A motor control apparatus, including: a current detection unit configured to detect a current flowing through a coil of a motor; a voltage application unit configured to apply a voltage to the coil; and a control unit configured to control the voltage application unit by outputting a PWM signal in order to rotate the motor at a predetermined rotation speed, wherein the control unit detects a rotation state of the motor based on a duty of the PWM signal and a current value detected by the current detection unit.

A fixing device includes a heater including a substrate and a resistance heating element disposed on the substrate, an endless belt, a first temperature sensor disposed at a position opposed to the heater and configured to detect a temperature at a center part of the heater in a longitudinal direction of the heater; and a second temperature sensor disposed at a position opposed to the heater and configured to detect a temperature at an end part of the heater in the longitudinal direction of the heater. The second temperature sensor is disposed at a position located on an outer side of the resistance heating element in the longitudinal direction of the heater.

An image forming apparatus includes a sheet-supplier, a photoconductor, a fuser and a controller. The controller is configured to, in a case where the number of sheets to be printed indicated by a printing job is less than a first predetermined number of sheets, start supplying a sheet by a sheet-supplier at a timing when a second period of time has been passed from a timing when the temperature in the fuser has reached a second temperature, and, in a case where the number of sheets to be printed is equal to or greater than the first predetermined number of sheets, start supplying the sheet by the sheet-supplier at a timing when the second period of time has been passed from a timing when the temperature in the fuser has reached a first temperature larger than the second temperature.

A device includes an operating portion, a switch and a controller. The device is operable in a first mode in which a predetermined operation is executed and in a second mode of which power consumption is reduced rather than in the first mode, and operates in a state connected to an image forming apparatus. The operating portion operates by an AC voltage supplied from an external power source. The switch supplies the AC voltage to the operating portion in a conductive state and cuts off supply of the AC voltage to the operating portion in a non-conductive state. The controller operates by a DC voltage generated from the AC voltage by a power source provided in the image forming apparatus. The controller controls to cause the switch to be in the non-conductive state so as to stop operation of the operating portion when the device shifts from the first mode to the second mode.

A fixing device includes a heater including a substrate and a resistance heating element, an endless belt, a holder, a first heat conductive member and a second heat conductive member arranged in a longitudinal direction of the heater such that a first end of the first heat conductive member and a second of the second heat conductive member in the longitudinal direction of the heater are adjacent to each other, a temperature sensor configured to detect a temperature at an end part of the heater. The temperature sensor is in contact with the first heat conductive member. A position located between first end of the first heat conductive member and the second end of the second heat conductive member is closer to the temperature sensor than a central position of the resistance heating element in the longitudinal direction of the heater.

An image forming system includes: an image forming apparatus that includes a transfer device that transfers a toner image onto a sheet and a fixing device that fixes the toner image; a sheet heating device that heats the sheet on an upstream of the fixing device in a sheet conveyance direction; a first detector that detects a temperature inside the image forming apparatus; a second detector that detects a temperature of the sheet before the sheet heating device heats the sheet; and a controller that causes the sheet heating device to heat the sheet based on a detection result by the second detector and a sheet passing condition of the sheet, and corrects at least one of a transfer current and a transfer voltage in the transfer device based on a detection result by the first detector in a case where the sheet heating device heats the sheet.

A fixing device includes a heater provided with a first heat generator on a substrate and a second heat generator of which a length in a longitudinal direction is shorter than that of the first heat generator, a temperature detector of the heater, a switch for switching a power supply path from an AC power source to the first heat generator or the second heat generator. A controller for controlling the switch to supply power to the first heat generator or the second heat generator. The controller executes a first control in which the switch supplies the power to the first heat generator, and switches a second control in which the switch supplies the power alternately to the first heat generator or the second heat generator when the detected temperature reaches a threshold temperature.

A fixing device includes: a first roller on which an elastic layer is formed; and a second roller that forms a clamping portion at which a recording medium is clamped between the first roller and the second roller, a groove extending in an axial direction being formed in an outer peripheral surface of the second roller, and the second roller not including an elastic layer.

An image forming apparatus, temperature control method, and temperature control device are provided. The apparatus includes the device, which acquires a first temperature difference between a temperature estimation value of a fixer, which is obtained by simulating a member temperature of a temperature control target serving as a heat capacitor-resistor circuit at an initial stage of operation of the fixer, and a detected temperature detected by a temperature sensor, and acquires a second temperature difference between a temperature estimation value of the fixer, which is obtained during an operation after the first temperature difference is acquired, and a detected temperature. The device calculates a difference between the first temperature difference and the second temperature difference, determines that the detected temperature is abnormal in response to the difference being equal to or greater than a threshold value, and performs temperature control for correcting a target temperature of the member temperature.

An image forming apparatus includes first and second rotatable members forming a nip therebetween, a heater disposed in inside of the second rotatable member, a first temperature sensor provided on a center of the heater, a second temperature sensor provided on an end side of the heater. A controller controls a feeding interval in which a trailing edge of a preceding sheet passes through the nip until a leading edge of a subsequent sheet reaches the nip. The controller controls the feeding interval to be a first interval in a case which a feeding speed of the sheet is a first speed and a detected temperature by the second sensor is a first temperature, and to be a second interval shorter than the first interval in a case which the feeding speed is a second speed lower than the first speed and the detected temperature is the first temperature.