Abstract: A chart recorder has a writing platen over which a moving strip of recording medium passes. The recording medium is Z folded along slotted lines. The tip of the tubular pen of a pressurized ink supply system is forced into contact with the strip as it passes over the platen. A pressure plate is positioned adjacent the pen for pressing the strip onto the platen. A capstan drive is located downstream of the writing platen to draw the strip off a Z folded supply stack past the pressure plate and over the writing platen. The pressure plate exerts a drag on the recording medium strip which tensions the strip to further cause it to lie flat across the writing platen. The pressure of the plate and the tension of the strip as well as the size relationship between the pen tip and the slots facilitate passage of the pen over the lines of slots.