Sheet Feeding Apparatus Fire Spread Prevention
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Solution Overview
Problem
Existing sheet feeding apparatus configurations, as per Japanese standards, fail to meet the fire spread prevention requirements of the IEC 62368-1 2nd Edition, particularly when using resin materials with a flame retardant grade lower than V-2, and result in increased component counts and assembly complexity.
Innovation Solution
A sheet feeding apparatus design featuring a main frame with strategically positioned support portions and openings that ensure all line segments from the sheet cassette to the electric circuit board form an angle of 45° or more with the vertical, and the lower opening portions are dimensioned to prevent fire spread, thereby adhering to the IEC 62368-1 2nd Edition standards while minimizing component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric circuit board is covered by a flame retardant casing to prevent fire spread, then fire safety is improved, but the device complexity and number of components increase
Solution Approach 1:
The patent integrates the fire prevention function directly into the existing side plate structure by forming support portions and openings therein, rather than adding a separate flame retardant casing. This merging of functions reduces component count while maintaining fire safety compliance with IEC 62368-1 2nd Edition standards.
Solution Approach 2:
The side plate is designed to serve multiple functions simultaneously: it provides structural support, forms support portions for the electric circuit board, creates controlled openings for fire prevention, and acts as a barrier to limit fire spread. This multi-functionality eliminates the need for dedicated fire retardant casings.
2Ease of manufacture
If flame retardant materials with grade lower than V-2 are used, then manufacturing cost and ease of manufacture are improved, but compliance with IEC 62368-1 2nd Edition fire spread prevention requirements deteriorates
Solution Approach 1:
The controlled openings in the side plate act as an intermediary barrier that limits fire spread without requiring high-grade flame retardant materials. By strategically positioning and dimensioning these openings, the design creates a physical barrier that complies with IEC 62368-1 2nd Edition fire spread prevention requirements while allowing the use of cost-effective resin materials.
3Device complexity
If the electric circuit board is positioned closer to the sheet cassette to reduce component count, then device complexity is reduced, but fire spread risk increases
Solution Approach 1:
The side plate incorporates locally optimized features including support portions and controlled openings at specific positions between the sheet cassette and electric circuit board. These localized structural modifications create fire barriers precisely where needed, enabling closer component positioning while maintaining fire spread prevention compliance.
Data Source
AI summary
A sheet feeding apparatus includes an upper support portion formed integrally with a side plate and configured to support an electric circuit board; an upper opening portion formed in the side plate near the upper support portion; a lower support portion provided at a separate part mounted to the side plate and configured to support the electric circuit board; and a lower opening portion provided between the side plate and the separate part. All line segments having a length of 50 mm or less, among line segments extending from arbitrary points in a main body portion of a sheet cassette, through arbitrary points in the upper opening portion, to the electric circuit board, form an angle of 45° or more with respect to a vertical line, and the lower opening portion has a dimension of 5 mm or less or a width of 1 mm or less.