Fixing Device Conductive Member Grounding for Banding Control
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Solution Overview
Problem
Image forming apparatuses experience uneven image density due to alternating current voltage affecting the transfer electric field, leading to banding images, especially in high-humidity environments or with thin sheets, and electrostatic offset causing faulty toner images.
Innovation Solution
A fixing device with a conductive member that pivots and is restricted by a pivot restrictor, grounded through a support, to release alternating current voltage and prevent electric charge accumulation on the fixing belt, thereby stabilizing the electric field and reducing electrostatic offset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the heater is applied with alternating current voltage to heat the fixing belt, then heating function is achieved, but the alternating current voltage is transmitted to the transfer nip through the sheet, causing banding images and uneven image density
Solution Approach 1:
The patent extracts the harmful alternating current voltage from the system by introducing a conductive member that grounds the fixing belt, removing the voltage that causes banding images while preserving the heating function
Solution Approach 2:
The conductive member acts as an intermediary between the fixing belt and ground, providing a path to discharge alternating current voltage without interfering with the thermal heating process
2Reliability
If the conductive member is made pivotable to accommodate belt deformation, then contact reliability is improved, but device complexity increases due to need for pivot restriction mechanism
Solution Approach 1:
The conductive member is designed to pivot dynamically, allowing it to adapt to fixing belt deformation while maintaining reliable contact, with the pivot restrictor providing necessary constraints
3Stability of the object's composition
If the pivot restrictor projects farther than the opposed portion to prevent pivoting, then pivoting is restricted, but assembly complexity increases
Solution Approach 1:
The pivot restrictor creates a stable configuration by preventing excessive pivoting, ensuring the conductive member maintains consistent contact pressure and position
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 banding images and faulty toner images by effectively grounding the electric charge on the fixing belt, ensuring consistent image quality and reducing assembly complexity.
Implementation Method 1
the resistive heat generator generates heat, thus heating an inner circumferential face of the fixing belt through the insulating layer and the like
Implementation Method 2
The conductive member contacts an inner face of the belt... effectively grounding the electric charge on the fixing belt
Data Source
AI summary
A fixing device includes a belt and a holder that holds a heater. A conductive member contacts an inner face of the belt and pivots. The conductive member includes one end portion in a rotation direction of the belt and an opposed portion that abuts on the one end portion. A support supports the holder and presses the conductive member against the holder. The holder includes a holding portion that holds the one end portion of the conductive member, a pivot restrictor that restricts pivoting of the conductive member about the one end portion, and a mount face from which the pivot restrictor projects in a projecting direction. The pivot restrictor projects farther than the opposed portion of the conductive member in the projecting direction of the pivot restrictor in a state in which the support does not press the conductive member against the holder.