| 摘要 |
A blackboard eraser comprising a base, an uppermost cover mounted on the base, two erasing rollers pivotedly mounted within the base, a controller and two scrapers wherein the controller normally engages with the rollers for erasing use and may be depressed to release the rollers for their free rotation to contact the scrapers formed atop the rollers so as to scrape the dust accumulated on roller into a storing chamber spaced between the base and the uppermost cover for final disposal of dust.
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