Abstract: An image forming apparatus includes an image bearing member, an intermediary transfer belt containing an ion conductive agent, a secondary transfer member, and a charging device. With respect to the intermediary transfer belt, when a difference in number of digits (or in log value) between resistivity measured by using a metal probe and resistivity measured by using a sputtering electrode is ?M, a difference in number of digits (or in log value) between resistivity in a first environment and resistivity in a second environment higher than the first environment in temperature or humidity is ?E, a length of the secondary transfer portion with respect to the movement direction of the intermediary transfer belt is La, and a distance from the charging portion to the primary transfer portion with respect to the movement direction is Lb, the following relationship is satisfied: ?M??E?log(Lb/La).

Abstract: A belt driving apparatus is configured so as to satisfy a relationship ?1(2T sin(?1/2)+f1)<?2(2T sin(?2/2)+f2), wherein ?1 is a dynamic friction coefficient between the supporting roller and the endless belt, ?2 is a dynamic friction coefficient between the steering roller and the endless belt, ?1 is a winding angle of the endless belt with respect to the supporting roller, ?2 is a winding angle of the endless belt with respect to the steering roller, f1 is the first external force applied to the supporting roller through the endless belt, f2 is the second external force applied to the steering roller through the endless, and T is a tension force applied to the endless belt by the tension roller.

Abstract: Preventing link members for monochrome and for color from coming off while suppressing the occurrence of an increase of a rotatory torque and a deficiency of clutch capacity for transmitting a driving force to a cam shaft is sought. Coming-off protection sections (second and third coming-off protection sections (236), (237)) for preventing the coming off of a second link member 22 which is the link member for color is provided in a cam section for monochrome (first cam section 233). In other words, it is not necessary to provide a coming-off protection section in a second cam section 234 which is a cam section for color requiring a large rotatory torque. This eliminates the need for a coming-off protection section of the cam section for color to act on the link member for color when a cam 23 is turned by a driving source, thereby making it possible to suppress the occurrence of the increase of the rotatory torque and the deficiency of clutch capacity for transmitting the driving force to the cam shaft.

Abstract: A belt formed of a single resin layer and having cavities within the resin layer. The belt may be a transfer belt that is arranged opposed to an image carrier which carries a developer image on a surface, and in which the developer image is transferred thereon from the image carrier.

Abstract: A control portion controls a drive of rotation of an image carrier and registers a second index with a first index passing through a transfer position at real time at the time of image formation. Before starting the image formation, the toner image forming portion is controlled to adjust misalignment between the first index and the second index. Accordingly, the second index is formed at a position on the image carrier which is registered with the first index in advance, so that a large amount of control for compensating a large amount of phase misalignment is no longer necessary.

Abstract: An image forming apparatus includes an image bearing member that bears a toner image; a transfer member that faces the image bearing member, nips a recording medium together with the image bearing member, and allows the recording medium to pass therebetween; a transfer-bias applying unit that applies transfer bias voltage to generate an electric field between the transfer member and the image bearing member; a cleaning member that is disposed in contact with the transfer member and removes toner from the transfer member; a cleaning-bias applying unit that applies cleaning bias voltage between the cleaning member and the transfer member; a transfer-toner-amount estimating unit that estimates an amount of toner to be transferred from the image bearing member to the transfer member when the recording medium does not pass therebetween; and a cleaning-bias controller that controls the cleaning bias voltage in correspondence with the estimated amount of toner.

Abstract: An image forming device according to one example embodiment includes a housing having an access door manually movable between a closed position and an open position. A carriage is mounted on an inner portion of the access door. A first roll is rotatably mounted to the carriage and forms a nip with a second member positioned in the interior of the housing when the access door is closed. The first roll is spaced away from the second member when the access door is open. The carriage is free to move relative to the access door and is biased away from the access door toward the second member. A clamping assembly is configured to clamp the first roll against the second member to form the nip as the access door is closed and unclamp the first roll from the second member as the access door is opened.

Abstract: An image forming apparatus includes: a first image forming unit including a first transfer unit forming a first nip with a first photosensitive drum for black; a second image forming unit including a second transfer unit forming a second nip with a second photosensitive drum for a color; and a control device which, when a first sheet and a second sheet are continuously conveyed in corresponding order by the conveyance belt at the monochrome mode, is configured to supply a first transfer current for a first time period during which the first sheet or the second sheet pass through the second nip and supply a second transfer current, which is smaller than the first transfer current, for a second time period that is a sheet interval between the first sheet and the second sheet.

Abstract: An image forming apparatus includes a photosensitive drum for bearing a toner image, a rotatable endless belt provided so that its outer surface opposes the drum, and a rigid transfer roller, provided so as to contact an inner surface of the belt, for transferring the toner image from the drum onto the belt or a recording material conveyed by the belt. A coefficient of static friction of a surface of the transfer roller is smaller than that of the inner surface of the belt. In addition, a stretching roller is provided so as to contact the inner peripheral surface of the belt for stretching the belt, with a coefficient of static friction of a surface of the stretching roller being larger than that of the inner peripheral surface of the belt. A cleaning member cleans the surface of the stretching roller.

Abstract: A transfer device includes an endless intermediate transfer belt that moves circularly, a first rotating body pressed into contact with the inner surface of the belt, and a second rotating body disposed at a position facing the first rotating body to contact with the outer surface of the belt. The belt includes a first pressing section that is in contact with the second rotating body due to a first pressure from the first rotating body such that a toner image that has been first-transferred to the outer surface of the belt is second-transferred onto a recording medium that passes between the belt and the second rotating body and a second pressing section that is in contact with the second rotating body due to a second pressure smaller than the first pressure on the upstream side of the first pressing section in the belt movement direction.

Abstract: An image forming apparatus includes a nip forming member and a transfer bias output device that outputs a transfer bias to form a transfer electric field in a transfer nip between the nip forming member and an intermediate transfer member. Upon transfer of a composite toner image including a particular toner image onto a recording medium in the transfer nip, the transfer bias output device outputs the transfer bias including a first superimposed bias in which a direct current (DC) component is superimposed on an alternating current (AC) component. Upon transfer of the composite toner image without the particular toner image onto the recording medium in the transfer nip, the transfer bias output device outputs one of the transfer bias including a second superimposed bias having a peak-to-peak value of the AC component smaller than that of the first superimposed bias and the transfer bias including only the DC component.

Abstract: An image forming apparatus includes a second transfer unit, and a control device. If a prescribed condition is satisfied, the control device sets a transfer current value for the second transfer unit so that an absolute value of a difference between the first current value and a second current value is greater than an absolute value of a difference between a third current value and a fourth current value. The first current value is set in a black-white mode, in which an image is formed by using black toner only, under the prescribed condition; the second current value is set if the prescribed condition is unsatisfied in the black-white mode; the third current value is set in a multi color mode, in which an multi-color image is formed, under the prescribed condition; and the fourth current value is set if the prescribe condition is unsatisfied in the multi color mode.

Abstract: An image forming apparatus includes an image bearing member which bears a toner image, an intermediate transfer member which bears the toner image transferred from the image bearing member, an endless recording material-conveying member which conveys a recording material, and a transfer portion which transfers the toner image to the recording material conveyed from the intermediate transfer member by the recording material-conveying member, wherein a perimeter of the intermediate transfer member is set to substantially an integral multiple of a perimeter of the recording material-conveying member.

Abstract: A driving device includes a stretched member, and a first rotation member and a second rotation member that support the stretched member in a stretched manner. The first rotation member has a first rotation axis, and the second rotation member has a second rotation axis. The first rotation member includes a plurality of members arranged in an axial direction of the first rotation axis.

Abstract: A roller device includes a roller main body, a shaft member, flanges, a position restricting member, a plate-shaped member, a biasing member, and a securing member. The shaft member is inserted into the roller main body and the flanges in contact with both ends of the roller main body. The position restricting member is secured to the shaft member at an end portion side of the shaft member with respect to the flange. The position restricting member restricts an axial position of the flange. Movement of the plate-shaped member toward the end portion side in an axial direction is restricted by the position restricting member. The biasing member biases the flange toward a center side in the axial direction. The securing member is disposed at the end portion side of the shaft member with respect to the plate-shaped member. The securing member engages the position restricting member.

Abstract: A belt conveyance apparatus includes an endless belt and a plurality of rollers around which the belt is stretched, and receives an image on the endless belt at a predetermined image receiving surface in a conveyance direction of the belt. At least one of the plurality of rollers is a steering roller arranged on a downstream side of an image receiving position and capable of changing an arrangement angle thereof with respect to the belt by being tilted. If an area of the belt between the steering roller and the image receiving position in an opposite direction of the conveyance direction of the belt is assumed to be a predetermined area, a tilt axis of the steering roller is arranged on the predetermined area side of a rotational axis of the steering roller when viewing in the tilt axis direction.

Abstract: An intermediate transfer member, including: a layer containing a thermoplastic resin, an electroconductive resin, and electroconductive inorganic particles, wherein the layer has a sea-island structure where discontinuous phases formed from the electroconductive resin are present in a continuous phase formed from the thermoplastic resin, wherein in a cross-sectional surface of the layer perpendicular to a rotation direction of the intermediate transfer member, the discontinuous phases formed from the electroconductive resin each have a cross-sectional shape of an ellipse, and a minor axis b of the ellipse is from 0.5 ?m to 5.0 ?m, and wherein in the cross-sectional surface of the layer perpendicular to the rotation direction of the intermediate transfer member, a rate ? of a total area of the discontinuous phases formed from the electroconductive resin in an area of the cross-sectional surface thereof is from 2.0% to 20.0%.

Abstract: A conductive resin belt includes at least one amorphous polymer selected from a first group consisting of polyether imide and polyether sulfone, at least one crystalline polymer selected from a second group consisting of polyether ether ketone and polyphenylene sulfide, at least one reactive polymer selected from a third group consisting of a copolymer of ethylene and glycidyl methacrylate and a polymer including an oxazoline group, and a conductivity imparting material. Surface resistivity of the conductive resin belt at 500V is 106 ?/sq. Volume resistivity of the conductive resin belt at 100V is 106 ?·cm to 1014 ?·cm. A cross-section of the conductive resin belt includes a dispersion phase and a continuous phase. The reactive polymer exists at a concentration of 30% to 70% within 10 nm to 1 ?m of an interface between the dispersion phase and the continuous phase.

Abstract: The image forming apparatus is capable of changing a state between a first state in which only a first image bearing member and transfer belt contact each other, and a second state in which respective image bearing members are separated from the transfer belt. A second transfer member is located at a first separating portion at which the second transfer member is separated from the image bearing member in the first state, and is located at a second separating position closer to the second image bearing member than the first separating position in the second state to regulate the position of the transfer belt.

Abstract: An image forming apparatus, including: a contact-separation mechanism configured to change over from a fully separated position in which an intermediate transfer member is separated from a first and a second image bearing members to a partly contacted position in which the intermediate transfer member is separated from the first image bearing member in contact with the second image bearing member to a fully contacted position in which the intermediate transfer member is in contact with the first and the second image bearing members; and a control portion configured to rotationally drive the first image bearing member when the contact-separation mechanism passes through the fully contacted position in association with an image formation for forming a toner image by only the second image bearing member in the partly contacted position.

Abstract: Disclosed is an intermediate transfer member including, a resin layer as an outermost layer, in which plural recessed portions having a curved inner wall are scattered on the surface thereof.

Abstract: In a constitution provided with no primary-transfer roller, in order to ensure a contact length between each of photosensitive drums and an intermediary transfer belt, the photosensitive drums are disposed in entering amounts at a plurality of levels with respect to a stretching surface of the intermediary transfer belt, and therefore an apparatus is upsized in a height direction. In order to avoid this, four image bearing members are arranged, along the intermediary transfer belt, in the same entering amount with respect to the stretching surface of the intermediary transfer belt, and a depressing member for depressing a belt surface between two central image bearing members toward an outside is provided.

Abstract: An image forming apparatus includes an image bearing member unit including a toner image carrying member, a transfer unit including a movable endless belt for transferring the toner image from the carrying member onto a transfer material, a plurality of stretching members for stretching the endless belt, and a supporting portion, provided at an end portion with respect to a widthwise direction, for supporting the stretching members. In addition, a main assembly frame is provided at a position opposing the supporting portion and includes a positioning portion for determining positions of the plurality of stretching members, wherein the supporting portion is movable relative to the main assembly frame.

Abstract: An image forming apparatus includes an image carrier, a transfer unit to transfer the image onto a recording medium, a torque limit unit to transmit drive force to the transfer unit at a torque less than the torque for transmitting drive force, and drive the transfer unit to rotate at a circumferential velocity higher than that of the image carrier when the image carrier and the transfer unit are in contact with each other, and a drive unit to output drive force to drive the transfer unit such that the transfer unit rotates at a circumferential velocity lower than that of the image carrier when the image carrier and the transfer unit are separate from each other, and the transfer unit rotates at a circumferential velocity higher than that of the image carrier when the image carrier and the transfer unit are in contact with each other.

Abstract: A rotation shaft coupling structure includes a roller drive shaft including a recessed portion having an internal thread; a rotation roller including a coupling member housing the recessed portion of the roller drive shaft; and a coupling shaft extending through the rotation roller in the axial direction. The coupling shaft includes a threaded portion at a first end portion thereof, the threaded portion mating with the internal thread of the recessed portion, and the coupling shaft couples the roller drive shaft and the rotation roller to each other. The first end portion of the coupling shaft in the axial direction is joined to the roller drive shaft and the rotation roller in the coupling member of the rotation roller, and a second end portion of the coupling shaft in the axial direction is a free end that allows the coupling shaft to extend and contract in the axial direction.

Abstract: In an image forming apparatus, one of a plurality of support members supporting an intermediate transfer belt is a guide member configured to regulate the rotational direction of the intermediate transfer belt while being held in sliding contact with the intermediate transfer belt at a position opposite the secondary transfer member across the intermediate transfer belt. This guide member is equipped with a first resistor portion in sliding contact with the intermediate transfer belt and a second resistor portion of a higher electrical resistance than the first resistor portion, with the second resistor portion provided upstream of the first resistor portion in the rotational direction of the intermediate transfer belt.

Abstract: An image forming apparatus may include a first and second mode. In the first mode, the image forming apparatus uses a second charging member to charge toner that remains on an intermediate transfer member and then transfers the charged, remaining toner to an image carrier in a primary transfer portion. In the second mode, the image forming apparatus transfers the remaining toner adhered to the second charging member in the first mode to the intermediate transfer member. Also in a second mode, the image forming apparatus controls so that a surface potential of the image carrier that reaches the primary transfer portion at a timing at which the remaining toner transferred to the intermediate transfer member passes through the primary transfer portion has a same polarity as that of a surface potential of the image carrier in the first mode and also has an absolute value smaller than that thereof.

Abstract: A belt feeding apparatus has a rotatable belt, first and second belt stretching members, and a steering unit which has a rotatable portion rotatable with rotation of the belt, a frictional portion, and a supporting portion for supporting the rotatable portion. The frictional portion is provided with an inclined surface so that the distance between the rotational axis of the rotatable portion and the surface of the frictional portion increases toward an outside with respect to the direction of a rotational axis of the rotatable portion, and a length of the belt member with respect to the rotational axis direction of the rotatable portion is longer than a length of the rotatable portion and is shorter than a sum of the lengths of the rotatable portion and the frictional portions provided at respective ends, and the belt member contacts both of the frictional portions simultaneously.

Abstract: An image forming apparatus includes a primary transfer device to transfer a toner image formed on a photosensitive member onto an intermediate transfer member formed into a loop, a secondary transfer device disposed outside the looped belt to contact the intermediate transfer member to form a secondary transfer nip therebetween and transfer the toner image from the intermediate transfer member onto a recording medium, a first power supply to apply a constant-current controlled direct current bias to an inner circumferential side of the intermediate transfer member, and a second power supply to form an alternating electric field between the intermediate transfer member and the recording medium. The direct current bias has the same polarity as that of the toner image. The first power supply and the second power supply apply predetermined biases simultaneously when the recording medium is in the secondary transfer nip to transfer the toner image thereon.

Abstract: An image forming apparatus that transfers a developer image onto a sheet and forms the developer image on the sheet includes a developer image carrier, a first pressing member, a transfer member, a first voltage supply, and an adherence part. The developer image carrier holds the developer image and moves in a predetermined direction in which the sheet is being carried. The first pressing member presses against the developer image carrier from a side opposite to a side on which a developer image is held. The transfer member is arranged against the first pressing member through the developer image carrier, the first pressing member and the transfer member being responsive to a first voltage applied therebetween to transfer the developer image from the developer image carrier toward the transfer member. The adherence part adheres the sheet to the developer image carrier upstream the first pressing member in the predetermined direction.

Abstract: An endless belt is held by a first roller and a second roller each having an axis extending in an axial direction. A transfer member is disposed opposite to an image supporting member with the belt therebetween. The transfer member is configured to transfer a developer image supported by the image supporting member to a sheet conveyed by the belt. The image supporting member extends in the axial direction. The belt and the transfer member each have a width in a direction parallel to the axial direction. A first portion of the image supporting member and a first portion of the transfer member directly oppose each other without the belt therebetween. A second portion of the image supporting member opposes a first surface of the belt, and a second portion of the transfer member opposes a second surface of the belt, which is opposite to the first surface.

Abstract: An intermediate transferer includes a polyvinylidene fluoride resin including polyvinylidene fluoride and a vinylidene fluoride-hexafluoropropylene copolymer, a conductive agent and an additive. The additive includes a polymer including a polyalkyleneoxide structure having a number-average molecular weight not less than 1,000. The polyvinylidene fluoride resin includes the vinylidene fluoride-hexafluoropropylene copolymer in an amount of from 5 to 30 parts by weight per 100 parts by weight of the polyvinylidene fluoride. The intermediate transferer includes the conductive agent in an amount of from 1.0 to 20 parts by weight and the additive in an amount of from 1.0 to 10 parts by weight per 100 parts by weight of the polyvinylidene fluoride resin.

Abstract: A cast-in reflective timing patch for a belt such as an intermediate transfer belt of a printing device. The timing patch is formed during manufacturing of the belt. As such, the presence, quality, location, and alignment of the timing patch is fixed and inspection and monitoring of the timing patch is no longer required.

Abstract: To provide a belt for an image forming apparatus, which contains: a base layer; an elastic layer; and spherical particles, wherein the belt for an image forming apparatus is provided across a plurality of rollers of the image forming apparatus to rotate, wherein the belt for an image forming apparatus has a laminate structure where at least the base layer and the elastic layer are provided in this order, wherein the spherical particles are partially embedded in an exposed surface of the elastic layer, and wherein, relative to a width direction of the belt for an image forming apparatus, a thickness of an edge portion of the belt for an image forming apparatus is 50% to 95% of a thickness of a center portion of the belt for an image forming apparatus, and an edge curling amount of the belt is 4 mm or less.

Abstract: Flexible members for use in imaging devices contain a non-ionic surfactant and a fluorinated surfactant.

Abstract: A belt drive device for an image forming apparatus includes a belt, a roller, a roller drive member, a state detector and a controller. The roller drive member drives the roller that entrains the belt. The state detector detects a state of the belt. The controller identifies a specific portion of the belt based on the state detected by the state detector, and controls the roller drive member to stop the belt so that the specific portion lies at a predetermined position.

Abstract: A belt assembly is disclosed. The belt assembly comprises an incompatible-polymer alloy including at least one crystalline resin which is selected from polyphenylene sulfide, polyetheretherketone, and polyvinylidene difluoride and at least one amorphous resin which is selected from polyethersulfone and polycarbonate, polyphenyleneether, polysulfone, and polyarylate. Wherein the weight ratio between the crystalline resin and the amorphous resin is from 70:30 to 95:5, carbon as a first conductive agent is distributed unevenly only in a successive layer, at least a second conductive agent which is selected from ZnO particles, SnO2 particles. Sb-doped SnO2 particles, In-doped SnO2 particles, P-doped SnO2 particles and metal-oxide particles covered by one of these particles is distributed unevenly only in the successive layer, and a flame-resistance value of the belt is VTM-0 under a condition that a thickness thereof is from 50 [?m] to 150 [?m] at a UL 94 standard.

Abstract: An image-forming apparatus includes: a plurality of image bearing members for carrying toner images; an intermediate transfer member that is capable of rotating endlessly and possesses conductivity; a current supply member that contacts an outer peripheral surface of the intermediate transfer member; a power supply that applies a voltage to the current supply member; a contact member disposed in a position corresponding to at least one of the image bearing members via the intermediate transfer member so as to contact an inner peripheral surface of the intermediate transfer member; an opposing member that opposes the current supply member via the intermediate transfer member; a constant voltage element connected to the opposing member and the contact member; and a resistance element electrically connected between the constant voltage element and the contact member.

Abstract: A transfer device includes a plurality of primary transfer rollers, a second link member and a regulatory member. The regulatory member restrains the second link member from moving further than a predetermined position toward the second direction. The second link member causes the primary transfer rollers to be displaced as it moves. The second link member is split into a plurality of link arms of which overall length is variable within a predetermined range; and its joint portion includes an elastic member urging the plurality of link arms toward a direction to which the overall length gets longer in a state where the second link member is most separate from a cam shaft, and a first locking section and a second locking section engaging the plurality of link arms with one another for the overall length not to get longer beyond a maximum value.

Abstract: An intermediate transfer member that includes a terpene polycarbonate, an optional polysiloxane, and an optional conductive filler component.

Abstract: An image forming apparatus includes image carriers that carry toner images; an intermediate transfer body that is brought into contact with the image carriers to carry the images before transferring them to a recording material; first transfer devices that include first transfer members and form first-transfer electric fields for transferring the images on the image carriers to the intermediate transfer body; a second transfer device that includes a second transfer member and forms a second-transfer electric field for transferring the images transferred to the intermediate transfer body to the recording material; and an adjusting device that adjusts an electric field to be formed in a second transfer area to a cleaning electric field, which is of the same polarity as and a lower intensity than the second-transfer electric field, when the images on the intermediate transfer body passes through the second transfer area without a recording material passing therethrough.

Abstract: An electrophotographic member which has resistance to discharge degradation and can maintain the toner releasability for a long period is provided. The electrophotographic member includes a substrate and a surface layer. The surface layer includes a binder resin having an acrylic skeleton and a modified silicone compound having a polyether group and a hydroxyl group in a molecule, the surface layer having a surface having a n-hexadecane contact angle of 30° or more.

Abstract: A belt driving device for driving an endless belt includes rollers configured to stretch the belt, the rollers including first and second steering rollers being provided in an upstream side and a downstream side of an image receiving surface of the belt for receiving a image, respectively, and being configured to change a position of the belt in a direction crossing with a moving direction of the belt by inclining respectively; a pivoting unit configured to pivot the first and second steering rollers, respectively; a detecting unit for detecting an inclination amount of the belt with respect to a feeding direction of the belt; and a controller configured to pivot the first and second steering rollers in the same direction by the pivoting unit on the basis of a result of detection of the detecting unit.

Abstract: A developer contains a toner having an external additive deposited thereon. The developer is used with an image-forming apparatus including an image carrier including a surface layer in which fluoropolymer resin particles are dispersed and a cleaning member disposed in contact with an outer surface of the image carrier. The external additive is a nonspherical external additive whose volume average particle size is smaller than the average particle size of exposed portions of the fluoropolymer resin particles in the surface layer of the image carrier.

Abstract: A paper conveying device includes an intermediate transfer member and a paper conveying member driven so as to rotate at the same rotational speed, and an adjusting device. On an outer peripheral surface of the intermediate transfer member, an elastic layer is provided. An axes distance between the intermediate transfer member and the paper conveying member is adjusted by the adjusting device so that drive torque for rotating the intermediate transfer member and the paper conveying member at the same rotational speed becomes smaller than a target set value. Accordingly, occurrence of the shear is suppressed without changing a rotational speed ratio of rollers arranged opposite to each other.

Abstract: A system and apparatus are provided for adhering steering ribs to an intermediate transfer belt (ITB). These steering ribs (one or more) are applied to the ITB by placing the rib material around a cylindrical fixture. The rib material is held in place by a vacuum that is applied to the rib material to hold it against the fixture. An ITB may be separately held in place on the fixture by another vacuum until the rib material is adhered to the inside surface of the ITB through application of compressed air to force the rib material outward against the ITB. Once the rib material is adhered to the ITB, a series of apertures directs compressed air against the rib and the ITB to release them from the fixture.

Abstract: It has been difficult to ensure satisfactory secondary transfer performance while ensuring satisfactory primary transfer performance by passing a current in the circumferential direction of an intermediate transfer belt from a current supply member. To satisfy a relationship of Rv>Rs, where Rv is resistance in the thickness direction of an intermediate transfer belt and Rs is resistance in the circumferential direction of the intermediate transfer belt over the distance between an image carrier located most upstream and an image carrier located most downstream in the movement direction of the intermediate transfer belt.

Abstract: An image forming apparatus including a conveyance unit to convey a transfer medium, a first image forming unit to form a monochrome image transferred at a first transfer position onto the transfer medium, and a second image forming unit disposed downstream from the first image forming unit in a direction of conveyance of the transfer medium, including an intermediate transfer body to form a multi-colored toner image on the intermediate transfer body. The multi-colored toner image is transferred onto the transfer medium at a second transfer position. The conveyance unit is separated from the intermediate transfer body at the second transfer position in a monochrome mode to form the monochrome image using only the first image forming unit, and contacts the intermediate transfer body at the second transfer position in a full-color mode to form a full-color image using both the first and second image forming units.

Abstract: An intermediate transfer belt that temporarily holds a toner image which is formed on an image carrier and transferred to the intermediate transfer belt includes a base member, an elastic layer laminated on the base member and a surface layer covering the elastic layer. With respect to the intermediate transfer belt, a volume resistivity of the surface layer is lower than a volume resistivity of an entirety of the intermediate transfer belt.

Abstract: Disclosed herein is an image forming apparatus that has a developing unit, an intermediate transfer body, and a transfer roller and may prevent contamination of the transfer roller and a printing medium by the toner remaining in a test pattern forming area of the intermediate transfer body. The image forming apparatus includes a developing unit to allow an image to be formed by a developing agent, an intermediate transfer body provided with an image forming area and a test pattern forming area, the image being transferred from the developing unit to the image forming area and the test pattern forming area, and a transfer roller allowing the image to be transferred from the image forming area to a printing medium, wherein a maximum transfer length of the transfer roller is less than a maximum image forming length of the developing unit.