Abstract: The invention relates to a system for replacement of sleeves (6, 6a) (6, 6a) that can be slipped on arbors (5, 5a) of ink transfer rollers (4) of at least one printing machine (1), with a storage device, in which the sleeves (6, 6a) (6, 6a), which are not used in the current ink transfer, can be stored, and/or with transport devices (8, 9), with which several sleeves (6, 6a) (6, 6a) can be transported to the printing machine (1). The inventive step lies in the means for the transfer of the sleeves (10-19, 21), with which the sleeves (6, 6a) can be transported between the storage device and/or the transport devices (8,9) and the arbors (5, 5a) of the ink transfer rollers (4) in at least one printing machine (1) and/or between the storage device and the transport devices (8, 9).

Abstract: A rotary drive device includes a motor including a rotary shaft, a planetary gear mechanism, and a rotation position detector. The planetary gear mechanism decelerates a rotation output of the motor at a reference reduction ratio and includes an outer gear, multistage gears, and an output shaft. The outer gear is fixed to a housing of the motor. The multistage gears are provided inside the outer gear. The output shaft transmits the decelerated rotation output of the motor to an outside of the rotary drive device. The rotation position detector detects a rotation position of the output shaft to control rotation of the motor. The motor, the planetary gear mechanism, and the rotation position detector are combined into a single integrated unit and aligned in an axial direction of the rotary shaft of the motor.

Abstract: An image forming apparatus includes: an image carrier that holds a toner image; an intermediate transfer body to which the toner image carried on the image carrier is transferred; an applicator that applies a protective agent which blocks cracks in the surface of the intermediate transfer body to the intermediate transfer body; and a controller that changes, in accordance with the degree of damage to the surface of the intermediate transfer body, the amount of the protective agent to be applied by the applicator to the surface of the intermediate transfer body.

Abstract: A transfer belt composed of a single layer or a plurality of layers is disclosed in which the single layer or the outermost layer of the layers constituting the transfer belt is a layer formed from a polymer composition. The polymer composition contains particles having an average particle diameter of 20 nm or less and a refractive index of 2.3 or more with respect to light of 800 nm in wavelength. The transfer belt has a surface roughness having a maximum height Rz of 0.3 ?m or less according to JIS B 0601, 2001.

Abstract: In a method for evaluating a fixing member to fix a toner having a surface layer, a hardness test is carried out by applying a pressure deformation from the surface side of the fixing member, and when a deformation of the surface layer by the pressure deformation is within an elastic range, the fixing member is regarded as a standard product.

Abstract: A printing system is provided that includes one or more printing modules, the one or more printing modules including a media web transport input; a media web image transfer point; a media web transport output; a primary image transfer system; a secondary image transfer system; and an intermediate image transfer point coupling the primary image transfer system and a secondary image transfer system. The secondary image transfer system is adapted to accept an image from the primary image transfer system at the intermediate image transfer point, and the secondary image transfer system is adapted to transfer the image from the secondary image transfer system to a media web at the media transfer point. The media web transport input and media web transport output provide a media web path to route the media web from the media web transport input to the media web transfer-point, and from the media web transfer point to the media web transport output.

Abstract: Transfer component monitoring methods, image forming devices, data signals, and articles of manufacture are described. According to one aspect, a transfer component monitoring method includes counting a plurality of imaging operations performed by an image forming device to form a plurality of hard images and adjusting a result of the counting to determine wear of a transfer component of the image forming device, wherein the transfer component is configured to assist with a transfer of a developing material to form the hard images.

Abstract: An image-forming apparatus includes an image-bearing member supporting a toner image; a transfer roller that rotates in contact with the image-bearing member so as to transfer the toner image to a recording material; first and second cleaning rollers, each having a brush provided on a circumferential surface thereof so as to electrostatically recover toner deposited on the transfer roller while rotating in contact therewith; a recovery roller that rotates in contact with the first and second cleaning rollers to electrostatically recover the toner therefrom; and a blade-like removing member that comes in contact with the recovery roller so as to remove the toner therefrom.

Abstract: An image forming apparatus comprises an exposure unit forming an electrostatic latent image on a photoconductor based on image information, a developing unit developing the electrostatic latent image by toner made of formation material of a circuitry layer, and an electrostatic transferring unit transferring a toner image on the photoconductor onto a substrate. The toner image is transferred so as to cover at least a part of a conductor layer formed on the substrate. At this time, excessive charges caused in the conductor layer accompanying the start of the transfer of the toner image are removed. Alternatively, charges of which polarity is reverse to that of the toner are added to the conductor layer. These allow the circuitry layer to be formed to have a desired pattern favorably and securely on the conductor layer.

Abstract: An image forming apparatus includes a belt-shaped image carrier that carries an image, an image transfer unit that transfers the image onto a recording medium, and a conveying unit that conveys the recording medium to the image transfer unit. The image carrier has a sloping surface that slopes down from upstream of the image transfer unit in a conveying direction. The conveying unit includes a linear conveying path that is arranged upstream of the image transfer unit in the conveying direction, below the sloping surface and above a horizontal line passing through the image transfer unit.

Abstract: What is disclosed is a system and method for minimizing the Inter-Document Zone (IDZ) in printing system architectures with print engines running at constant speed. The asymmetric IDZ precession disclosed herein is intended for those multi-pass systems where there is a difference in required start and stop durations of various transition subsystems such as transfer engagement and disengagement processes. This mode reduces the required inter-document zone region by shifting the zone in accordance with asymmetric timing of start and stop times of processes that must occur during this time. Advantageously, productivity gains are effectuated without altering process speeds.

Abstract: A control unit controls a drive signal for determining a voltage to be supplied to the motor. A drive unit drives the motor by applying a current corresponding to the voltage determined based on the drive signal to the motor. The control unit includes a velocity detecting unit that detects a rotation velocity of the motor and an output unit that outputs the drive signal corresponding to a voltage with which a current lower than a predetermined current limit is applied to the motor, based on the rotation velocity of the motor detected by the velocity detecting unit.

Abstract: An apparatus and method for cleaning a transfer roller of a wet-type image forming apparatus are provided. The method includes applying a measured voltage to the transfer roller; measuring a resistance among a transfer backup roller, an intermediate transfer medium, and the transfer roller based on the applied measured voltage; calculating a density of a toner of a developer on the transfer roller based on the measured resistance; and if the density of the toner is more than or equal to a predetermined reference value, supplying a carrier or applying the cleaning voltage. Thus, the cleaning voltage can be adjusted depending on the density of the toner of the developer on the transfer roller so as to maintain appropriate cleaning efficiency. If the density of the toner is greater than or equal to the predetermined reference value, the carrier can be supplied so as to improve the cleaning efficiency.

Abstract: A transfer unit of an image forming apparatus includes a belt to receive an image developed on a photosensitive medium while rotating in a regular cycle and in contact with an outer circumference of at least one photosensitive medium. A blade arm, which is installed adjacent to the belt, moves to a first position to position a cleaning blade, which is supported by the blade arm, to be in contact with the belt. The cleaning blade is coupled to a pressure unit to bias the cleaning blade towards the belt.

Abstract: An electrophotographic endless belt containing a polyamide resin, carbon black and a filler, characterized in that the polyamide resin is at least one resin selected from the group consisting of polyamide 610, polyamide 612, polyamide 11 and polyamide 12, the filler is at least one filler selected from the group consisting of an oxide, a hydroxide, a carbonate and a silicate, and weight (A) of the polyamide resin and total weight (B) of the carbon black and the filler is in a ratio (A:B) of from 90:10 to 50:50. Also disclosed are an electrophotographic apparatus having the electrophotographic endless belt, and a process for producing the electrophotographic endless belt.

Abstract: A process of MICR and non-MICR electrostatic magnetic imaging of two independent electrostatic latent images including a) optionally pre-treating a blank check with a wax-based coating comprising an aqueous polyethylene wax emulsion; (b) forming a first electrostatic latent image in a MICR printing apparatus; (c) developing the first electrostatic latent image by contacting the first electrostatic latent image with a MICR toner to produce a developed MICR toner image; (d) transferring and optionally fusing the developed MICR toner image onto a check; (e) forming a second electrostatic latent image in a non-MICR printing apparatus; (f) developing the second electrostatic latent image by contacting the second electrostatic latent image with a non-MICR toner to produce a developed non-MICR image; (g) transferring the developed non-MICR toner image to the check; (h) fusing the developed MICR toner image and the developed non-MICR toner image to the check, wherein a fuser oil is supplied to the check during fusing

Abstract: The present application is directed to cleaner units and methods for removing waste toner from a transfer member within an image forming device. The device may include a blade that is positioned against the transfer member to remove the waste toner. The blade directs the waste toner into a cleaner house where the waste toner is removed. The cleaner unit is positioned within the image forming device to prevent contact with the media sheets moving along the media path. The cleaner unit may also be positioned to utilize existing elements to facilitate the removal of the waste toner from the transfer member.

Abstract: An image forming apparatus for performing a printing job using an intermediate transfer belt is provided. The image forming apparatus has a voltage determination part for determining a predetermined level of a refresh charge corresponding to a potential difference which is generated on opposite surfaces of the intermediate transfer belt, and a power supply for supplying the refresh charge to the intermediate transfer belt so that the potential difference is offset. The power supply supplies the refresh charge to the intermediate transfer belt through a certain roller which is in contact with the intermediate transfer belt. Accordingly, the potential difference caused by the polarization in the intermediate transfer belt is offset by the refresh charge, and the variation of the resistance caused by the potential difference is prevented.

Abstract: In an electrophotographic conductive member composed of at least a thermoplastic resin composition, the thermoplastic resin composition contains a thermoplastic resin, a conductive filler and a conductive-filler dispersing agent, and the conductive-filler dispersing agent is a polyhydric alcohol type nonionic surface-active agent.

Abstract: An enhanced or optimized cast-coated paper for enhancing or improving toner adhesion, and a method for forming an image on the enhanced or optimized cast-coated paper, includes a paper sheet with a coating solution on at least one surface of the paper sheet, the cast-coated paper having at least: a thermal diffusivity of less than approximately 9.0 mm2/s and total surface free energy component of less than 38 erg/cm2. Printing the cast-coated paper in an electrophotographic apparatus includes forming an image with an electrophotographic toner in the electrophotographic apparatus and transferring the image to the cast-coated paper having the thermal diffusivity of less than approximately 9.0 mm2/s and the total surface free energy component of less than 38 erg/cm2. The cast-coated paper may be used in apparatuses utilizing an electrophotographic process, such as a copying machine, a printer, a facsimile machine, a color-copying machine, and the like.

Abstract: An image forming apparatus may include: a photoreceptor and a corona charging device or bias transfer roller that provides a charge to an image receiving medium. A cover may be disposed over a portion of the corona charging device or the bias transfer roller to shield the photoreceptor from exposure to the charge from the corona charging device when image receiving medium is charged and in contact with the photoreceptor.

Abstract: An image forming device including a cleaning member that is made of an elastic material and cleans the surface of the image carrier by contacting with the surface. The drive unit rotates the image carrier in a reverse direction while the cleaning member is contacting with the surface of the image carrier, before the image carrier is rotated in a positive direction for an image formation. The control unit controls the rotation of the image carrier in the reverse direction, in accordance with information indicating a size of a frictional force generated between the cleaning member and the image carrier being rotated.

Abstract: To provide an image forming apparatus, image forming method and process cartridge, which are excellent in low-temperature fixation properties, storage stability, durability and filming resistance, can reduce generation of odor, and are capable of forming an extremely high quality image. The apparatus includes: a latent electrostatic image bearing member; a charging unit; an exposing unit; a developing unit; a transferring unit; and a fixing unit; wherein the toner comprises a binder resin and coloring agent, and the binder resin comprises a polyester-based resin (A) and polyester-based resin (B) having a melting point at least 10° C. higher than that of the polyester-based resin (A), and at least one of the polyester-based resins (A) and (B) is a resin derived from a (meth)acrylic acid modified rosin and includes a polyester unit obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing a (meth)acrylic acid modified rosin.

Abstract: A cleaning system includes a rotating member and a cleaning blade which is forced against a curved outer surface of the rotating member to scrape off matter to be removed (toner) which is present along the outer surface of the rotating member. The cleaning blade has greater hardness than the outer surface of the rotating member.

Abstract: A felt that cleans the surface of a drive roller or secondary transfer supporting roller that stretches an intermediate transfer belt is supported by a Mylar at its one free end, the other end thereof being fixed to a bracket. The felt is swingably brought into contact with the drive roller or secondary transfer supporting roller by an elastic force of the Mylar.

Abstract: An image forming apparatus includes at least two image bearing members, a transferring unit that makes a physical contact with both the image bearing members, and a lubricant applying unit that applies lubricant on the surface of the image bearing members. Images can be selectively formed on any one of the image bearing member. Although an image is being formed on one image bearing member, the transferring is made to come in physical contact with the other image bearing member.

Abstract: The image forming apparatus of this invention comprises: an image bearing member which bears a toner image; a toner image forming means which forms a plurality of the toner images on the image bearing member continuously; a transfer means which transfers the toner image on the image bearing member to a recording material; a cleaning web which wipes off toner remaining on the image bearing member after the toner image is transferred to the recording material; and a separating unit which separates the image bearing member cleaning member from the image bearing member when the toner image forming means is forming a plurality of the toner images on the image bearing member continuously.

Abstract: A cleaning device is used in an image forming apparatus to remove residual attachments including toner and paper powders from a surface of a movable intermediate transfer element onto which toner images are transferred from an image carrier. The cleaning device includes a cleaning brush that contacts the surface of the intermediate transfer element to apply a bias having a predetermined polarity to the toner adhered onto the surface of the intermediate transfer element so as to make uniform a polarity of the toner. The cleaning device further includes a pressing member that contacts the surface of the intermediate transfer element with a predetermined pressure. The pressing member is disposed at a position upstream of the cleaning brush in a direction of movement of the intermediate transfer element.

Abstract: A photosensitive drum 18 is provided to carry electrostatic latent images. Developers 23K through 23Y supply toner to the electrostatic latent images formed on the photosensitive drum 18. Images formed on the photosensitive drum 18 are transferred to an intermediate transfer belt 12. A primary transfer roller 16 transfers toner images formed on the photosensitive drum 18 onto the intermediate transfer belt 12. The secondary transfer roller 7 transfers toner images on the intermediate transfer belt 12 onto sheets. The belt cleaning unit 17 has a fur brush 32 that electrically recovers toner, and recovers residual transfer toner remaining on the intermediate transfer belt 12 after a secondary transfer by the secondary transfer roller 7. The drive roller 13 is disposed in a position in opposition to the fur brush 32 sandwiching the intermediate transfer belt 12, and charges both the fur brush 32 and the secondary transfer roller 7.

Abstract: A laser printer includes a photoreceptor drum, a transfer roller contacting the photoreceptor drum, a transfer roller frame holding the transfer roller, an outer frame holding the transfer roller frame, a diselectrification brush fixed to the transfer roller frame, and a spring at least having a surface formed of conductive material for biasing the transfer roller toward the photoreceptor drum. The spring is formed of a single member and has a first extension contacting the diselectrification brush and a second extension contacting the outer frame.

Abstract: An image forming apparatus that can prevent a transfer belt from being polluted by used developer on a belt cleaning member is disclosed. The apparatus includes at least one photoconductor on which a developer image is formed, a transfer belt, a belt cleaning member, and a first pollution control unit. The transfer belt transfers the developer image formed on the photoconductor to an image receiving medium, and the transfer belt is rotatably supported by a driving roller and a driven roller. The belt cleaning member cleans used developer remaining on the transfer belt after the developer image is transferred. The belt cleaning member is able to move into contact with the transfer belt or be separated from the transfer belt.

Abstract: A transfer belt on which a developed toner image is transferred in an electrophotographic process, comprising: a matrix resin; and a chain silicone, contained in the range from 0.5 to 10% by weight to the matrix resin, and an image-forming apparatus provided therewith.

Abstract: Disclosed is a fluoroelastomer loaded with an inorganic filler which is coupled to the fluoroelastomer by a titanate, zirconate or aluminate for use as a base layer and/or a release layer on a fuser, transfix, receiver or rheological transfer member in a copy machine. The coupled filler bonds tightly to the fluorocarbon matrix, significantly decreasing the wear rate of the member. These fillers also significantly increase the thermal conductivity of the compound as is often desirable in fusing applications.

Abstract: In an electrophotographic belt member comprising a resin composition, the resin composition contains from 30% by weight to 90% by weight of a thermoplastic resin, from 2% by weight to 30% by weight of a compound selected from the group consisting of a polyether-ester amide, a polyether ester and a polyether amide, from 0% by weight to 5% by weight of an electrolyte, and from 2% by weight to 50% by weight of an insulating filler. Also disclosed are a process for producing the electrophotographic belt member, and an electrophotographic apparatus having the electrophotographic belt member.

Abstract: A color image forming apparatus is described, which makes highly durable image transferring possible.

Abstract: The present invention provides an electrophotographic lamination film which can be easily laminated by using the film as it is without significantly modifying a conventional electrophotographic device, can be printed with letters of high resolution directly on a surface of the film capable of softening at relatively low temperatures, and can form an image of high quality having sufficient heat resistance and light resistance with good recognizability even in outdoor use, as well as a method of producing the same and a method of forming an image. In the electrophotographic lamination film, a surface resistance of at least one surface of a substrate thereof is in a range of 108 to 1013 ?/?, and a Vicat softening temperature of the substrate is in a range of 70 to 130° C.

Abstract: In an electrophotographic endless belt having a resin layer formed of a resin composition containing a polyamide, the resin composition further contains a copolymer obtained by copolymerization of an olefin and an oxygen-containing heterocyclic compound, a curve (T-log10 ? curve) showing the relationship between temperature T (° C.) and common logarithm log10 ? of melt viscosity ? (Pa·s), of the resin composition has, in the range of log10 ? of from log10 1,000 to log10 8,000, a gently inclined region the inclination ? log10 ?/?T of which is from ?0.02 to 0, and the gently inclined region has a temperature range of 10° C. or more, and the resin layer has a thickness the maximum thickness of which is 115% or less of the average value of the thickness of the resin layer and the minimum thickness of which is 85% or more of the average value of the thickness of the resin layer. Also disclosed is a process for producing the above electrophotographic endless belt.

Abstract: An image forming apparatus including an intermediate transfer device capable of making a change in a degree of expansion and contraction of an intermediate transfer belt slow is provided. A position and a moving range of a cleaning roll are set in order to make a rear surface contact position on a rear surface of the intermediate transfer belt relative to the contact position where the cleaning roll comes in contact with the intermediate transfer belt, away from a cleaning backup roll while an intermediate transfer belt cleaner rocks and moves to a contact position of the cleaner. Because of the intermediate transfer belt being not sandwiched between the cleaning and backup rolls, the change in the degree of expansion and contraction of the intermediate transfer belt is made slow, and the intermediate transfer belt is kept to have the degree of expansion and contraction within a predetermined range.

Abstract: In an image forming apparatus, a toner image is formed on a photosensitive element and a transfer roller, which carries a transfer medium, is pressed against a photosensitive element at a pressure of from 20.4 N/cm2 to 200 N/cm2.

Abstract: A rotating cleaning brush positioned to clean toner and debris from the back of an imaging belt. Additionally, a plurality of cleaning brushes assembled to clean the back of the imaging belt wherein charging a first and a second brush to approximately equal potential but opposite polarity provides superior discharge of static and other electrical charges from the back of the imaging belt.

Abstract: Provided are photosensitive body or bodies 31b carrying toner; transfer roller(s) 31d, rotating and coming in contact with photosensitive body or bodies 31b, for causing toner image(s) formed on photosensitive body or bodies 31b to be electrostatically relocated onto paper 5; and paper transport means disposed upstream in transport direction(s) from transfer roller(s) 31d and comprising drive roller(s) 36d1 and idler roller(s) 36d2 holding lead edge portion(s) 5a of paper 5 in nip(s) formed therebetween and rotating so as to cause transport of same; drive roller(s) 36d1 and idler roller(s) 36d2 being disposed to the side, on which photosensitive body or bodies 31b is or are present, of a plane L more or less tangent to nip(s) formed between photosensitive body or bodies 31b and transfer roller(s) 31d; and direction(s) R of transport of paper from drive roller(s) 36d1 and idler roller(s) 36d2 being disposed so as to be directed toward transfer roller(s) 31d.

Abstract: The present invention relates to an image forming apparatus comprising: an image bearing member; toner image forming means for forming a plurality of toner images on the image bearing member; primary transfer means for superimposing the plurality of toner images on the image bearing member on one another in succession to primary transfer the same to a moving intermediate transfer belt in a primary transfer region; a driving source for moving the intermediate transfer belt through a driving transmitting member with respect to a driving roller which supports the intermediate transfer belt and which moves the intermediate transfer belt; a secondary transfer means for collectively secondary transferring the toner images on the intermediate transfer belt to a recording material; removing means which can abut against and separate from the intermediate transfer belt in a approaching and separating region on the intermediate transfer member and which removes toner on the intermediate transfer belt; and locus varying

Abstract: A belt driver includes a belt having a constant number of regions dividing the belt in the perimeter direction thereof. A plurality of marks have different widths in the perimeter direction and are formed in the respective regions of the belt. A sensor detects the marks on the belt. A storage part stores in advance the relationship between position information of the belt and speed variation of the belt for one rotation of the belt. Speed variation of the belt is reduced by correcting the drive speed of the belt based on the relationship. The position of the belt is detected from a time required for one of the marks to pass the sensor, and speed correction control of the belt is performed in accordance with the detected position.

Abstract: An image forming apparatus comprising a plurality of image forming units, an intermediate transfer member, and an intermediate transfer member cleaning device to remove toner remaining the intermediate transfer member with plural cleaning blades, wherein each color toner used in the developing device of the plurality of image forming units contains 10 number % or less of toner particles whose diameter is (0.7×50% number particles diameter (Dp50)) or less and contains 300 ppm or less of a remaining monomers is disclosed.

Abstract: An electrophotographic printing device with a developer unit and a photoconductor. The photoconductor is either directly connected to a substrate to be printed in the region of a transfer zone, or is connected by an intermediate circuit of one or several transfer media. At least one charger is provided for the substrate and the substrate may be transported through the transfer zone by a transport device. According to this invention, an effective transfer of toner to the substrate surface can be achieved with such an arrangement, even with a poor electrically-conducting and thick-walled, sheet-like substrate, whereby a charger is arranged as the primary charger in the transport direction and a secondary charger is arranged in the region after the transfer zone and both primary and secondary chargers affect the surface of the substrate to be printed.

Abstract: Image transfer method and apparatus in which scratches due to entrainment of particles on an image carrier for a toner image having maximum spectroreflectivity at a wavelength of 550 nm do not produce perceptible flaws in resulting images transferred to a recording medium, since images formed with toner of maximum spectroreflectivity at 550 nm on white recording medium are difficult for human eyes to discern. When cleaning residual toner from transfer belts, reverse bias voltage is applied to at least one transfer roller, the peripheral velocity of the photosensitive drum on which a yellow toner image having maximum spectroreflectivity at 550 nm is formed is allowed to differ from the transfer velocity of the transfer belt, and at least the photosensitive drum on which the yellow toner image of maximum spectroreflectivity at 550 nm is formed is detached from the transfer belt.

Abstract: An electrophotographic printing device including a toner-developer unit, a lighting device, a developer drum, a photoconductor, a transfer unit and an earthed charging device. The substrate to be printed is placed on a transport device and moved along the transfer unit and the toner image of the transfer unit is transmitted to the substrate. A clear, sharp and shadow-free printed image is obtained by arranging the substrate on a non-earthed, electrically conductive layer which is insulated relative to the earthed transport device by an insulator extending along the charging device that is located above the substrate and the measurement of substrate that is to be printed and that is oriented in the direction of transport. The charging device can be charged at a potential, exciting voltage UF, of between 1 to 10 kV, more particularly 1.5 to 4 kV.

Abstract: An image forming device for preventing the lowering of the cleaning performance due to rolling up of the blade-like member, by reducing a force of rolling up both end parts of the blade-like member. The blade-like member is provided which presses the contact part extending in parallel in the axial direction of the support member against at least one support member with a belt-like member wound therearound and having the roller shape, with the belt-like member having an endless form interposed therebetween. Provision of tapered parts sloped with outer diameters reduced toward both end parts in the axial direction at both end parts in the axial direction of the one support member having a roller shape, makes the contact pressure of the contact parts at the blade-like member against the one support member having the roller shape, smaller at both end parts than at the central part in the axial direction of the support member.

Abstract: A method and apparatus to prevent a transfer roller from being contaminated by toner in an image forming system, the method comprising setting a print region for a scanning operation according to a comparison result between a previous paper size in a paper cassette and a paper size in a driver; determining a current paper size in the paper cassette based on a time when front and rear ends of the paper are detected by a paper feeding sensor; comparing the current paper size in the paper cassette with the paper size in the driver; and if the paper size in the driver size is larger than the paper size in the paper cassette and the print region for the previous paper size in the paper cassette has not been set, determining a separation time of a transfer roller from a transfer belt in consideration of a delay time when the transfer roller is mechanically separated from the transfer belt after a separation command is applied to the transfer roller.

Abstract: An image forming apparatus includes an endless belt stretched over a plurality of rollers. The apparatus also includes a potential detecting device for detecting a potential of the endless belt. The detecting device is positioned downstream, along a sheet transport path, of a transfer position where the belt has direct contact with the image bearing member. The apparatus further includes a transferring member for transferring a toner image formed on the image bearing member to a sheet. An image forming process is halted when the potential detecting device does not detect a change in potential caused by presence of a sheet on the endless belt.