Print element substrate, printhead, and printing apparatus

A printhead comprising:

• a print element substrate comprising:
• a pad for receiving a predetermined logic signal;
• a plurality of layers including:
• a silicon layer;
• a heater layer;
• an insulating layer arranged on the heater layer;
• and
• an anti-cavitation layer arranged on the insulating layer that is for protecting the insulating layer;
• and
• a switch that has a control terminal that is electrically connected to the silicon layer via a register and to the pad and has a first terminal that is electrically connected to the anti-cavitation layer and a second terminal that is electrically connected to the silicon layer, the switch causing the anti-cavitation layer and the silicon layer to have an electrical disconnection when the pad receives the predetermined logic signal and causing the anti-cavitation layer and the silicon layer to have an electrical connection so as to release charge caused by electric-static discharge to the silicon layer when the pad does not receive the predetermined logic signal.

A printing apparatus comprising:

• a print element substrate comprising:
• a pad for receiving a predetermined logic signal;
• a plurality of layers including:
• a silicon layer;
• a heater layer;
• an insulating layer arranged on the heater layer;
• and
• an anti-cavitation layer arranged on the insulating layer that is for protecting the insulating layer;
• and
• a switch that has a control terminal that is electrically connected to the silicon layer via a register and to the pad and has a first terminal that is electrically connected to the anti-cavitation layer and a second terminal that is electrically connected to the silicon layer, the switch causing the anti-cavitation layer and the silicon layer to have an electrical disconnection when the pad receives the predetermined logic signal and causing the anti-cavitation layer and the silicon layer to have an electrical connection so as to release charge caused by electric-static discharge to the silicon layer when the pad does not receive the predetermined logic signal.