Image Forming Apparatus Voltage Control for Transfer Defects
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Solution Overview
Problem
In image forming apparatuses where voltages of positive and negative polarity are superimposed to form a transfer voltage, the output of positive polarity voltage often reaches its upper limit, leading to insufficient transfer voltage and potential transfer defects, especially when resistance increases with the use of transfer members.
Innovation Solution
The apparatus includes a control unit that adjusts the discharging voltage to ensure a sufficient transfer voltage is maintained by modifying the discharging voltage from one value to another of the same polarity but lower value when the transfer voltage falls below a target value, using a secondary transfer power source with a positive voltage circuit and a negative voltage circuit connected in series.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If voltage of positive polarity is increased to compensate for resistance increase, then transfer voltage can be maintained, but the positive polarity output reaches upper limit and transfer voltage becomes insufficient
Solution Approach 1:
The control unit dynamically adjusts the discharging voltage parameter (changing from first value to second value) to compensate for resistance changes in the transfer member, ensuring the transfer voltage remains within the effective range without exceeding the power source upper limit
Solution Approach 2:
The control unit monitors the transfer voltage and resistance changes, and adjusts the discharging voltage accordingly to maintain optimal transfer conditions, preventing transfer defects when resistance increases
2Power
If voltage of negative polarity is increased to maintain transfer voltage, then transfer performance improves, but discharging performance deteriorates
Solution Approach 1:
The control unit dynamically adjusts the discharging voltage based on the transfer voltage requirements, making the voltage value variable rather than fixed, allowing optimization of both transfer and discharging performance under different operating conditions
Solution Approach 2:
The control unit changes the discharging voltage parameter from a first value to a second value according to transfer needs, ensuring sufficient transfer voltage while maintaining adequate discharging performance
3Productivity
If upper limit voltage is used to increase image formation speed, then productivity improves, but transfer voltage becomes insufficient when resistance increases
Solution Approach 1:
The control unit proactively adjusts the discharging voltage in response to resistance changes before transfer defects occur, preventing image quality degradation while maintaining high image formation speed
Solution Approach 2:
The control unit monitors transfer conditions and adjusts discharging voltage in real-time to maintain optimal transfer voltage within the effective range, ensuring both high speed and quality
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 suppresses transfer defects and maintains image quality by ensuring a stable transfer voltage, even when resistance increases, by dynamically adjusting the discharging voltage to prioritize transfer voltage within the permissible voltage limits.
Implementation Method 1
transfer voltage is outputted from a power source to a transfer member disposed opposing an image bearing member such as a drum-like photosensitive member or intermediate transfer member; as a result, a toner image that is born on the image bearing member becomes electrostatically transferred to a recording material such as paper
Implementation Method 2
static from the recording material having passed through the transfer portion may be discharged by the discharging member
Data Source
AI summary
An image forming apparatus comprising a transfer means for transferring, a developer image onto a recording material; a discharging unit for discharging the recording material; a first circuit that applies a first voltage of reverse polarity to the developer to the transfer unit; a second circuit that applies a second voltage of identical polarity to the developer to the transfer unit and the discharging unit; and a control unit. The control unit applies a transfer voltage which is a superposition of the first and the second voltage to the transfer unit, and applies a discharging voltage which is a partial voltage from the second voltage. When the discharging voltage is set to the first value, the control unit reduces the discharging voltage in a case where the transfer voltage is lower than a target value.