A motor control apparatus includes: a motor configured to drive a load; and a control unit configured to control the motor. The control unit is configured to, when activating the motor, determine whether a predetermined condition for determining that fluctuation in magnitude of the load occurs is satisfied, activate the motor in a first mode when the predetermined condition is satisfied, and activate the motor in a second mode when the predetermined condition is not satisfied, and the first mode is a mode in which an increase in rotation speed of the motor is gentler than an increase in rotation speed of the motor in the second mode.

An image forming apparatus includes a process unit, a heating unit, and a controller unit. The process unit is configured to transfer an image onto a sheet. The heating unit is configured to fix the image transferred at the process unit onto the sheet, and to transfer a transfer layer onto an image formed on a sheet overlaid on a multilayer film. The controller unit is capable of operating in a first printing mode in which processes of transferring an image at the process unit, fixing the image at the heating unit, and transferring the transfer layer at the heating unit are executed, and a second printing mode in which processes of transferring an image at the process unit and fixing the image at the heating unit are not executed, and a process of transferring the transfer layer at the heating unit is executed.

A fixing unit includes a first heater, a first switch, a second heater, and a second switch. In an image forming mode, a controller controls the first switch and the second switch to keep a temperature of the fixing unit at a fixing temperature serving as a target temperature for fixing the image on the sheet. In a standby mode, the controller controls the first and second switches to keep the temperature of the fixing unit at a standby temperature, and controls the first and second switches such that a period in which a first current is supplied to the first heater and a period in which a second current is supplied to the second heater do not overlap.

A controller obtains a first duty cycle of a first current to be supplied to a first heater and a second duty cycle of a second current to be supplied to a second heater and controls the first switch and the second switch after the reduction control period, such that the temperature of a fixing unit maintains a target temperature for fixing the image by the fixing unit.

In a caser where a first current is supplied to a first heater, a controller gradually increases the first current in a first period, supplies the first current based on a first duty cycle in a second period, and gradually reduces the first current to stop supplying the first current in a third period. In a case where a second current is supplied to a second heater, the controller gradually increases the second current in a fourth period, supply the second current based on a second duty cycle in a fifth period, and gradually reduces the second current to stop supplying the second current in a sixth period. The controller controls the supply of the second current such that part of the fourth period overlaps with the third period.

Disclosed is an image forming apparatus including: a fixation unit configured to heat a toner image formed corresponding to image data and fix the heated toner image onto a recording material; and a control unit configured to determine a fixation target temperature used by the fixation unit to heat the toner image on the basis of the image data, wherein the control unit performs a first determination to calculate a first target temperature on the basis of image density information in each of a plurality of regions in which the image data is divided in a main-scanning direction and a sub-scanning direction and a second determination to determine whether the image data is a text image, and determines the fixation target temperature on the basis of results of the first determination and the second determination.

A fixing unit includes a tubular film, a pressure roller, a heater including a first heating element and a second heating element, a detector configured to detect a temperature of the heater, a switcher configured to switch which of the first heating element and the second heating element is supplied power from a power supply, and a controller configured to control the switcher. The controller is configured to execute a first control of determining a first electric energy and a second electric energy based on the temperature of the heater detected by the detector and a target temperature of the heater, and a second control of causing the switcher to switch between a state in which power is supplied to the first heating element by the first electric energy and a state in which power is supplied to the second heating element by the second electric energy.

An image forming apparatus is disclosed. A fixing device includes a heating rotary member and a pressing rotary member. The fixing device further includes an acquisition means that acquires information about a printing medium for a predetermined number of sheets beforehand, and a temperature control means that controls a temperature of the heating rotary member based on the information about a basis weight acquired by the acquisition means. A job in which different basis weights are mixed is a mixed job. In a case where the mixed job is executed and the temperature of the heating rotary member is changed while the mixed job is executed, a change amount of the temperature of the heating rotary member is reduced based on the information about the basis weight of the printing medium acquired by the acquisition means.

A heater control device includes a triac connected in series between an alternating-current power supply and a heater, the triac including a first main electrode, a second main electrode, and a gate electrode; a phototriac coupler configured to transmit a heater trigger signal to the gate electrode of the triac; a first resistor and a second resistor each of which is connected in series to the phototriac coupler and configured to limit current in accordance with a phase control enable signal indicative of a period of phase control; and a resistor selection circuit configured to select one of the first resistor and the second resistor and connect the selected resistor to the second main electrode of the triac. The first resistor and the second resistor have different rated powers and different breakabilities from each other.

According to one embodiment, a temperature control device stores a fixing device temperature estimation value and a storage time obtained by WAE control in a memory at any time during operation. After an electric power supply to the temperature control device is stopped, the next time the electric power supply is started, an electric power supply stop period until the electric power supply is started is calculated. If the electric power supply stop period is shorter than a set time, the WAE control is started by using the stored fixing device temperature estimation value, and if the electric power supply stop period exceeds the set time, the WAE control is started based on an initial set value.