US 2026/0072382 A1Published application

Image heating apparatus and image forming apparatus

AssigneeCanon Kabushiki Kaisha

InventorKENTA OGASAWARA

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Abstract

An image heating apparatus includes a tubular rotary member, a magnetic core, an exciting coil, an inverter, at least one temperature detecting portion configured to detect a temperature of the rotary member, and a storage configured to store a reference value of a variation amount per unit time of a detected temperature. The control portion is configured to change a driving frequency of the inverter. The control portion is configured to change a driving frequency of the inverter, acquire the variation amount per unit time of the detected temperature detected by the temperature detecting portion, correct the reference value based on the drive frequency of the inverter at the time when the variation amount is acquired, and stop heating of the rotary member in a case where the variation amount is smaller than the reference value being corrected.

Claims12

Dependent claims

An image heating apparatus configured to heat an image formed on a recording material, the image heating apparatus comprising:

a tubular rotary member including a conductive layer;
a magnetic core disposed in an interior of the rotary member and configured to form an open magnetic path in a longitudinal direction of the rotary member;
an exciting coil wound around the magnetic core such that a helical axis thereof is arranged along the longitudinal direction;
an inverter configured to flow alternating current in the exciting coil;
a control portion configured to control the inverter to cause alternating current to flow through the exciting coil such that alternating magnetic flux is generated in the magnetic core to heat the rotary member by electromagnetic induction;
at least one temperature detecting portion configured to detect a temperature of the rotary member;
and
a storage configured to store a reference value of a variation amount per unit time of a detected temperature detected by the temperature detecting portion,
wherein the control portion is configured to change a driving frequency of the inverter, and
wherein the control portion is configured to:
acquire the variation amount per unit time of the detected temperature detected by the temperature detecting portion;
correct the reference value based on the drive frequency of the inverter at the time when the variation amount is acquired;
and
stop heating of the rotary member in a case where the variation amount is smaller than the reference value being corrected.

11 more elements

An image heating apparatus configured to heat an image formed on a recording material, the image heating apparatus comprising:

a tubular rotary member including a conductive layer;
a magnetic core disposed in an interior of the rotary member and configured to form an open magnetic path in a longitudinal direction of the rotary member;
an exciting coil wound around the magnetic core such that a helical axis thereof is arranged along the longitudinal direction;
an inverter configured to flow alternating current in the exciting coil;
a control portion configured to control the inverter to cause alternating current to flow through the exciting coil such that alternating magnetic flux is generated in the magnetic core to heat the rotary member by electromagnetic induction;
and
a first temperature detecting portion configured to detect a temperature of the rotary member at a center portion in the longitudinal direction of the rotary member,
wherein, when a drive frequency of the inverter is a first drive frequency, the control portion is configured to stop heating of the rotary member in a case where a variation amount per unit time of a detected temperature of the first temperature detecting portion is smaller than a first value;
and
wherein, when a drive frequency of the inverter is a second drive frequency that is greater than the first drive frequency, the control portion is configured to stop heating of the rotary member in a case where a variation amount per unit time of the detected temperature of the first temperature detecting portion is smaller than a second value that is smaller than the first value.

7 more elements

An image heating apparatus configured to heat an image formed on a recording material, the image heating apparatus comprising:

a tubular rotary member including a conductive layer;
a magnetic core disposed in an interior of the rotary member and configured to form an open magnetic path in a longitudinal direction of the rotary member;
an exciting coil wound around the magnetic core such that a helical axis thereof corresponds to the longitudinal direction;
an inverter configured to flow alternating current in the exciting coil;
a control portion configured to control the inverter to cause alternating current to flow through the exciting coil such that alternating magnetic flux is generated in the magnetic core to heat the rotary member by electromagnetic induction;
a first temperature detecting portion configured to detect a temperature of the rotary member at a first position in the longitudinal direction of the rotary member;
and
a second temperature detecting portion configured to detect a temperature of the rotary member at a second position that differs from the first position in the longitudinal direction,
wherein, when a drive frequency of the inverter is a first drive frequency, the control portion is configured to stop heating of the rotary member in a case where a variation amount per unit time of a detected temperature of the first temperature detecting portion is smaller than a fifth value corresponding to the first drive frequency, or in a case where a variation amount per unit time of a detected temperature of the second temperature detecting portion is smaller than a sixth value obtained based on the fifth value and an information related to correlation of the detected temperature of the first temperature detecting portion and the detected temperature of the second temperature detecting portion;
and
wherein, when a drive frequency of the inverter is a second drive frequency that differs from the first drive frequency, the control portion is configured to stop heating of the rotary member in a case where a variation amount per unit time of the detected temperature of the first temperature detecting portion is smaller than a seventh value corresponding to the second drive frequency, or in a case where a variation amount per unit time of the detected temperature of the second temperature detecting portion is smaller than an eighth value obtained based on the seventh value and an information related to correlation of the detected temperature of the first temperature detecting portion and the detected temperature of the second temperature detecting portion.

8 more elements

Dependencies are inferred from the claim text.