HEATER AND IMAGE HEATING APPARATUS INCLUDING THE SAME

摘要

A heater includes: a substrate; a first electrical contact; second electrical contacts; first electrode portions and second electrode portions; heat generating portions; a first electroconductive line portion electrically connecting the first electrical contact and the first electrode portions; and a second electroconductive line portion electrically connecting one of the second electrical contacts and a part of the second electrode portions. A cross-sectional area of a portion, of the first electroconductive line portion, into which all of currents flowing through the first electrode portions merge when the currents flow from the first electrode portions toward the first electrical contact is larger than a cross-sectional area of a portion, of the second electroconductive line portion, into which all of currents flowing through the part of the second electrode portions merge when the currents flow from the part of the second electrode portions toward the one of second electrical contacts.

主权项

1. A heater usable with an image heating apparatus including an electric energy supplying portion provided with a first terminal and a second terminal, and an endless belt for heating an image on a sheet, wherein said heater is contactable to the belt to heat the belt, said heater comprising:
a substrate; a first electrical contact provided on said substrate and electrically connectable with the first terminal; a plurality of second electrical contacts provided on said substrate and electrically connectable with the second terminal; a plurality of electrode portions including first electrode portions electrically connected with said first electrical contact and second electrode portions electrically connected with said second electrical contacts, said first electrode portions and said second electrode portions being arranged alternately with predetermined gaps in a longitudinal direction of said substrate; a plurality of heat generating portions provided between adjacent ones of said electrode portions so as to electrically connect between adjacent electrode portions, said heat generating portions being capable of generating heat by electric power supply between adjacent electrode portions; a first electroconductive line portion configured to electrically connect said first electrical contact and said first electrode portions; and a second electroconductive line portion configured to electrically connect one of said plurality of second electrical contacts and a part of said second electrode portions; wherein a cross-sectional area of a portion, of said first electroconductive line portion, into which all of currents flowing through said first electrode portions merge when the currents flow from said first electrode portions toward said first electrical contact is larger than a cross-sectional area of a portion, of said second electroconductive line portion, into which all of currents flowing through the part of said second electrode portions merge when the currents flow from the part of said second electrode portions toward said one of second electrical contacts.