Abstract: An image forming apparatus according to an aspect of the present disclosure includes a fixing device and a controller. The fixing device includes a fixing member, a pressure member, a heating member, and a temperature sensor. The controller cuts off power supply to the heating member when the temperature detected by the temperature sensor has risen to a cutoff temperature higher than the target temperature and thereafter resumes power supply to the heating member when the detected temperature has fallen below the cutoff temperature, and performs the PID control while limiting a maximum power supplied to the heating member to an upper limit power, which is a power supplied to the heating member at the time when the detected temperature has risen to the cutoff temperature, during a period from when power supply is resumed until a predetermined specific period of time elapses.

Abstract: The fixing device includes: a rotatable endless fixing belt; a heater that heats the fixing belt; a holding member that holds the heater so that a front surface thereof is in contact with an inner peripheral surface of the fixing belt; and a pressure member that is pressed against the heater with the fixing belt therebetween and to form a pressure area between the pressure member and the fixing belt where a sheet to which a toner image has been transferred is heated and pressed. A uniform heating layer is formed on a rear side of the heater without any gaps.

Abstract: An image forming apparatus includes an image forming device, a fixing device, and a controller. The fixing device includes a fixing belt, a heater, a pressure roller, a drive device, and a pressure adjustment mechanism that adjusts pressure to the nip region from the pressure roller, by switching between a normal level and a low level. When executing a print job, the controller causes the drive device to rotate the pressure roller, thereby causing the fixing belt to start to rotate, after causing the pressure adjustment mechanism to switch the pressure to the nip region to the low level, causes the pressure adjustment mechanism to switch the pressure to the nip region from the low level to the normal level, when a predetermined time has elapsed after the fixing belt started to rotate, and causes the image forming device to form an image according to the print job.

Abstract: An image forming apparatus includes an image forming device, a fixing belt, a heater including a main heater and two sub heaters, a pressure member, a drive device, a main temperature sensor that detects a temperature of the main heater, a sub temperature sensor that detects a temperature of only one of the two sub heaters, a controller, and an abnormality decision device that decides whether a duty ratio adopted by the controller, to control the power amount to be supplied to the two sub heaters, is an appropriate value corresponding to a transport status of the recording medium in a regular transport mode. The controller executes, when the abnormality decision device decides that the duty ratio adopted to control the power amount to be supplied to the two sub heaters is not the appropriate value, a predetermined preventive operation for suppressing an excessive temperature increase of the heater.

Abstract: A fixing device includes a fixing belt formed in a cylindrical shape, with a lubricant applied to an inner circumferential surface, and set such that a circumferential surface rotates in a circumferential direction, a heater retention member that retains the heater, inside of the fixing belt, and a pressure member that defines a nip region, through which a recording medium is transported in a nipped state, between the pressure member and a portion of the fixing belt heated from inside by the heater, and drives the fixing belt to rotate. The heater retention member includes a first opposing face extending in a rotation axis direction of the fixing belt, and opposed to the inner circumferential surface of the fixing belt. The first opposing face includes slits aligned in the rotation axis direction of the fixing belt, and a lubricant is applied in advance inside the slits.

Abstract: A fixing device includes a first fixing member, a second fixing member, a pressing member, and a heating device. The first fixing member is in an ungrounded state and comes into contact with a toner image on a sheet. The second fixing member is arranged opposite the first fixing member. The pressing member presses the first fixing member against the second fixing member so as to form, at the contact portion between the first fixing member and the second fixing member, a nip portion through which the sheet passes. The heating device heats the first fixing member.

Abstract: A heater includes electrodes and heating element pieces. The electrodes energize the heating element pieces with electricity. The heating element pieces are connected to the electrodes and arranged through a gap portion in the heater in a main scanning direction. A ratio of a second surface area of the gap portion to a first surface area of the heating element pieces is 0<(second surface area of the gap portion)/(first surface area of the heating element pieces)?0.5.

Abstract: A fixing device includes a first fixing member, a second fixing member, a pressing member, and a heating device. The first fixing member is in an ungrounded state and comes into contact with a toner image on a sheet. The second fixing member is arranged opposite the first fixing member. The pressing member presses the first fixing member against the second fixing member so as to form, at the contact portion between the first fixing member and the second fixing member, a nip portion through which the sheet passes. The heating device heats the first fixing member.

Abstract: An image forming apparatus includes a fixing belt, a pressing member, a heating source, a temperature detecting element, a recording medium detection unit, and a control unit. The heating source is arranged to be opposed to the pressing member via the fixing belt so as to be in contact with an inner circumferential surface of the fixing belt and heats the fixing belt at a fixing nip between the fixing belt and the pressing member. The temperature detecting element detects a temperature of the heating source. The recording medium detection unit is arranged, on a conveyance path, on an upstream side of the fixing nip in a conveyance direction of a recording medium and detects presence/absence of the recording medium being conveyed. Based on the presence/absence of the recording medium detected by the recording medium detection unit, the control unit controls timing for energizing the heating source.

Abstract: 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.

Abstract: A fixing belt heats and fixes a toner image. A pressure roller rotates the fixing belt while in contact with the fixing belt. A heater heats the fixing belt. A lubricating oil forms an oil film between the heater and an inner peripheral surface of the fixing belt. A pressure roller driver rotates the pressure roller so that the lubricating oil causes the fixing belt to be out of contact with the heater.

Abstract: An image forming apparatus includes a fixing section, a detection section, and a controller. The detection section detects a passing range of a recording medium in terms of a direction intersecting with a conveyance direction of the recording medium. A heating section of the fixing section includes a first heater and a second heater. The first heater has a longitudinal direction extending in an axis direction. The second heater has a longitudinal direction extending in terms of the axis direction from each of opposite ends of the first heater in terms of the axis direction. When a result of detection by the detection section indicates that the passing range of the recording medium does not overlap with a specific range of the second heater, the controller restricts heat generation by the second heater.

Abstract: A fixing belt heats and fixes a toner image formed on a sheet. A plurality of heating element pieces is arranged on an opposing surface of a heater in a main scanning direction. The opposing surface faces the sheet. A heat capacity of the fixing belt and a clearance, in the main scanning direction, of a gap portion between the heating element pieces adjacent to each other have a relationship expressed as follows: (the heat capacity (J/K) of the fixing belt)?(24×(the clearance (mm))?9).

Abstract: A heater includes electrodes and heating element pieces. The electrodes energize the heating element pieces with electricity. The heating element pieces are connected to the electrodes and arranged through a gap portion in the heater in a main scanning direction. A ratio of a second surface area of the gap portion to a first surface area of the heating element pieces is 0<(second surface area of the gap portion)/(first surface area of the heating element pieces)?0.5.

Abstract: A temperature detection section is disposed opposite to a heater so as to be out of contact with the heater, and detects a temperature of the heating element. A spacer is disposed so that the heater and the temperature detection section are out of contact with each other. The spacer includes a separator that separates the temperature detection section from the heater and that has a gap through which the heat is transferred from the heater to the temperature detection section and that melts upon the temperature of the heating element increasing to a specific temperature or higher. The separator after melting fills the gap.

Abstract: A fixing belt heats and fixes a toner image. A pressure roller rotates the fixing belt while in contact with the fixing belt. A heater heats the fixing belt. A lubricating oil forms an oil film between the heater and an inner peripheral surface of the fixing belt. A pressure roller driver rotates the pressure roller so that the lubricating oil causes the fixing belt to be out of contact with the heater.

Abstract: A heater includes a fixing device including a heater substrate, electrodes, a heating element, and a heat conducting member. The heating element is disposed on a facing surface of the heater substrate that is to face a sheet, and includes a plurality of heating element pieces arranged in a line in a main scanning direction of the sheet with a gap therebetween. The heat conducting member stores heat generated from the heating element and radiates the heat toward the sheet passing over the gap.

Abstract: 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.

Abstract: A sliding member is a tubular member surrounding a base member, and allows, by rotation, its lubricant-coated inner surface to slide in a sheet conveyance direction with respect to a surface of the base member. A heater heats the sliding member. A pressure roller forms a nip between the pressure roller and the sliding member and makes, by rotation, the sliding member rotate following the rotation. A temperature sensor measures a temperature of the base member or the sliding member. A roller driving device rotates the pressure roller at a preset initial speed and subsequently at a normal speed higher than the initial speed, in a temperature-rise process in which the temperature measured by the temperature sensor is raised to a target temperature by operation of the heater.

Abstract: The fixing device includes a cylindrical heated member and a heating part. The cylindrical heated member is long in a width direction of a sheet, and is supported in a rotatable manner with coming into contact with a fixing face of the sheet. The heating part is provided in an inner space of the heated member and heating an inner circumferential face of the heated member. The heating part includes a plurality of heaters disposed side by side in a longitudinal direction of the heated member; and a first temperature sensor measuring a first heater of the plurality of heaters or a heated area of the heated member heated by the first heater. The plurality of heaters and the first temperature sensor are connected in series by a first power supply line.