Planar-Heater Fixing Device with Charge Elimination for Banding
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Solution Overview
Problem
Existing heating devices in image forming apparatuses face electrical issues such as toner electrostatic offset and banding images due to charging of the fixing belt and pressure roller surfaces, which are exacerbated in low-humidity environments or with high-resistance sheets, and AC voltage propagation affecting transfer electric fields.
Innovation Solution
Incorporation of conductive layers and charge eliminators, including a conductive pressure roller and charge eliminating brushes grounded via resistors, to neutralize surface charges and prevent AC voltage propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an AC voltage is applied to the heater, then heating function is achieved, but AC voltage propagates to the transfer nip causing banding images
Solution Approach 1:
A charge eliminator is introduced as an intermediary component between the heater and the transfer nip. The charge eliminator includes a conductive layer that contacts the fixing belt and a ground connection that provides a discharge path for AC voltage, preventing its propagation to the transfer nip while maintaining the heating function
2Reliability
If the fixing belt and pressure roller surfaces are charged, then toner image fixing is achieved, but electrostatic offset occurs causing abnormal images
Solution Approach 1:
The charge eliminator acts as a mediator that selectively discharges surface charges from the fixing belt and pressure roller. It maintains necessary charges for toner fixing while removing excess charges that cause electrostatic offset, achieving a balanced state
3Object-affected harmful factors
If charge eliminators are added to neutralize surface charges, then electrostatic offset is prevented, but device complexity increases
Solution Approach 1:
The charge eliminator uses a thin conductive layer structure that can be integrated into the existing fixing device architecture. The conductive layer is disposed on a flexible support structure that conforms to the cylindrical shape of the fixing belt, maintaining simplicity while providing effective charge neutralization
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
Prevents toner electrostatic offset and banding images by effectively neutralizing surface charges and blocking AC voltage transmission, ensuring high-quality image formation across varying environmental conditions.
Implementation Method 1
The heater generates heat as an alternating current (AC) voltage is to a resistive heat generator on a base of the heater
Implementation Method 2
The one or more charge eliminators contact the conductive layer and the outer surface of the pressure rotator
Implementation Method 3
The pressure rotator presses the heating rotator and has an outer surface including a conductive material
Data Source
AI summary
A heating device includes a planar heater, a heating rotator, a pressure rotator, and one or more charge eliminators. The planar heater includes a base and a resistive heat generator. The heating rotator contacts the heater and includes a conductive layer. The pressure rotator presses the heating rotator and has an outer surface including a conductive material. The one or more charge eliminators contact the conductive layer and the outer surface of the pressure rotator.