Ink Ribbon Cassette with Differential-Gap Take-Up Spool Supports
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Solution Overview
Problem
Conventional cassettes for ink ribbons in printers are prone to defects in the winding process due to the cantilevered design of the inner walls, which can cause the ink ribbon to skew and result in winding issues on the take-up spool.
Innovation Solution
The cassette design includes a lower case with specific wall configurations and support portions that create varying gap sizes between the take-up spool ends and the support portions, allowing the spool to tilt and align with the ribbon's width, preventing skewing and ensuring proper winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lower edge of the first inner wall is cantilevered between the upper and lower walls, then the structure is simplified and easier to manufacture, but the ink ribbon may contact the cantilevered edge causing it to skew and resulting in winding defects on the take-up spool
Solution Approach 1:
A support portion is introduced as an intermediary element between the ink ribbon and the cantilevered lower edge of the first inner wall. This support portion prevents the ink ribbon from contacting the vulnerable cantilevered edge, thereby eliminating the skewing problem while preserving the simplified cantilevered structure. The support portion acts as a mediator that protects the structural design from causing winding defects.
Solution Approach 2:
The support portion is strategically positioned only at the specific location where the ink ribbon passes between the front wall and the first inner wall. This localized support addresses the specific problem area without modifying the overall cantilevered structure. The local addition of the support portion maintains the ease of manufacture of the cantilevered design while preventing winding defects at the critical location.
2Stability of the object's composition
If the take-up spool is rigidly fixed to the lower case, then the structure is more stable, but the spool cannot tilt to align with the ribbon's width causing skewing during winding
Solution Approach 1:
The take-up spool is designed with rotational freedom about a tilt axis, transforming it from a rigidly fixed component to a dynamic component that can adapt its orientation. This dynamic capability allows the spool to tilt and align with the ink ribbon's width, ensuring proper winding without skewing, while the lower case maintains overall structural stability.
Solution Approach 2:
The support portion and the tilt mechanism are integrated into a unified structure where the support portion serves dual functions: providing structural support and enabling the tilt motion. This merging of functions maintains structural stability while achieving the alignment capability needed for precise winding.
Data Source
AI summary
A cassette includes: a lower case; a ribbon roll which is a roll of an ink ribbon; and a take-up spool configured to take up the ink ribbon from the ribbon roll. The lower case includes: a first wall and a second wall arranged in an up-down direction; and a peripheral wall extending between the first wall and the second wall. The first wall includes a lower support portion supporting a lower end of the take-up spool. The lower support portion and the lower end of the take-up spool form a first gap therebetween in a radial direction of the take-up spool. The second wall includes an upper support portion supporting an upper end of the take-up spool. The upper support portion and the upper end of the take-up spool form a second gap therebetween in the radial direction. The first gap is different in size from the second gap.