Granted Patent B2

US 12,730,397 · App. 18/912,689 · Granted Sep 8, 2026

Inventors: Noriaki Sato (Shizuoka, JP); Rikuo Kawakami (Shizuoka, JP)

Assignee: Canon Kabushiki Kaisha

G03G15/205G03G15/5004G03G15/5045G03G15/80G03G2215/00978

Abstract

Claims (72)

1 . An image forming apparatus comprising:

an attachment portion to which a fixing apparatus is attached; and

a power supply circuit including a plurality of parallel branches, each of the branches including a wire and a triac,

wherein the fixing apparatus includes at least one heating element configured to generate heat in a case where the triac of one of the branches is in a conducting state such that electric power is supplied to the at least one heating element via the wire of the one of the branches,

wherein the image forming apparatus further comprises a connector configured to be connected with a mating connector provided in the fixing apparatus in a state where the fixing apparatus is attached to the image forming apparatus, the mating connector including terminals electrically connected with the at least one heating element, and

wherein the connector includes:

(a) a first terminal electrically connected with the wire of the one of the branches and configured to come in contact with one of the terminals of the mating connector in the state where the fixing apparatus is attached to the image forming apparatus; and

(b) a second terminal electrically connected with the wire of another of the branches and configured not to come in contact with any of the terminals of the mating connector in the state where the fixing apparatus is attached to the image forming apparatus.

2 . The image forming apparatus according to claim 1 ,

wherein the branches include:

a first branch of which the wire has a largest allowable current value among wires included in the branches, the first terminal being provided at an end of the wire of the first branch, and the first branch being electrically connected with the at least one heating element via the first terminal in a state where the fixing apparatus is attached to the image forming apparatus; and

a second branch of which the wire has an allowable current value smaller than the largest allowable current value, the second terminal being provided at an end of the wire of the second branch, and the second branch being not electrically connected with the at least one heating element via the second terminal in the state where the fixing apparatus is attached to the image forming apparatus.

3 . The image forming apparatus according to claim 2 ,

wherein the triac of the first branch has a largest allowable current value among triacs included in the branches.

4 . The image forming apparatus according to claim 2 ,

wherein the allowable current value of the wire of the first branch is equal to or larger than three times a maximum current value of the at least one heating element, or is larger than the maximum current value by 5 A or more.

5 . The image forming apparatus according to claim 2 ,

wherein, in the state where the fixing apparatus is attached to the image forming apparatus, only the first branch is electrically connected with the at least one heating element, and none of the branches other than the first branch is electrically connected with the at least one heating element.

6 . The image forming apparatus according to claim 2 ,

wherein the wire of the second branch has a smallest allowable current value among the wires included in the branches, and is not electrically connected with the at least one heating element in the state where the fixing apparatus is attached to the image forming apparatus.

7 . The image forming apparatus according to claim 1 ,

wherein the attachment portion is configured to allow attachment of a first fixing apparatus instead of the fixing apparatus, the first fixing apparatus including a plurality of first heating elements grouped into a plurality of groups whose number is equal to the number of the branches, plurality of groups including a first group that has a largest resistance value among the plurality of groups, and

wherein the second terminal is electrically connected with the first group of the first heating elements in a state where the first fixing apparatus is attached to the image forming apparatus, and is not electrically connected with the at least one heating element in the state where the fixing apparatus is attached to the image forming apparatus.

8 . The image forming apparatus according to claim 1 ,

wherein the fixing apparatus includes:

a temperature-detection portion configured to issue a detection signal in accordance with a temperature of the at least one heating element;

an abnormality-detection portion configured to issue an abnormality notification signal depending on the detection signal from the temperature-detection portion; and

a signal line configured to transmit the abnormality notification signal to the image forming apparatus, and

wherein the image forming apparatus further comprises a power-shut-off portion configured to shut off the electric power supplied to the fixing apparatus when the abnormality notification signal is received through the signal line.

9 . The image forming apparatus according to claim 8 ,

wherein the fixing apparatus further includes at least one of:

(i) a crack-detection portion configured to issue an abnormality notification signal in accordance with cracking of a board on which the at least one heating element is disposed, and

(ii) a breakage-detection portion configured to issue an abnormality notification signal in accordance with breakage of the at least one heating element, and

wherein the power-shut-off portion is configured to receive an abnormality notification signal from the crack-detection portion or the breakage-detection portion via the signal line.

10 . The image forming apparatus according to claim 2 ,

wherein the at least one heating element includes a first group of heating elements having a largest maximum current value and a second group of heating elements having a smallest maximum current value, and

wherein, among the branches, an allowable current value of the wire of a branch that corresponds to the first group of heating elements is larger than an allowable current value of the wire of a branch that corresponds to the second group of heating elements.

11 . An image forming apparatus comprising:

an attachment portion to which a fixing apparatus is attached; and

a power supply circuit including a plurality of parallel branches, each of the branches including a wire and a triac,

wherein the fixing apparatus includes at least one heating element configured to generate heat in a case where the triac of one of the branches is in a conducting state such that electric power is supplied to the at least one heating element via the wire of the one of the branches, and

wherein the branches include:

(a) a first branch configured to be electrically connected with the at least one heating element in a state where the fixing apparatus is attached to the image forming apparatus, such that electric power is supplied to the at least one heating element via the first branch; and

(b) a second branch configured not to be electrically connected with the at least one heating element in the state where the fixing apparatus is attached to the image forming apparatus, such that no electric power is supplied to the at least one heating element via the second branch.

12 . The image forming apparatus according to claim 11 ,

wherein the wire of the first branch has a largest allowable current value among the wires included in the branches, and

wherein the wire of the second branch has an allowable current value smaller than the largest allowable current value.

13 . The image forming apparatus according to claim 11 ,

wherein the triac of the first branch has a largest allowable current value among triacs included in the branches, and is electrically connected with the at least one heating element in the state where the fixing apparatus is attached to the image forming apparatus.

14 . The image forming apparatus according to claim 12 ,

wherein the allowable current value of the wire of the first branch is equal to or larger than three times a maximum current value of the at least one heating element, or is larger than the maximum current value by 5 A or more.

15 . The image forming apparatus according to claim 11 ,

wherein, in the state where the fixing apparatus is attached to the image forming apparatus, only the first branch is electrically connected with the at least one heating element, and none of the branches other than the first branch is electrically connected with the at least one heating element.

16 . The image forming apparatus according to claim 12 ,

wherein the wire of the second branch has a smallest allowable current value among wires included in the branches, and is not electrically connected with the at least one heating element in the state where the fixing apparatus is attached to the image forming apparatus.

17 . The image forming apparatus according to claim 11 ,

wherein the attachment portion is configured to allow attachment of a first fixing apparatus instead of the fixing apparatus, the first fixing apparatus including a plurality of first heating elements grouped into a plurality of groups whose number is equal to the number of the branches, the plurality of groups including a first group that has a largest resistance value among the plurality of groups, and

wherein the second branch is electrically connected with the first group of the first heating elements in a state where the first fixing apparatus is attached to the image forming apparatus, and is not electrically connected with the at least one heating element in the state where the fixing apparatus is attached to the image forming apparatus.

18 . The image forming apparatus according to claim 11 ,

wherein the fixing apparatus includes:

a temperature-detection portion configured to issue a detection signal in accordance with a temperature of the at least one heating element;

an abnormality-detection portion configured to issue an abnormality notification signal depending on the detection signal from the temperature-detection portion; and

a signal line configured to transmit the abnormality notification signal to the image forming apparatus, and

wherein the image forming apparatus further comprises a power-shut-off portion configured to shut off the electric power supplied to the fixing apparatus when the abnormality notification signal is received through the signal line.

19 . The image forming apparatus according to claim 18 ,

wherein the fixing apparatus further includes at least one of:

(i) a crack-detection portion configured to issue an abnormality notification signal in accordance with cracking of a board on which the at least one heating element is disposed, and

(ii) a breakage-detection portion configured to issue an abnormality notification signal in accordance with breakage of the at least one heating element, and

wherein the power-shut-off portion is configured to receive an abnormality notification signal from the crack-detection portion or the breakage-detection portion via the signal line.

20 . The image forming apparatus according to claim 12 ,

wherein the at least one heating element includes a first group of heating elements having a largest maximum current value and a second group of heating elements having a smallest maximum current value, and

wherein, among the branches, an allowable current value of the wire of a branch that corresponds to the first group of heating elements is larger than an allowable current value of the wire of a branch that corresponds to the second group of heating elements.

Priority Claims (1)

Continuity (2)

References Cited (14)