Many resolution enhancement techniques have been developed and used to convert a low resolution image into a higher resolution image in a printing system. Generally, the printout of the high resolution images has more density levels than that of the low resolution images. It means that the high resolution image has more bits for each pixel than the low resolution image. In this paper, we propose a resolution enhancement method which can make a multi-bit image from a 1bit image. The present method generates a multi-bit image by improving the uniformity in each halftone pattern for each super-cell. Based on the edge map generated by a window having a size of n×n pixels and a LPI (lines per inch) value and an angle of the screen mask, the 1bit image is converted to a multi-bit image adaptively. Experimental results show 1bit image has multi level density variously according to its edge map.