Abstract: An image forming apparatus includes an image forming unit to form an image on a sheet, a sheet ejection section to which a relay unit and a sheet processing apparatus are removably coupled, a driving-side ejection roller disposed in the sheet ejection section, to eject the sheet outside the apparatus, a plurality of driven-side ejection rollers that are replaceable, one of which is disposed facing the driving-side ejection roller, and a roller holder removably secured to the sheet ejection section to hold the one of the plurality of driven-side ejection rollers. Each driven-side ejection roller has a shaft and a plurality of roller bodies attached to the shaft and lined in an axial direction of the shaft. The driven-side ejection roller is replaced with another driven-side ejection roller in accordance with whether or not the relay unit and the sheet processing apparatus are coupled to the sheet ejection section.

Abstract: A sheet size detector to detect a sheet size of a recording medium includes a movable member to move in a sheet size detection direction to a position corresponding to the sheet size, a magnetic flux detector including a coil disposed on a board face parallel to the sheet size detection direction to generate a magnetic flux in a direction perpendicular to the board face, and a target to oppose the board face and including a material to affect the magnetic flux. The target is different in configuration in the sheet size detection direction to change the magnetic flux in the direction perpendicular to the board face as the movable member moves. The magnetic flux detector outputs a signal corresponding to changes in magnetic flux in the direction perpendicular to the board face, and the signal corresponds to the position of the movable member.

Abstract: An image forming apparatus includes an image forming unit to form an image on a sheet, a sheet ejection section to which a relay unit and a sheet processing apparatus are removably coupled, a driving-side ejection roller disposed in the sheet ejection section, to eject the sheet outside the apparatus, a plurality of driven-side ejection rollers that are replaceable, one of which is disposed facing the driving-side ejection roller, and a roller holder removably secured to the sheet ejection section to hold the one of the plurality of driven-side ejection rollers. Each driven-side ejection roller has a shaft and a plurality of roller bodies attached to the shaft and lined in an axial direction of the shaft. The driven-side ejection roller is replaced with another driven-side ejection roller in accordance with whether or not the relay unit and the sheet processing apparatus are coupled to the sheet ejection section.

Abstract: A sheet size detector to detect a sheet size of a recording medium includes a movable member to move in a sheet size detection direction to a position corresponding to the sheet size, a magnetic flux detector including a coil disposed on a board face parallel to the sheet size detection direction to generate a magnetic flux in a direction perpendicular to the board face, and a target to oppose the board face and including a material to affect the magnetic flux. The target is different in configuration in the sheet size detection direction to change the magnetic flux in the direction perpendicular to the board face as the movable member moves. The magnetic flux detector outputs a signal corresponding to changes in magnetic flux in the direction perpendicular to the board face, and the signal corresponds to the position of the movable member.

Abstract: An image forming apparatus includes an image forming mechanism for forming a toner image on a recording medium, and a fixing device for fixing the toner image on the recording medium. The fixing device including a fixing film, a pressure member, a contact member, a heating device, a holding member, and at least one of a low friction member and a thermal conductivity improving member provided between the fixing film and the contact member. The fixing film heated by the heating device via the contact member comes into contact with the recording medium. The pressure member comes into pressure contact with the fixing film. The contact member comes into pressure contact with the pressure member via the fixing film to form, between the fixing film and the pressure member, a nip portion through which the recording medium is passed. The holding member holds the contact member and the heating device.

Abstract: A sheet tray for feeding a sheet toward an image forming part of an image forming apparatus. The sheet tray is detachably attachable to the image forming apparatus in a sheet feeding direction and includes a tray portion, a detachable cover member provided apart from the tray portion with a gap interposed therebetween through which the sheet passes in an engaged state in which the tray portion and the cover member are engaged with each other, a lock assembly that engages the tray portion and the cover member with each other in the engaged state and disengages the cover member and the tray portion from each other in a disengaged state, and a switching mechanism that puts the lock assembly into the engaged state in absence of the sheet within the gap and into the disengaged state at presence of the sheet within the gap.

Abstract: A sheet tray for feeding a sheet toward an image forming part of an image forming apparatus. The sheet tray is detachably attachable to the image forming apparatus in a sheet feeding direction and includes a tray portion, a detachable cover member provided apart from the tray portion with a gap interposed therebetween through which the sheet passes in an engaged state in which the tray portion and the cover member are engaged with each other, a lock assembly that engages the tray portion and the cover member with each other in the engaged state and disengages the cover member and the tray portion from each other in a disengaged state, and a switching mechanism that puts the lock assembly into the engaged state in absence of the sheet within the gap and into the disengaged state at presence of the sheet within the gap.

Abstract: A fixing device includes a flexible fixing member that heats a toner image to fuse, a contact member fixedly disposed internal to the fixing member and comes into contact with a pressure member via the fixing member to form a nip part, a plurality of heating devices that heats the contact member, wherein the contact member always maintains the contact state with the pressure member via the fixing member, the plurality of heating devices generally remain disposed in the fixing device under an operational state for heating and are freely removable for replacement under a non-operational state for heating.

Abstract: A fixing device includes a flexible fixing member that heats a toner image to fuse, a contact member fixedly disposed internal to the fixing member and comes into contact with a pressure member via the fixing member to form a nip part, a plurality of heating devices that heats the contact member, wherein the contact member always maintains the contact state with the pressure member via the fixing member, the plurality of heating devices generally remain disposed in the fixing device under an operational state for heating and are freely removable for replacement under a non-operational state for heating.

Abstract: An image forming apparatus includes an image forming mechanism for forming a toner image on a recording medium, and a fixing device for fixing the toner image on the recording medium. The fixing device including a fixing film, a pressure member, a contact member, a heating device, a holding member, and at least one of a low friction member and a thermal conductivity improving member provided between the fixing film and the contact member. The fixing film heated by the heating device via the contact member comes into contact with the recording medium. The pressure member comes into pressure contact with the fixing film. The contact member comes into pressure contact with the pressure member via the fixing film to form, between the fixing film and the pressure member, a nip portion through which the recording medium is passed. The holding member holds the contact member and the heating device.