Fixing device and image forming apparatus

A fixing device comprising:

• an endless belt rotatable in a predetermined direction of rotation;
• a nip formation pad disposed opposite an inner circumferential surface of the endless belt,
• the nip formation pad including:
• a base;
• and
• an increased thermal conductivity conductor being interposed between the base and the endless belt and having a thermal conductivity increased relative to a thermal conductivity of the base;
• an opposed rotator to press against the nip formation pad via the endless belt to form a fixing nip between the endless belt and the opposed rotator, the fixing nip through which a recording medium bearing a toner image is conveyed;
• a primary heat generator disposed opposite the endless belt;
• a secondary heat generator disposed opposite the endless belt and disposed outboard from the primary heat generator in an axial direction of the endless belt;
• a primary temperature detector to detect a temperature of the endless belt;
• and
• a secondary temperature detector, disposed opposite the secondary heat generator and disposed outboard from the primary temperature detector in the axial direction of the endless belt, to detect the temperature of the endless belt,
• the secondary heat generator including:
• an inboard edge;
• and
• an outboard edge disposed outboard from the inboard edge in the axial direction of the endless belt,
• the secondary heat generator having an inboard length defined between a center of the secondary temperature detector and the inboard edge in the axial direction of the endless belt,
• the secondary heat generator further having an outboard length defined between the center of the secondary temperature detector and the outboard edge in the axial direction of the endless belt,
• the secondary heat generator defining a ratio of the outboard length to the inboard length that is greater than 7/3,
• wherein the secondary temperature detector is a most outboard temperature detector in the axial direction of the endless belt.

An image forming apparatus comprising:

• an image forming device to form a toner image;
• and
• a fixing device, disposed downstream from the image forming device in a recording medium conveyance direction, to fix the toner image on a recording medium,
• the fixing device including:
• an endless belt rotatable in a predetermined direction of rotation;
• a nip formation pad disposed opposite an inner circumferential surface of the endless belt,
• the nip formation pad including:
• a base;
• and
• an increased thermal conductivity conductor being interposed between the base and the endless belt and having a thermal conductivity increased relative to a thermal conductivity of the base;
• an opposed rotator to press against the nip formation pad via the endless belt to form a fixing nip between the endless belt and the opposed rotator, the fixing nip through which the recording medium bearing the toner image is conveyed;
• a primary heat generator disposed opposite the endless belt;
• a secondary heat generator disposed opposite the endless belt and disposed outboard from the primary heat generator in an axial direction of the endless belt;
• a primary temperature detector to detect a temperature of the endless belt;
• and
• a secondary temperature detector, disposed opposite the secondary heat generator and disposed outboard from the primary temperature detector in the axial direction of the endless belt, to detect the temperature of the endless belt, the secondary temperature detector having a detection span in the axial direction of the endless belt,
• the secondary heat generator including:
• an inboard edge;
• and
• an outboard edge disposed outboard from the inboard edge in the axial direction of the endless belt,
• the secondary heat generator having an inboard length defined between a center of the detection span of the secondary temperature detector and the inboard edge in the axial direction of the endless belt,
• the secondary heat generator further having an outboard length defined between the center of the detection span of the secondary temperature detector and the outboard edge in the axial direction of the endless belt,
• the secondary heat generator defining a ratio of the outboard length to the inboard length that is greater than 7/3,
• wherein the secondary temperature detector is a most outboard temperature detector in the axial direction of the endless belt.