Triboelectric nanogenerator (TENG)-based sensors, which convert mechanical stimuli into electrical signals, have attracted significant attention for wearable device applications. This interest has driven the development of diverse structural designs and fabrication methods. However, challenges persist due to complex manufacturing processes and limitations in miniaturization. To address these issues, this study introduces a cartridge-based co-extrusion 3D printing technology. This method utilizes a compartmentalized cartridge that integrates multiple materials and extrudes them simultaneously through a syringe, enabling one-step fabrication without the need for post-assembly. The internal architecture of the cartridge and the specifications of the attached micro-nozzle allow for precise internal patterning and the miniaturization of printed structures. To ensure reliable extrusion and structural integrity, the inks were formulated with tailored viscoelastic properties, including sufficient shear-thinning behavior for smooth deposition and shape retention. Based on this stable process, the electrical performance of TENG sensors was evaluated by varying inner layer ratios, fiber diameters, and printing configurations. The sensors consistently generated distinguishable signals under different motion types and contact conditions, demonstrating high sensitivity and functional reliability. Moreover, the printed devices also showed potential as actuators, broadening their applications in wearable electronics, healthcare, robotics, and human–machine interfaces.