Transfer Voltage Control for Low Resistance Paper Density
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Solution Overview
Problem
Image forming apparatuses face issues with toner density differences and transfer failures when using low resistance paper, due to varying system resistances and electric fields during the transfer process, leading to defects such as density differences and toner scattering.
Innovation Solution
The image forming apparatus includes a transfer unit, a guide unit, and a supply unit that sets the transfer voltage to maintain a predetermined range of transfer current, and adjusts the transfer nip and bias application to ensure consistent toner transfer across low resistance paper, using a backup roller and second transfer roller configuration to manage resistances and electric fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional transfer process is used with low resistance paper, then the paper can be processed, but toner density differences and transfer failures occur due to varying system resistances and electric fields
Solution Approach 1:
The patent applies dynamics by making the transfer voltage adjustable and variable during the transfer process. The control unit dynamically adjusts the transfer voltage based on the transfer state, allowing the system to adapt to changing resistance conditions throughout the paper transfer process, thereby maintaining consistent toner density and preventing transfer failures on low resistance paper
Solution Approach 2:
The patent implements feedback through the control unit that monitors the transfer process and adjusts transfer voltage accordingly. By detecting the actual transfer conditions and modifying the voltage in response, the system compensates for varying system resistances and maintains uniform toner density distribution across the transferred image
2Manufacturing precision
If transfer voltage is increased to maintain strong electric field, then toner transfer improves, but system resistance variations cause density differences and toner scattering
Solution Approach 1:
The patent applies parameter changes by varying the transfer voltage level during different stages of the transfer process. Instead of using a fixed high voltage, the control unit adjusts the voltage parameter dynamically, maintaining it within an optimal range that ensures consistent toner transfer while preventing excessive voltage that would cause toner scattering and density variations
3Device complexity
If fixed transfer voltage is used, then the system is simple, but it cannot compensate for varying system resistances leading to image defects
Solution Approach 1:
The patent transforms the static fixed voltage system into a dynamic adjustable voltage system. The control unit continuously monitors transfer conditions and adjusts the transfer voltage in real-time, enabling the system to compensate for varying resistances and maintain uniform image quality without requiring overly complex hardware modifications
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 reduces toner density differences and prevents transfer failures by maintaining a strong electric field and consistent toner transfer, even with low resistance paper, thereby improving image quality and reducing defects.
Implementation Method 1
a transfer unit TR that transfers a toner image to a transfer body P
Implementation Method 2
a supply unit SP that supplies a transfer voltage to the transfer unit TR; and a setting unit SS that sets the transfer voltage supplied by the supply unit SP so that a transfer current supplied to the transfer unit TR is within a predetermined range
Data Source
AI summary
An image forming apparatus includes a transfer unit that transfers a toner image to a transfer body; a guide unit disposed upstream of the transfer unit in a direction in which the transfer body is transported, the guide unit guiding the transfer body; a supply unit that supplies a transfer voltage to the transfer unit; and a setting unit that sets the transfer voltage supplied by the supply unit so that a transfer current supplied to the transfer unit is within a predetermined range at the time when the transfer body becomes separated from the guide unit.