Abstract: A system for manufacturing two-way mailers constituted by a single blank imprinted with data on both faces thereof, the blank then being formed into superposed panels that not only define pre-addressed forwarding and return envelopes but also a printed statement of charges and a return stub to accompany payment, thereby making it possible for a company to forward to a customer a statement of charges and for the customer to remit to the company. In the system, the blanks are individually printed on both faces thereof in a printing stage that includes a conveyor loop wherein fresh blanks admitted into the loop are fed under the printing head for imprinting on one face thereof, each blank then being turned over and advanced on the loop toward a two-position output gate. In its first position, the gate passes the blank into a reentry mechanism acting to readmit the turned-over blank into the loop for imprinting on the other face thereof.