Patent ID: 7309120

Claim:
A head substrate comprising: a plurality of printing elements for printing; a plurality of first driving elements which correspond to said plurality of printing elements, respectively, for driving said plurality of printing elements; a fuse ROM which stores information; a second driving element for driving said fuse ROM; input means for inputting a printing signal to cause said plurality of printing elements to print and a block selection signal to time-divisionally drive said plurality of printing elements; selective driving means for selectively driving said plurality of first driving elements on the basis of the printing signal and the block selection signal input by said input means; a first pad for applying a first voltage to said fuse ROM to write information; and a second pad for applying a second voltage to read out the information from said fuse ROM, wherein, in order to selectively drive said second driving element to operate said fuse ROM, said second driving element connects to said selective driving means, and said fuse ROM is selectively operative on the basis of signals input from said input means.