Transfer Current Control for Stable Image Formation
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Solution Overview
Problem
Existing image forming apparatuses face issues with image defects due to fluctuations in the electric resistance of transfer members, which are not adequately addressed by current methods that set transfer current ranges based on recording material sizes alone, as they fail to account for variations in the electric resistance of non-sheet passing portions.
Innovation Solution
An image forming apparatus that adjusts the allowable range of transfer current based on fluctuations in the electric resistance of the transfer member, using a control system that incorporates environmental and operational conditions to determine the upper and lower limits of the transfer current, ensuring stable image formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transfer voltage is excessively high, then the transfer efficiency is improved, but electric discharge occurs and causes white void defects
Solution Approach 1:
The patent implements constant current control that continuously monitors the transfer current and adjusts the transfer voltage in real-time to maintain the current within a predetermined range. This feedback mechanism prevents electric discharge by ensuring the current does not exceed safe levels, while still maintaining high transfer efficiency through optimal current regulation.
Solution Approach 2:
The patent changes the control parameter from constant voltage to constant current control. By controlling the transfer current directly rather than the voltage, the system can maintain optimal transfer efficiency while preventing electric discharge, as the current is kept within a safe predetermined range regardless of fluctuations in transfer portion resistance.
2Object-affected harmful factors
If the transfer voltage is excessively low, then electric discharge is avoided, but poor image density occurs due to insufficient transfer
Solution Approach 1:
The constant current control system continuously monitors transfer current and adjusts voltage to maintain current within an optimal range. This ensures sufficient transfer current for high image density while preventing electric discharge, as the current is kept within predetermined safe and effective levels through real-time feedback adjustment.
Solution Approach 2:
By switching from voltage control to current control, the patent directly regulates the transfer current to remain within a predetermined range that ensures both sufficient transfer for high image density and prevention of electric discharge. This parameter change allows simultaneous achievement of both objectives.
3Device complexity
If the transfer current range is set based on recording material size only, then the control is simple, but fluctuations in transfer member resistance cause image defects
Solution Approach 1:
The patent implements constant current control that continuously monitors transfer current and adjusts transfer voltage in real-time based on actual conditions. This feedback mechanism automatically compensates for fluctuations in transfer member resistance, maintaining stable image quality without requiring complex pre-setting of current ranges for different material sizes.
Solution Approach 2:
The patent transitions from static current range setting to dynamic constant current control. The transfer current is continuously adjusted in real-time according to actual transfer conditions, including resistance fluctuations, allowing the system to adapt automatically and maintain stable image quality without complex manual configuration.
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 stabilizes image quality by accounting for variations in transfer member resistance, preventing defects such as white voids and poor image density by maintaining the transfer current within optimal ranges.
Implementation Method 1
a toner image is electrostatically transferred from a photosensitive member or an intermediary transfer belt as an image bearing member onto a recording material such as paper
Implementation Method 2
a detecting portion for detecting a current flowing through the transfer member
Data Source
Figure 1~2
Figure 3
Figure 4(a)~4(b)
AI summary
An information which includes an image bearing member 1, an intermediary transfer belt 7, a transfer member 8, a voltage source 20 for applying a voltage to the transfer member 8, a detecting portion 21 for detecting a current flowing through the transfer member 8, and a controller 50 for carrying out constant-voltage control so that the voltage applied to the transfer member when a recording material P passes through a transfer portion N2 and in which the controller 50 is capable of changing the voltage applied to the transfer member 8 so that a detection result detected by the detecting portion 21 during transfer falls within a predetermined pass has a constitution in which said controller 50 changes the predetermined range on the basis of the detection result detected by the detecting portion 21 when the voltage is applied to the transfer member 8 in a state in which the recording material P is absent in the transfer portion N2.