Heating Member Temperature Control for Toner Fixing

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Solution Overview

Problem

Existing image forming apparatuses using cylindrical film fixing units face challenges in controlling temperature rise in non-paper passing portions, leading to inefficient heat distribution and potential fixing failures, especially during high-speed printing and high printing rate images.

Innovation Solution

The apparatus incorporates a temperature detection system and a controller that adjusts the target temperature and power supply to the heating member based on the printing rate information, particularly focusing on the end portions of the recording material, to maintain optimal surface temperature and prevent fixing failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the caloric value of the heater in the non-paper passing portion is reduced to control temperature rising, then temperature control is improved, but the toner image in the end portion may not be sufficiently fixed

Engineering Contradiction:

Improvetemperature in non-paper passing portionVSAvoidfixing quality of toner image

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent applies dynamics by making the target temperature of the heater dynamically adjustable based on real-time detection of toner image area ratio. The controller modifies the target temperature according to the printing rate, allowing the system to adapt between different operating conditions (high printing rate vs. low printing rate) to resolve the contradiction between temperature control and fixing quality

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of target temperature based on the detected toner image area ratio. When the printing rate is high (large toner image area ratio), the target temperature is set lower to prevent overheating in non-paper passing portions. When the printing rate is low (small toner image area ratio), the target temperature is set higher to ensure sufficient fixing. This parameter change resolves the technical contradiction

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If the heater caloric value is reduced to prevent temperature rising in non-paper passing portion, then temperature stability is improved, but fixing performance at end portions deteriorates

Engineering Contradiction:

Improvetemperature stabilityVSAvoidfixing quality

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent changes the target temperature parameter dynamically based on the toner image area ratio detection. By adjusting the target temperature according to printing rate conditions, the system maintains temperature stability when needed (high printing rate) while ensuring sufficient fixing temperature when required (low printing rate), thus resolving the contradiction between temperature stability and fixing quality

Inventive Principle:

Principle #35Parameter changes

3Temperature

If a fan is used to blow breeze onto the fixing film to control temperature rising, then temperature control is improved, but device complexity and cost increase

Engineering Contradiction:

Improvetemperature in non-paper passing portionVSAvoidapparatus structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical cooling system (fan blowing breeze) with a control system that adjusts the heater's target temperature electronically. The controller detects the toner image area ratio and modifies the target temperature parameter accordingly, eliminating the need for additional mechanical cooling components and their associated complexity and cost

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Instead of using a fan to physically cool the fixing film, the patent changes the thermal parameter (target temperature) of the heater based on detected printing conditions. This parameter-based control approach achieves temperature management without adding mechanical complexity

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 solution effectively maintains the surface temperature of the fixing film within optimal ranges, ensuring reliable fixing performance even at high printing rates and extending the durability of the fixing unit by dynamically adjusting the target temperature based on printing rate data.

Implementation Method 1

a heater that contacts the inner surface of the film... The fixing apparatus heats the recording material bearing a toner image using the nip portion

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS9442437B2Image forming apparatus changing target temperature of heating member or interval between preceding and subsequent recording material in accordance with ratio of toner image area in predetermined region to predetermined region area

Publication Date: 2016.09.13 CANON KK

AI summary

An image forming apparatus that forms a toner image on a recording material includes: a temperature detection portion that detects the temperature of a heating member; a controller that controls the power to be supplied to the heating member so that the temperature detected by the temperature detection portion becomes the target temperature; and an acquisition portion that acquires information on a ratio of a region, where the toner image is formed, in a predetermined region located in an end portion of the recording material in a width direction thereof, and this controller changes the target temperature in accordance with the ratio.