Transfer Voltage Control for High-Speed Image Formation
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Solution Overview
Problem
Conventional image forming apparatuses face challenges in maintaining optimal transfer voltage control, especially during high-speed printing, due to variations in transfer member resistance caused by temperature and humidity changes, which can lead to suboptimal transfer currents and difficulties in shortening the sheet interval for increased printing speed.
Innovation Solution
An image forming apparatus that includes a current detecting member to monitor the current during non-sheet passing periods and adjust the voltage applied to the transfer member to ensure a predetermined current flows during sheet passing, allowing for consistent voltage application between sheet passing and non-sheet passing periods, thereby enabling shorter sheet intervals and faster image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the sheet interval is shortened to increase image forming speed, then productivity is improved, but the time required for current detection and voltage stabilization cannot be ensured
Solution Approach 1:
The patent applies preliminary action by performing current detection during the non-sheet-passing period before the sheet-passing period begins. The controller detects the current flowing through the transfer member during the non-sheet-passing period, and based on this detection result, determines the voltage to be applied during the subsequent sheet-passing period. This allows voltage determination to be completed in advance, enabling the sheet interval to be shortened without compromising detection accuracy.
2Reliability
If different voltages are applied during sheet-passing and non-sheet-passing periods to control current, then transfer voltage control is improved, but the system complexity increases
Solution Approach 1:
The patent applies dynamics by making the voltage applied to the transfer member variable rather than constant. The controller dynamically adjusts the voltage based on the detection results from the non-sheet-passing period. Specifically, the voltage during the sheet-passing period is determined based on the current detection result from the non-sheet-passing period, allowing the system to adapt to changing conditions while maintaining reliable transfer voltage control.
3Ease of operation
If constant voltage control is used after ATVC, then ease of operation is improved, but optimal transfer current cannot be maintained during continuous image formation due to resistance changes
Solution Approach 1:
The patent applies feedback by using the current detection result from the non-sheet-passing period to determine the voltage for the subsequent sheet-passing period. The controller continuously monitors the current during non-sheet-passing periods and adjusts the voltage accordingly to maintain optimal transfer current during sheet-passing periods. This feedback mechanism compensates for resistance changes in the transfer member caused by temperature and humidity variations during continuous image formation.
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 ensures proper control of transfer voltage, stabilizes current detection, and allows for shorter sheet intervals, facilitating high-speed image formation while maintaining optimal transfer efficiency.
Implementation Method 1
a power source that applies a voltage to the transfer member so that a level of the voltage in a non-sheet-passing period in which the recording material is not in the transfer position is the same as that in a preceding sheet-passing period
Implementation Method 2
a current detecting member that detects a current flowing through the transfer member
Data Source
AI summary
An image forming apparatus includes: an image bearing member; a toner image forming portion; a transfer member; a power source configured to apply a voltage to the transfer member so that a level of the voltage in a non-sheet-passing period in which a recording material is not in a transfer position is the same as that in a preceding sheet-passing period in which the recording material is in the transfer position; a current detecting member configured to detect a current flowing through the transfer member; and a controller configured to correct the voltage applied by the power source for the subsequent sheet-passing period on the basis of the detected current by the current detecting member in the non-sheet-passing period so that a predetermined current flows through the transfer member in the sheet-passing period.