The center pin 20 is cylindrical and tube-shaped, and each of the planes formed by the external surface of the center pin 20 in the vicinity of the edges 22a and 22b of the slit 21 is angled toward the inside of the center pin 20. The filter plate includes a filter part that filters the liquid and a damper part that reduces a pressure variation in the common liquid chamber, and the filter part is arranged to be thicker than the damper part. In other words, the amount of information used in the entire edge code image is compressed by reducing the number of bits to assign to each pixel and effectively using the number of bits assigned to each pixel as a whole.