Patent ID: 6249657
Filing Date: 2001-06-19
Classification: G03G

Abstract:
In a fixing device for developers, which comprises a fixing member adapted to be heated, and a pressing member adapted to be contacted with said fixing member, wherein a recording medium carrying an unfixed developer thereon is transferred to an interface between said fixing member and said pressing member so as to allow the surface carrying said unfixed developer thereon to be contacted with said fixing member; the improvement in that;a magnitude of thermal energy (Qh) to be fed from the fixing member to the developer and the recording medium, and a magnitude of thermal energy (Qp) to be fed from the pressing member to the developer and the recording medium at the moment of fixing process of the developer by means of the fixing member and the pressing member meet the following formula:Qp/Qh.ltoreq.0.7wherein said magnitude of thermal energies are calculated immediately before the fixing process from the temperatures of said developer, said recording medium, said fixing member and said pressing member; anda difference in temperature between a temperature of an uppermost layer of the developer and the temperature of a lowermost layer of the developer is represented by the following formula:.DELTA.t.gtoreq.0.135 (Wn/Vp).sup.-1.26wherein .DELTA.t is the difference in temperature between the temperature of the uppermost layer of the developer and the temperature of the lowermost layer of the developer at the moment of finishing the fixing process, the temperatures of the uppermost layer and the temperature of the lowermost layer being calculated immediately before the fixing process from the temperatures of said developer, said recording medium, said fixing member and said pressing member; Vp is a transferring speed (mm/sec) of said recording medium; and Wn is a width (mm) of a press-contacted portion to be formed between said fixing member and said pressing member in a transferring direction of said recording medium.