Heating-fixing roller and fixing device having the same
AssigneeCanon Kabushiki Kaisha
InventorHiroshi Satomura
Life of this patent
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Abstract
A heating-fixing roller has over the axial direction thereof a heat-generating layer formed via the step of mixing a raw material capable of obtaining a positive temperature coefficient of resistivity characteristic by baking and a binder for holding the raw material and forming an unbaked annular substrate and the step of providing an electrode to which an applied voltage is supplied on the mixture during the forming step, and thereafter via the step of baking the unbaked annular substrate on which the electrode is formed. The heat-generating layer has a positive temperature coefficient of resistivity characteristic after the baking and has the electrode formed on the surface thereof.
Claims26
A heating-fixing roller having over an axial direction thereof a heat-generating layer formed through the step of mixing a raw material capable of obtaining a positive temperature coefficient of resistivity characteristic by sintering and a binder for holding said raw material and forming an unsintered annular substrate and the step of providing an electrode to which an applied voltage is supplied on said mixture during said forming step, and thereafter through the step of sintering said unsintered annular substrate on which said electrode is formed, said heat-generating layer having a positive temperature coefficient of resistivity characteristic after said sintering and having said electrode formed on the surface thereof.
A heat-fixing foller roller conveying a recording material sandwiched between said roller and another roller for fixing an unfixed image on the recording material which has a variety of different widthwise sizes, said heat-fixing roller comprising a cylindrical heat-generating layer having obtained a positive temperature coefficient of resistivity characteristic by sintering, and a pair of electrodes secured to the surface of said heat-gnerating layer after said sintering, said pair of eletrodes having conductors forming a positive pole and conductors forming a negative pole alternatively with respect to the circumferential direction of said cylindrical heat-generating layer, said pair of electrodes being provided over more than the width of the largest recording material in the lengthwise direction of said heat-generating layer, whereby a portion of said heat-generating layer of a positive temperature coefficient of resistivity characteristic which is between the conductors of different polarities renders uniform the surface temperature with respect to the lengthwise direction of said heat-fixing roller.
A heating-fixing roller having a first and a second cylindrical heat-generating layer having obtained a positive temperature coefficient of resistivity characteristic by sintering, said first heat-generating layer being outside said second heat-generating layer, the resistance of said first heat-generating layer being smaller than the resistance of the second heat-generating layer corresponding thereto, and a pair of electrodes provided between said first and said second heat-generating layer to apply a voltage to said heat-generating layers.
Dependencies are inferred from the claim text.