Image Recording Apparatus Roller Nip Positioning Mechanism
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Solution Overview
Problem
The position of the nip of the conveying roller pair in image recording apparatuses is unstable when the cover is closed, affecting the sheet conveying direction and distance, due to the release mechanism used in conjunction with the cover opening.
Innovation Solution
A design where a first roller and a second roller are separated by a guide member that is pivotable between open and closed positions, with an urging portion to ensure accurate positioning of the second roller relative to the first roller when the guide member is closed, using an engaging portion to maintain contact between the rollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the nip of the conveying roller pair is released in conjunction with opening of the cover, then the conveyance path is accessible for maintenance and paper jam clearance, but the position of the nip becomes unstable when the cover is closed, affecting sheet conveying direction and distance
Solution Approach 1:
The conveying roller pair is divided into a first roller fixed to the housing and a second roller mounted on the guide member. This segmentation allows the second roller to be independently positioned and secured relative to the first roller, ensuring stable nip position while maintaining cover accessibility for maintenance operations
Solution Approach 2:
The guide member is designed with a guide groove that preliminarily positions the second roller at the correct location before the cover is closed. This preliminary positioning action ensures that when the cover is closed, the nip position is automatically accurate without requiring additional adjustment mechanisms
2Adaptability or versatility
If the second roller is freely movable on the guide member, then the guide member can pivot between open and closed positions, but the second roller cannot maintain accurate positioning relative to the first roller
Solution Approach 1:
The guide groove acts as an intermediary element between the guide member and the second roller. It provides a constrained path that allows the second roller to move with the guide member during pivoting while maintaining precise positioning relative to the first roller when the guide member is in the closed position
Solution Approach 2:
The guide groove is designed with specific geometric characteristics that provide different degrees of freedom at different locations. Along the pivot path, it allows movement for adaptability, while at the closed position, it provides precise constraint for positioning accuracy
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 design stabilizes the position of the nip, ensuring consistent sheet conveying direction and distance, improving the accuracy and reliability of the image recording process.
Implementation Method 1
an urging portion configured to urge the second roller in a direction directed from the second roller toward the first roller
Data Source
AI summary
An image recording apparatus includes: a housing including a frame and a conveyance path; a recording device which records an image on a sheet conveyed along the conveyance path; a first roller located upstream of the recording device; a second roller opposed to the first roller; a guide member pivotable between a first position for partly defining the conveyance path and a second position where the conveyance path is open; a roller holder coupled to the guide member and supporting the second roller; an urging portion which urges the second roller toward the first roller; and an engaging portion supported by the roller holder and configured to, when the guide member is located at the first position, be engaged with the frame to position the roller holder to a third position where the second roller contacts the first roller by an urging force of the urging portion.