Image Transfer Resistance Measurement in Electrophotographic Apparatus
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Solution Overview
Problem
Existing image forming apparatuses face challenges in accurately measuring the electrical resistance values of recording media before voltage application, which can lead to transfer failures and image defects due to insufficient or inappropriate resistance values on the image and non-image surfaces.
Innovation Solution
The apparatus includes a pair of measuring units that measure the electrical resistance values of the image and non-image surfaces in a direction crossing the thickness direction of the recording medium before voltage application, using terminals and a facing roller to apply a voltage and detect current, allowing for precise measurement and prevention of transfer failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If voltage is applied to transfer image onto recording medium, then image transfer is achieved, but transfer failures and image defects occur when electrical resistance values are insufficient or inappropriate
Solution Approach 1:
The measuring units measure the electrical resistance values of the recording medium before the voltage application for image transfer. This preliminary measurement allows the system to detect inappropriate resistance values in advance and prevent transfer failures, thereby improving image transfer reliability without adding complexity to the transfer process itself.
2Reliability
If measuring units are added to measure electrical resistance values, then transfer failures are prevented, but device complexity increases
Solution Approach 1:
The measuring units utilize the same pair of electrodes that are used for voltage application during image transfer. By serving dual purposes - both measurement and transfer functions - the system prevents transfer failures without requiring completely separate measurement equipment, thereby limiting the increase in device complexity.
Solution Approach 2:
A facing roller is introduced as an intermediary component to facilitate contact between the measuring electrodes and the recording medium. This roller enables reliable electrical contact for measurement while maintaining the simplicity of the overall system architecture, as the roller serves as a mechanical mediator rather than a complex electronic measurement system.
3Measurement precision
If electrical resistance measurement is performed before voltage application, then image defects are prevented, but measurement precision is challenged by surface properties of recording medium
Solution Approach 1:
The facing roller acts as an intermediary that ensures consistent and reliable electrical contact between the measuring electrodes and the recording medium surface. By providing a controlled contact interface, the roller minimizes the interference from surface properties such as irregularities or coatings, thereby improving measurement precision without requiring direct electrode-to-surface contact.
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 the detection of potential transfer failures and prevents image defects by ensuring that the electrical resistance values are within acceptable limits, thereby improving the reliability of the image forming process.
Implementation Method 1
the pair of measuring units measure respective electrical resistance values of a front surface and a rear surface of the at least one recording medium
Implementation Method 2
The transfer unit transfers an image onto at least one recording medium by applying a voltage between the at least one recording medium and the image along a thickness direction
Data Source
AI summary
An image forming apparatus includes a transfer unit and a pair of measuring units. The transfer unit transfers an image onto at least one recording medium by applying a voltage between the at least one recording medium and the image along a thickness direction of the at least one recording medium. Before the transfer unit applies the voltage, the pair of measuring units measure respective electrical resistance values of a front surface and a rear surface of the at least one recording medium in a direction crossing the thickness direction.