Patent application number | Description | Published |
20090041495 | IMAGE FORMING APPARATUS AND CONTROL METHOD - The present invention provides an image forming apparatus comprising an image forming unit configured to form an image on an image carrier, a transfer unit configured to transfer the image formed on the image carrier onto a transfer medium, a voltage applying unit configured to apply a voltage to the transfer unit, a current detection unit configured to detect a current that flows through the transfer unit when the voltage applying unit applies the voltage, and a control unit configured to control the voltage applying unit based on a detection result of the current detection unit. | 02-12-2009 |
20090268363 | POWER SUPPLY, IMAGE FORMING APPARATUS, AND ELECTRIC CURRENT SUPPLY METHOD - This invention provides a power supply which supplies an AC electric current to the coil of a heating unit employing the electromagnetic induced heating method via a connector connecting a plurality of wires, and a method for the power supply. The method includes the steps of supplying electric currents to the coil via 1st and 2nd wires from 1st and 2nd electric current supply units and detecting feedback electric currents via 3rd and 4th wires through the coil. Whether an electric current is abnormally supplied to the coil is monitored on the basis of these detected electric currents. It is controlled in accordance with the monitoring result to stop driving the 1st and 2nd electric current supply units and supply an electric current to the coil. | 10-29-2009 |
20100119248 | POWER SUPPLY CIRCUITRY FOR INDUCTIVE HEATING ELEMENT - A fixing apparatus includes an induction heating coil configured to heat a heat generating member including a conductive heating element, a boosting circuit configured to boost a DC voltage obtained by rectifying AC power, a switching element configured to input a DC voltage boosted by the boosting circuit and to supply a high-frequency current to the induction heating coil, a driving circuit configured to drive the switching element, a temperature detection unit configured to detect a temperature of the heat generating member, and a control unit configured to control power supplied to the induction heating coil by controlling a boosting ratio of the boosting circuit and a driving frequency of the switching element by the driving circuit so that the temperature detected by the temperature detection unit reaches a target temperature. | 05-13-2010 |
20100124429 | FIXING CONTROLLER AND IMAGE FORMING APPARATUS - A fixing controller capable of rapidly detecting an excessive temperature rise, even if an abnormal temperature rise takes place in a state that a rotor of a fixing unit, such as a thin-walled roller or belt, stops rotating. A rotating belt is heated by a coil, a belt temperature is detected by a thermistor, and a drive frequency of a driving circuit for driving the coil is controlled by a control circuit. When the temperature detected by the thermistor becomes equal to or higher than a predetermined temperature, the drive circuit is stopped by an excessive temperature rise detecting circuit. The thermistor is heated such that a difference between the temperatures detected by the thermistor when the belt is rotating and when the belt stops rotating becomes equal to or larger than a predetermined temperature difference. | 05-20-2010 |
20110085812 | IMAGE FORMING APPARATUS AND CONTROL METHOD - The present invention provides an image forming apparatus comprising an image forming unit configured to form an image on an image carrier, a transfer unit configured to transfer the image formed on the image carrier onto a transfer medium, a voltage applying unit configured to apply a voltage to the transfer unit, a current detection unit configured to detect a current that flows through the transfer unit when the voltage applying unit applies the voltage, and a control unit configured to control the voltage applying unit based on a detection result of the current detection unit. | 04-14-2011 |
20110223533 | SERIAL COMMUNICATION APPARATUS AND IMAGE FORMING APPARATUS INCLUDING THE SAME - An image forming apparatus including a fixing device using an induction heating method determines a driving frequency for a switching element configured to drive an induction coil, according to a difference between a detected temperature of an electrically conductive heating element provided in the fixing device and a target temperature. When the determined frequency is a predetermined minimum frequency and a current flowing through the induction coil is at a predetermined value or less, the image forming apparatus generates a signal indicating the abnormality of electric power supplied to the induction coil. | 09-15-2011 |
20130251391 | POWER SUPPLY CIRCUITRY FOR INDUCTIVE HEATING ELEMENT - A fixing apparatus includes an induction heating coil configured to heat a heat generating member including a conductive heating element, a boosting circuit configured to boost a DC voltage obtained by rectifying AC power, a switching element configured to input a DC voltage boosted by the boosting circuit and to supply a high-frequency current to the induction heating coil, a driving circuit configured to drive the switching element, a temperature detection unit configured to detect a temperature of the heat generating member, and a control unit configured to control power supplied to the induction heating coil by controlling a boosting ratio of the boosting circuit and a driving frequency of the switching element by the driving circuit so that the temperature detected by the temperature detection unit reaches a target temperature. | 09-26-2013 |
20140037346 | SUPPRESSING TONER OFFSET IN IMAGE FORMING APPARATUS WITH FIXING UNIT - By connecting a first diode between a conductive heating element of a fixing roller and ground, electric charge with the same polarity as the charged polarity of toner can be held on the surface of the fixing roller. Meanwhile, by connecting a second diode between the surface of a pressing roller that does not contact an un-fixed toner image, electric charge with the reverse polarity of the charged polarity of the toner can be held at the surface of the pressing roller. The polarity of the electric charge that is induced by electromagnetic induction is held at the polarity decided by the two diodes, and as a result the fixing offset can be suppressed without newly adding a collector member or a charging capacitor. | 02-06-2014 |