Charge Supply Unit Prevents Toner Smudging in Image Forming Apparatus
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Solution Overview
Problem
In image forming apparatuses, the transfer of toner images from an intermediate transfer belt to a continuous sheet of paper often results in smudging due to incomplete removal of toner from the belt, especially when test patterns in non-image regions are aggressively transferred, leading to potential smudging on the back surface of the paper.
Innovation Solution
An electric charge supply unit, such as a pin corotron, is positioned upstream of the transfer position to prevent the transfer of toner images in non-image regions by applying a voltage that shields the toner in these areas, allowing for effective removal by a cleaner and preventing smudging on the continuous sheet of paper.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If test patterns are formed in non-image regions of the intermediate transfer belt, then the transfer unit aggressively transfers toner images, but this causes smudging on the back surface of the continuous sheet of paper
Solution Approach 1:
The electric charge supply unit applies electric charge to the toner in non-image regions upstream of the transfer position, creating a preliminary counter-action that prevents the toner from being transferred to the continuous sheet of paper. This preliminary charging creates an electrostatic barrier that repels the toner particles, stopping them from adhering to the paper surface and thus preventing smudging while maintaining efficient transfer of intended images.
Solution Approach 2:
The electric charge supply unit is positioned to supply charge selectively to specific regions of the intermediate transfer belt corresponding to non-image areas. This local application of electric charge creates a differentiated treatment: toner in non-image regions receives charge to prevent transfer, while toner in image regions remains unaffected and transfers normally. This spatially selective charging resolves the contradiction by locally preventing harmful transfer only where needed.
2Object-affected harmful factors
If an electric charge supply unit is added upstream of the transfer position, then smudging is prevented, but device complexity increases
Solution Approach 1:
The electric charge supply unit is integrated into the existing image forming apparatus and can serve multiple functions: preventing smudging in non-image regions, controlling toner transfer characteristics, and potentially assisting in the main transfer process. By making this component multi-functional, the patent reduces the need for separate dedicated devices, thereby limiting the increase in device complexity while achieving smudging prevention.
Solution Approach 2:
The electric charge supply unit acts as an intermediary component between the intermediate transfer belt and the continuous sheet of paper. Rather than directly modifying the transfer mechanism or the paper handling system, it introduces a mediating electric field that influences toner behavior. This intermediary approach allows smudging prevention without requiring fundamental changes to the core transfer mechanism, thus limiting complexity increase.
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 effectively prevents smudging on the back surface of the continuous sheet of paper by ensuring that toner in non-image regions is not transferred, maintaining image quality and preventing unwanted toner spread.
Implementation Method 1
an electric charge supply unit that is disposed upstream of the transfer position in a transport direction of the continuous sheet of paper by the sheet transport unit and at a position at which the continuous sheet of paper is placed between the toner image carrier and the electric charge supply unit, and that supplies electric charge having an orientation, in which transfer by the transfer unit is prevented, to a toner image present in a region on the toner image carrier, which is out of the continuous sheet of paper in a width direction intersecting with the transport direction
Data Source
AI summary
An image forming apparatus includes a toner image carrier on which a toner image is formed, a transfer unit that transfers the toner image onto a continuous sheet of paper, a fixing machine that fixes the transferred toner image onto the continuous sheet of paper, a sheet transport unit that transports the continuous sheet of paper through a transport path passing through a transfer position and a fixing position, and an electric charge supply unit that is disposed at a position at which the continuous sheet of paper is placed between the toner image carrier and the electric charge supply unit and that supplies electric charge having an orientation, in which transfer by the transfer unit is prevented, to a toner image present in a region on the toner image carrier, which is out of the continuous sheet of paper.