Circuit Board Damping Ribs for Drop Impact Protection
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Solution Overview
Problem
Printed circuit boards in image forming apparatuses with holes are prone to damage from impacts during transportation due to stress concentration at the edges of holes, making it difficult to provide the necessary creepage distance without increasing the board's size or using insufficiently spaced damping ribs.
Innovation Solution
The image forming apparatus is designed with a circuit board having an opening portion between a protruding first abutting portion from the frame and a second abutting portion from the cover, allowing the impact to be distributed evenly across the board's edges, preventing stress concentration and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If holes are provided in the circuit board substrate to ensure creepage distance, then the creepage distance is improved, but the impact resistance deteriorates due to stress concentration at hole edges
Solution Approach 1:
The patent applies beforehand cushioning by positioning damping ribs on the circuit board substrate at specific locations before impact occurs. These ribs are strategically placed at distances of 5mm or more from hole edges to prevent stress concentration during impact events. The damping ribs act as pre-positioned protective elements that distribute impact forces away from critical hole edges, thereby maintaining both creepage distance requirements and impact resistance.
2Device complexity
If the circuit board is positioned next to heavy components to maintain structural layout, then the device complexity is reduced, but the impact damage risk increases
Solution Approach 1:
The patent introduces damping ribs as intermediary protective elements between heavy components and the circuit board substrate. These ribs serve as mediators that intercept and distribute impact forces before they reach the circuit board, particularly protecting areas around holes where stress concentration would occur. This allows the circuit board to remain positioned next to heavy components for structural efficiency while significantly reducing impact damage risk.
3Volume of moving object
If damping ribs are placed close to holes to maximize protection space, then the device size is reduced, but the stress concentration at hole edges increases
Solution Approach 1:
The patent applies local quality by creating different functional zones on the circuit board substrate. Damping ribs are positioned in specific local areas at optimized distances (5mm or more) from hole edges, providing enhanced protection exactly where needed while maintaining compact overall device dimensions. This localized protection strategy ensures hole edge strength is preserved in critical areas without unnecessarily increasing the overall device volume.
Data Source
AI summary
An image forming apparatus includes an image forming portion, a frame, which is a part of a main assembly frame, extending along a predetermined plane, a cover provided outside of the frame and extending along the predetermined plane and a circuit board, provided between the frame and the cover with in a direction perpendicular to the predetermined plane and extending along the predetermined plane. An opening portion penetrating the circuit board is formed in the circuit board. The frame includes a first abutting portion protruding toward the circuit board and the cover includes a second abutting portion protruding toward the circuit board. The first and second abutting portions are opposite to each other via the circuit board and positioned in an area where the opening portion of the circuit board is sandwiched therebetween in the direction perpendicular to the predetermined plane.