Transfer Belt Bias Control for Uniform Toner Transfer on Uneven Media
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increase in charge amount of toner on the intermediary transfer belt due to electric discharge between the intermediary transfer belt and the photosensitive drum downstream of the primary transfer portion leads to difficulties in uniform toner transfer onto recording materials with surface unevenness and creates a narrow secondary transfer latitude, particularly with high-resistance materials like coated paper and synthetic paper.
Innovation Solution
An image forming apparatus with a potential regulating member, an electroconductive electrode, is provided downstream of the primary transfer portion, applying a bias of the same polarity as the photosensitive drum to suppress toner charge increase, and a controller adjusts this bias based on the recording material type to enhance transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a secondary transfer bias is increased to transfer toner onto embossed paper with surface unevenness, then transfer capability is improved, but toner scattering and image disturbance occur due to excessive electric field strength
Solution Approach 1:
The patent applies a preliminary discharge treatment before secondary transfer by applying a discharge bias to the intermediary transfer belt. This preliminary action removes excess charge from the toner image, preventing excessive mirror force during the subsequent secondary transfer process, thereby eliminating toner scattering while maintaining transfer capability
Solution Approach 2:
The patent changes the electrical parameter (charge amount) of the toner on the intermediary transfer belt by applying a controlled discharge bias. This parameter change reduces the charge amount to an optimal level that prevents scattering during secondary transfer while maintaining sufficient adhesion for transfer onto the recording material
2Force
If the charge amount of toner on the intermediary transfer belt is increased, then transfer force is improved, but uniform transfer onto embossed paper becomes difficult due to mirror force increase
Solution Approach 1:
The patent applies a preliminary discharge treatment before secondary transfer by applying a discharge bias to the intermediary transfer belt. This preliminary action removes excess charge from the toner image, preventing excessive mirror force during the subsequent secondary transfer process, thereby eliminating toner scattering while maintaining transfer capability
Solution Approach 2:
The patent changes the electrical parameter (charge amount) of the toner on the intermediary transfer belt by applying a controlled discharge bias. This parameter change reduces the charge amount to an optimal level that prevents scattering during secondary transfer while maintaining sufficient adhesion for transfer onto the recording material
3Reliability
If a potential regulating member is provided downstream of the primary transfer portion, then toner charge increase is suppressed, but device complexity increases
Solution Approach 1:
The patent makes the intermediary transfer belt serve multiple functions: it acts as both the transfer medium for toner images and as the electrode member for charge regulation. By forming the electrode layer directly on the belt, the structure eliminates the need for separate potential regulating members, reducing device complexity while maintaining charge control functionality
Solution Approach 2:
The patent merges the intermediary transfer belt and the electrode member into a single integrated structure. The electrode layer is formed directly on the belt surface, combining the transfer function and the charge regulation function into one component, thereby simplifying the overall apparatus structure
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 suppresses toner scattering and image disturbance, ensuring uniform toner transfer even on materials with surface unevenness and maintaining a wide secondary transfer latitude across various recording materials.
Implementation Method 1
a bias (potential regulating bias) of the same polarity as the charge polarity of the photosensitive drum is applied to the potential regulating member
Implementation Method 2
the toner is subjected to electric discharge between the intermediary transfer belt and the photosensitive drum
Implementation Method 3
the toner images formed on the photosensitive drums are electrostatically primary transferred successively onto the intermediary transfer belt
Implementation Method 4
the toner images primary transferred on the intermediary transfer belt are electrostatically secondary transferred onto a recording material such as paper
Data Source
AI summary
An image forming apparatus includes a photosensitive member, an intermediary transfer belt, a primary transfer member, an electrode member, a first applying portion configured to apply, to the primary transfer member, a bias of a polarity opposite to a predetermined polarity, a second applying portion configured to apply, to the electrode member, a bias of the same polarity as the predetermined polarity, and a controller configured to control the second applying portion so as to change the bias applied to the electrode member on the basis of a kind of a recording material.