the stop members 40 acting to limit the extent to which the calender rolls 20a and 21 move downwardly this in fact contributes to minimizing the duration of production interruption by virtue of the rapid manner in which the nips can be opened the portion of the web entering the calender apparatus is denoted in the figures by w in while the portion of the web being discharged from the calender apparatus is designated w out further guide rolls 27 are illustrated in the figures such rolls functioning to guide the web w through the calender apparatus reeling apparatus 28 are provided at the discharge end of the calender apparatus further apparatus 31 and 32 for metering the moisture of the web are provided at the outlet and inlet sides of the calender respectively guide plates 30 are provided for facilitating the threading of the initial end of the web w through the calender preferably together with suitable blow devices not shown the equipment for threading the end of the web through the calender further includes pairs of ropes 41 and pulleys 42 which are in themselves conventional and need not be described for present purposes it is an important feature of the present invention that the soft calender rolls may be easily replaced in a rapid manner when the same are damaged or become worn thus the upper soft calender roll 20b of group r 2 in each of the embodiments illustrated in fig1 and 2 can be.