An image heating device includes a heater having a plurality of heating elements that heat a plurality of heating regions and a control portion that controls the supply of electric power to the plurality of heating elements. The power supply is controlled so that a first average temperature, which is an average value of control target temperatures of heating regions included in a first region located closer to one end side than a central heating region in a direction orthogonal to a conveying direction of a recording material, and a second average temperature, which is an average value of control target temperatures of heating regions included in a second region located closer to the other end side than the central heating region, are within a predetermined temperature range.

According to one embodiment, a temperature control device includes a temperature estimation unit and a frequency generation unit. The temperature estimation unit is configured to estimate a temperature of an object being heated by an induction heating coil, the temperature being estimated based on a frequency of a drive signal supplied to an inverter connected to the induction heating coil. The frequency generation unit is configured to set the frequency of the drive signal based on the temperature estimated by the temperature estimation unit, a detected temperature of the object from a temperature sensor, and a target temperature for the object.

A temperature control device according to one embodiment includes a temperature estimation unit, a comparison unit, and an energization control unit. The temperature estimation unit estimates a temperature of an object based on energization of elements related to temperature control of the object. The comparison unit compares a difference between a detected temperature of the object and an estimated temperature of the object. If the difference exceeds a reference value, the energization control unit stops energizing the elements related to the temperature control of the object.

An image forming apparatus includes an image fixing unit to pass a sheet carrying an unfixed toner image on a first side. The image fixing unit includes: a first fixing section adjacent to the first side of the sheet; a first heating section to heat the first fixing section; a second fixing section adjacent to a second side opposite to the first side of the sheet; and a second heating section to heat the second fixing section. The image forming apparatus further includes: sheet feeding trays holding sheets; a storage unit storing fixing temperatures of the fixing sections preset for each type of the sheets in the sheet feeding trays; and a controller to select standby temperatures from the fixing temperatures, based on temperature profiles of the fixing sections, and to instruct the heating sections to respectively maintain the fixing sections at the selected standby temperatures during a standby mode.

A fuser unit for a hot fuse printer system includes a heating roller having a heating element which does not extend the entire length of the roller. The roller may include at least two heating elements, one of which heats a first heating zone and the other which heats a second heating zone.

An image forming apparatus includes a forming part that forms an image on a ribbon-like medium that is being transported; and a fixing part disposed downstream of the forming part in a medium transport direction, the fixing part including multiple fixing members, which are arranged in the transport direction and fix the image to the medium by applying heat and pressure to the medium. An upstream-downstream tension difference, in the medium transport direction, of the fixing member located on the most upstream side in the transport direction is greater than those of the other fixing members in the medium transport direction.

A heating device includes a conveying unit, a heating unit, a temperature detecting unit and a controller. The conveying unit conveys a recording material. The heating unit includes a plurality of heat sources which are disposed so that locations thereof are different from each other in a conveying direction of the recording material, and heats the convey ed recording material. The temperature detecting unit is positioned on an upstream side in the conveying direction of the recording material with respect to the plurality of heat sources, and detects a temperature of the heating unit. The controller controls one of the plurality of heat sources based on a detecting result obtained by the temperature detecting unit. The one of the plurality of heat sources is positioned on the upstream side in the conveying direction of the recording material.

An example image forming apparatus includes, a main body, a first fixing device disposed in the main body to primarily fix a toner image transferred on a printing medium while passing through a transfer device, a first discharge device to discharge the printing medium having passed through the first fixing device from the main body, and a second fixing device disposed in the main body to additionally fix the toner image on the printing medium having passed through the first fixing device, wherein the second fixing device may be supplied with the printing medium through a connection path returning from the first discharge device into the main body and connected to the second fixing device.

In an image heating device including a heater including a substrate, a first conductor provided on the substrate, a second conductor provided at a position different from the first conductor on the substrate in a direction orthogonal to a longitudinal direction of the substrate, and a plurality of heat-generating resistors, each having the same shape and electrically connected in parallel between the first conductor and the second conductor on the substrate and a plurality of temperature detection elements for detecting a temperature of the heater and heating an image formed on a recording material by the heater, the plurality of temperature detection elements includes at least two temperature detection elements whose relative positions with respect to the closest heat-generating resistor in the plurality of heat-generating resistors are the same, respectively, the closest heat-generating resistors corresponding to the at least two temperature detection elements are independently controlled.

In an image forming device, a first fixing member has a roller. A second fixing member has a belt to form a nip together with the first fixing member. A pressure modifying mechanism modifies a nip pressure at the nip to selected one of a first nip pressure and a second nip pressure smaller than the first nip pressure. A controller drives the first motor to drive the roller and fixes the developer image on a sheet in a state that the nip pressure is the first nip pressure. The controller modifies the nip pressure from the first nip pressure to the second nip pressure while driving the first motor in a case where a final sheet among one or more sheets fixed according to a print job has passed the nip, and halts the first motor after the nip pressure is modified to the second nip pressure.