Dual Power Supply Control for Primary Transfer Current
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Solution Overview
Problem
Existing image forming apparatuses using intermediate transfer members often fail to supply sufficient current for primary transfer, resulting in inappropriate image formation due to insufficient charging and transfer efficiency.
Innovation Solution
An image forming apparatus with an endless, rotatable intermediate transfer member and a control unit that manages current flow through a primary transfer region by using a transfer member, a charging member, and power supply units to optimize the primary transfer process, ensuring adequate current supply and toner charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single power supply unit is used to supply current through the intermediate transfer member, then the device complexity is reduced, but the current supply is insufficient resulting in inappropriate image formation
Solution Approach 1:
The power supply system is segmented into two independent power supply units: a first power supply unit connected to the transfer member and a second power supply unit connected to the charging member. This segmentation allows each unit to contribute separately to the current flowing through the intermediate transfer member, ensuring sufficient total current supply for reliable primary transfer while maintaining manageable device complexity through modular design.
2Productivity
If the current through the intermediate transfer member is insufficient, then the device structure remains simple, but the primary transfer efficiency is inadequate resulting in toner image degradation
Solution Approach 1:
The patent merges the functions of two separate power supply units to achieve sufficient current supply for primary transfer. The first power supply unit supplies current through the transfer member while the second power supply unit supplies current through the charging member, and both currents combine to flow through the intermediate transfer member in the circumferential direction, achieving high primary transfer efficiency without requiring an overly complex single-unit system.
Solution Approach 2:
The intermediate transfer member acts as an intermediary that receives current from both the transfer member (via the first power supply unit) and the charging member (via the second power supply unit). This intermediary structure allows the system to accumulate sufficient current from multiple sources while maintaining a relatively simple overall device configuration, thereby improving primary transfer efficiency without proportionally increasing device complexity.
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 configuration enhances primary transfer efficiency, minimizing toner image degradation and improving image quality by ensuring sufficient current is passed through the intermediate transfer member in the circumferential direction, leading to higher-grade image formation.
Implementation Method 1
a charging member provided downstream of the secondary transfer region in a rotating direction of the intermediate transfer member and upstream of the primary transfer region to charge toner remaining on the intermediate transfer member
Implementation Method 2
a current is passed through the intermediate transfer member in a circumferential direction thereof via a transfer member in contact with an inner peripheral surface of the intermediate transfer member or a tensing member tensing the intermediate transfer member to carry out the primary transfer step by the current flowing through the intermediate transfer member in the circumferential direction
Data Source
AI summary
A control unit is provided which controls at least one of a first power supply unit (a secondary transfer power supply connected to a secondary transfer roller) and a second power supply unit (high-voltage power supplies connected to a conductive brush and a conductive roller) so that a current supplied to a primary transfer region from a beginning of primary transfer until a beginning of secondary transfer has a magnitude larger than a magnitude of a current supplied to the primary transfer region from a beginning of image formation until the beginning of the primary transfer.