Granted Patent B2

US 9,551,962 · App. 14/144,110 · Granted Jan 24, 2017

Abstract

Claims (57)

1. A heater, comprising:

a positive temperature coefficient (PTC) material having a first surface and an opposed second surface, a length of the PTC material sized to extend substantially across a width of a fuser nip of a fuser assembly;

first and second electrodes, the first electrode being disposed against the first surface of the PTC material and the second electrode being disposed against the second surface thereof, the first and second electrodes for applying a voltage differential across the PTC material to generate heat therefrom;

at least one intermediate layer disposed against the second electrode;

at least one resistive trace disposed along the at least one intermediate layer so as to extend substantially across the length of the PTC material, the at least one resistive trace for generating heat upon passage of a current therethrough; and

a protective layer covering the at least one resistive trace and the at least one intermediate layer,

wherein the heater further comprises a first conductor disposed along the at least one intermediate layer and the second electrode for electrically connecting the second electrode and a first end portion of the at least one resistive trace.

2. The heater of claim 1 , wherein the at least one intermediate layer comprises a glass layer.

3. The heater of claim 1 , wherein the at least one intermediate layer comprises a polyimide layer.

4. A heater, comprising:

a positive temperature coefficient (PTC) material having a first surface and an opposed second surface, the PTC material sized to extend substantially across a width of a fuser nip of a fuser assembly;

first and second electrodes, the first electrode being disposed against the first surface of the PTC material and the second electrode being disposed against the second surface thereof, the first and second electrodes for applying a voltage differential across the PTC material to generate heat therefrom;

at least one intermediate layer disposed against the second electrode;

at least one resistive trace disposed along the at least one intermediate layer so as to extend substantially across a length of the PTC material, the at least one resistive trace for generating heat upon passage of a current therethrough; and

at least one protective layer covering the at least one resistive trace and the at least one intermediate layer,

wherein the at least one intermediate layer comprises a substrate having a length substantially corresponding to the length of the PTC material, the substrate having no permanent bond with the second electrode.

5. The heater of claim 4 , wherein the at least one intermediate layer further comprises a thermally conductive layer disposed between the second electrode and the substrate.

6. The heater of claim 5 , wherein the thermally conductive layer directly contacts the second electrode and the substrate.

7. The heater of claim 4 , wherein the substrate comprises a ceramic material.

8. The heater of claim 1 , wherein the at least one protective layer comprises at least one layer of polyimide material.

9. The heater of claim 1 , further comprising a second conductor connected to a second end portion of the at least one resistive trace, a first wire connected to the first conductor and a second wire connected to the second conductor.

10. A fuser assembly, comprising:

a housing;

a belt rotatably positioned about the housing and having an inner surface;

a backup roll disposed substantially against the belt so as to form a fuser nip therewith; and

a heater member disposed substantially within the housing, the heater member including:

a positive temperature coefficient (PTC) material having a first surface and an opposed second surface, a length of the PTC material sized to extend substantially across a width of the fuser nip;

first and second electrodes, the first electrode being disposed against the first surface of the PTC material and the second electrode being disposed against the second surface thereof, the first and second electrodes for applying a voltage differential across the PTC material to generate heat therefrom;

at least one intermediate layer disposed against the second electrode;

at least one resistive trace disposed along the at least one intermediate layer so as to extend substantially across the length of the PTC material, the at least one resistive trace for generating heat upon passage of a current therethrough, and the at least one resistive trace disposed in proximity to the inner surface of the belt for heating thereof; and

a protective layer covering the at least one resistive trace and the at least one intermediate layer,

wherein the heater member further comprises a first conductor disposed along the intermediate layer and the second electrode for electrically connecting the second electrode and a first end portion of the at least one resistive trace.

11. The fuser assembly of claim 10 , wherein one or more of the at least one intermediate layer and the protective layer comprises polyimide material.

12. A fuser assembly, comprising:

a housing;

a belt rotatably positioned about the housing and having an inner surface;

a backup roll disposed substantially against the belt so as to form a fuser nip therewith; and

a heater member disposed substantially within the housing, the heater member including:

a positive temperature coefficient (PTC) material having a first surface and an opposed second surface, a length of the PTC material sized to extend substantially across a width of the fuser nip;

first and second electrodes, the first electrode being disposed against the first surface of the PTC material and the second electrode being disposed against the second surface thereof, the first and second electrodes for applying a voltage differential across the PTC material to generate heat therefrom;

at least one intermediate layer disposed against the second electrode;

at least one resistive trace disposed along the at least one intermediate layer so as to extend substantially across the length of the PTC material, the at least one resistive trace for generating heat upon passage of a current therethrough, and the at least one resistive trace disposed in proximity to the inner surface of the belt for heating thereof; and

at least one protective layer covering the at least one resistive trace and the at least one intermediate layer, an outermost surface of the at least one protective layer contacting the inner surface of the belt at the fuser nip,

wherein the at least one intermediate layer comprises a substrate having a length corresponding to the length of the PTC material, the substrate and the second electrode not being permanently bonded to each other.

13. The fuser assembly of claim 12 , wherein the at least one intermediate layer further comprises a thermally conductive layer disposed between the second electrode and the substrate.

14. The fuser assembly of claim 13 , wherein the thermally conductive layer directly contacts and is disposed between the second electrode and the substrate.

15. The fuser assembly of claim 12 , wherein the substrate comprises a ceramic substrate.

16. The fuser assembly of claim 12 , further comprising at least one bias member disposed between the first electrode and the housing for securing the first electrode, the PTC material and the second electrode relative to the substrate.

17. The fuser assembly of claim 10 , further comprising at least one bias member having a first end and an opposed second end, the first end disposed substantially over a center portion along a width of the PTC material to directly contact the heater member, and the opposed second end disposed substantially against the housing.

18. The heater of claim 4 , further comprising at least two wires coupled to the first and second electrodes and the at least one resistive trace, the at least two wires defining a first current path through the PTC material and a second current path through the at least one resistive trace, the first current path being separate from the second current path.

19. The heater of claim 4 , further comprising at least two wires coupled to the first and second electrodes and the at least one resistive trace, the at least two wires defining parallel current paths through the heater, including a first current path through the PTC material and a second current path through the at least one resistive trace.

20. The heater of claim 5 , wherein the thermally conductive layer comprises a thermally conductive grease layer.

21. The fuser assembly of claim 12 , further comprising at least two wires coupled to the first and second electrodes and the at least one resistive trace, the at least two wires defining a first current path through the PTC material and a second current path through the at least one resistive trace, the first current path being separate from the second current path.

22. The fuser assembly of claim 12 , further comprising at least two wires coupled to the first and second electrodes and the at least one resistive trace, the at least two wires defining parallel current paths through the heater member, including a first current path through the PTC material and a second current path through the at least one resistive trace.

23. The fuser assembly of claim 12 , wherein the at least one protective layer comprises at least one layer of glass or polyimide.

24. The fuser assembly of claim 12 , wherein the at least one protective layer comprises at least one polyimide layer.

25. The fuser assembly of claim 13 , wherein the thermally conductive layer comprises a thermally conductive grease layer.

Assignments (8)