Device for fusing toner on print medium

A unit for fusing a toner image, the unit comprising:

• an insulation unit for generating an induced current, the insulation unit comprising a primary coil separated from a heater of the unit and which is switchably controlled by an alternating current generator electrically coupled to the primary coil;
• the heater which is resistance-heated when input with the predetermined induced current;
• a toner fusing unit comprised of a roller which fuses the toner image using the heat received from the heater;
• and
• an adhesion portion disposed inside the toner fusing unit and closely adhering the heater to the toner fusing unit,
• wherein the adhesion portion is comprised of a tube-expansion adhesion portion for closely adhering the heater to the toner fusing unit using a predetermined tube-expansion pressure, and
• wherein the preferable tube-expansion pressure applied to the tube-expansion adhesion portion is determined to a degree in which a circumferential tube-expansion pressure of the tube-expansion adhesion portion reaches a yield stress “σ” of a material used for the tube-expansion adhesion portion and which produces permanent plastic deformation.

A image forming apparatus including a unit for fusing a toner image, the unit included in the image forming apparatus comprising:

• an insulation unit for generating an induced current, the insulation unit comprising a primary coil separated from a heater of the unit and which is switchably controlled by an alternating current generator electrically coupled to the primary coil;
• the heater which is resistance-heated when input with the predetermined induced current;
• a toner fusing unit comprised of a roller which fuses the toner image using the heat received from the heater;
• and
• an end cap installed to at least one of opposite ends of the unit, and in which an air vent is formed,
• wherein an internal space of the unit is ventilated via the air vent.

A image forming apparatus including a unit for fusing a toner image, the unit included in the image forming apparatus comprising:

• an insulation unit for generating an induced current, the insulation unit comprising a primary coil separated from a heater of the unit and which is switchably controlled by an alternating current generator electrically coupled to the primary coil;
• the heater which is resistance-heated when input with the predetermined induced current;
• a toner fusing unit comprised of a roller which fuses the toner image using the heat received from the heater;
• and
• an adhesion portion disposed inside the toner fusing unit and closely adhering the heater to the toner fusing unit,
• wherein the adhesion portion is comprised of a tube-expansion adhesion portion for closely adhering the heater to the toner fusing unit using a predetermined tube-expansion pressure, and
• wherein the preferable tube-expansion pressure applied to the tube-expansion adhesion portion is determined to a degree in which a circumferential tube-expansion pressure of the tube-expansion adhesion portion reaches a yield stress “σ” of a material used for the tube-expansion adhesion portion and which produces permanent plastic deformation.