Patent ID: 7865128

Claim:
A discharging unit for discharging printing medium from an image forming apparatus, comprising: a plurality of elastic rollers coupled to a first shaft rotatably driven by a driving source, the plurality of elastic rollers arranged to be spaced apart from one another; a crossing roller unit comprising one or more first crossing rollers coupled to the first shaft between elastic rollers and one or more second crossing rollers arranged to respectively cross the one or more first crossing rollers, the one or more second crossing rollers each being coupled to a second shaft engaged to interlock with the first shaft; and a plurality of curl preventing roller units respectively corresponding to the plurality of elastic rollers, each of the plurality of curl preventing roller units comprising a first curl preventing roller and a second curl preventing roller arranged along transfer path of the printing medium to form a nip with respective corresponding one of the plurality of elastic rollers for passing the printing medium therethrough, the first and second curl preventing rollers being supported by shafts having their respective rotational centers different from those of the first shaft and second shaft, wherein at least one of the plurality of curl preventing roller units is configured to move in a direction such that the size of the nip can be adjusted to accommodate different printing medium of varying thickness to pass through the nip.