| 摘要 |
A method of detecting the amount of remaining sheets of paper in a paper feeding cassette of a printing apparatus, wherein the printing apparatus receives a paper feeding cassette having a knock-up plate on which paper is placed, and which pivots as paper is removed therefrom, a pickup roller installed in the printing apparatus which elastically moves up and down within a predetermined range to contact the paper, the pickup roller being made to rotate in close contact with the paper to sequentially feed the paper into the printing apparatus, a lifting mechanism which lifts the knock-up plate step by step according to the consumption of paper, thereby placing the loaded paper against the pickup-roller, calculating a difference in the number of operations of the lifting mechanism for lifting the knock-up plate toward the pickup roller when a maximum number of sheets of paper is loaded into the paper feeding cassette and when only a single sheet of paper is placed in the paper feeding cassette, calculating an amount of consumed paper per one operation of the lifting mechanism as a set value from the calculated difference, lifting the knock-up plate when the paper feeding cassette enters into the printing apparatus until the loaded paper closely contacts the pickup roller, and counting the number of operations of the lifting mechanism, and calculating the amount of paper remaining in the paper feeding cassette based on the number of operations counted and the set value calculated. As a result, a user is always able to roughly determine how many sheets of paper are left in the cassette, thereby avoiding situations where the printing job is stopped due to a lack of paper.
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