Abstract: Provided is an image forming system capable of accurately detecting the resistance of a recording material. The image forming system includes an application roller that applies a voltage to a recording material on a conveyance path, and a controller that calculates the electric resistance of the recording material from a relationship between the voltage applied to the application roller and a current. The controller calculates the resistance of the recording material based on first profile information that is acquired by changing the applied voltage and corresponds to a change in the resistance of the application roller, and second profile information that is acquired by changing the applied voltage in a state where the recording material is sandwiched and corresponds to the change in the resistance of the application roller.

Abstract: An image forming device includes: a transfer unit transferring a toner image to a sheet; a resistance measurement member disposed on the upstream side in a sheet carriage direction of the transfer unit and for measuring resistance of the sheet; a charge elimination member disposed between the transfer unit and the resistance measurement member in the sheet carriage direction; a first voltage applying unit applying voltage for resistance measurement to the resistance measurement member; and a second voltage applying unit applying voltage of reverse bias of the voltage for resistance measurement to the charge elimination member. The width of a charge elimination region by the charge elimination member is wider than that of a charged region by the resistance measurement member in a direction perpendicular to the sheet carriage direction. The absolute value of the voltage for charge elimination is smaller than that of the voltage for resistance measurement.

Abstract: An image forming device includes: a transfer unit transferring a toner image to a sheet; a resistance measurement member disposed on the upstream side in a sheet carriage direction of the transfer unit and for measuring resistance of the sheet; a charge elimination member disposed between the transfer unit and the resistance measurement member in the sheet carriage direction; a first voltage applying unit applying voltage for resistance measurement to the resistance measurement member; and a second voltage applying unit applying voltage of reverse bias of the voltage for resistance measurement to the charge elimination member. The width of a charge elimination region by the charge elimination member is wider than that of a charged region by the resistance measurement member in a direction perpendicular to the sheet carriage direction. The absolute value of the voltage for charge elimination is smaller than that of the voltage for resistance measurement.

Abstract: A power supply apparatus includes a predetermined mode in which power consumption is suppressed and a normal mode in which the power consumption is not suppressed and which supplies power to an apparatus. the power supply apparatus includes the following, a cutting member which cuts off supply of the power to a fixing heater; a noise removing member which is positioned in a later stage of the cutting member and which removes noise in the power; and a controller which controls the cutting member. The controller controls the cutting member to cut off supply of the power to the noise removing member in the predetermined mode.

Abstract: A heater includes: a planar heat generator; a power supply circuit that controls supply of power to the planar heat generator; a plurality of temperature sensors that is provided on the planar heat generator and measures a temperature; and a hardware processor that detects abnormality of the temperature sensor in a case where a difference in temperature measured by each of two of the temperature sensors out of the plurality of temperature sensors exceeds an abnormality threshold value after a predetermined waiting time has elapsed since the supply of power to the planar heat generator is stopped.

Abstract: A heater includes: a planar heat generator; a power supply circuit that controls supply of power to the planar heat generator; a plurality of temperature sensors that is provided on the planar heat generator and measures a temperature; and a hardware processor that detects abnormality of the temperature sensor in a case where a difference in temperature measured by each of two of the temperature sensors out of the plurality of temperature sensors exceeds an abnormality threshold value after a predetermined waiting time has elapsed since the supply of power to the planar heat generator is stopped.

Abstract: A heater includes: a planar heat generator; a power supply circuit that controls supply of power to the planar heat generator; a plurality of temperature sensors that is provided on the planar heat generator and measures a temperature; and a hardware processor that controls the power supply circuit in a predetermined condition to maintain a temperature measured by at least one of the plurality of temperature sensors at a target value, wherein the planar heat generator includes: an insulator; and a heat generator disposed on the insulator, the heat generator includes each of a plurality of linear parts extending in parallel with each other at a predetermined interval P, and each of the plurality of temperature sensors is disposed along a direction orthogonal to an extending direction of each of the plurality of linear parts at a position mutually shifted by a predetermined distance D.

Abstract: An image forming device includes: a conductive roller that abuts an image carrier to rotate; a power supply circuit that applies voltage to the roller; a controller that controls the power supply circuit so as to apply the voltage to the roller over a predetermined detection period in a state in which the image carrier and the roller are rotated; a detection value acquirer that acquires a detection value acquired by the application of the voltage indicating a state of the image carrier in the detection period; and a state detector that detects a state of the image carrier on the basis of a plurality of acquired detection values, wherein a length of the detection period is set to a length at which both the numbers of rotations of the image carrier and the roller from a start of the detection period are integers.

Abstract: An image forming device includes: a conductive roller that abuts the image carrier to rotate; a power supply circuit that applies voltage to the roller; a controller that controls the power supply circuit so as to apply the voltage to the roller over a predetermined detection period in a state in which the image carrier and the roller are rotated; a detection value acquirer that acquires a detection value acquired by the application of the voltage indicating a state of the image carrier in the detection period; and a state detector that detects a state of the image carrier on the basis of a plurality of acquired detection values, wherein a length of the detection period is set to a length at which both the numbers of rotations of the image carrier and the roller from a start of the detection period are integers.

Abstract: A power supply device includes: a power supply circuit that converts an AC voltage into a DC voltage; and a control circuit that controls the power supply circuit, wherein the power supply circuit includes: a rectifying and smoothing circuit that rectifies and smoothes the AC voltage; a first voltage converting circuit that converts the voltage and outputs a first DC voltage; a second voltage converting circuit that switches the first DC voltage by a switching circuit to output a second DC voltage; a feedback circuit that detects and feeds back an output voltage of the first voltage converting circuit; and a selection circuit that switches a reference voltage of the feedback circuit, and the control circuit sets the switching circuit to be in a continuous connection state when a normal mode is shifted to a power saving mode and gradually switches the reference voltage.

Abstract: A power supply apparatus includes: a first primary winding; a first AC voltage outputter connected to one side of the first primary winding so as to output a first AC voltage; a second AC voltage outputter connected to the other side of the first primary winding and capable of outputting a second AC voltage with an inverted phase of the first AC voltage; a first secondary winding that generates a third AC voltage by mutual induction of the first primary winding to which the first AC voltage and the second AC voltage are applied; a second primary winding having one side receiving an input of the second AC voltage and the other side connected to a fixed voltage; and a second secondary winding that generates a fourth AC voltage by mutual induction of the second primary winding to which the second AC voltage is applied.

Abstract: A power supply device includes: a power supply circuit that converts an AC voltage into a DC voltage; and a control circuit that controls the power supply circuit, wherein the power supply circuit includes: a rectifying and smoothing circuit that rectifies and smoothes the AC voltage; a first voltage converting circuit that converts the voltage and outputs a first DC voltage; a second voltage converting circuit that switches the first DC voltage by a switching circuit to output a second DC voltage; a feedback circuit that detects and feeds back an output voltage of the first voltage converting circuit; and a selection circuit that switches a reference voltage of the feedback circuit, and the control circuit sets the switching circuit to be in a continuous connection state when a normal mode is shifted to a power saving mode and gradually switches the reference voltage.

Abstract: A power supply apparatus includes: a first primary winding; a first AC voltage outputter connected to one side of the first primary winding so as to output a first AC voltage; a second AC voltage outputter connected to the other side of the first primary winding and capable of outputting a second AC voltage with an inverted phase of the first AC voltage; a first secondary winding that generates a third AC voltage by mutual induction of the first primary winding to which the first AC voltage and the second AC voltage are applied; a second primary winding having one side receiving an input of the second AC voltage and the other side connected to a fixed voltage; and a second secondary winding that generates a fourth AC voltage by mutual induction of the second primary winding to which the second AC voltage is applied.

Abstract: A power supply device including: a transformer generating, from an input voltage, low output voltage and high output voltage; an upper limiter circuit receiving the high output voltage and controlling the high output voltage not to exceed a maximum; a power controller performing feedback control on the input voltage so that the low output voltage matches a target voltage; an operation mode acquirer configured to acquire an operation mode of an image forming device; and a target value controller configured to change the target voltage depending upon the acquired operation mode. The target voltage when consumption amount of current with the high output voltage is relatively great ensures that the high output voltage does not fall below a minimum of a rated voltage range of the high output voltage, and is higher than the target voltage when consumption amount of current with the high output voltage is relatively small.

Abstract: An image forming apparatus includes: a plurality of image forming units forming an image in the corresponding color by electrophotographic system; a high-voltage power supply circuit capable of generating a bias voltage; and a control unit that controls a first printing mode and a second printing mode, wherein in the second printing mode, the control unit performs such control that the photosensitive bodies provided on the image forming units not used in the second printing mode continuously rotate at a speed lower than a speed in the first printing mode, and/or such control that a bias voltage whose absolute value is less than an absolute value of a bias voltage in the first printing mode is supplied from the high-voltage power supply circuit to the processing components of the same type provided on the image forming units not used in the second printing mode.

Abstract: A power supply device including: a transformer generating, from an input voltage, low output voltage and high output voltage; an upper limiter circuit receiving the high output voltage and controlling the high output voltage not to exceed a maximum; a power controller performing feedback control on the input voltage so that the low output voltage matches a target voltage; an operation mode acquirer configured to acquire an operation mode of an image forming device; and a target value controller configured to change the target voltage depending upon the acquired operation mode. The target voltage when consumption amount of current with the high output voltage is relatively great ensures that the high output voltage does not fall below a minimum of a rated voltage range of the high output voltage, and is higher than the target voltage when consumption amount of current with the high output voltage is relatively small.

Abstract: An image forming apparatus includes: a plurality of image forming units forming an image in the corresponding color by electrophotographic system; a high-voltage power supply circuit capable of generating a bias voltage; and a control unit that controls a first printing mode and a second printing mode, wherein in the second printing mode, the control unit performs such control that the photosensitive bodies provided on the image forming units not used in the second printing mode continuously rotate at a speed lower than a speed in the first printing mode, and/or such control that a bias voltage whose absolute value is less than an absolute value of a bias voltage in the first printing mode is supplied from the high-voltage power supply circuit to the processing components of the same type provided on the image forming units not used in the second printing mode.

Abstract: A developing device includes a toner bearing member holding a toner on its surface for conveyance of the toner to a development region where the toner bearing member opposes an image bearing member via a predetermined gap therebetween; a regulating member pressed against the surface of the toner bearing member for regulation of the amount of toner conveyed to the development region; and a developing bias source for applying an alternating electric field between the toner bearing member and the image bearing member. The developing device features the use of the toner bearing member including a conductive substrate formed with an elastic layer, an intermediate layer and a surface layer on the surface thereof, respective volume resistances &rgr;1, &rgr;2 and &rgr;3 of which layers satisfy a condition &rgr;2≦&rgr;1≦&rgr;3, the toner bearing member having an arithmetic average surface roughness in the range of 0.8 to 2.5 &mgr;m, and the use of the toner having a volume-average particle size of 3 to 8 &mgr;m.

Abstract: A developing device includes a toner bearing member holding a toner on its surface for conveyance of the toner to a development region where the toner bearing member opposes an image bearing member via a predetermined gap therebetween; a regulating member pressed against the surface of the toner bearing member for regulation of the amount of toner conveyed to the development region; and a developing bias source for applying an alternating electric field between the toner bearing member and the image bearing member. The developing device features the use of the toner bearing member including a conductive substrate formed with an elastic layer, an intermediate layer and a surface layer on the surface thereof, respective volume resistances &rgr;1, &rgr;2 and &rgr;3 of which layers satisfy a condition &rgr;2≦&rgr;1≦&rgr;3, the toner bearing member having an arithmetic average surface roughness in the range of 0.8 to 2.5 &mgr;m, and the use of the toner having a volume-average particle size of 3 to 8 &mgr;m.

Abstract: In order to achieve such effects that memories such as image memory due to untransferred residual toner can be sufficiently prevented, and good images can be obtained by suppressing base fogging and reduction of entire image density for a long term, an oscillating voltage composed of a DC ingredient and an oscillating ingredient is applied to a charging device for charging a photosensitive member, while the charging device is in a position facing an image forming region of the photosensitive member. While the charging device is in a position facing an image non-forming region of the photosensitive member, only a DC voltage is applied to the charging device for at least a predetermined time.