An image forming system includes a first developing unit to form an image using a dry developer and a second developing unit to form an image using a wet developer. The first developing unit forms an image using yellow, magenta, cyan and black developers, and the second developing unit forms an image using a developer having lighter colors than the yellow, magenta, cyan and black developers. Therefore, light colors requiring high resolution and high definition may be printed using a wet type image forming module capable of easily expressing the light colors, and original and dark colors may be printed using a dry image forming module. Hence, it is possible to print a color image having high resolution and high definition, and enhance the color reproducibility of the image.