Exchangeable cap gripper cartridge for capping and de-capping of test tubes

A cap gripper cartridge for releasably connecting to a head unit of a screw cap test tube capper-decapper device and having a common axis of engagement after connecting, said cap gripper cartridge comprising:

• a cap gripper holder defining a head unit side and a test tube side and rotatably bearing a plurality of cap grippers arranged in a two-dimensional array, said common axis of engagement being perpendicular to said two-dimensional array, wherein
• a respective cap gripper comprises a respective cap socket arranged for engaging and retaining a test tube screw cap during and after a capping or a de-capping of said test tube screw cap to or from a screw cap test tube,
• a respective cap socket is connected by a respective cap gripper axle arranged in parallel to said common axis of engagement, to a respective head unit connector, said respective head unit connector arranged for connecting to said head unit, and transferring after connection a rotation received from said head unit to a rotation of said respective cap socket, and wherein
• each respective cap socket presents to said test tube side, and each respective head unit connector presents to said head unit side;
• said cap gripper cartridge further comprising:
• a cap ejector plate comprising a plurality of respective throughbores, a respective throughbore arranged around a respective cap gripper axle of a respective cap gripper comprised in said two-dimensional array, between said cap gripper holder and said respective cap socket;
• and
• at least one actuable cap ejector plate displacer;
• wherein
• said cap ejector plate is arranged for being displaced by said actuable cap ejector plate displacer along said common axis of engagement relative away from said cap gripper holder for engaging all respective test tube screw caps retained in all respective cap sockets comprised in all respective cap grippers held by said cap gripper cartridge, and effecting by said displacement a release of said all retained test tube screw caps from all respective cap sockets holding a screw cap.