Intermediate Transfer Belt Discharge Current Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increase in electric resistance of the intermediate transfer belt in image forming apparatuses using an electrophotographic system leads to image defects due to uneven ion distribution, particularly when using an ion-conductive material with an elastic layer, causing issues with primary and secondary transfer processes and resulting in image density unevenness when adjusting discharge currents during print jobs.
Innovation Solution
An image forming apparatus with a control unit that manages discharge currents by detecting primary and secondary transfer currents and adjusting them to maintain a constant current balance, ensuring the discharge current is changed before the image forming region passes through the primary transfer portion, thereby balancing ion distribution and reducing electric resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an ion-conductive material is used in the intermediate transfer belt to adjust electric resistance, then transferability to recording materials with uneven surfaces is improved, but the electric resistance increases unevenly due to ion distribution imbalance
Solution Approach 1:
The control unit continuously monitors the discharge current and automatically adjusts it to maintain a constant balance between inward and outward ion currents. This feedback mechanism ensures that ion distribution remains uniform and electric resistance stays stable, preventing image defects while preserving the benefits of ion-conductive material for transferability to uneven surfaces.
2Manufacturing precision
If discharge current is adjusted during print jobs to maintain ion balance, then image quality is improved, but image density unevenness occurs when current changes are made during active printing
Solution Approach 1:
The control unit is configured to change the discharge current only during image interval periods, before the next image forming region reaches the primary transfer portion. This preliminary timing ensures that current adjustments are completed before they could affect active image transfer, preventing image density unevenness while still maintaining ion balance for consistent image quality.
3Stability of the object's composition
If constant current control is applied to the discharge member, then ion distribution uniformity is improved, but the system complexity increases due to additional control mechanisms
Solution Approach 1:
The control unit automatically performs constant current control of the discharge member using detection results from the current detection unit. The system self-regulates the discharge current to maintain a predetermined balance between inward and outward currents without requiring external manual adjustment or complex additional control mechanisms, achieving ion distribution uniformity through automated self-service control.
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 approach effectively suppresses image density unevenness and extends the endurance life of the intermediate transfer belt by maintaining optimal ion distribution and reducing electric resistance, preventing image defects caused by discharge current changes during continuous print jobs.
Implementation Method 1
In an ion-conductive belt containing the ion-conductive material, cations and anions causing the ion conductivity receive a force due to an electric field generated in the belt when a current flows
Implementation Method 2
The positively charged cations move in the direction of the electric field, and the negatively charged anions move in the direction opposite to the electric field
Implementation Method 3
The primary transfer is often performed by applying a primary transfer voltage to a primary transfer member provided to be contactable with the inner peripheral surface of the intermediate transfer belt
Implementation Method 4
The secondary transfer is often performed by applying a secondary transfer voltage to a secondary transfer member provided to be contactable with the outer peripheral surface of the intermediate transfer belt
Implementation Method 5
The cleaning by this device is performed, for example, by applying a cleaning voltage to a cleaning member provided to be contactable with the outer peripheral surface of the intermediate transfer belt and supplying a cleaning current
Data Source
AI summary
An image forming apparatus includes an image bearing member, an intermediate transfer belt, first, second, and third power sources, and a control unit. During print job execution, the control unit controls the third power source such that a discharge current supplied to the intermediate transfer belt is constant current controlled based on first and second power source current supply detection results. When changing from a first to a second discharge current, the control unit controls the third power source such that, after a first image forming region passes through a primary transfer portion, an intermediate transfer belt trailing edge to which the first discharge current is supplied initially passes through the primary transfer portion and such that, before a second image forming region passes through the primary transfer portion, an intermediate transfer belt leading edge to which the second discharge current is supplied initially passes through the primary transfer portion.