PURPOSE: To permit the easy coping with the improvement of smoothing, tone processing, picture printing speed and the like by a method wherein interchangea bility is provided between high-speed data transfer mode and low-speed data transfer mode while the high-speed data transfer is facilitated.

CONSTITUTION: A parallel input port of 2-bit is provided and two sets of input ports L1, L2 are provided in a shift register 2. Further, a 32-bit counter 20 is provided and under a serial input mode, input is effected from the input port L1 into the shift register 2, the signal of the counter 20 is divided by 1/2, switching is effected between a right shift input and a left shift input, a latch signal is generated and strobe demanding signal and/or a block selecting signal are generated. Under the 2-bit parallel input mode, two sets of input ports L1, L2 are employed, the inputting direction into the shift register 2 is switched under the unit of 32 clocks omitting 1/2 dividing, a latch signal is generated and a strobe demanding signal or a block selecting signal is generated.