Transfer Voltage Control for Image Forming Apparatus
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Solution Overview
Problem
The existing electrophotographic image forming apparatuses face challenges in maintaining a predetermined primary-transfer voltage when using a voltage source exclusively for primary-transfer, leading to potential transfer defects due to reduced current flow with wider recording materials, which increases costs and reduces transfer contrast.
Innovation Solution
An image forming apparatus that omits the voltage source exclusively for primary-transfer by using a constant-voltage element grounded to maintain a predetermined voltage, with a controller ensuring the voltage is maintained during secondary-transfer, especially for recording materials of varying widths, by adjusting the voltage applied to the transfer member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voltage source exclusively for primary-transfer is provided, then primary-transfer voltage can be maintained, but cost increases
Solution Approach 1:
The power source for secondary-transfer is made to serve dual purposes: it provides voltage for secondary-transfer while also maintaining primary-transfer voltage through the constant-voltage element. This multi-functionality eliminates the need for a separate primary-transfer voltage source, reducing cost while maintaining voltage stability.
Solution Approach 2:
The constant-voltage element automatically maintains the intermediary transfer member at a predetermined potential without requiring an external voltage source. The system uses itself to regulate voltage, eliminating the need for additional dedicated power supply components.
2Reliability
If the intermediary transfer member is grounded through a constant-voltage element, then primary-transfer voltage is maintained, but current flow decreases with wider recording materials
Solution Approach 1:
The controller dynamically adjusts the voltage applied to the transfer member based on the width of the recording material. When wider materials are detected, the controller increases the voltage to compensate for reduced current flow through the constant-voltage element, maintaining stable primary-transfer voltage across different material widths.
3Length of moving object
If current flow decreases at secondary-transfer portion with wider recording materials, then transfer distance increases, but primary-transfer contrast deteriorates
Solution Approach 1:
The controller monitors the width of the recording material and provides feedback to adjust the voltage applied to the transfer member. This feedback mechanism ensures that the primary-transfer voltage remains sufficient to maintain contrast even when current flow is reduced due to wider material dimensions.
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 solution prevents transfer defects by maintaining a stable primary-transfer electric field, even with wider recording materials, ensuring consistent image transfer without the need for an additional voltage source, thereby reducing costs and enhancing transfer contrast.
Implementation Method 1
a constant-voltage element, electrically connected between the intermediary transfer member and a ground potential, for maintaining a predetermined voltage by passing of a current therethrough
Implementation Method 2
a power source for forming, by applying a voltage to the transfer member to pass the current through the constant-voltage element, both of a secondary-transfer electric field at the secondary-transfer position and a primary-transfer electric field at the primary-transfer position
Data Source
AI summary
A controller controls a voltage to be applied to the transfer member when there is a recording material having a predetermined largest width at a secondary-transfer position, so that a constant-voltage element maintains a predetermined voltage, whereby it is possible to prevent transfer defect due to short of a primary-transfer electric field at a primary-transfer portion when a toner image is secondary-transferred onto the recording material.