Abstract: An image apparatus which minimizes temperature differences between end portions and a central portion of a print medium includes heater members having different heat distributions, a temperature detecting unit for detecting a temperature of an area where a print medium passes through, a heat controlling unit for controlling a fusing unit temperature by an individual heat controlling of the heater members based on the temperature detected by the temperature detecting unit, and a rate determination unit for determining a divisional rate of heat to be charged per unit time to the fusing unit by means of the heater members. The rate determination unit determines the divisional rate based on the fusing condition input and the heat controlling unit which controls the heater members individually on the basis of the divisional rate determined by the rate determination unit.

Abstract: An image forming apparatus has a fuser that fuses a toner image onto a printing medium by heat and pressure. The fuser temperature is sensed, and a heater in the fuser is controlled to keep the fuser at a constant temperature appropriate for fusing. In addition to constant-temperature control, the fuser is preheated to prevent an anticipated drop in its temperature when the printing medium encounters the fuser. The preheating process is carried out selectively and is omitted when not required, as determined from, for example, the temperature of the fuser when the printing medium enters the image forming unit of the image forming apparatus, the interval between the transport of different sheets of the printing medium, or the average amount of heat generated by the heater during a preceding interval.

Abstract: In a duplex printing or a simplex printing, upper and lower rollers of a fixing unit are separated from each other or stop rotating during a period after the fixing operation of the first side of a recording medium (or a preceding recording medium) and before the fixing operation of the second side of the recording medium (or a subsequent recording medium). With such an arrangement, it is possible to prevent the excessive heating of the lower roller, and thereby to prevent the degradation of the printed image.

Abstract: A purpose of the present invention is to minimize a temperature difference between end portions and a central portion of a print medium caused by a difference of fusing conditions. The image recording apparatus according to the present invention includes a plurality of heater members 34, 35 having different heat distributions, a temperature detecting unit 36 for detecting a temperature of an area where a print medium passes through, a heat controlling unit 51 for controlling a fusing unit at a prescribed temperature by an individual heat controlling of the plurality of heater members on the basis of the temperature detected by the temperature detecting unit, a rate determination unit 52 for determining a divisional rate of heat amount to be charged per unit time to said fusing unit by means of said plurality of heater members.

Abstract: An image forming apparatus has a fuser that fuses a toner image onto a printing medium by heat and pressure. The fuser temperature is sensed, and a heater in the fuser is controlled to keep the fuser at a constant temperature appropriate for fusing. In addition to constant-temperature control, the fuser is preheated to prevent an anticipated drop in its temperature when the printing medium encounters the fuser. The preheating process is carried out selectively and is omitted when not required, as determined from, for example, the temperature of the fuser when the printing medium enters the image forming unit of the image forming apparatus, the interval between the transport of different sheets of the printing medium, or the average amount of heat generated by the heater during a preceding interval.

Abstract: In a duplex printing or a simplex printing, upper and lower rollers of a fixing unit are separated from each other or stop rotating during a period after the fixing operation of the first side of a recording medium (or a preceding recording medium) and before the fixing operation of the second side of the recording medium (or a subsequent recording medium). With such an arrangement, it is possible to prevent the excessive heating of the lower roller, and thereby to prevent the degradation of the printed image.

Abstract: An ink cartridge is removably attached to a serial printer. The ink cartridge has a memory device in which information on the ink cartridge is stored. The information may include information such as viscosity, temperature coefficient, the hue and brightness of color ink, various user's settings of density of a printed image and color tone of a printed color image, and identification data indicative of a kind of the ink cartridge. A controller in the printer determines whether the attached cartridge is suitable for use with the printer, by comparing the identification data read from the ink cartridge with the reference data stored in the printer. The information may also include data of a maximum count of dots that the ink cartridge is capable of printing and data of a cumulative count of printed dots that the cartridge has printed.