperature distribution across the heating surface.

Inventive Principle:

Principle #3Local quality

2Reliability

If connectors are placed at the ends of the base, then electrical connection is achieved, but heat generation from feeders causes temperature unevenness

Engineering Contradiction:

Improveelectrical connectionVSAvoidtemperature uniformity

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The base serves as an intermediary thermal conductor that distributes heat from the heat generators to the recording medium. By positioning connectors at opposite ends and using the base as a thermal mediator, the system achieves both reliable electrical connection and more uniform heat distribution across the heating surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The problem of temperature unevenness in the longitudinal direction is solved by introducing connector placement in both longitudinal dimensions (at both ends). This dimensional approach allows heat to be introduced from multiple points along the length, compensating for thermal gradients.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Device complexity

If a simple heater structure is used, then device complexity is reduced, but temperature control precision deteriorates

Engineering Contradiction:

Improveheater structureVSAvoidtemperature control

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The heater is segmented into multiple heat generator units with independent connectors, allowing each section to contribute to the overall heating while maintaining relative structural simplicity. This modular approach enables better temperature control without significantly increasing device complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The position parameters of the connectors are changed (placed at opposite ends rather than at a single location), which fundamentally alters the heat distribution pattern. This parameter change achieves improved temperature control precision while maintaining a relatively simple overall structure.

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 significantly reduces temperature unevenness, preventing failures like uneven gloss and maintaining image quality by optimizing heat distribution across the heater's longitudinal direction.

Implementation Method 1

a first heat generator mounted on the base, and a second heat generator arranged with the first heat generator in the longitudinal direction of the base. Each of the first heat generator and the second heat generator has a hypothetical center line in the longitudinal direction of the base

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11487231B2Heater, heating device, and image forming apparatus

Publication Date: 2022.11.01 RICOH CO LTD

AI summary

A heater includes a first heat generator and a second heat generator each of which has a hypothetical center line that divides each of the first heat generator and the second heat generator into a first section and a second section. A first conductor connects a first electrode to the first heat generator and the second heat generator. A second conductor connects a second electrode to the first heat generator and the second heat generator. A first primary connector connects the first conductor to the first section of the first heat generator. A second primary connector connects the first conductor to the second section of the second heat generator. A first secondary connector connects the second conductor to the first heat generator. A second secondary connector connects the second conductor to the second heat generator.