Shutter for imaging device fuser assembly triggered by cartridge

1. An imaging device having a removably insertable cartridge with activation device, comprising:

a fusing nip that heats during use;

a shutter to open or block access to the fusing nip;

a frame having an opening to allow passage of the activation device of the cartridge; and

an activation surface, wherein the shutter blocks access to the fusing nip until the activation device of the cartridge passes through the frame and contacts the activation surface thereby beginning opening of the shutter and allowing opening through a range of movement until fully opened when the cartridge is fully inserted into the frame.

2. The imaging device of claim 1 , wherein the activation surface attaches to a shutter gear rotatable about a pivot axis.

3. The imaging device of claim 2 , wherein the shutter gear connects to a tang.

4. The imaging device of claim 3 , further including a shutter pivot rotatable about an axis corresponding to an axis of rotation of the shutter, the tang impeding movement of the shutter pivot until the activation surface of the shutter gear causes rotation of the shutter gear about the pivot axis.

5. The imaging device of claim 4 , wherein there exists a gear ratio of about 8:1 between the shutter gear and the shutter pivot allowing the shutter to move from a fully closed position blocking access to the fusing nip to a fully opened position allowing media to pass unimpeded through the fusing nip during use.

6. The imaging device of claim 5 , wherein the gear ratio allows the shutter to move 72 degrees from the fully closed position to the fully opened position.

7. The imaging device of claim 4 , wherein the frame defines the axis of rotation of the shutter.

8. The imaging device of claim 2 , wherein the frame defines the pivot axis of the shutter gear.

9. The imaging device of claim 1 , wherein the opening in the frame is a slot sized and shaped to accept passage of a tab defining the activation device of the cartridge.

10. The imaging device of claim 1 , further including a spring to bias the activation surface toward the opening of the frame.

11. The imaging device of claim 10 , wherein one end of the spring attaches to the frame while the other end of the spring attaches to a shutter gear connected to the shutter.

12. A fuser assembly for an imaging device having a removably insertable cartridge with a tab, comprising:

a fusing nip that heats during use;

a shutter movable between a fully opened and fully closed position to open or block access to the fusing nip;

a frame having a slot to allow passage of the tab of the cartridge; and

an activation surface, wherein the shutter blocks access to the fusing nip until the tab of the cartridge passes through the frame and contacts the activation surface thereby beginning opening of the shutter and allowing opening through a range of movement until reaching the fully opened position when the cartridge is fully inserted into the frame.

13. The fuser assembly of claim 12 , wherein the frame defines a pivot axis of a shutter gear connected to the frame, wherein the activation surface attaches to the shutter gear.

14. The fuser assembly of claim 13 , wherein the frame connects to a shutter pivot rotatable about an axis corresponding to an axis of rotation of the shutter.

15. The fuser assembly of claim 14 , further including a tang connected to the shutter gear, the tang impeding movement of the shutter pivot until the activation surface of the shutter gear causes rotation of the shutter gear about the pivot axis.

16. The fuser assembly of claim 14 , wherein there exists a gear ratio of about 8:1 between the shutter gear and the shutter pivot allowing the shutter to move from the fully closed position blocking access to the fusing nip to the fully opened position allowing media to pass unimpeded through the fusing nip during use.

17. The fuser assembly of claim 12 , wherein the shutter moves about 72 degrees from the fully opened position to the fully closed position.

18. The fuser assembly of claim 12 , further including a spring to bias the activation surface toward the slot of the frame.

19. The fuser assembly of claim 18 , wherein one end of the spring attaches to the frame.

20. An imaging device having a removably insertable cartridge with a tab, comprising:

a fusing nip that heats during use;

a shutter movable about 72 degrees between a fully opened and fully closed position to open or block access to the fusing nip;

a frame having a slot to allow passage of the tab of the cartridge;

a shutter gear rotatable about a first axis of rotation defined by the frame;

a lever connected to the shutter gear for being contacted by the tab of the cartridge;

a shutter pivot rotatable about a second axis of rotation corresponding to an axis of rotation of the shutter as the shutter moves from the fully opened to fully closed position, the shutter gear being engaged by the shutter pivot; and

a tang connected to the shutter gear, wherein the shutter blocks access to the fusing nip until the tab of the cartridge passes through the frame and contacts the lever thereby beginning opening of the shutter and allowing opening through a range of movement until reaching the fully opened position when the cartridge is fully inserted into the frame, the tang impeding movement of the shutter pivot until the lever causes rotation of the shutter gear about the first axis of rotation, and there existing a gear ratio of about 8:1 between the shutter gear and the shutter pivot allowing the shutter to move about said 72 degrees from the fully opened to the fully closed position with only about 9+/−2 degrees of movement of the lever.