Abstract: Whether a first heating region is actually a passing heating region or a non-passing heating region which a recording material does not pass through, is detected by the temperature detected by a temperature detecting portion, based on a difference between a detected temperature by a temperature detecting portion in a reference heating region, which is specified to a heating region including a conveyance reference position of the recording material, and a detected temperature in a first heating region which does not include the conveyance reference position and is specified to a passing heating region which the recording material passing through. In a case where it is determined that the first heating region is the non-passing heating region, a prevention control, to prevent overheat of the first heating region is performed in the heating processing of the recording material that passes the nip portion after the determination.

Abstract: An image forming apparatus, including: an image forming portion that forms an image on a recording material based on image data; a fixing portion that includes a heater having a plurality of heat generating members arranged in a direction perpendicular to a conveying direction of a recording material, and that fixes the image to the recording material using heat of the heater; a storage portion that stores history information on the recording material when image forming operation is performed in which the image forming portion forms the image and the fixing portion fixes the image, a control portion that sets power to be supplied to the heat generating members based on the history information before a type of the recording material on which the image is formed or content of the image data of the image to be formed on the recording material is determined.

Abstract: An image forming apparatus includes an image forming unit, a fixing unit, and a control unit. The image forming unit forms a toner image on a recording material. The fixing unit heats and fix the toner image formed on the recording material to the recording material in a fixing nip portion. The fixing unit includes a heater and a nip portion forming member that forms the fixing nip portion to pinch and convey the recording material. The control unit control the power to be supplied to the heater so as to change a temperature gradient at time of warm-up of the fixing unit to a target temperature in accordance with time from start of power supply to the heater until entry of the recording material into the fixing nip portion.

Abstract: A control unit controls power to be supplied to a common power supply path in a first period, using a selected first temperature detection member, and controls power to be supplied to the common power supply path in a second period, using a selected second temperature detection member. The first temperature detection member has a higher detected temperature than that of the second temperature detection member, and in the second period, the first detected temperature and the second detected temperature fall within a temperature range between a first temperature and a second temperature lower than the first temperature.

Abstract: An image forming apparatus, including: an image forming portion that forms an image on a recording material based on image data; a fixing portion that includes a heater having a plurality of heat generating members arranged in a direction perpendicular to a conveying direction of a recording material, and that fixes the image to the recording material using heat of the heater; a storage portion that stores history information on the recording material when image forming operation is performed in which the image forming portion forms the image and the fixing portion fixes the image, a control portion that sets power to be supplied to the heat generating members based on the history information before a type of the recording material on which the image is formed or content of the image data of the image to be formed on the recording material is determined.

Abstract: In an image forming apparatus, in continuous image formation in which images are continuously formed and fixed on a plurality of recording materials in a fixing portion, with a period from start of the continuous image formation on a first recording material to arrival thereof at the fixing unit being regarded as a first period, and with a period from the arrival of the first recording material at the fixing portion to the end of the continuous image formation being regarded as a second period, a second maximum energizing duty that is set when the control portion supplies power to a plurality of heating elements in the second period is higher than a first maximum energizing duty that is set when the control portion supplies power to the plurality of heating elements in the first period.

Abstract: An image forming apparatus, including: an image forming portion that forms an image on a recording material based on image data; a fixing portion that includes a heater having a plurality of heat generating members arranged in a direction perpendicular to a conveying direction of a recording material, and that fixes the image to the recording material using heat of the heater; a storage portion that stores history information on the recording material when image forming operation is performed in which the image forming portion forms the image and the fixing portion fixes the image, a control portion that sets power to be supplied to the heat generating members based on the history information before a type of the recording material on which the image is formed or content of the image data of the image to be formed on the recording material is determined.

Abstract: A control unit controls power to be supplied to a common power supply path in a first period, using a selected first temperature detection member, and controls power to be supplied to the common power supply path in a second period, using a selected second temperature detection member. The first temperature detection member has a higher detected temperature than that of the second temperature detection member, and in the second period, the first detected temperature and the second detected temperature fall within a temperature range between a first temperature and a second temperature lower than the first temperature.

Abstract: In an image heating device, a plurality of count values representing a heat storage amount in each of a plurality of heating regions heated by a plurality of heating elements are acquired, and electric power for the heating elements is controlled so that a difference between a heat storage maximum count value representing the heat storage amount of the heating region in which the heat storage amount is the largest among the plurality of heating regions, and a heat storage reduction count value representing the heat storage amount of a heat storage reduction region that is a heating region having a smaller heat storage amount than the heating region having the maximum heat storage amount, is maintained within a range of a predetermined value; and the predetermined value is set based on a width of the heat storage reduction region of a recording material.

Abstract: In an image forming apparatus, in continuous image formation in which images are continuously formed and fixed on a plurality of recording materials in a fixing portion, with a period from start of the continuous image formation on a first recording material to arrival thereof at the fixing unit being regarded as a first period, and with a period from the arrival of the first recording material at the fixing portion to the end of the continuous image formation being regarded as a second period, a second maximum energizing duty that is set when the control portion supplies power to a plurality of heating elements in the second period is higher than a first maximum energizing duty that is set when the control portion supplies power to the plurality of heating elements in the first period.

Abstract: An image forming apparatus, including: a control portion that controls a conveying speed of recording materials when the recording materials pass through a nip portion; wherein the control portion, in a case of continuous sheet passing of the recording materials each having a smaller width than the recording materials each having a maximum width: executes, in a case where a representative value of the number of the recording materials having the smaller width for one operation of the continuous sheet passing is smaller than a predetermined threshold, a first operating mode in which the conveying speed is controlled to a first speed; and executes, in a case where the representative value is the threshold or more, a second operating mode in which the conveying speed is controlled to a second speed lower than the first speed.

Abstract: An image forming apparatus, including: an image forming portion that forms an image on a recording material based on image data; a fixing portion that includes a heater having a plurality of heat generating members arranged in a direction perpendicular to a conveying direction of a recording material, and that fixes the image to the recording material using heat of the heater; a storage portion that stores history information on the recording material when image forming operation is performed in which the image forming portion forms the image and the fixing portion fixes the image, a control portion that sets power to be supplied to the heat generating members based on the history information before a type of the recording material on which the image is formed or content of the image data of the image to be formed on the recording material is determined.

Abstract: A heater wherein an elongated substrate, a first electroconductive member, a second electroconductive member, a plurality of heat generating resistors, and a temperature detecting element. The following relationships are satisfied: W?L and W?S, where W represents a dimension of the temperature detecting element measured in a longitudinal direction of the substrate, L represents a dimension, measured in the longitudinal direction, of one of the heat generating resistors at least partially overlapping with the temperature detecting element with respect to the longitudinal direction, and S represents a dimension between adjacent heat generating elements of the heat generating elements.

Abstract: An image forming apparatus, including: an image forming portion that forms an image on a recording material based on image data; a fixing portion that includes a heater having a plurality of heat generating members arranged in a direction perpendicular to a conveying direction of a recording material, and that fixes the image to the recording material using heat of the heater; a storage portion that stores history information on the recording material when image forming operation is performed in which the image forming portion forms the image and the fixing portion fixes the image, a control portion that sets power to be supplied to the heat generating members based on the history information before a type of the recording material on which the image is formed or content of the image data of the image to be formed on the recording material is determined.

Abstract: An image heating apparatus includes a heater including a first heat generating block and a second heat generating block, and a power control portion that controls electrical power to be supplied to the respective heat generating blocks. When a recording material passes the position of the heater, and, in a longitudinal direction of the heater, when an entire range in which the second heat generating block is provided is a range in which the recording material passes and only a portion of a range in which the first heat generating block is provided is a range in which the recording material passes, the power control portion controls the electrical power to be supplied to the respective heat generating blocks so that electrical power Wd supplied to the first heat generating block is less than electrical power Wc supplied to the second heat generating block.

Abstract: An image heating device has a paper-passing heating region in which a recording material passes through at least a part of a heating region and a non-paper-passing heating region in which the recording material does not pass through the heating region, and changes a heating amount applied to a fixing member in the non-paper-passing heating region in accordance with a longitudinal distance between a boundary position between the paper-passing heating region and the non-paper-passing heating region in the longitudinal direction and the boundary position side end portion of the recording material in the paper-passing heating region.

Abstract: An image forming apparatus, including: an image forming portion that forms an image on a recording material based on image data; a fixing portion that includes a heater having a plurality of heat generating members arranged in a direction perpendicular to a conveying direction of a recording material, and that fixes the image to the recording material using heat of the heater; a storage portion that stores history information on the recording material when image forming operation is performed in which the image forming portion forms the image and the fixing portion fixes the image, a control portion that sets power to be supplied to the heat generating members based on the history information before a type of the recording material on which the image is formed or content of the image data of the image to be formed on the recording material is determined.

Abstract: An image forming apparatus, including: a control portion that controls a conveying speed of recording materials when the recording materials pass through a nip portion; wherein the control portion, in a case of continuous sheet passing of the recording materials each having a smaller width than the recording materials each having a maximum width: executes, in a case where a representative value of the number of the recording materials having the smaller width for one operation of the continuous sheet passing is smaller than a predetermined threshold, a first operating mode in which the conveying speed is controlled to a first speed; and executes, in a case where the representative value is the threshold or more, a second operating mode in which the conveying speed is controlled to a second speed lower than the first speed.

Abstract: An image heating apparatus includes first and second heat generating elements arranged adjacent to each other, and a control portion that controls power supplied to the first and second heat generating elements, and that is capable of individually controlling the first and second heat generating elements, the first and second heat generating elements being respectively controlled so as to maintain a control temperature. When an image exists in a second region on the recording material heated by the second heat generating element, and an image does not exist in a first region on the recording material heated by the first heat generating element, the control portion sets the control temperature of the second heat generating element, when heating the second region, in accordance with a distance between an end section of the image in the second region and a boundary of the first region and the second region.

Abstract: In an image heating device, a plurality of count values representing a heat storage amount in each of a plurality of heating regions heated by a plurality of heating elements are acquired, and electric power for the heating elements is controlled so that a difference between a heat storage maximum count value representing the heat storage amount of the heating region in which the heat storage amount is the largest among the plurality of heating regions, and a heat storage reduction count value representing the heat storage amount of a heat storage reduction region that is a heating region having a smaller heat storage amount than the heating region having the maximum heat storage amount, is maintained within a range of a predetermined value; and the predetermined value is set based on a width of the heat storage reduction region of a recording material.