Surgical instrument systems comprising an articulatable end effector and means for adjusting the firing stroke of a firing member

A surgical instrument system, comprising:

• an end effector, comprising:
• an anvil;
• and
• a staple cartridge comprising a plurality of staple cavities and a plurality of staples removably stored in the staple cavities;
• a shaft defining a longitudinal axis;
• an articulation joint, wherein the end effector is rotatably connected to the shaft at the articulation joint between an unarticulated position and a plurality of articulated positions relative to the longitudinal axis;
• a flexible firing bar extending through the articulation joint, wherein the flexible firing bar comprises:
• a proximal end positioned proximal to the articulation joint;
• a distal end positioned distal to the articulation joint;
• and
• a plurality of lateral portions extending through the articulation joint, wherein the lateral portions are configured to shift relative to each other at the proximal end when the end effector is moved to an articulated position;
• and
• a sensor configured to defect shifting between a first lateral portion and a second lateral portion at the proximal end of the flexible firing bar.

A surgical instrument system, comprising:

• an end effector, comprising:
• an anvil;
• and
• a staple cartridge comprising a plurality of staple cavities and a plurality of staples removably stored in the staple cavities;
• a shaft defining a longitudinal axis;
• an articulation joint, wherein the end effector is rotatably connected to the shaft at the articulation joint between an unarticulated position and at least one articulated position relative to the longitudinal axis;
• a flexible firing member extending through the articulation joint, wherein the flexible firing member comprises a plurality of lateral portions, and wherein the lateral portions are configured to shift relative to each other when the end effector is moved to the at least one articulated position;
• and
• a relief feature configured to accommodate shifting of the lateral portions of the flexible firing member.