Ribbed Discharge Skid Roller for Toner Image Protection
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Solution Overview
Problem
Existing sheet conveying apparatuses in image forming devices suffer from image quality deterioration due to roller traces, which are exacerbated by the use of expensive insulating rollers or rollers with minute protrusions that can cause toner peeling and uneven contact, leading to increased manufacturing costs and reduced conveying efficiency.
Innovation Solution
A sheet conveying apparatus featuring a discharge skid with a circumferential surface having a plurality of ribs, where the ribs are continuous in the axial direction, with specific diameter and height differences to minimize contact pressure and prevent toner peeling, while maintaining conveying efficiency and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a roller having an insulating property is used as a conveying roller contacted with a toner image that is heated and fixed at a high temperature, then the generation of roller trace is prevented, but the manufacturing cost is increased and the hardness is low causing compression of the insulator layer
Solution Approach 1:
The roller surface is segmented into multiple ribs rather than using a continuous insulating layer. This segmentation achieves the anti-roller trace effect while using less insulating material, reducing manufacturing cost. The ribs create discrete contact points that prevent continuous heat dissipation and surface property changes.
Solution Approach 2:
Instead of making the entire roller surface insulating, only specific localized regions (the ribs) have insulating properties. This local quality approach prevents roller trace at critical contact points while reducing overall material usage and cost.
2Object-affected harmful factors
If a roller having an insulating property is used as a conveying roller contacted with a toner image that is heated and fixed at a high temperature, then the generation of roller trace is prevented, but the hardness of the insulator is low causing compression when skid comes into pressure contact
Solution Approach 1:
The roller uses a composite structure combining a hard base material with insulating ribs. The base material provides the necessary hardness and structural support, while the insulating ribs provide the anti-roller trace effect. This composite approach solves both the hardness and insulating requirements simultaneously.
3Object-affected harmful factors
If the urging force of a spring that presses a skid against the roller is increased to prevent compression of the insulator layer, then the insulating effect is maintained, but the conveying force of the rollers is lowered making it difficult to reliably discharge sheets
Solution Approach 1:
The segmented rib structure reduces the total contact area between the skid and roller, thereby reducing the total compressive force required to maintain the insulating effect. This leaves more urging force available for reliable sheet conveying and discharge.
4Object-affected harmful factors
If a roller with minute protrusions is used to reduce contact area with the sheet, then the generation of roller trace is prevented, but the toner parting property deteriorates causing toner peeling
Solution Approach 1:
The ribs provide localized insulating contact points that prevent roller trace without creating the excessive pressure concentration of minute protrusions. The rib geometry and spacing are optimized to maintain toner parting property while preventing heat dissipation and surface property changes.
Data Source
AI summary
A sheet conveying apparatus for conveying a sheet having an image formed thereon includes: a first rotator; a second rotator that comes into pressure contact with the first rotator and contacts a surface of the sheet having the image formed thereon; and a plurality of ribs that are formed on a circumferential surface of the second rotator and disposed in an axial direction so as to be continuous in a circumferential direction. Among the plurality of ribs, the ribs disposed at both ends of the second rotator in the axial direction have a diameter that is smaller than those of the other ribs.