Conveying belt assembly for a printing device, comprising: - an endless conveyor belt having a conveying part and a return part; wherein a rotational direction is defined by the conveying direction of the endless conveyor belt and a transverse direction is defined as a direction extending perpendicular to the rotational direction; - two sliding supports (301;302) having a surface curved in rotational direction of the conveyor belt; one sliding support being arranged at the downstream end of the conveying part defining the downstream transition between the conveying part and the return part, the other sliding support being arranged at the upstream end of the conveying part defining the upstream transition between the conveying part and the return part; - a driving roller arranged downstream of the conveying part in urging contact with the conveyor belt; - a friction element arranged upstream of the conveying part in urging contact with the conveyor belt for tensioning the conveying part; - a control system for controlling the position of the conveying part with respect to the transverse direction; wherein the control system comprises: - a position sensing device for sensing the position of the conveying part with respect to the transverse direction and/or the position of an object transported or to be transported by the conveying part with respect to the transverse direction; - at least one actuator device (313a; 313b; 314a; 314b), like an upstream actuator device and/or a downstream actuator device, said actuator device being adapted for moving the conveying part in transverse direction; - a controller which is, on the one hand, operatively connected with the position sensing device for receiving sensor signals representing one or more of said sensed positions and, on the other hand, operatively connected with, respectively, the upstream and downstream actuator device for transmitting control signals, generated by the controller on the basis of the sensor signals, to the upstream and downstream actuator. - an endless conveyor belt having a conveying part and a return part; wherein a rotational direction is defined by the conveying direction of the endless conveyor belt and a transverse direction is defined as a direction extending perpendicular to the rotational direction; - two sliding supports (301;302) having a surface curved in rotational direction of the conveyor belt; one sliding support being arranged at the downstream end of the conveying part defining the downstream transition between the conveying part and the return part, the other sliding support being arranged at the upstream end of the conveying part defining the upstream transition between the conveying part and the return part; - a driving roller arranged downstream of the conveying part in urging contact with the conveyor belt; - a friction element arranged upstream of the conveying part in urging contact with the conveyor belt for tensioning the conveying part; - a control system for controlling the position of the conveying part with respect to the transverse direction; - a position sensing device for sensing the position of the conveying part with respect to the transverse direction and/or the position of an object transported or to be transported by the conveying part with respect to the transverse direction; - at least one actuator device (313a; 313b; 314a; 314b), like an upstream actuator device and/or a downstream actuator device, said actuator device being adapted for moving the conveying part in transverse direction; - a controller which is, on the one hand, operatively connected with the position sensing device for receiving sensor signals representing one or more of said sensed positions and, on the other hand, operatively connected with, respectively, the upstream and downstream actuator device for transmitting control signals, generated by the controller on the basis of the sensor signals, to the upstream and downstream actuator.