Image Forming Apparatus Secondary Transfer Bias Control
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Solution Overview
Problem
Existing image forming apparatuses face challenges in reliably transferring toner images onto recording media with varying surface roughness and environmental conditions, such as temperature and humidity, which can lead to insufficient image density and voids.
Innovation Solution
The image forming apparatus incorporates a control system that adjusts the peak-to-peak voltage of the secondary transfer bias based on temperature and humidity, using a power source that outputs a bias with varying duty cycles to optimize toner transfer, and employs an intermediate transfer belt with a layered structure for enhanced elasticity and toner adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a superimposed bias with high peak-to-peak voltage is used to enhance toner transfer onto rough surfaces, then transferability to recesses is improved, but image density becomes insufficient under high temperature and humidity conditions
Solution Approach 1:
The patent applies dynamics by making the bias voltage adjustable based on environmental conditions. The control unit dynamically changes the peak-to-peak voltage of the superimposed bias according to detected temperature and humidity levels, transitioning from a static voltage system to an adaptive one that responds to environmental variations.
Solution Approach 2:
The patent implements parameter changes by modifying the peak-to-peak voltage of the superimposed bias based on environmental parameters (temperature and humidity). When temperature and humidity exceed predetermined thresholds, the system reduces the peak-to-peak voltage to prevent insufficient image density, thereby adjusting electrical parameters in response to environmental conditions.
2Reliability
If the peak-to-peak voltage of the superimposed bias is increased to improve transfer to rough surfaces, then toner adherence to recesses is enhanced, but discharge occurs under high temperature and humidity
Solution Approach 1:
The system performs preliminary anti-action by detecting temperature and humidity conditions in advance and preemptively adjusting the bias voltage to prevent discharge. When environmental conditions indicate high temperature and humidity, the control unit reduces the peak-to-peak voltage before discharge can occur, thereby preventing the harmful effect rather than correcting it after occurrence.
Solution Approach 2:
The patent implements feedback by using detection units to monitor environmental conditions (temperature and humidity) and feeding this information back to the control unit, which then adjusts the bias voltage accordingly. This closed-loop control system continuously monitors and responds to environmental changes to maintain optimal transfer conditions and prevent discharge.
3Ease of operation
If a fixed superimposed bias is used for toner transfer, then the system is simple to operate, but it cannot adapt to varying environmental conditions
Solution Approach 1:
The system applies self-service by automatically detecting environmental conditions and adjusting the bias voltage without requiring manual intervention. The detection units and control unit work autonomously to monitor temperature and humidity and make real-time adjustments to the superimposed bias, enabling the system to adapt to environmental changes independently.
Solution Approach 2:
The patent implements universality by creating a control system that handles multiple functions: detecting temperature, detecting humidity, processing detection signals, and adjusting the bias voltage. This multi-functional control unit can adapt to various environmental conditions and maintain optimal transfer performance across different operating environments.
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 ensures reliable transfer of toner images onto both smooth and rough surfaces, maintaining sufficient image density across different environmental conditions, preventing voids and improving overall image quality.
Implementation Method 1
a secondary transfer bias is applied to an opposed roller that contacts an inner circumferential surface of the intermediate transfer belt to sandwich the intermediate transfer belt with the transfer roller, thereby forming the area of contact between the intermediate transfer belt and the transfer roller
Implementation Method 2
An optical scanner irradiates the surface of the photoconductor thus charged with a light beam to form an electrostatic latent image on the surface of the photoconductor according to the image data
Implementation Method 3
The top layer has a greater elasticity than the elasticity of the base layer, and rests on an outer circumferential surface of the base layer. The top layer of the intermediate transfer belt has an elasticity to adhere to recesses on the rough surface of the recording medium, helping reliable transfer of toner to the recesses
Data Source
AI summary
An image forming apparatus includes an image bearer, an image forming device to form a toner image on the image bearer with toner, a power source to output a bias to transfer the toner image onto a recording medium, and control circuitry. The circuitry controls the power source to decrease a peak-to-peak voltage of the bias in response to increase in at least one of temperature and humidity, when a time-averaged voltage of the bias is on a transfer side of transferring the toner to the recording medium, from a median value of maximum and minimum voltages of the bias. The circuitry controls the power source to increase the peak-to-peak voltage of the bias in response to increase in at least one of temperature and humidity, when the time-averaged voltage of the bias is on a return side of returning the toner to the image bearer, from the median value.