| 摘要 |
PURPOSE:To prevent the deterioration of a pressure roller, the wrinkles and bias of a transfer material, the offset of toner against a fixing roller, etc., based on the fact that the paper nonpassing part of the fixing roller is unnecessarily heated, in a fixing device. CONSTITUTION:A bar-like heater 2 is disposed along the shaft of a cylidrical fixing roller 1, inside it. Shield members 12 are arranged so as to come and go freely in the direction of the arrow K1, between the fixing roller 1 and the heater 2 in the vicinities of both right and left ends of the fixing roller 1. When the paper passing width W1 of the transfer material passing between the fixing roller 1 and the pressure roller is maximum, respective shield members 12 are retreated so as to set the top end parts 12a in the locations of M1 and a region having radiation A1 is made large. When a paper passing width W2 is small, respective shield members are inserted so as to set the top end parts 12 in the location of M2 and the region having the radiation A2 is made small. Thus, when the paper passing width W2 is small, respective shield members 12 shield the radiant heat of the heater 2 to prevent the paper nonpassing part of the fixing roller 1 from being needlessly heated. |
