Method and apparatus for avoiding slip in transporting a recording substrate in a fixing station of an electrographic printer or copier

A system for avoiding slip during transport of a recording substrate in a fixing station of an electrographic printer or copier, the recording substrate having a continuous form, comprising:

• the recording substrate being transportable by friction in a recording substrate transport direction by two rollers contained in the fixing station;
• said rollers being preceded by a braking device for tautening the recording substrate in the recording substrate transport direction;
• the braking device being preceded by a loop tensioner which is pivotable about a pivot axis for equalizing the length of the recording substrate transport path to the length of the recording substrate, which is feedable to the fixing station at constant speed;
• sensors respectively assigned to the loop tensioner at first and second deflection points thereof;
• a roller drive controller controlling a rotational speed of the rollers as a function of reaching said first and second deflection points of the loop tensioner;
• a time registering module registering a deflection and dwell time between reaching the first deflection point, at which there is a maximum length of the recording substrate transport path, and reaching the second deflection point of the loop tensioner;
• a comparison device comparing the registered deflection and dwell time with a desired deflection and dwell time;
• a braking force controller controlling a braking force of the braking device acting on the recording substrate, the control being such that the braking force is reduced if the desired deflection and dwell time is exceeded by the registered deflection and dwell time;
• and
• device for varying a basic setting of braking force and roller rotational speed when a limiting value of the braking force is reached.