Patent application number | Description | Published |
20080231220 | Image Forming Apparatus Appropriately Setting Current Value for Driving Motor - When a printing instruction is provided, a CPU causes a stepping motor M to drive a developer and calculates the value of a load of the stepping motor M before printing operations are performed. Then, CPU determines whether the value of the load is within a predetermined range stored in advance. If the value is not within the predetermined range, CPU causes a display to display an error message. | 09-25-2008 |
20090153091 | IMAGE FORMATION APPARATUS - An error detector determines whether or not there is a frequency error. In a case where it is determined that there is the frequency error, the error detector further determines whether or not the frequency error stays within a targeted error range. In a case where it is determined that the frequency error stays within the targeted error range, a proportional gain is decreased. In a case where it is determined that the frequency error fails to stay within the targeted error range, the proportional gain is increased. Then, a frequency proportional-integral-derivative operation processing is executed based on a set gain. | 06-18-2009 |
20090317103 | IMAGE FORMATION APPARATUS AND PREPARATION OPERATION EXECUTION METHOD - Upon completing a preparation operation including different processes, an image formation apparatus shifts to ready state in which image formation is executable, the processes including at least one process executed using a corresponding motor. The image formation apparatus comprises: an obtainer for obtaining, for each process, an estimated time period between start and completion thereof; and a controller for starting execution of, out of the processes, (i) one process whose estimated time period is the longest, then (ii) any other process so that any other process is executed in parallel with said one process. When said one process is included in the at least one process, the controller initiates the motor by high-speed initiation by applying thereto first voltage that is higher than second voltage. When any other process is included in the at least one process, the controller initiates the motor by normal initiation by applying thereto first voltage. | 12-24-2009 |
20110187043 | SHEET TRANSPORTATION DEVICE INCLUDING ELECTROMAGNETIC COMPONENT AND CONTROL METHOD THEREOF - A sheet transportation device includes a transportation path for transportation of a sheet, a transportation unit for applying force to a sheet on the transportation path, and an electromagnetic component for driving the transportation unit by receiving supply of electric power. At the sheet transportation device, the absence/presence of a sheet is detected at a downstream side of the region where the transportation unit applies force to a sheet in the transportation path, and counter electromotive force induced in response to electric power being supplied to the electromagnetic component is supplied as the electric power for the detector. | 08-04-2011 |
20120241442 | INDUCTION HEATING DEVICE AND IMAGE FORMING APPARATUS HAVING THE SAME - An induction heating device comprises: a resonant circuit provided with a coil heating a workpiece inductively and a capacitor, the coil and the capacitor being coupled in parallel with each other; a switching element coupled in series with the resonant circuit; a power supply which applies to the resonant circuit, a direct-current input voltage whose instantaneous value can be changed with the lapse of time; and a power controller which controls power to the workpiece by turning the switching element ON at a certain time and changing an ON period of the switching element, and the power controller is characterized by turning the switching element ON with a delay of an integral multiple of a resonant period of the resonant circuit if a value of power to the workpiece is equal to or lower than a first threshold which is predetermined. | 09-27-2012 |
20120275810 | INDUCTION HEATING DEVICE AND IMAGE FORMING APPARATUS - An induction heating device including a coil which inductively heats a workpiece of a fuser with an input voltage obtained from an alternating current voltage by rectification; a switching element coupled in series with the coil; a peak voltage detector which detects a peak value of the input voltage; an effective voltage detector which detects an effective value of the input voltage; a crest factor calculator which calculates an actual crest factor of the input voltage based on the peak value of the input voltage and the effective value of the input voltage; and a power controller which achieves control of power to the fuser by controlling the duty ratio of ON and OFF periods of the switching element. | 11-01-2012 |
20140064768 | IMAGE FORMATION APPARATUS - An electromagnetic induction heating apparatus comprises: a resonance circuit that includes a inductor and a capacitor; a direct-current electric power supply; and a switching element performing ON and OFF switching of electric power supplied to the resonance circuit by the direct-current electric power supply; performs intermittent control of the electric power supply by controlling the ON and OFF switching at regular intervals, and by performing control to stop the electric power supply when not controlling the ON and OFF switching, wherein during the intermittent control, the switching control unit performs gradual control such that, upon beginning the control of the ON and OFF switching, the electric power supply gradually increases to reach a target value, and upon stopping the control of the ON and OFF switching, the electric power supply gradually decreases from the target value until stopping, such that the gradual decrease involves fewer steps than the gradual increase. | 03-06-2014 |
20140219668 | IMAGE FORMING APPARATUS DETECTING OCCURRENCE OF JAM - An image forming apparatus includes a timing roller for conveying paper in the image forming apparatus, a first motor receiving supply of electric power from a power source for driving the timing roller, a second motor receiving supply of electric power from the power source, a sensor for detecting whether a jam occurs at the conveyance roller, a drive relay for cutting off supply of electric power from the power source to the first and second motors, if occurrence of a jam is detected, and a control circuit for controlling an operating state of the second motor such that regenerative power produced at the first motor due to rotation of the conveyance roller is supplied to the second motor, if occurrence of a jam is detected. | 08-07-2014 |
20140233976 | IMAGE FORMING APPARATUS AND CONTROL METHOD - An image forming apparatus having: a power source applying alternating current voltage to the magnetizing coil; a demagnetizing coil switchable between a conductive state and a cutoff state, and when in the conductive state, cancelling out a portion of a magnetic flux produced by the magnetizing coil; a contact switch and a semiconductor switch electrically connected in parallel, and, in combination, bringing the demagnetizing coil into the conductive state or the cutoff state; and a control unit opening or closing the switches separately. The control unit: opens or closes the semiconductor switch in synchronization with a zero-crossing of the alternating current voltage at least when the contact switch is open; opens or closes the contact switch only when the semiconductor switch is closed; and opens the semiconductor switch when the demagnetizing coil brought into the conductive state by the contact switch needs to be maintained in the conductive state. | 08-21-2014 |
20150028791 | IMAGE FORMING APPARATUS - An image forming apparatus drives and rotates at least one of a photosensitive drum and a transport roller with use of a stepping motor in a multi-phase excitation mode. The image forming apparatus includes: a constant-voltage control unit controlling the stepping motor by applying a constant voltage for each phase; a constant-current control unit controlling the stepping motor by regulating an amount of current for each phase by a chopping control; a measuring unit measuring a chopping count of each phase on a per-step basis; a chopping count determination unit determining whether the chopping count of each phase is less than or equal to a predetermined count; and a control switching unit causing the constant-voltage control unit to control the stepping motor when the chopping count determination unit determines affirmatively, and causing the constant-current control unit to control the stepping motor when the chopping count determination unit determines negatively. | 01-29-2015 |