Abstract: An image forming apparatus, having a photosensitive drum, a developing roller movable between a contacting position, in which the developing roller contacts the photosensitive drum, and a separated position, in which the developing roller is separated from the photosensitive drum, a moving mechanism to move the developing roller between the contacting position and the separated position, a fuser including a heating member and a pressing member to nip a sheet at a position between the heating member and the pressing member, a nipping-force adjuster to switch a nipping force in the fuser between a first nipping force and a second nipping force being greater than the first nipping force, a motor, and a driving-force transmitter to transmit a driving force from the motor to the developing roller, is provided. The driving-force transmitter transmits the driving force further to the moving mechanism and the nipping-force adjuster.

Abstract: An image forming apparatus, having a first photosensitive drum, a first developing roller, a first shifting member movable between a contacting position and a separating position, a motor, a first joint, a first clutch operable in one of a transmittable condition and a discontinuing condition, a first shifting cam rotatable between a first position, in which the first shifting cam locates the first shifting member at the contacting position, and a second position, in which the first shifting cam locates the first shifting member at the separating position, and a first switching cam rotatable between a third position, in which the first switching cam places the first clutch in the transmittable condition, and a fourth position, in which the first switching cam places the first clutch in the discontinuing condition, alongside the first shifting cam rotating between the first position and the second position, is provided.

Abstract: An image-forming apparatus includes a motor, a photosensitive drum, a developing roller, and a separation mechanism for moving the developing roller relative to the photosensitive drum. The separation mechanism includes: an end cam rotatable in a rotational direction; and a cam follower movable in accordance with a rotation of the end cam. The end cam includes a first surface, a second surface, a first sloped surface connecting the second surface to the first surface, and a second sloped surface connecting the first surface to the second surface in the rotational direction. The second sloped surface includes: a steep slope surface connected to the second surface; and a gentle slope surface connecting the first surface to the steep slope surface. The gentle slope surface slopes relative to the first surface by an angle smaller than an angle by which the steep slope surface slopes relative to the first surface.

Abstract: In an image-forming apparatus, when a sheet length of a first sheet is shorter than or equal to a predetermined length, a controller supplies power to an electromagnetic clutch to convey the first sheet and a second sheet so that a sheet gap of the second sheet is equivalent to a first gap. When the sheet length of the first sheet is longer than the predetermined length, the controller supplies power to the electromagnetic clutch to successively convey a first number of sheets so that the sheet gap of each of the first number of sheets is equivalent to the first gap. After the first number of sheets has been conveyed, the controller supplies power to the electromagnetic clutch to convey at least one sheet so that the sheet gap of each of the at least one sheet is equivalent to a second gap greater than the first gap.

Abstract: An image forming apparatus includes a controller configured to, before driving a development motor, obtain a temperature inside a housing from a temperature sensor, determine whether the obtained temperature inside the housing is equal to or lower than a particular temperature, when determining that the temperature inside the housing is higher than the particular temperature, execute a full-speed mode to control the development motor to rotate at a first target speed and control a process motor to rotate at a second target speed, and when determining that the temperature inside the housing is equal to or lower than the particular temperature, execute a low-temperature mode to control the development motor to rotate at a third target speed lower than the first target speed and control the process motor to rotate at the second target speed that is the same as in the full-speed mode.

Abstract: An image forming apparatus, having a first photosensitive drum, a first developing roller, a first shifting member movable between a contacting position and a separating position, a motor, a first joint, a first clutch operable in one of a transmittable condition and a discontinuing condition, a first shifting cam rotatable between a first position, in which the first shifting cam locates the first shifting member at the contacting position, and a second position, in which the first shifting cam locates the first shifting member at the separating position, and a first switching cam rotatable between a third position, in which the first switching cam places the first clutch in the transmittable condition, and a fourth position, in which the first switching cam places the first clutch in the discontinuing condition, alongside the first shifting cam rotating between the first position and the second position, is provided.

Abstract: An image forming apparatus, having first, second, and third photosensitive drums, a first developing cartridge including a first developing roller, a second developing cartridge including a second developing roller, a third developing cartridge including a third developing roller, an exposure device, a conveyer, and a moving mechanism, is provided. The first developing roller, the second developing roller, and the third developing roller are arranged in the recited order from upstream to downstream in a moving direction for the sheet to be conveyed. When the second developing roller is at the separated position thereof, the second developing cartridge coincides with a light path of the laser beam for scanning the first photosensitive drum. When the third developing roller is at the separated position thereof, the third developing cartridge coincides with a light path of the laser beam for scanning the second photosensitive drum.

Abstract: An image forming apparatus, having a photosensitive drum, a developing roller movable between a contacting position, in which the developing roller contacts the photosensitive drum, and a separated position, in which the developing roller is separated from the photosensitive drum, a moving mechanism to move the developing roller between the contacting position and the separated position, a fuser including a heating member and a pressing member to nip a sheet at a position between the heating member and the pressing member, a nipping-force adjuster to switch a nipping force in the fuser between a first nipping force and a second nipping force being greater than the first nipping force, a motor, and a driving-force transmitter to transmit a driving force from the motor to the developing roller, is provided. The driving-force transmitter transmits the driving force further to the moving mechanism and the nipping-force adjuster.

Abstract: An image forming apparatus includes: a first gear train including a first clutch; a second gear train including a second clutch; a third gear train including a third clutch; a fourth gear train including a fourth clutch; a motor including an output shaft; an output gear rotatable with the output shaft; a fifth gear train connected to the first and second clutches; and a sixth gear train connected to the third and fourth clutches. The first clutch engages transmission of a driving force to a first developing unit, the second clutch engages transmission of a driving force to a second developing unit, the third clutch engages transmission of a driving force to a third developing unit, and the fourth clutch engages transmission of a driving force to a fourth developing unit. The fifth and sixth gear trains are connected to the output gear independently from each other.

Abstract: An image forming apparatus, having first, second, and third photosensitive drums, a first developing cartridge including a first developing roller, a second developing cartridge including a second developing roller, a third developing cartridge including a third developing roller, an exposure device, a conveyer, and a moving mechanism, is provided. The first developing roller, the second developing roller, and the third developing roller are arranged in the recited order from upstream to downstream in a moving direction for the sheet to be conveyed. When the second developing roller is at the separated position thereof, the second developing cartridge coincides with a light path of the laser beam for scanning the first photosensitive drum. When the third developing roller is at the separated position thereof, the third developing cartridge coincides with a light path of the laser beam for scanning the second photosensitive drum.

Abstract: An image forming apparatus, having a photosensitive drum, a developing roller movable between a contacting position, in which the developing roller contacts the photosensitive drum, and a separated position, in which the developing roller is separated from the photosensitive drum, a moving mechanism to move the developing roller between the contacting position and the separated position, a fuser including a heating member and a pressing member to nip a sheet at a position between the heating member and the pressing member, a nipping-force adjuster to switch a nipping force in the fuser between a first nipping force and a second nipping force being greater than the first nipping force, a motor, and a driving-force transmitter to transmit a driving force from the motor to the developing roller, is provided. The driving-force transmitter transmits the driving force further to the moving mechanism and the nipping-force adjuster.

Abstract: An image forming apparatus includes a controller configured to, before driving a development motor, obtain a temperature inside a housing from a temperature sensor, determine whether the obtained temperature inside the housing is equal to or lower than a particular temperature, when determining that the temperature inside the housing is higher than the particular temperature, execute a full-speed mode to control the development motor to rotate at a first target speed and control a process motor to rotate at a second target speed, and when determining that the temperature inside the housing is equal to or lower than the particular temperature, execute a low-temperature mode to control the development motor to rotate at a third target speed lower than the first target speed and control the process motor to rotate at the second target speed that is the same as in the full-speed mode.

Abstract: An image forming apparatus, having first, second, and third photosensitive drums, a first developing cartridge including a first developing roller, a second developing cartridge including a second developing roller, a third developing cartridge including a third developing roller, an exposure device, a conveyer, and a moving mechanism, is provided. The first developing roller, the second developing roller, and the third developing roller are arranged in the recited order from upstream to downstream in a moving direction for the sheet to be conveyed. When the second developing roller is at the separated position thereof, the second developing cartridge coincides with a light path of the laser beam for scanning the first photosensitive drum. When the third developing roller is at the separated position thereof, the third developing cartridge coincides with a light path of the laser beam for scanning the second photosensitive drum.

Abstract: An image forming apparatus, having a first photosensitive drum, a first developing roller, a first shifting member movable between a contacting position and a separating position, a motor, a first joint, a first clutch operable in one of a transmittable condition and a discontinuing condition, a first shifting cam rotatable between a first position, in which the first shifting cam locates the first shifting member at the contacting position, and a second position, in which the first shifting cam locates the first shifting member at the separating position, and a first switching cam rotatable between a third position, in which the first switching cam places the first clutch in the transmittable condition, and a fourth position, in which the first switching cam places the first clutch in the discontinuing condition, alongside the first shifting cam rotating between the first position and the second position, is provided.

Abstract: An image forming apparatus including an image forming unit, a fixing unit, a temperature sensor, and a controller to execute a printing operation is provided. The printing operation is conducted at one of a first high-temperature printing pace, a first low-temperature printing pace, a second high-temperature printing pace, and a second low-temperature printing pace depending on a temperature detected by the temperature sensor. The first low-temperature printing pace is one of lower and equal to the first high-temperature printing pace. The second low-temperature printing pace is one of lower and equal to the second high-temperature printing pace. An absolute difference between the second high-temperature printing pace and the second low-temperature printing pace is greater than an absolute difference between the first high-temperature printing pace and the first low-temperature printing pace.

Abstract: A heating roller includes: a core bar having a cylindrical shape; a rubber layer arranged on an outer circumferential surface of the core bar; and a release layer arranged on an outer circumferential surface of the rubber layer, wherein when thermally fixing a developer on a recording medium, the heating roller is heated to a temperature within a fixing temperature range including a minute particle-scattering start temperature at which minute particles start to scatter from the rubber layer. The heating roller is arranged inside a casing which is connected to a minute particle density measuring device; then the core bar of the heating roller inside the casing is heated to 230° C. by a heater; and when the density of the minute particles inside the casing is measured after elapse of 20 minutes since start of the heating, the density of the minute particles is less than 2,000 pieces/cm3.

Abstract: A fixing device includes a tubular body extending in a first direction, a heater disposed in an internal space of the tubular body, a frame supporting the tubular body and a plate-like member provided on the frame. The tubular body has an open end in the first direction. The heater includes a hollow tube extending in the first direction, a heat generating element disposed in a hollow space of the tube, a terminal fixed to the frame, and a pin connecting the heat generating element and the terminal. The frame has a first surface positioned to oppose the open end of the tubular body in the first direction. The plate-like member is positioned between the open end and the first surface in the first direction, the plate-like member being formed with a pin opening for permitting the pin to penetrate therethrough.

Abstract: An image forming apparatus including an image forming unit, a fixing unit, a temperature sensor, and a controller to execute a printing operation is provided. The printing operation is conducted at one of a first high-temperature printing pace, a first low-temperature printing pace, a second high-temperature printing pace, and a second low-temperature printing pace depending on a temperature detected by the temperature sensor. The first low-temperature printing pace is one of lower and equal to the first high-temperature printing pace. The second low-temperature printing pace is one of lower and equal to the second high-temperature printing pace. An absolute difference between the second high-temperature printing pace and the second low-temperature printing pace is greater than an absolute difference between the first high-temperature printing pace and the first low-temperature printing pace.

Abstract: A heating roller includes: a core bar having a cylindrical shape; a rubber layer arranged on an outer circumferential surface of the core bar; and a release layer arranged on an outer circumferential surface of the rubber layer, wherein when thermally fixing a developer on a recording medium, the heating roller is heated to a temperature within a fixing temperature range including a minute particle-scattering start temperature at which minute particles start to scatter from the rubber layer. The heating roller is arranged inside a casing which is connected to a minute particle density measuring device; then the core bar of the heating roller inside the casing is heated to 230° C. by a heater; and when the density of the minute particles inside the casing is measured after elapse of 20 minutes since start of the heating, the density of the minute particles is less than 2,000 pieces/cm3.

Abstract: A fixing device includes a tubular body extending in a first direction, a heater disposed in an internal space of the tubular body, a frame supporting the tubular body and a plate-like member provided on the frame. The tubular body has an open end in the first direction. The heater includes a hollow tube extending in the first direction, a heat generating element disposed in a hollow space of the tube, a terminal fixed to the frame, and a pin connecting the heat generating element and the terminal. The frame has a first surface positioned to oppose the open end of the tubular body in the first direction. The plate-like member is positioned between the open end and the first surface in the first direction, the plate-like member being formed with a pin opening for permitting the pin to penetrate therethrough.