Switchback Roller Direction Control for Developing Device Wear Reduction
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Solution Overview
Problem
In image forming apparatuses that form images on both surfaces of a recording sheet, the developing device continues to operate unnecessarily when re-conveying the sheet, leading to degradation of its components and increased energy consumption.
Innovation Solution
An image forming apparatus with a switchback roller and a control device that stops the developing device's driving and reverses the switchback roller's direction during re-conveyance, ensuring the developing device is only active when forming images, thereby preventing unnecessary operation and component degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the developing device continues to operate during sheet re-conveyance, then the image forming apparatus can maintain readiness for the next image formation, but the developing device components and developer degrade unnecessarily and energy is wasted
Solution Approach 1:
The developing device is controlled to operate periodically rather than continuously. It runs during image formation, stops during sheet re-conveyance, and restarts when the next sheet is fed. This periodic operation eliminates unnecessary energy consumption while maintaining system readiness through rapid restart capability.
Solution Approach 2:
The control device is configured to anticipate the sheet re-conveyance phase and proactively stop the developing device before this phase begins. By detecting when the current sheet is being re-conveyed for dual-sided printing, the system preemptively halts the developing device, preventing unnecessary operation and energy waste.
2Productivity
If the developing device operates continuously, then image formation can be maintained without interruption, but component lifespan is reduced due to unnecessary wear
Solution Approach 1:
The developing device operates in periodic cycles aligned with the actual image formation needs. It remains active during sheet feeding and image formation, then pauses during the re-conveyance interval, and resumes when the next sheet is ready. This periodic operation extends component lifespan by eliminating unnecessary runtime while maintaining productivity through rapid reactivation.
Solution Approach 2:
The control device automatically manages the developing device's operation state based on the sheet conveyance phase detection. The system self-regulates by stopping the developing device during re-conveyance and automatically restarting it when needed, eliminating the need for manual intervention while preserving component life.
3Ease of operation
If the switchback roller rotates in reverse direction during re-conveyance, then the sheet can be guided back to the image forming unit, but the developing device should not operate to avoid unnecessary wear
Solution Approach 1:
The control device stops the developing device in advance before the switchback roller begins its reverse rotation for sheet re-conveyance. This preliminary action ensures that the developing device is already halted when the re-conveyance phase commences, preventing any unnecessary operation that could degrade components or affect developer quality.
Solution Approach 2:
The control device monitors the sheet conveyance status and detects when the switchback roller is rotating in reverse direction. Based on this feedback, the control device adjusts the developing device operation state, stopping it during re-conveyance and restarting it when the sheet returns to the image forming unit, thereby optimizing both function and reliability.
Data Source
AI summary
An image forming apparatus includes: a rotatable first developer carrier; a tray on which a recording sheet is to be discharged; a switchback roller configured to rotate in a first rotating direction to convey the recording sheet in a direction coming close to the tray, and a control device configured to switch a rotating direction of the switchback roller from the first rotating direction to a second rotating direction opposite to the first rotating direction after rotation of the first developer carrier is stopped.