An image forming apparatus comprising: a heating rotary member configured to heat toner born on a recording material; a pressure rotary member configured to pressurize the heating rotary member, wherein the heating rotary member and the pressure rotary member form a fixing nip portion and fix a toner image to the recording material at the fixing nip portion while nipping and conveying the recording material with the toner born thereon; a web configured to collect toner adhering to a surface of the heating rotary member without being fixed to the recording material; a winding roller configured to wind the web; a motor configured to rotate the winding roller to wind the web; the image forming apparatus being characterised in that it further comprises: a contact member configured to make contact with an outer surface of the web wound by the winding roller and move based on a position of the outer surface; a variable resistor having a resistance value and configured to change the resistance value depending on a position of the contact member; and control means configured to control a rotation amount of the motor based on the resistance value, wherein the contact member includes a first lever configured to make contact with the outer surface of the web, wherein the first lever is configured to swing based on an outer diameter of the web wound by the winding roller, and wherein the contact member includes a second lever operatively coupled to a gear mechanism (222, 223, 224) of the image forming apparatus, the second lever being arranged to be rotated when the first lever swings, the second lever being further arranged to rotate the gear mechanism (222, 223, 224), the gear mechanism (222, 223, 224) being arranged to rotate a rotation portion of the variable resistor, the rotation angle of the variable resistor corresponding to a rotation angle of the said rotation portion. a heating rotary member configured to heat toner born on a recording material; a pressure rotary member configured to pressurize the heating rotary member, wherein the heating rotary member and the pressure rotary member form a fixing nip portion and fix a toner image to the recording material at the fixing nip portion while nipping and conveying the recording material with the toner born thereon; a web configured to collect toner adhering to a surface of the heating rotary member without being fixed to the recording material; a winding roller configured to wind the web; a motor configured to rotate the winding roller to wind the web; the image forming apparatus being characterised in that it further comprises: a contact member configured to make contact with an outer surface of the web wound by the winding roller and move based on a position of the outer surface; a variable resistor having a resistance value and configured to change the resistance value depending on a position of the contact member; and control means configured to control a rotation amount of the motor based on the resistance value, wherein the contact member includes a first lever configured to make contact with the outer surface of the web, wherein the first lever is configured to swing based on an outer diameter of the web wound by the winding roller, and wherein the contact member includes a second lever operatively coupled to a gear mechanism (222, 223, 224) of the image forming apparatus, the second lever being arranged to be rotated when the first lever swings, the second lever being further arranged to rotate the gear mechanism (222, 223, 224), the gear mechanism (222, 223, 224) being arranged to rotate a rotation portion of the variable resistor, the rotation angle of the variable resistor corresponding to a rotation angle of the said rotation portion. a contact member configured to make contact with an outer surface of the web wound by the winding roller and move based on a position of the outer surface; a variable resistor having a resistance value and configured to change the resistance value depending on a position of the contact member; and control means configured to control a rotation amount of the motor based on the resistance value, wherein the contact member includes a first lever configured to make contact with the outer surface of the web, wherein the first lever is configured to swing based on an outer diameter of the web wound by the winding roller, and wherein the contact member includes a second lever operatively coupled to a gear mechanism (222, 223, 224) of the image forming apparatus, the second lever being arranged to be rotated when the first lever swings, the second lever being further arranged to rotate the gear mechanism (222, 223, 224), the gear mechanism (222, 223, 224) being arranged to rotate a rotation portion of the variable resistor, the rotation angle of the variable resistor corresponding to a rotation angle of the said rotation portion.