Abstract: An image heating device includes a heater that includes a heating resistor; a rotatable tubular film in which the heater is provided in an inner space of the rotatable tubular film; a roller; and an electrification control portion configured to perform wave number control by changing the ratio of electrification ON to electrification OFF for each set control cycle. In the image heating device F1, relations tON?? and tOFF?? are satisfied, where tON represents a longest continuous electrification period in electrification patterns in which electrification is turned both on and off in the control cycle, tOFF represents a longest continuous shutoff period in the electrification patterns, and ? represents a time constant of thermal conduction with the shortest distance from the heating resistor to a contact surface of the heater that is in contact with the film.

Abstract: A heater includes a substrate, a first heating element and a second heating element disposed on a first surface of the substrate, a temperature detection element, and a conductor. The temperature detection element is disposed on a second surface of the substrate opposite the first surface of the substrate. The conductor is disposed on the second surface and connected to the temperature detection element. The first heating element has a first distance from the temperature detection element in a lateral direction of the substrate orthogonal to a longitudinal direction of the substrate, and the second heating element has a second distance that is greater than the first distance from the temperature detection element in the lateral direction. As viewed in a thickness direction of the substrate orthogonal to the lateral direction and the longitudinal direction of the substrate, the conductor overlaps the first heating element and the second heating element.

Abstract: An image forming apparatus includes a rotatable photosensitive member, a charging member, an exposing unit to form an electrostatic latent image by exposing the surface of the photosensitive member charged by the charging member to light, a developing member to develop the electrostatic latent image with toner. A controller controls so that a predetermined charging voltage is charged and the light is emitted by a small light quantity to a first non-print area which is a non-print area provided with the print area and the non-print area with respect to a main scanning direction, and controls so that a charging voltage smaller than the predetermined voltage is charged and exposure is not performed to a second non-print area which is provided with only the non-print area with respect to the main scanning direction.

Abstract: A fixing apparatus includes an endless first rotary member, a heating element, a second rotary member configured to form a nip portion, and a nip member configured to receive radiant heat from the heating element and heat the nip portion. The nip member includes a main-body portion that contains aluminum or aluminum alloy and a protective layer that includes an oxide film formed on a surface of the main-body portion. The main-body portion contains a heat receiving surface that faces the heating element and receives radiant heat from the heating element, and a rubbed surface that is rubbed against the inner circumferential surface of the first rotary member. The protective layer contains coloring agent that causes an emissivity of the heat receiving surface and the rubbed surface to be higher than an emissivity of a natural color oxide film.

Abstract: A fixing apparatus includes an endless first rotary member, a heating element, a second rotary member configured to form a nip portion, and a nip member configured to receive radiant heat from the heating element and heat the nip portion. The nip member includes a main-body portion that contains aluminum or aluminum alloy and a protective layer that includes an oxide film formed on a surface of the main-body portion. The main-body portion contains a heat receiving surface that faces the heating element and receives radiant heat from the heating element, and a rubbed surface that is rubbed against the inner circumferential surface of the first rotary member. The protective layer contains coloring agent that causes an emissivity of the heat receiving surface and the rubbed surface to be higher than an emissivity of a natural color oxide film.

Abstract: An image heating device includes a heater that includes a heating resistor; a rotatable tubular film in which the heater is provided in an inner space of the rotatable tubular film; a roller; and an electrification control portion configured to perform wave number control by changing the ratio of electrification ON to electrification OFF for each set control cycle. In the image heating device F1, relations tON?? and tOFF?? are satisfied, where tON represents a longest continuous electrification period in electrification patterns in which electrification is turned both on and off in the control cycle, tOFF represents a longest continuous shutoff period in the electrification patterns, and z represents a time constant of thermal conduction with the shortest distance from the heating resistor to a contact surface of the heater that is in contact with the film.

Abstract: A fixing apparatus includes an endless first rotary member, a heating element, a second rotary member configured to form a nip portion, and a nip member configured to receive radiant heat from the heating element and heat the nip portion. The nip member includes a main-body portion that contains aluminum or aluminum alloy and a protective layer that includes an oxide film formed on a surface of the main-body portion. The main-body portion contains a heat receiving surface that faces the heating element and receives radiant heat from the heating element, and a rubbed surface that is rubbed against the inner circumferential surface of the first rotary member. The protective layer contains coloring agent that causes an emissivity of the heat receiving surface and the rubbed surface to be higher than an emissivity of a natural color oxide film.

Abstract: An image forming apparatus, includes: an image forming portion configured to form a toner image on a recording material according to image information on a predetermined image; a fixing portion configured to fix the toner image on the recording material by heating the recording material having thereon the toner image while conveying the recording material by a nip portion; an acquisition portion configured to acquire an image end position that is a position of one end of the toner image in a main scanning direction perpendicular to a conveying direction of the recording material; a determination portion configured to determine a target temperature based on the image end position; and a control portion configured to control the fixing portion based on the target temperature.

Abstract: A fixing apparatus includes an endless first rotary member, a heating element, a second rotary member configured to form a nip portion, and a nip member configured to receive radiant heat from the heating element and heat the nip portion. The nip member includes a main-body portion that contains aluminum or aluminum alloy and a protective layer that includes an oxide film formed on a surface of the main-body portion. The main-body portion contains a heat receiving surface that faces the heating element and receives radiant heat from the heating element, and a rubbed surface that is rubbed against the inner circumferential surface of the first rotary member. The protective layer contains coloring agent that causes an emissivity of the heat receiving surface and the rubbed surface to be higher than an emissivity of a natural color oxide film.

Abstract: An image forming apparatus, includes: an image forming portion configured to form a toner image on a recording material according to image information on a predetermined image; a fixing portion configured to fix the toner image on the recording material by heating the recording material having thereon the toner image while conveying the recording material by a nip portion; an acquisition portion configured to acquire an image end position that is a position of one end of the toner image in a main scanning direction perpendicular to a conveying direction of the recording material; a determination portion configured to determine a target temperature based on the image end position; and a control portion configured to control the fixing portion based on the target temperature.

Abstract: An image forming apparatus includes: an acquiring portion configured to acquire image information and operation information of the image forming apparatus; an image forming portion configured to form a toner image on a recording material; a fixing portion configured to fix the toner image to the recording material by heating the recording material on which the toner image is formed; and a control portion configured to, when the acquiring portion acquires image information corresponding to a first page and fails to acquire image information corresponding to a second page following the first page, set a temperature of the fixing portion for fixing the first page as a first temperature based on the image information corresponding to the first page and the operation information, and set the temperature of the fixing portion for fixing the second page as a second temperature based on the operation information.

Abstract: An image forming apparatus, including: a fixing, onto a recording material, a toner image that is formed in accordance with image data, and constituted of a first image that is formed by a toner of a first color and a second image that is formed by a toner of a second color which is different from the first color, and that is superimposed on the first image; an acquiring a gradation value of the first image and a gradation value of the second image based on the image data; a determining a target temperature and target speed based on the gradation value of the first image and the gradation value of the second image; a controlling power to be supplied to the fixing unit based on the target temperature; and a controlling conveying speed of the recording material based on the target speed.

Abstract: An image forming apparatus, including: a dividing the image data into regions including pixels; an obtaining a first ratio by dividing a total number of the pixels included in groups, the pixels having a density equal to or higher than a predetermined value and arranged consecutively in a predetermined direction, by a total number of the pixels having the density and included in each of the regions; an obtaining a second ratio by dividing the total number of pixels having the density and included in each of the regions by a total number of the pixels included in each of the regions; a determining a target temperature for maintaining a temperature of a fixing portion based on the first and second ratios; and a controlling power to be supplied to the fixing portion so that the fixing portion is maintained at the target temperature.

Abstract: An image forming apparatus includes: an acquiring portion configured to acquire image information and operation information of the image forming apparatus; an image forming portion configured to form a toner image on a recording material; a fixing portion configured to fix the toner image to the recording material by heating the recording material on which the toner image is formed; and a control portion configured to, when the acquiring portion acquires image information corresponding to a first page and fails to acquire image information corresponding to a second page following the first page, set a temperature of the fixing portion for fixing the first page as a first temperature based on the image information corresponding to the first page and the operation information, and set the temperature of the fixing portion for fixing the second page as a second temperature based on the operation information.

Abstract: An image forming apparatus, including: a fixing, onto a recording material, a toner image that is formed in accordance with image data, and constituted of a first image that is formed by a toner of a first color and a second image that is formed by a toner of a second color which is different from the first color, and that is superimposed on the first image; an acquiring a gradation value of the first image and a gradation value of the second image based on the image data; a determining a target temperature and target speed based on the gradation value of the first image and the gradation value of the second image; a controlling power to be supplied to the fixing unit based on the target temperature; and a controlling conveying speed of the recording material based on the target speed.

Abstract: An image forming apparatus, including: a dividing the image data into regions including pixels; an obtaining a first ratio by dividing a total number of the pixels included in groups, the pixels having a density equal to or higher than a predetermined value and arranged consecutively in a predetermined direction, by a total number of the pixels having the density and included in each of the regions; an obtaining a second ratio by dividing the total number of pixels having the density and included in each of the regions by a total number of the pixels included in each of the regions; a determining a target temperature for maintaining a temperature of a fixing portion based on the first and second ratios; and a controlling power to be supplied to the fixing portion so that the fixing portion is maintained at the target temperature.

Abstract: A fixing apparatus includes a heating member, a supporting member that supports the heating member, a film slidably disposed on the heating member, and a pressing member that forms a nip portion, in collaboration with the film, through which the recording medium is conveyed. The fixing apparatus further includes a first thermally conductive member and a second thermally conductive member that are disposed between the heating member and the supporting member. The first thermally conductive member has a thermal conductivity higher than that of a substrate of the heating member. The thermal conductivity in in-plane directions of the second thermally conductive member is higher than the thermal conductivity in a thickness direction thereof. The second thermally conductive member is in contact with the heating member, and the first thermally conductive member is in contact with the second thermally conductive member.

Abstract: A fixing apparatus includes a heating member, a supporting member that supports the heating member, a film slidably disposed on the heating member, and a pressing member that forms a nip portion, in collaboration with the film, through which the recording medium is conveyed. The fixing apparatus further includes a first thermally conductive member and a second thermally conductive member that are disposed between the heating member and the supporting member. The first thermally conductive member has a thermal conductivity higher than that of a substrate of the heating member. The thermal conductivity in in-plane directions of the second thermally conductive member is higher than the thermal conductivity in a thickness direction thereof. The second thermally conductive member is in contact with the heating member, and the first thermally conductive member is in contact with the second thermally conductive member.

Abstract: A fixing apparatus includes a heating member, a supporting member that supports the heating member, a film slidably disposed on the heating member, and a pressing member that forms a nip portion, in collaboration with the film, through which the recording medium is conveyed. The fixing apparatus further includes a first thermally conductive member and a second thermally conductive member that are disposed between the heating member and the supporting member. The first thermally conductive member has a thermal conductivity higher than that of a substrate of the heating member. The thermal conductivity in in-plane directions of the second thermally conductive member is higher than the thermal conductivity in a thickness direction thereof. The second thermally conductive member is in contact with the heating member, and the first thermally conductive member is in contact with the second thermally conductive member.

Abstract: A fixing device includes a first rotatable member, a second rotatable member, a heat generating member that heats the first rotatable member, and a temperature detecting member that detects a temperature of the heat generating member. A motor drives one of the first rotatable member and the second rotatable member. In addition, a controller controls the fixing device by causing the motor to rotate in a state in which a predetermined amount of electrical power is supplied to the heat generating member, and then, supply of the electrical power to the heat generating member is stopped. On the basis of a temperature lowering rate of a detected temperature of the temperature detecting member during rotation of said motor, the controller detects, after stopping supply of the electrical power to the heat generating member, a rotational state of the one of the first rotatable member and the second rotatable member.