Image Forming Apparatus Transfer Current Control
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Solution Overview
Problem
The conventional image forming apparatus experiences energization deterioration during cleaning control, leading to degraded image quality due to excessive transfer current and varying resistance values in the transfer rollers.
Innovation Solution
The apparatus controls the transfer current to maintain an average absolute value that is smaller during cleaning control than in printing control, by switching the electric field between the image carrier and cleaning roller, allowing efficient toner transfer while minimizing resistance changes in the transfer rollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a transfer current with substantially the same magnitude as in printing control is applied during cleaning control, then toner collected by cleaning rollers is transferred to the belt, but the total amount of transfer current becomes too large causing energization deterioration and varying resistance values in the transfer roller
Solution Approach 1:
The patent changes the parameter of transfer current magnitude during cleaning control. Specifically, the transfer current is controlled to have a smaller average absolute value during cleaning control compared to printing control, while still maintaining sufficient current to transfer toner from cleaning rollers to the belt. This parameter adjustment prevents energization deterioration and resistance value variations in the transfer roller.
2Productivity
If a large transfer current is applied during cleaning control, then toner transfer is efficient, but image quality degrades due to energization deterioration
Solution Approach 1:
The patent adjusts the transfer current parameter to an optimal level that balances transfer efficiency and image quality. By controlling the average absolute value of transfer current to be smaller during cleaning control than during printing control, the system achieves sufficient toner transfer while preventing energization deterioration that would degrade image 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 suppresses energization deterioration, enhancing image quality by reducing the total transfer current and maintaining stable resistance values in the transfer rollers.
Implementation Method 1
a transfer current is applied between each of the photoconductor drums and the belt (the corresponding transfer roller) so that toner images carried on the photoconductor drums are transferred onto a recording sheet conveyed on the belt
Implementation Method 2
an electric current is applied between each of the photoconductor drums and the corresponding cleaning roller so that toner collected by the cleaning rollers is transferred to the belt through the photoconductor drums
Data Source
AI summary
An image forming apparatus includes a controller capable of performing a printing control and a cleaning control. In the printing control, developer images carried on the image carriers are transferred toward the opposing surface or a recording sheet by applying a transfer current between each of the image carriers and the transfer device. In the cleaning control, developer collected by the cleaning rollers is transferred toward the image carriers and the transfer device and collected by the cleaning device by applying a transfer current between each of the image carriers and the transfer device and switching an electric field established between the image carrier and the corresponding cleaning roller. The controller is configured to control the transfer current such that an average absolute value of the transfer current in the cleaning control is smaller than that in the printing control.