Printing system that positions web at accurate waiting position

A printing system comprising:

• a first printing means for printing images on a first surface of a web;
• a second printing means for printing images on a second surface of the web;
• and
• a control means for controlling both the first and second printing means, the control means generating a reference signal, wherein
• the second printing means includes:
• a photosensitive member;
• an irradiating unit that irradiates a laser light onto the photosensitive member for forming latent images thereon, wherein the control means generates the reference signal when the irradiating unit completes irradiating a laser light for a last page image;
• a developing means for developing the latent images into toner images;
• a calculating means for calculating a time duration required for the web to reach a predetermined waiting position after the reference signal was generated;
• a transport means for transporting the web both in a forward direction and a reverse direction, wherein the transport means stops transporting the web in the forward direction after a last-page toner image is completely transferred from the photosensitive member onto the web;
• and
• a measuring means for measuring a web transport distance between when the time duration elapses from when the reference signal was generated and when the transport means stops transporting the web in the forward direction, wherein
• the transport means transports the web in the reverse direction by the web transport distance measured by the measuring means so as to transport the web back to the web waiting position;
• and
• the calculating means calculates the time duration based on a web transport speed at the time of when the reference signal was generated.