Primary Transfer Roller Resistance Detection in Image Forming Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately controlling transfer voltages and determining resistance values of primary transfer rollers, which can lead to inefficiencies and errors in the image formation process.
Innovation Solution
The image forming apparatus includes a photosensitive drum, primary and charging rollers, voltage applicators, and controllers that apply and control voltages to detect current values and determine resistance values by varying detection voltages and applying voltages with smaller absolute values during the transfer voltage control period, allowing for precise resistance calculation and efficient image transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a specific constant current bias is applied to detect initial voltage for transfer voltage control, then transfer voltage can be controlled during printing, but the resistance value of the primary transfer roller cannot be accurately determined
Solution Approach 1:
The patent applies a detection voltage to the primary transfer roller before the printing operation to measure its resistance value. This preliminary measurement allows the system to know the roller's resistance in advance, enabling accurate transfer voltage control during printing without interference from the roller's resistance characteristics.
Solution Approach 2:
The patent introduces a detection voltage as an intermediary measurement signal applied to the primary transfer roller. This detection voltage is separate from the printing operation and serves as a mediator to accurately measure the roller's resistance value without being affected by the complex electrical conditions during actual printing.
2Measurement precision
If detection voltage is applied to primary transfer roller to measure resistance, then resistance value can be determined, but charging time of photosensitive drum increases
Solution Approach 1:
The resistance measurement is performed in advance before the printing operation begins. By completing the detection voltage application and resistance measurement beforehand, the system eliminates the need to charge the photosensitive drum during the measurement process, thus avoiding time loss in the actual printing workflow.
Solution Approach 2:
The patent implements periodic resistance measurement at predetermined intervals (e.g., when the apparatus is not printing or at scheduled maintenance intervals). This periodic approach allows resistance verification without continuously interrupting the printing process or requiring repeated charging of the photosensitive drum.
3Reliability
If voltage is applied to primary transfer roller during printing operation, then transfer voltage control is achieved, but measurement accuracy decreases due to interference from printing process
Solution Approach 1:
The patent performs resistance measurement before the printing operation starts, when the primary transfer roller is in a stable, non-operational state. This preliminary measurement avoids interference from toner transfer, drum rotation, and other printing process variables that would compromise measurement accuracy.
Solution Approach 2:
The detection voltage serves as an intermediary measurement signal that is applied separately from the printing operation. This intermediary approach isolates the resistance measurement from the complex electrical and mechanical conditions during printing, ensuring accurate resistance determination.
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 enables accurate determination of resistance values and efficient transfer voltage control, reducing the time needed before printing and minimizing errors, thereby improving the overall image formation process.
Implementation Method 1
The first voltage applicator applies a voltage to the primary transfer roller. The current detector detects a current value of a current flowing through the primary transfer roller.
Implementation Method 2
The current detector detects a current value of a current flowing through the primary transfer roller, enabling resistance calculation through Ohm's Law.
Implementation Method 3
The charging roller charges the photosensitive drum. The second voltage controller causes a voltage having a smaller absolute value than a dark potential of the photosensitive drum to be applied to the photosensitive drum.
Data Source
AI summary
An image forming apparatus includes a photosensitive drum, a primary transfer roller, first and second voltage applicators, first and second voltage controllers, a current detector, and a charging roller. The first voltage controller controls a voltage applied to the primary transfer roller through the first voltage applicator. The current detector detects a current value of a current flowing through the primary transfer roller. The second voltage controller controls a voltage applied to the charging roller through the second voltage applicator. The second voltage controller causes a voltage having a smaller absolute value than a dark potential of the photosensitive drum to be applied to the photosensitive drum during a transfer voltage control period. During the transfer voltage control period, the first voltage controller causes a voltage to be applied to the primary transfer roller, and the current detector detects the current value.