A developing cartridge includes a housing having a photosensitive medium, and a protective cover movable between a first position where the protective cover covers the photosensitive medium and a second position where a part of the photosensitive medium is exposed. The flux in the splitter is less than 6 m3h of dilfroth fed per m2 of horizontal cross-sectional rag area. During the welding process, the expulsion rate is monitored and used to modify the weld energy. An optoelectronic position sensor is also included, and its signal corresponds to the deflection of the coil from a zero position which occurs as a result of placing a load on the load receiver. The invention also relates to novel polycondensation catalysts having a guanidine structure, in silicone chemistry, and to the uses thereof as catalysts for the organopolysiloxane polycondensation reaction.