Head substrate, printhead, head cartridge, and printing apparatus

A head substrate comprising:

• an ink supply port;
• a heater array which is arrayed along a longitudinal direction of the ink supply port and includes a plurality of heaters;
• a transistor array which is arrayed along an arrayed direction of said heater array and includes a plurality of transistors for driving the plurality of heaters;
• and
• a logic circuit which drives said transistor array,
• wherein said logic circuit is arranged between said heater array and said transistor array,
• a pitch of the plurality of heaters with respect to a direction in which each of the plurality of heaters is arranged differs from a pitch at which the plurality of transistors is arranged, and
• the pitch at which the plurality of transistors is arranged is set smaller than the pitch at which the plurality of heaters is arranged, forming an empty space in the arrayed direction of said transistor array.