Switchback Conveying Path for Laser Printer Paper Retrieval
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Solution Overview
Problem
Vertical tandem type laser printers face difficulties in paper retrieval due to rear discharge configuration, which reverses page order and increases device depth when an original-reading unit is mounted, limiting layout freedom in paper conveyance.
Innovation Solution
Incorporating a switchback conveying path and reverse conveying unit that reverses the paper direction after the fixing unit, allowing for discharge onto a tray with the image formation surface facing down, thus maintaining page order and reducing device depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the discharge tray is positioned on the front side of the fixing unit to discharge paper toward the front, then paper retrieval is facilitated, but the page order is reversed and the device depth increases
Solution Approach 1:
The patent applies the inversion principle by discharging paper in the opposite direction to the conventional front discharge. The discharge tray is positioned on the rear side of the fixing unit, and paper is discharged toward the rear with the image formation surface facing down. This reverse discharge configuration maintains the correct page order while still facilitating easy paper retrieval through the rear discharge location.
2Ease of operation
If the discharge tray is positioned on the front side of the fixing unit, then paper curves toward the front for discharge, but the device depth increases due to tray protrusion
Solution Approach 1:
The patent resolves the device depth issue by inverting the discharge direction. Instead of discharging paper toward the front which requires the discharge tray to protrude forward, the patent discharges paper toward the rear side of the main body. This allows the discharge tray to be positioned within the rearward space of the main body, eliminating the need for forward protrusion and reducing the overall device depth.
3Length of stationary object
If the discharge tray is positioned on the rear side of the fixing unit, then device depth is reduced, but paper retrieval becomes difficult when original-reading unit is mounted
Solution Approach 1:
The patent introduces an intermediary mechanism - a discharge roller - that facilitates paper retrieval from the rear discharge location. The discharge roller is disposed at the discharge location on the rear side and works in conjunction with the discharge tray to guide and assist users in retrieving discharged paper, making the rear discharge configuration practical despite the increased distance from the front access point.
Data Source
AI summary
An image-forming device includes: a main device body; a plurality of process cartridges; a fixing unit; a tray; a switchback conveying path; and a reverse conveying unit. The plurality of process cartridges are detachably mounted in the main device body. The process cartridges are arranged in a row in the main device body when the process cartridges are mounted in the main device body. Each process cartridge has an image-carrying member that transfers a developer image carried thereon to a sheet by opposing the sheet. The fixing unit is provided in the main device body and fixes the developer image to the sheet after the image has been transferred thereto. The tray is provided in the main device body and supports the sheet after the developer image has been fixed thereon. The switchback conveying path is provided in the main device body and guides the sheet from the fixing unit to the tray, while switching a conveying direction of the sheet. The reverse conveying unit is disposed in the main device body along the switchback conveying path and reverses the conveying direction of the sheet.