Abstract: PID control performs integral control using an integral value of a deviation between a set temperature and current temperature, and therefore when a proportionality factor Kp is large, a fixing belt 230 reaches a target temperature quickly but a subsequent overshoot increases. On the other hand, when the proportionality factor Kp is small, the output is reduced gradually, and therefore the fixing belt 230 reaches a target temperature slowly but the overshoot is small. Thus, a heat value control section 300 changes the control value of the PID control according to the temperature (belt temperature) a fixing belt 230 at the start of heating of detected by a temperature detector 270. More specifically, a proportionality factor Kp of a calculation expression of the PID calculation is changed according to the belt temperature of the fixing belt 230. This makes it possible to reduce an overshoot when the temperature of the fixing belt 230 increases.

Abstract: The present invention provides an induction heating apparatus including a fixing belt that heats an unfixed image on recording paper, an excitation coil that induction-heats the fixing belt, an inverter circuit that supplies power to the excitation coil, a harness that electrically connects the excitation coil and the inverter circuit. The harness is constructed of a litz wire having a resistance of the harness section of 0.016 ? or below formed by stranding several tens of wires which are conductive wires coated with an insulator into a predetermined thickness.

Abstract: Disclosed is a printer apparatus that ensures temperature control of a heat-up roller in a fixing unit thereof. An image-forming unit forms an image to be transferred onto a recording material. The fixing unit fixes the image onto the recording material. The fixing unit includes a heat-up roller, a heating section for heating the heat-up roller, a power supply section for supplying power to the heating section, and a heat controller for controlling the power supply section. The heat controller is disposed in contact with the inner circumferential surface of the heat-up roller. When heated to temperatures above a predetermined value, the heat controller is thermally deformed and leaves the inner circumferential surface of said heat-up roller to interrupt the power supply of the power supply section to the heating section.

Abstract: A heat generating member for fixing a toner image onto a recording medium, an induction heating means arranged to oppose to the heat generating member, for generating heat in the heat generating member by electromagnetic induction, an inverter circuit for driving the induction heating means, a power controlling means for controlling a power value that is output from the inverter circuit, a power-value calculating means for calculating the power value, a power-value sensing means for acquiring the power value output from the power controlling means, and a temperature sensing means for sensing a temperature at least at one point of the heat generating member are provided, and thus either the power value sensed by the power-value sensing means or a temperature value sensed by the temperature sensing means is used as a reference value used to calculate the power value by the power-value calculating means. Therefore, the image fixing device can be controlled with the high reliability.

Abstract: A power apparatus including a switching unit for supplying a power to an exciting coil, switching unit voltage detecting means for detecting that a voltage to be applied to the switching unit exceeds a safe operating voltage range, and power control means for controlling a power to be supplied to the coil in response to a detection signal of the switching unit voltage detecting means.

Abstract: When a temperature control does not operate, and a thermal runaway state occurs, the temperatures of a heating roller and a thermostat rise rapidly. When the rise in the temperature occurs such that the temperature of the thermostat reaches or exceeds a predetermined temperature, both ends of a thermostat are brought into an open circuit state. Thus the supply of a power from a commercial power source to an exciting coil is directly cut off.

Abstract: A printer includes, in its fixing device operable to fix toner particles onto a recording medium, a heating roller containing magnetic metal, a fixing roller disposed parallel to the heating roller, an endless belt containing magnetic metal bridged across the heating roller and the fixing roller. The printer also includes a press roller pressed to the fixing roller via the endless belt and the recording medium, and a coil core being operable to produce magnetic fields so as to cause both of the heating roller and the endless belt to generate heat with the magnetic metals contained therein.

Abstract: A printer includes, in its fixing device operable to fix toner particles onto a recording medium, a heating roller containing magnetic metal, a fixing roller disposed parallel to the heating roller, an endless belt containing magnetic metal bridged across the heating roller and the fixing roller. The printer also includes a press roller pressed to the fixing roller via the endless belt and the recording medium, and a coil core being operable to produce magnetic fields so as to cause both of the heating roller and the endless belt to generate heat with the magnetic metals contained therein.

Abstract: A printer includes, in its fixing device operable to fix toner particles onto a recording medium, a heating roller containing magnetic metal, a fixing roller disposed parallel to the heating roller, an endless belt containing magnetic metal bridged across the heating roller and the fixing roller. The printer also includes a press roller pressed to the fixing roller via the endless belt and the recording medium, and a coil core being operable to produce magnetic fields so as to cause both of the heating roller and the endless belt to generate heat with the magnetic metals contained therein.

Abstract: Disclosed is a printer apparatus that ensures temperature control of a heat-up roller in a fixing unit thereof. An image-forming unit forms an image to be transferred onto a recording material. The fixing unit fixes the image onto the recording material. The fixing unit includes a heat-up roller, a heating section for heating the heat-up roller, a power supply section for supplying power to the heating section, and a heat controller for controlling the power supply section. The heat controller is disposed in contact with the inner circumferential surface of the heat-up roller. When heated to temperatures above a predetermined value, the heat controller is thermally deformed and leaves the inner circumferential surface of said heat-up roller to interrupt the power supply of said power supply section to said heating section.

Abstract: The fixing device includes a heating roller made of magnetic metal and heated by electromagnetic induction; a fixing roller disposed parallel to the heating roller; an endless toner heating medium belt bridged across the heating roller and the fixing roller, and a press roller pressed to the fixing roller via the toner heating medium. The press roller rotates in the same direction as the toner heating medium belt to form a fixing nip region, and the belt is heated by the heating roller and rotated by the two rollers. The construction of the present invention achieves stable temperature control of the toner heating medium, and provides a stable fixing quality of the toner image.

Abstract: The printer includes, in its fixing means for fixing toner particles onto recording medium, a heating roller containing magnetic metal, a fixing roller disposed parallel to the heating roller, an endless belt containing magnetic metal bridged across the heating roller and the fixing roller, a press roller pressed to the fixing roller via the endless belt and recording medium, and means for producing magnetic fields so as to cause both of the heating roller and the endless belt to generate heat with the magnetic metals contained therein.

Abstract: A registering pattern having a predetermined configuration for each color is formed on a transfer material, and color misregistering is detected and corrected by laser beams and a photosensor.

Abstract: The fixing device includes a heating roller made of magnetic metal and heated by electromagnetic induction; a fixing roller disposed parallel to the heating roller; an endless toner heating medium belt bridged across the heating roller and the fixing roller, and a press roller pressed to the fixing roller via the toner heating medium. The press roller rotates in the same direction as the toner heating medium belt to form a fixing nip region, and the belt is heated by the heating roller and rotated by the two rollers. The construction of the present invention achieves stable temperature control of the toner heating medium, and provides a stable fixing quality of the toner image.

Abstract: An image forming apparatus forms test patches with no lowering of image density and no unevenness of image density. The image forming device includes a unit for generating image data for at least one test patch, an image bearing medium on which a latent image of the test patch is formed being based upon the image data generated by the test patch generating unit, developing unit for supplying toner by means of a developing roller onto the latent image so as to manifest the latent image in order to obtain a toner image, a density sensor for detecting a toner density of a toner image in the manifested test patch, and a compensator for compensating the density, being based upon a value of an output from the density sensor. With this arrangement, the test patch generating unit is adapted to create the test patches after the toner on the developing roller is consumed by a quantity corresponding to one turn of the developing roller.

Abstract: By increasing/deceasing electric energy per unit time supplied to heat energy generation means arranged in a liquid chamber having a nozzle, the amount of the ink emitted from the nozzle can be changed to correct a difference in dot diameter which occurs nozzle by nozzle and a change in dot diameter with time and to permit gradational printing.

Abstract: An ink discharging device includes arrayed nozzle holes and corresponding ink flow paths leading thereto. An electrode is provided between the adjacent ink flow paths in such a manner as to be exposed to both of the adjacent ink flow paths so that each electrode works as a common electrode for both of the adjacent ink flow paths. By energizing a conductive ink between the electrodes within the corresponding ink flow path, a portion of the conductive ink is discharged through the corresponding nozzle hole.

Abstract: In an ink-jet printer of the type wherein a current is passed through a conductive ink contained between a pair of electrodes to cause the ink to become vaporized and cause trapped gasses or bubbles to expand suddenly, exerting a sufficient pressure upon the ink to force droplets of ink from a nozzle, a current value flowing between the electrodes is detected to determine the amount of wear of the electrodes, and when the detected current value is lower than a predetermined value, an alarm indicative of the replacement of the currently used ink-jet head is given and, at the same time, ejection of the ink from the nozzle is stopped. Thus, printing operation is always achieved with stable ejection of ink, guaranteeing high printing qualities.