CONVERSION OF BINARY TO MULTI-LEVEL IMAGE DATA

When binary image pixel data is converted into multi-level pixel data, the values of multi-level pixel data are previously set in predetermined registers. A circuit is provided for deciding whether or not the values set in the register are written in memory in accordance with the state of binary pixel data. N control circuits are provided in parallel, and N memory units to be respectively connected to the control circuits are also provided. This simultaneously multi-levelizes N items of binary pixel data.