Fixing Nip Entrance Guide Control for Stiff Sheet Wrinkling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional image forming apparatuses experience issues such as image unevenness and sheet wrinkling due to the impact of the sheet leading end hitting a hard fixing roller, which affects print quality.
Innovation Solution
A fixing device with a first roller, a second roller having higher surface hardness, and a rotatable entrance guide that adjusts its rotation position based on sheet stiffness information to guide the sheet smoothly into the fixing nip, preventing impact and wrinkling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the sheet leading end hits a hard fixing roller, then the sheet is positioned at the fixing nip, but image unevenness occurs due to impact
Solution Approach 1:
A rubber cushion member is provided between the sheet and the hard fixing roller. The cushion member absorbs the impact when the sheet leading end contacts the fixing roller, preventing image unevenness while maintaining positioning accuracy. The cushion member is positioned to contact the sheet before the sheet contacts the hard fixing roller surface.
Solution Approach 2:
The rubber cushion member acts as an intermediary between the sheet and the hard fixing roller. It mediates the contact by providing a compliant surface that reduces impact forces while still enabling the sheet to be positioned correctly at the fixing nip.
2Object-affected harmful factors
If the sheet is guided to enter close to the fixing nip, then impact is suppressed, but sheet wrinkling may occur if the sheet does not smoothly enter
Solution Approach 1:
The rubber cushion member is positioned to provide cushioning before the sheet enters the fixing nip, allowing the sheet to be guided closer to the fixing nip without causing impact. This enables smooth sheet entry that prevents wrinkling while maintaining sheet flatness.
Solution Approach 2:
The cushion member changes the mechanical parameters of the contact interface by providing a compliant surface with appropriate hardness and elasticity. This allows the sheet to enter the fixing nip smoothly with reduced impact forces, preventing both impact damage and sheet wrinkling.
3Reliability
If a hard fixing roller is used, then fixing durability is improved, but sheet impact and image unevenness occur
Solution Approach 1:
The fixing roller system is segmented into two functional zones: a hard fixing roller surface for durable toner fixing, and a separate rubber cushion member for impact absorption. This segmentation allows each component to optimize its function - the hard roller provides fixing durability while the cushion member prevents sheet impact and image unevenness.
Solution Approach 2:
The rubber cushion member serves as an intermediary element between the sheet and the hard fixing roller. It allows the hard fixing roller to maintain its durability while preventing direct impact contact that would cause image unevenness.
Data Source
AI summary
A fixing device pressurizes a sheet having a toner image to fix the toner image, and includes a first roller, a second roller that faces the first roller to form a fixing nip and has a higher surface hardness than the first roller, an entrance guide that is rotatable around a rotation axis parallel to the second roller and guides the sheet that is about to enter the fixing nip, and a hardware processor that controls a rotation position of the entrance guide around the rotation axis based on sheet stiffness information on a hardness of the sheet.