Abstract: Machines for stapling and folding a stack of paper sheets, having a reciprocable tray to receive and move a stack of paper sheets between a rest, stapling position and a sheet-folding position; solenoid-operated staplers to staple together said sheets in a stapling line, a blade on said machine reciprocally movable between a rest position and a sheetfolding, extended position wherein an edge of said blade presses against said stack of paper sheets at said stapling line, a power-driven pair of spaced, opposed rollers with the nip between rollers aligned with said blade to allow said blade in its extended position and the bent stack of paper sheets thereon to enter said nip, whereupon said power-driven rollers grip and fold said sheets along said stapling line, electrically powered drive means to move said blade to extended position when said tray is moved into said sheet-folding position, whereby said power-driven pair of rollers lift the stapled, folded sheets off of said blade and convey said stapled, folded