To eliminate a problem that the print throughput deteriorates when ink drop ejection timing is shifted.

The ASIC 23 performing drive control of a recording head 7 based on print data received from a host 200 comprises a register 23c having a delivery data area for storing print data of predetermined shots at significant bits and a nondelivery data area not performing shot at insignificant bits. A data processing circuit 23b adds regulation pixel value data indicative of existence of a regulation pixel not forming a dot to the head and tail of raster data delivered from an image buffer 21c and then shift the pixel before the data is stored in the register 23c.