| 摘要 |
PROBLEM TO BE SOLVED: To surely detect the roughness of a sheet surface with simple and small constitution by contacting a contact means on a conveyed sheet surface and detecting such physical phenomena as vibration and sliding sound with a roughness detection means. SOLUTION: A sheet surface detector 24 is constituted by pinching a piezoelectric vibration sensor (roughness detection means, piezoelectric element) 20 with a molded sensor base 21 and a precopy guide (contact means, support means) 17 as a sheet metal such as aluminum and the like. The precopy guide 17 smoothly guides a sheet P to a copy nip part formed on a touching part of a sensing drum 1 and a copy roller 8 and is arranged in the position bending the angle of the sheet P during coming in and out the precopy guide 17 for 5 degrees to change copy image quality and improve the resolution. With this constitution, the vibration energy receiving of the precopy guide 17 by the sheet P surface roughness concentrates on the piezoelectric vibration sensor 20 so that the roughness of the sheet P surface can be measured with good sensitivity. |
