Fixing Unit Grounding to Suppress AC-Induced Banding
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Solution Overview
Problem
Existing fixing units in image forming apparatuses using an electrophotographic system are prone to AC-induced banding, especially when recording materials are used that have been left standing in high temperature and high humidity environments.
Innovation Solution
The proposed fixing unit includes a tubular film, a heater with a heating resistor, an insulator, and a sliding member with electric conductivity. The sliding member is electrically connected to a conductive member grounded via at least one impedance element, which helps to suppress AC-induced banding by reducing the influence of AC voltage on the transfer process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heater with heating resistor is used to heat the toner image, then the toner image can be fixed to the recording material, but AC voltage transmitted through the recording material causes AC-induced banding and image defects
Solution Approach 1:
A conductive member (grounding plate) is introduced as an intermediary between the heater substrate and ground potential. This conductive member provides a controlled path for AC voltage dissipation, preventing AC voltage from being transmitted through the recording material to the transfer nip portion, thereby eliminating AC-induced banding while maintaining the heating function
Solution Approach 2:
The electrical potential of the heater substrate is changed from floating or isolated to being electrically connected to ground potential through the conductive member. This parameter change (electrical connection state) allows AC voltage to be dissipated safely, preventing its transmission through the recording material and eliminating the harmful AC-induced banding effect
2Object-affected harmful factors
If the heater substrate is electrically connected to ground potential, then AC-induced banding is suppressed, but the complexity of the electrical connection system increases
Solution Approach 1:
The grounding function is merged with the existing heater substrate structure by making the substrate itself electrically conductive and connecting it to ground potential through a conductive member. This combines the heating substrate's structural role with the electrical grounding function, eliminating the need for separate grounding structures and reducing overall system complexity
Solution Approach 2:
The heater substrate is given dual functionality: it serves both as the heating element carrier and as an electrical path to ground potential. By making the substrate electrically conductive and connecting it to ground, it simultaneously performs mechanical support and electrical grounding functions, simplifying the overall design
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 AC-induced banding by reducing the amplitude of the AC voltage at the fixing nip, thereby improving image density uniformity and reducing the occurrence of image defects.
Implementation Method 1
a heater arranged inside the film and including a heating resistor configured to generate heat by passing alternating current therethrough
Data Source
AI summary
A fixing unit includes a film including a tubular shape and configured to rotate, a heater arranged inside the film and including a heating resistor configured to generate heat by passing alternating current therethrough and an insulator configured to cover the heating resistor, a sliding member arranged between the heater and the film and configured to be in sliding contact with an inner surface of the film, the sliding member having electric conductivity, a pressing member configured to be in pressure contact with the sliding member across the film to form a nip portion between the sliding member and the pressing member, and a conductive member electrically connected to a ground potential via at least one impedance element. The sliding member is electrically connected to the conductive member.