Abstract: In the case where a sheet on which a transparent toner image is to be formed has low glossiness, when the transparent toner image is formed in an area in which a user wishes to partly lower the glossiness, the glossiness in the area in which the user wishes to lower the glossiness is increased. For that reason, a print as desired by the user cannot be obtained by fixing the transparent toner image in an area corresponding to the area in which the user wishes to lower the glossiness. In the case where the sheet to be subjected to printing is judged as low glossy paper, the transparent toner image is placed in an image formable area except for the area in which the user wishes to lower the glossiness.

Abstract: A method of producing a print having a matte finish on a receiver having a surface type includes depositing toner with a viscosity of less than about 10 kpoise in a selected pattern on a receiver. A fixing system is provided including a rotatable fixing member and a pressure member arranged to form a fixing nip between them. The fixing member has a selected non-smooth surface that includes silicone. A release lubricant is applied to the fixing member. A fixing temperature and a fixing speed are selected based on the receiver surface type. The fixing member is heated to have a surface temperature substantially equal to the selected fixing temperature. The fixing member is rotated at the selected fixing speed to draw the toned receiver through the fixing nip, so that the toner is heated and fixed to the receiver and the resulting print has a matte finish.

Abstract: An image forming apparatus capable of forming an image with a color toner and a transparent toner does not always form an image using the transparent toner. Under the circumstance where the image in which the transparent toner is more easily deteriorated than the color toner is output, if the deteriorated transparent toner is frequently discharged, the productivity may be lowered. Thus, when an amount of the transparent toner applied to the recording material that is acquired by an acquisition device is less than a predetermined amount, the transparent toner in the amount more than that acquired by the acquisition device is applied to the recording material.

Abstract: An image heating apparatus including: an image heating member configured to heat an image on a sheet; a heating device configured to heat the image heating member so that a temperature of the image heating member is kept to a target temperature; an air blowing device configured to blow an air toward the image heating member when a predetermined sheet is separated from the image heating member; and an actuating device configured to actuate the air blowing device to cool the image heating member by blowing the air when the target temperature of the image heating member is lowered.

Abstract: An electrophotographic method is disclosed that reduces damage to a fusing roller by taking into account the thickness of the receiver sheet and adjusting the spacing between the fusing rollers in accordance with such thickness to ensure that a toned image is fully fixed on a receiver sheet while reducing damage to the fusing rollers.

Abstract: An image forming apparatus including: an image bearing belt that bears an image; an image creation unit that transfers the image on the image bearing belt; a first driving source; a driving roller that is rotationally driven by the first driving source and causes the image bearing belt to move; a transfer roller that has a concaved portion in a circumferential surface, forms a transfer nip by the transfer roller making contact with the image bearing belt, and transfers the image on the image bearing belt to a recording material; a second driving source that rotationally drives the transfer roller; a material type determination unit that determines a type of the recording material; and a control unit that controls a rotational frequency of the transfer roller when the recording material is nipped by the transfer nip based on information of the type determined by the material type determination unit.

Abstract: An image forming device includes a first medium container for a first printing medium; a second medium container for a second printing medium; a medium feeder for feeding one of the first and second media from one of the first and second medium containers; a special process unit that performs a special process on the first printing medium fed by the medium feeder when image data, including instruction information instructing the special process, is received; a detector that detects a characteristic of the first printing medium; a special process capability determination unit for determining whether or not the special process can be performed based on the characteristic; and a control unit that ejects the printing medium and that causes the second medium to be fed from the second medium container when the special process capability determination unit determines that the special process cannot be performed.

Abstract: An image forming apparatus including an image formation device that forms an image on a recording medium at an image formation position; a transfer path that reverses and transfers the recording medium to the image formation position; a pair of rotation rollers that nip the recording medium in the transfer path at an upstream position relative to the position where the recording medium is completely reversed; a pull-in path provided at a downstream position relative to the pair of rotation rollers situated in the transfer path, to which the recording medium is pulled in; and a transfer control device that controls pulling in the recording medium to the pull-in path after the rear end of the recording medium passes through the pair of rotation rollers when the recording medium is fed to and transferred in the transfer path, wherein no pair of rollers that impart a transfer force to the recording medium are provided in the pull-in range of the recording medium in the pull-in path.

Abstract: A recording material determination apparatus includes a transmission unit configured to transmit an ultrasonic wave, a reception unit configured to receive an ultrasonic wave transmitted from the transmission unit and then via a recording material, and a control unit configured to cause the transmission unit to transmit an ultrasonic wave a plurality of times under different conditions, measure an output value a plurality of times, and determine the recording material based on the output values measured a plurality of times.

Abstract: An image heating apparatus heats an image on a recording material and includes: a rotatable belt; a pressor contacting the belt to nip and feed the recording material; a stretcher stretching the belt; a detector detecting a position of the belt perpendicular to a rotational direction of the belt; an executor executing a first control mode for controlling a position of the belt by inclination of the stretcher on the basis of an output of the detector, and a second control mode for controlling the position of the belt member by inclination of the stretcher on the basis of the output of the detector and for stabilizing the position of the belt; an inputter inputting information relating to the recording material; and a selector for selecting the first control mode or the second control mode in accordance with the information inputted to the inputter.

Abstract: An image forming apparatus capable of both normal printing and special-purpose printing includes a first identification unit, a second identification unit, and a selection unit. The first identification unit identifies a type of print data. The second identification unit identifies a type of print material. The selection unit selects a print resource in accordance with a combination of the type of print data identified by the first identification unit and the type of print material identified by the second identification unit. The selection unit selects the print resource so as to prevent unauthorized printing from being performed when the print data is for special-purpose printing.

Abstract: This invention provides an image forming apparatus which performs fixing control complying with sheet characteristics in consideration of the productivity of a printing process and the precision of fixing control, and a control method thereof. To accomplish this, upon receiving a print job, the image forming apparatus extracts a sheet type used in the print job, and determines whether one set value in fixing control can be used for the extracted sheet type. If one set value can be used for the extracted sheet type, the image forming apparatus decides a common set value. If one set value cannot be used for the extracted sheet type, the image forming apparatus decides a set value for each type. In accordance with the decided set value, the image forming apparatus executes a printing process.

Abstract: In an image forming apparatus, a discrimination unit discriminates the type of printing medium conveyed to an image forming unit. A comparator compares the type of a printing medium that has been designated and the type of a printing medium that has been discriminated. A setting unit sets a second image forming condition in the image forming unit if it has been determined not to add identification information to image information in accordance with the type of printing medium designated and, moreover, the type of printing medium designated and the type of printing medium discriminated by the discrimination unit do not match. The second image forming condition is different from a first image forming condition that conforms to the type of printing medium discriminated by the discrimination unit.

Abstract: An intermediate transfer device including an intermediate transfer body having a primary transfer portion and a secondary transfer portion which bears a secondary image formed by transferring a primary image from an image bearing member; a pair of secondary transfer rollers having a secondary transfer roller and a support roller provided in contact with each other via the intermediate transfer body at the secondary transfer portion, which transfers the secondary image to a recording medium at the secondary transfer portion; a variation detection device that detects an amount of variance occurring to a transfer rotation body when the recording medium is transferred to the secondary transfer portion; and an adjustment device that adjusts the distance between the pair of the secondary transfer rollers according to the amount of variance detected by the variation detection device.

Abstract: A fixing device includes a fixing member, a heating member to heat the fixing member, a pressing member to press against the fixing member with a predetermined pressure, forming a nip where an image is fixed on a recording medium with heat and pressure, a heating controller to cause the heating member to heat the fixing member to a predetermined temperature set in advance and to preheat the fixing member while maintaining the temperature of the fixing member, a recording-medium data receiver to acquire recording-medium data before a fixing process is started, and a preheating-time adjuster to adjust a preheating time during which the heating member preheats the fixing member based on the data acquired by the recording-medium data receiver.

Abstract: A transfer device includes a transfer device, a facing member, and a prepressing member. The transfer member transfers a toner image, which is carried on an intermediate transfer member, to a recording medium. The facing member is disposed so as to be in pressed contact with the transfer member with the intermediate transfer member therebetween. The prepressing member is disposed so as to be in pressed contact with the transfer member with the intermediate transfer member therebetween at a position that is upstream of a contact section in which the facing member is in pressed contact with the transfer member and that is immediately behind a position at which the toner image starts to come into contact with the recording medium. A pressure applied by the prepressing member is lower than a pressure with which the facing member is in pressed contact with the transfer member.

Abstract: An image forming apparatus has an image forming station for forming an image and a display unit for displaying specified information. A mode changing section switches a mode of the image forming apparatus between a first mode for waiting on standby with a first power consumption and a second mode for waiting on standby with second power consumption lower, than the first power consumption. A determining section determines whether an image can be formed after the mode is switched from the second mode to the first mode and a starting section starts the display unit when the determining section determines that no image can be formed. A notifying section generates a display on the display unit of information indicating that no image can be formed.

Abstract: When glossiness in an area designated by a user was adjusted, the glossiness adjustment was achieved by exchanging a plurality of toners having different glass transition points. Thus, the user was required to select an appropriate toner when the glossiness in the area designated by the user was adjusted. Further, the user took some time or effort to set the selected toner every glossiness adjustment. In the present invention, how to adjust the glossiness in the area designated by the user is obtained as mode information and on the basis of the obtained mode, control is effected so that a transparent image is selectively formed in the area designated by the user or an image formable area except for the area designated by the user.

Abstract: According to a method and apparatus for controlling a voltage of an image forming apparatus, a transferring roll resistance, which indicates the resistance between a transferring roller and a photoconductor drum, is detected by applying a first voltage to the transferring roller. A transferring voltage, which corresponds to the detected transferring roll resistance, is applied to the transferring roller with reference to a transferring table which corresponds to the paper resistance, and a transferring is performed on a printing paper by using a transferring roller to which a transferring voltage is applied.

Abstract: A fixing unit includes a fixing member, a pressing member, a heating device, a sheet width detector, and a heating area adjustor. The pressing member faces the fixing member to form a fixing nip between the fixing member. An un-fixed toner image is fixed on a recording medium when the recording medium passes through the fixing nip. The heating device heats the fixing member while maintaining a non-contact condition with the fixing member. The sheet width detector detects sheet width of the recording medium. The heating area adjustor changes a heating area of the fixing member, heatable by the heating device, based on the sheet width detected by the sheet width detector. The heating area adjustor is moveable in a space between the fixing member and the heating device along a sheet width direction to change a size of the heating area.

Abstract: An image recording device includes a first detecting unit, a recording unit, and a control unit. The first detecting unit detects a position of a perforation pre-formed in a recording sheet. The recording unit records an image on the recording sheet based on printing data. The control unit is configured to imaginarily divide the recording sheet into a first region including a portion where the perforation is pre-formed, and a second region excluding the first region based on the position of the perforation detected by the first detecting unit. The control unit prohibits the recording unit from recording the image on the first region and controls the recording unit to record the image at least partially on the second region.

Abstract: A fixing device includes a first fixing member a second fixing member that are movable to engage and disengage a fixing nip defined by the first and second fixing member. The fixing nip is disengaged to accommodate entry and exit of a cut sheet, and engaged to accommodate warm-pressure fixing a marking material image to the cut sheet.

Abstract: A method and apparatus for confirming attributes of media loaded in a media tray in an image production device is disclosed. The method may include determining which media tray of one or more media trays is being loaded with media using one or more media tray sensors, displaying a graphical representation of the media tray being loaded to a user on a user interface, prompting the user to enter and confirm attributes of the media being loaded into the media tray through the user interface, determining if confirmation has been received from the user interface, wherein if it is determined that the confirmation has been received from the user interface, storing the confirmed attributes for the determined media tray in a memory, and processing print jobs using the stored media tray attributes.

Abstract: A printing apparatus includes a memory used for storing a preset temperature value indicating a preset temperature of a heating portion controlled by a CPU when print processing including transfer processing and fixing processing is performed in association with a plurality of types of sheets that are usable by the printing apparatus. The CPU of the printing apparatus calculates a maintenance temperature value, which is a temperature value to be maintained by the heating portion when the print processing is not performed, based on a plurality of preset temperature values that are set in association with the plurality of types of sheets, and controls the temperature of the heating portion to become equal to the maintenance temperature value.

Abstract: This disclosure provides printing methods, systems and apparatus to compensate for distortions by fusing toner applied to a media substrate. According to one exemplary method, image data is processed according to media characterization data for a toner density value associated with the image. The processed image data compensates for media substrate distortions due to fusing of a printed image on the media substrate.

Abstract: The sheet thickness detector includes a fixed member, a displacement roller disposed opposite the fixed member and movable in such a linear direction as to be contacted with or separated from the fixed member when the sheet passes through a nip therebetween, bearings rotatably supporting a shaft of the displacement roller, a displacement member movable in the linear direction in conjunction with the displacement roller and integrated with at least one of the bearings, and a displacement sensor operatively connected to the displacement member and detecting displacement of the displacement member. The thickness of the sheet passing through the nip is determined based on the amount of displacement of the displacement member.

Abstract: A fixing device including: a heated fixing member to fix a toner image on a recording medium; a pressing member to form a nip portion between the pressing member and the fixing member; a first blowing unit that blows air to a position close to a leading edge of the recording medium; and a second blowing unit that blows air to the recording medium, wherein a discharge pressure of the air discharged by the first blowing unit is larger than that of the air ejected by the second blowing unit; a discharged air volume discharged by the first blowing unit is less than that discharged by the second blowing unit; and a first discharge port from which air is blown by the first blowing unit is arranged upstream of a second discharge port from which air is blown by the second blowing unit.

Abstract: There is provided a recording medium imaging device capable of properly selecting pixels used for determining the kind of the recording medium from the captured surface image to remove pixels from which the surface property of the recording medium cannot be properly determined because the pixels extremely high in light quantity are affected by some sort of dirt or scratches in determining the kind of a recording medium. This allows the determination of kind of the recording medium based on the normally captured surface image to reduce the decrease in accuracy in determining the kind of the recording medium.

Abstract: Hard imaging devices and hard imaging methods are described. According to one embodiment, a hard imaging device includes an image engine configured to provide a marking agent upon media to form hard images, and a media sensing system configured to sense the media and to provide at least one signal comprising information indicative of a direction of grain of the media responsive to the sensing of the media, and processing circuitry configured to receive the at least one signal provided by the media sensing system and to control an operation of the hard imaging device using the information indicative of the direction of the grain of the media of the at least one signal.

Abstract: A developing device includes: a developer storage portion which stores a liquid developer including toner and carrier liquid; a first coating member which rotates and coats the liquid developer stored in the developer storage portion; a second coating member which comes into contact with the first coating member and rotates in a direction opposite to that of the first coating member and slower than a rotary peripheral velocity of the first coating member; and a developer supporting body which comes into contact with the second coating member and rotates in the same direction as that of the second coating member and faster than a rotary peripheral velocity of the second coating member.

Abstract: An image forming apparatus includes an image forming unit and a surface reflection detector. The image forming unit includes an image forming station to form a detection sample image and a toner image on a recording medium, a controller to set a detection sample image output mode to output the detection sample image, and a fixing device to fix the detection sample image and the toner image on the recording medium. The surface reflection detector is connected to the controller to detect reflection characteristics of a surface of the recording medium and includes a projector to project parallel light against a target and an angular distribution detector to detect an angular distribution of light reflected from the recording medium and the detection sample image. Based on the detection result, imaging conditions are adjusted and an output image is formed.

Abstract: An image forming apparatus includes an image bearing member for carrying a toner image; a transfer member forming a nip with the image bearing member to transfer the toner image from the image bearing member onto a transfer material at the nip, wherein the image forming apparatus is operable in a marginless printing mode in which the toner image formed on the image bearing member is larger than a size of the transfer material, and the toner image is transferred as far as edges of the transfer material; and a charging member for effecting electric discharge toward the image bearing member, the charging member being disposed at such a position as is opposed to a side of the transfer material which receives the toner image in an upstream side of the nip with respect to a feeding direction of the transfer material, wherein when the apparatus operates in the marginless printing mode, the charging member effects the electric discharge toward the toner existing in an area of the image bearing member which correspond

Abstract: An image forming apparatus includes a rotatable image bearing member; a developing device, including a developer carrying member and developing bias application means for applying a developing bias for developing a developer image; a rotatable intermediary transfer member; a primary transfer member for forming a primary transfer nip and for transferring the developer image from the image bearing member onto the intermediary transfer member; a secondary transfer member for secondary-transferring the developer image from the intermediary transfer member onto a recording material; wherein an area of the image bearing member includes a first area at least containing an area located in primary transfer nip at a time when a speed of the intermediary transfer member is temporarily decreased and includes a second area located in the primary transfer nip when there is no temporary change in speed; and a control device for controlling a developing bias.

Abstract: A method of removing charge from a charged sheet prior to stacking the charged sheet is disclosed. The method includes moving the charged sheet through a set of nipped rollers while a first roller has an AC voltage applied thereto so that a first side of the charged sheet is in contact with the first roller and has its charge substantially dissipated, whereby charge substantially remains on a second side of the charged sheet in contact with a second roller. The method further includes using at least one non-contact charge removal device to remove charge from the second side of the charged sheet, and stacking the discharged sheet.

Abstract: A grammage detection sensor which detects a grammage of a recording medium using an ultrasonic wave includes a transmitting unit configured to transmit the ultrasonic wave and a receiving unit including a first vibration member configured to receive the ultrasonic wave that is transmitted from the transmitting unit and passes through the recording medium. The receiving unit includes a guide member configured to guide the ultrasonic wave that passes through the recording medium to the first vibration member. A length from a surface of the first vibration member to a plane including an end plane of the guide member along a line that passes through a center of the first vibration member and is perpendicular to the first vibration member is approximately n times of one-half wavelength of the ultrasonic wave transmitted from the transmitting unit where n is an integer of one or greater.

Abstract: A transfer device comprising: a transfer section which forms a nip portion between the transfer section and an image carrier and transfers a toner image on an image carrier onto a sheet passing through the nip portion; an application section which applies a voltage to the transfer section; a determining section which determines a timing of applying voltage from the application section to the transfer section, wherein the control section controls the application section to apply a voltage having an opposite polarity to a transfer polarity to the transfer section until the timing determined by the determination section in a period since a leading edge of the sheet in a conveyance direction advances into the nip portion until a predetermined non image area of the sheet has passed through the nip portion, and then, at a timing determined, switch to apply a voltage having the transfer polarity.

Abstract: In a second mode to form an image based on a pre-designated type of recording medium, a detection is performed to a recording medium which is fed, and in a first mode to form an image based on the detected type, image forming conditions are set based on a result of the sheet type detection in the second mode without executing the sheet type detection.

Abstract: A method of controlling the inverter dwell time of the first print engine in order to print any sheet size within a pitch mode without the need for a belt sync dead-cycle. The method uses a small nominal inverter dwell time based on the maximum sheet size for a given pitch mode. For any sheet size within the pitch mode that is smaller than the maximum sheet size, the inverter dwell time will increase proportionally.

Abstract: A print or logo data generating system and method in which a width dimension of a printable medium is identified and original source data obtained. The processing further involves automatically resizing the source data to a predefined maximum width not greater than the width dimension of the printable medium prior to executing any user-requested changes, and displaying a first image representation of the original source data. Upon receipt of a user-requested change in the size of the original source data and a user-requested change in the number of colors of the original source data, the size change request is executed first.

Abstract: A fixing device including a heating roller; a pressure roller forming a nip section by making contact with the heating roller; a controller for controlling the surface temperature of the heating roller so that it becomes a predetermined set temperature; an amount of decrease detector for detecting an amount of decrease in the surface temperature of the pressure roller between before and after the passing of the paper sheet through the nip section; a determiner for specifying a required temperature required to perform the fixing for the paper sheet on the basis of the amount of decrease and for determining whether the set temperature is acceptable as the required temperature; and a temperature compensator for correcting the set temperature so that the set temperature is acceptable as the required temperature in the case that the determiner has determined that the set temperature is not acceptable as the required temperature.

Abstract: A method and apparatus for determining whether borderless printing can be done based on media type and desired gloss level is provided. Also provided is a method, printer, and system whereby a defect-free borderless print can be achieved regardless of media type and gloss level of the finished print, wherein the method includes pre-heating of the leading edge of the media before it enters a fuser area of the printer.

Abstract: An information processor includes a storage unit storing a first coefficient in correspondence with a characteristic of a sheet of paper, a first acquisition unit acquiring a first signal based on the water content of a first sheet of paper not having an image formed thereon, a second acquisition unit acquiring a second signal based on the water content of the first sheet of paper having an image formed thereon and being heated for fixing, a determination unit determining the characteristic of the first sheet of paper, a first calculation unit calculating a variation in water content of the first sheet of paper using the difference between the first signal and the second signal and the first coefficient stored in correspondence with the determined characteristic, and a second calculation unit calculating an expansion and contraction ratio of the first sheet of paper using the variation in water content.

Abstract: An image forming apparatus includes a consumable supply remaining amount detection unit for detecting a remaining amount of a consumable supply; a printable length detection unit for determining a printable length of a medium printable with the remaining amount; a printable length determining processing unit for determining whether the printable length is smaller than a requested print length of the medium requested with print data; and a printing processing unit for performing a partial printing operation when the printable length determining processing unit determines that the printable length is smaller than the requested print length.

Abstract: An image forming device includes a sensor to detect whether a paper is discharged or not, a determiner to determine a paper width according to whether a sensing signal is output from the sensor when a printing job is executed, and a controller to control a subsequent printing operation according to the determination result of the determiner. After the printing job is initiated, the determiner determines a normal width when the sensing signal is output within a preset time, and the determiner determines a narrow width when the sensing signal is not output within the present time. Accordingly, using an existing sensor, the paper width can be detected and the appropriate printing process can be performed.

Abstract: A method and apparatus for determining media thickness in a feeder section of an image production device is disclosed. The method may include receiving one or more multi-dimensional images of a media stack from an imaging device, the media stack including one or more media clips that each contain a plurality of media sheets, deriving a multi-dimensional feature signal from the received one or more multi-dimensional images, converting the derived multi-dimensional feature signal to a one-dimensional feature signal, estimating media clip thickness using the one-dimensional signal, estimating media sheet thickness using the estimated media clip thickness, and adjusting at least one image production device parameter based on the estimated media sheet thickness.

Abstract: An image forming apparatus includes an image bearing member for carrying a toner image; a rotatable transfer member constituting a transfer portion for transferring the toner image from the image bearing member onto a recording material; a voltage source for applying a voltage to the transfer member; an executing portion for executing an image forming mode for continuously forming an image on a plurality of recording materials having different widths measured in a direction of a rotational axis of the transfer member; an interval adjustment portion for adjusting, during execution of the image forming mode, an interval between adjacent recording materials to a first interval when the width of the recording material is larger than the width of the previous recording material, and for adjusting, during execution of the image forming mode, the interval between adjacent recording materials to a second interval when the width of the recording material is smaller than the width of the previous recording material.

Abstract: An image forming apparatus which includes a photosensitive member and an image forming station. The image forming station includes a charging device for charging the member, an exposure device for exposing the member to light, a developing device for developing an electrostatic latent image on the member, and a bias applying device for applying a developing bias. The image forming apparatus also includes, a transfer device for transferring a toner image to a sheet, a setting device for setting an AC voltage, an executing device for executing a test mode, a density detecting device for detecting the density of the test image, and an adjusting device for adjusting an image forming condition for the station. When the executing device executes the test mode, test images can formed at various AC voltages.

Abstract: Constant current control is performed with a target current It in each delivery interval between recording materials to sample a control voltage V1 applied to a secondary transfer roller. A transition to the constant current control with the target current It is made after a recording material divided voltage according to a kind of the recording material is applied to the constant voltage V1 at a head of the recording material. A voltage in which 0.9 is multiplied by addition of the sampled control voltage V1 and the recording material divided voltage Vp according to the kind of the recording material is set to a lower limit value Vlimit to perform the constant current control, and the constant voltage Vlimit is applied to the secondary transfer roller when a control voltage is lower than the lower limit value Vlimit in a calculation stage.

Abstract: An image forming apparatus includes a forming section that forms an image on a side of paper; a fixing section that applies heat to fix the image onto the side of the paper; a paper reversing section that reverses a front and back of the paper having the image fixed onto a first side in the fixing section; a first measuring section that is provided between a registration roller and the forming section to measure a first moisture content of the paper before an image is formed on the first side, and a second moisture content of the paper before an image is formed on a second side, after the image is fixed on the first side; and a calculating section that calculates amount of change of the size of the paper on the basis of the difference between the first moisture content and the second moisture content.

Abstract: In an image forming apparatus transferring a toner image on an intermediate transfer member onto a sheet in a transfer nip between a nip forming member and the transfer member, a resistance or environment detection device detects electrical resistance of the sheet or an environmental parameter correlated with the resistance, an output device outputs a transfer current, a storage device stores, as an algorithm for calculating a transfer current target value according to an image area ratio in the nip, algorithms corresponding to different resistances or environmental parameters, and a control device selects and uses, from the algorithms, an algorithm according to the detection result of the resistance or environment detection device as the algorithm for calculating the target value, and controls an output current value to equalize a current value based on the image area ratio in the nip with the target value based on the algorithm.