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Walk into almost any business office, and you'll probably find a photocopier ("copier") with a line of people waiting to use it. For most businesses, small or large, the copier has become standard equipment, much like having a desk to work at and a chair to sit in.

　现代电子技术的广泛应用给人们带来了许多方便，大大的提高了工作效率。要想复印一件试卷、一份文件，只要花几毛钱，几分钟就完事了。这都要归功于静电复印机。
静电复印机是利用静电正、负电荷能互相吸引的原理制成的。
　　一、直接复印和间接复印
　　 早期的复印机采用直接复印，先让复印纸按图画文字深浅，分别带上相应的静电电荷，深处电荷密，浅处电荷稀，从而形成一张与图画文字相对应的静电图像。然后一种显示黑色的墨粉末直接被静电图像吸引，通过定影，最后成为一张图画文字的复印品。
但是近三十年国际上...