Switchback Mechanism for Duplex Printing Without Reverse Drive
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Solution Overview
Problem
Conventional image forming apparatuses require a drive source capable of rotating conveying rollers in both forward and reverse directions to perform duplex printing, which complicates the configuration and increases costs.
Innovation Solution
A switchback mechanism using a first roller group, a second roller group, a switching guide, a drive gear, and transmission-gear groups that allow the conveying path to switch between switchback and non-switchback paths without needing a drive source for reverse rotation, utilizing a link mechanism and solenoid mechanism to transmit drive forces effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a drive source capable of rotating conveying rollers in both forward and reverse directions is provided to perform duplex printing, then duplex printing capability is achieved, but the configuration becomes complicated and costs increase
Solution Approach 1:
The conveying path is segmented into multiple paths (first conveying path for switchback, second conveying path for direct discharge). The switching guide divides the single conveying path into these separate paths, allowing the sheet to be directed to different destinations based on printing needs. This segmentation eliminates the requirement for reverse rotation capability while maintaining duplex printing functionality.
Solution Approach 2:
The switching guide acts as an intermediary mechanism between the conveying rollers and the sheet. It controls the sheet's path by guiding it to either the first conveying path (for switchback to form image on other side) or the second conveying path (for direct discharge). This intermediary component enables path switching without requiring the drive source to rotate in reverse directions.
2Productivity
If three conveying rollers are used to perform simultaneous discharge and switchback, then work efficiency is improved, but the configuration becomes more complex
Solution Approach 1:
The three conveying rollers (first, second, and third discharge rollers) are designed to perform multiple functions. The second discharge roller, positioned between the first and third rollers, can participate in both the direct discharge path (with first roller) and the switchback path (with third roller). This multi-functionality allows simultaneous discharge and switchback operations using the same set of rollers, improving productivity without proportionally increasing complexity.
3Adaptability or versatility
If a branch guide is provided to switch conveying path for duplex printing, then duplex printing is enabled, but the device configuration becomes more complex
Solution Approach 1:
The switching guide merges the functions of path switching and roller control into a single integrated mechanism. It simultaneously controls which conveying path the sheet follows and coordinates with the conveying rollers to ensure proper sheet direction. This merging of functions reduces the number of separate components needed compared to having independent branch guides and roller control systems.
Data Source
AI summary
In a color printer in which a drive force of a fixed gear that rotates not in both a forward direction and a reverse direction but in either one direction only is transmitted to a discharging unit, a swing gear is attached to a branch guide via a switching link and a transmission link as a link mechanism. When a solenoid mechanism starts driving, the transmission link rotates. In accordance with the rotation of the transmission link, the switching link rotates, so that a switching among a discharge conveying path, a duplex-printing conveying path, and a switchback conveying path by the branch guide and a switching of a rotating direction of a transmission gear can be simultaneously performed.