Disk type inverter-stacker with improved sheet handling slots for different paper weights

In a disk type sheet inverting and stacking system, for stacking sheets inverted in a stacking position, with rotatable disk units with narrow sheet transporting slots, in which a single printed sheet outputted by a reproduction system is sequentially fed into a single said sheet transporting slot of said disk units to be transported therein and inverted by rotation of said disk units and then released from said sheet slot of said disk units at said stacking position;

• the improvement wherein:
• said narrow sheet transporting slots of said disk units have a convolute sheet path formed by plural internal transverse sheet corrugating protuberances extending transversely past one another within said sheet transporting slots;
• wherein respective said plural internal transverse sheet corrugating protuberances are alternatingly spaced along said sheet transporting slot and extend towards and transversely past one another from opposing sides of said sheet transporting slot to form a convolute sheet transporting slot which forces the corrugation of said single sheet in said sheet transporting slot;
• and
• wherein said protuberances have smoothly arcuate large diameter surfaces, with small surface angles in the direction of sheet insertion, to provide relatively low resistance to the insertion of a sheet into said sheet transporting slots;
• and
• wherein said plural internal transverse sheet corrugating protuberances increase the retention of said sheet within said sheet transporting slot without substantially increasing the resistance to lateral movement of said sheet within said sheet transporting slot.