A duration measuring section measures a plurality of times. A temperature measuring section measures a temperature of a heater at each of the times. A temperature information outputting section outputs heater temperature information. A temperature tendency computing section outputs temperature tendency information of the heater. A drive controller outputs linear velocity information for controlling the linear velocity of a pressure roller. A pressure roller drive section drives the pressure roller.

An image forming apparatus includes an image bearer, a developing device, a fixing device, and circuitry. The developing device contains a developer and develops a latent image on the image bearer with the developer. The developing device includes a stirrer to stir the developer. The fixing device fixes a toner image onto a sheet. The circuitry performs start-up operations after receiving a print start command and before starting a printing operation. The start-up operations includes starting a warm-up operation of the fixing device and starting, during the warm-up operation, a stirring operation in which the stirrer stirs the developer.

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.

An image forming apparatus that includes a plurality of heaters and in which a combination of each of the heaters to be turned on can be changed includes a current detection unit including a through-type current transformer in which current supply lines are inserted into or wound around a through hole; a turn-on information acquisition unit that acquires information on a turn-on mode indicating the combination of each of the heaters to be turned on as turn-on information; a connection information acquisition unit that acquires connection information on additive polarity connection and subtractive polarity connection of the heaters, wherein the current supply lines include an additive polarity connection line, and a subtractive polarity connection line; and an energization information acquisition unit that acquires information on an energized state of the plurality of heaters as energization information, based on the turn-on information, the connection information, and a current value.

There is provided an image forming apparatus and method, in which performed are reading an image of an original document, converting a read image to raster data, raising a temperature of a fixing device to a fixing temperature, after raising the temperature of the fixing device, recording an image on the sheet on a sheet and causing the fixing device to fix the developing agent image onto the sheet. When a preview setting is enabled, after performing the converting, the preview image is displayed on the display and the raising is performed after the displaying and in response to an execution instruction of the forming. When the preview setting is not enabled, after performing a pre-heating of the fixing device so that the temperature of the fixing device is lower than the fixing temperature, performing the raising without displaying the preview image.

According to an embodiment, an image forming apparatus includes: a motor that drives a fixing device; and a controller. The motor outputs a signal corresponding to a driving current value of the motor. The controller performs a first operation where a magnitude value of the signal has fallen out of a first range while driving the motor in a first operation mode. The controller performs a second operation where the magnitude value of the signal has fallen out of a second range while driving the motor in a second operation mode.

Provided is an image heating apparatus including: a heater having a plurality of heating elements arranged in a direction orthogonal to a conveying direction of the recording material; and a control portion that controls electric power to be supplied to the plurality of heating elements and is capable of individually controlling the plurality of heating elements, the image heating apparatus heating an image formed on the recording material with heat by the heater, wherein the control portion sets a heating condition when controlling each of the plurality of heating elements, according to the thermal history of a heating region heated by one heating element and the thermal history of a heating region heated by a heating element adjacent to the one heating element.

Method of heating control includes preheating a heater to a first target temperature when an image forming device is powered on, is woken up from sleep, or receives a task to be processed; determining a voltage parameter of the heater or a characteristic of temperature change of a heating process of the heater, under the current environment of the power supply, according to a prior-preheating temperature, a post-preheating temperature, and a time length of the preheating; and according to the voltage parameter or the characteristic of temperature change under the current environment of the power supply, determining a heating start time of a second heating for the preheated heater and triggering the second heating at the heating start time, to allow a temperature of the heater to reach a second target temperature within a set time before an image to-be fixed arrives at the fixing assembly.

According to an embodiment, an image forming apparatus performs an image forming process to form an image on a sheet, and performs an image erasing process to erase an image formed on a sheet. A conveying device conveys the sheet. A heater heats the sheet conveyed by the conveying device. A cooling device cools the heater. A processor controls the cooling device so that the cooling device cools the heater between an interval of heating the sheet by the heater.

An image forming apparatus that forms an image on a long paper sheet conveyed along a conveyance path extending from a paper feeding side to a paper discharging side includes: an image forming unit configured to transfer a toner image onto the long paper sheet; a fixing unit configured to fix the toner image onto the long paper sheet; a paper existence determining unit configured to determine whether the long paper sheet exists along the conveyance path; a temperature determining unit configured to determine whether a fixing temperature of the fixing unit is equal to or lower than a predetermined temperature when the paper existence determining unit determines that the long paper sheet exists along the conveyance path; and a state setting unit configured to disable a fixing operation of the fixing unit when the temperature determining unit determines that the fixing temperature is higher than the predetermined temperature.