| 摘要 |
PURPOSE: To provide a binary picture element value for each picture line in a rasterizing device by supplying a value by a command to the picture element of a series value corresponding to a half bit pattern. CONSTITUTION: When exposed, a charged pattern on a belt is provided with a gradual transition part between a non-charged area 40 and a charged area 41. Then, by covering the belt with toner powder at a position where an electric field on the belt is larger than a critical value applied to a system, a development station obtains visible pictures provided with a slightly wavy boundary line 42 at a center part. Then, in order to process contour data to the picture element value, the use of straight 'valid' boundary lines 43-45 is allowed and the respective boundary lines 43-45 run similarly to the boundary line between the picture element to be exposed and the picture elements not to be exposed for continuous boundary picture elements and are passed through the middle of half bit picture element at a boundary provided with a half bit picture element pattern. Thus, the boundary is correctly positioned on a half picture element between a black image part and a white image part. |
