An electrophotography apparatus prevents the edge effect without causing the blurring or loss of a single-dot image or a single-dot-width line. Based on a measurement of a testing patch, two templates with different sizes are generated. Image data to be printed is subjected to template matching using the templates to obtain a difference region as an image edge region of the image data where, when the image data is developed, the amount of attached toner is increased. The exposure amount for the image edge region is controlled based on a measurement of the amounts of attached toner in edge portions of the testing patch so that the difference in the attached toner amounts are minimized.