Abstract: An image forming apparatus includes a sheet feeding section for feeding a sheet, and a sheet transportation path defining a transportation path for the sheet fed by the sheet feeding section. An image formation section may be provided so as to form an image. The image formation section may include a photo-conductive member arranged in the sheet transportation path. A fixing section may be provide so as to fix a toner image transferred onto the sheet from the photo-conductive member with heating and pressure rollers. A sheet type recognition device may be provided so as to set information related to a sheet type that is selected by an operator. A sheet linear velocity control device may also be provided so as to change a sheet linear velocity of the feeding section in accordance with the sheet type in order to create relaxation of the sheet.

Abstract: In an image forming apparatus which has a primary sheet feeder, a secondary sheet feeder for conveying a recording sheet which is fed from the primary sheet feeder to an image forming position in timed relationship with image formation, and a controller for controlling the primary sheet feeder and the secondary sheet feeder, the controller selects long and short two kind of sheet feed intervals according to a detection signal of a recording sheet detector provided upstream of the secondary sheet feeder.

Abstract: An image forming apparatus comprises, a rotatable image carrier, a writing exposure device to write the image and form a latent image in the rotatable image carrier, a developing device to form a toner image, a registration roller to convey a transfer sheet to an image transfer area where the toner image is transferred from the image carrier onto the transfer sheet, and a fixing roller to heat and fix the toner image, wherein when the length of a transfer sheet is longer than the length of the transfer sheet path between the registration roller and the fixing roller, according to the size of the transfer sheet, the controller changes and controls the relative rotating speed of the registration roller to a rotating speed of the fixing roller, and one of a rotating speed of the rotatable image carrier and a writing speed of the image.

Abstract: A sheet transferring apparatus for use in an image forming apparatus includes a sheet transferring mechanism and a controller. The sheet transferring mechanism transfers a recording sheet at a transfer speed to an image forming mechanism in the image forming apparatus. The controller determines the transfer speed based on a transfer speed used for an immediately previous recording sheet.

Abstract: An apparatus and method for moving a receiver having a lead edge and a trailing edge from an upstream engaging nip into registered relationship with an image-bearing member moving at an image-bearing member speed. A motor, a drive member operable to engage the receiver, and a drive coupling connecting the motor with the drive member are provided. A controller drives the motor in accordance with a velocity profile if the receiver is of a predetermined optimal receiver length, and drives the motor in accordance with a second velocity profile if the receiver is longer than the predetermined optimal receiver length.

Abstract: An image forming apparatus includes a photosensitive member, a transfer mechanism, a fixing mechanism, a sheet ejection mechanism, and a driving source. The transfer mechanism including a transfer roller that transfers a toner image carried on a photosensitive member onto a recording sheet. The fixing mechanism fixes the toner image onto the recording sheet with heat and pressure. The fixing mechanism includes a fixing roller and a pressure plate, and applies heat and pressure to the toner image on the recording sheet when the recording sheet is caused to pass through a fixing nip portion. The sheet ejection mechanism ejects the recording sheet and includes sheet ejection rollers. The driving source drives the photosensitive member, the transfer roller, the fixing roller, and the sheet ejection rollers to transfer the recording sheet at a linear speed in a substantially constant manner from the photosensitive member through to the sheet ejection mechanism.

Abstract: An image forming apparatus is provided with a sheet support on which sheets are supported thereon, a sheet feeding unit for feeding the sheets from the sheet support, a first conveying unit for conveying the sheets fed by the sheet feeding unit to the vicinity of an image forming device for forming images on the sheets, a second conveying unit for feeding the sheets conveyed by the first conveying unit to the image forming device so as to be cable of forming images thereon, and a control for controlling the sheet conveying speed of the sheet feeding unit, the first conveying unit and the second conveying unit, and the control controls so that the sheet conveying speed may become higher in the order of the sheet feeding unit, the second conveying unit and the first conveying unit.

Abstract: An image forming apparatus such as a printer and a copier has rotating devices such as a drum and a press roller to print an image on a paper sheet while rotating and a paper-transporting mechanism having guide rollers and timing rollers for transporting a paper sheet to these rotary devices, controlled by a control device such that irregularities in the printed images due to fluctuations in the speed of transportation of the paper sheets. The guide rollers may be operated to transport the paper sheet at a faster speed than the paper sheet is transported by the rotary devices such that the paper sheet becomes bent before being delivered to the rotary devices to be printed on. The control may be such that the guide rollers transport the paper sheet while the timing rollers downstream is released from the transportation of paper sheets. The control device may also operate so as to stop the guide rollers when the paper sheet comes to a position where the rotary devices can start transporting it.

Abstract: An image forming apparatus includes an LED array for performing exposure according to an input image signal, a photoconductive drum on which an electrostatic latent image is formed by exposure with the LED array, a developing device for making the electrostatic image visible, a transfer charger for transferring the visible image onto a transfer material, and a fixing device for fixing the image on the transfer material. When the operating speed in an image forming process equals the image forming speed, and the image forming speed can be switched among a plurality of levels, the image forming condition is changed in accordance with the image forming speed.

Abstract: A paper feeding control method for compensating the rotational speed of a paper feeding roller by varying the rotational speed appropriately according to the paper feed delay when detecting the presence of the paper feed delay on a paper feeding path of a liquid electrophotographic color printing device. The paper feeding control method measures the time taken for a paper to be fed on the paper feeding path to a certain part of the feeding path, and determines the presence and degree of the paper delayed at the certain part by comparing the measured time at the certain part with a preset paper feeding time for the certain part. Next, according to the determination made, the method adjusts the rotational speed of the driving motor for driving the paper feeding roller to increase the rotational speed of the paper feeding roller, and to compensate for the paper feed delay.

Abstract: An image forming apparatus according to the present invention is capable of making accurate adjustments so that a medium (for example, a sheet of paper) may fall in a proper relative speed range agreeing with the amount of allowable bend in the bending space of the medium, reliably preventing a color shift from occurring particularly in the color mode, which thereby improves the reliability.

Abstract: An improved printing apparatus provides for very accurate synchronization between cut sheet print media and the unfixed image which is conveyed on an Intermediate Transfer Member (ITM) such as a belt or a drum, and which is targeted for said print media. The printing apparatus is constructed as a single-pass ITM-based electrophotographic (e.g., laser) printer, and the length of the input print media pathway prior to image-to-media transfer is significantly shorter than the sum of the lengths of the image travel along a photoconductive drum and ITM. The print media is typically launched after imaging has been initiated on the photoconductive drum by an imaging apparatus. Variance in the leading edge of the print media with respect to the leading edge of image can be introduced due to phenomena such as pick errors, velocity variation, and uncertainties in the paper stack height.

Abstract: An image forming apparatus includes image forming portion for forming an image on a sheet, separating and feeding portion for feeding sheets stacked on sheet supporting portion one by one toward the image forming portion, sheet conveying portion for conveying the sheets fed by the separating and feeding portion, registration rollers of a variable rotating speed disposed upstream of the image forming portion with respect to a sheet conveying direction, and sheet conveyance controlling portion for causing the registration rollers to effect the conveyance of the sheets at a speed higher than the image forming speed in the image forming portion, and thereafter decelerating the registration rollers so as to assume substantially the same speed as the image forming speed at timing earlier than the latest image forming timing in the image forming portion.

Abstract: An image forming apparatus capable of realizing an improvement in terms of apparatus size and productivity and obtaining a satisfactory image includes a conveyance driving motor M1 for driving conveyance roller pairs 41, 42, and 43, a pre-registration conveyance roller pair 44, and a registration roller pair 10; an image formation driving source for driving photosensitive drums 1a, 1b, 1c, and 1d; and a control unit for controlling the conveyance driving motor M1 and the image formation driving source such that the speed at which a sheet material is conveyed by the conveyance roller pairs 41, 42, and 43, and the pre-registration conveyance roller pair 44 is variable, and that the speed at which the sheet material is conveyed by the registration roller pair 10 is substantially the same as the speed at which the sheet material is conveyed by an image forming device.

Abstract: In an image forming apparatus wherein toner images formed on photo-conductive drums are transferred on a sheet of paper conveyed on a transferring belt, belt registration marks written on the transferring belt and sheet of paper registration marks written on a sheet of paper are detected by a photo-sensor, and from this result of detection, a conveying speed difference among aligning rollers, the transferring belt and fixing rollers is detected. Using this detected conveying speed difference, the sheet of paper conveying speed of the aligning roller, transferring belt or fixing rollers is fed back and the sheet of paper conveying speeds of the aligning rollers, transferring belt and fixing rollers are controlled to almost the same speed.

Abstract: It enables an image forming apparatus to switch back a recording medium without increasing costs and apparatus size. In order to do so, the image forming apparatus comprises a switchback unit for switching back the recording medium of which an image was recorded on one face, to record an image on the other face thereof, a DC blushless motor for driving the switchback unit, and a controller for performing operation control of the DC blushless motor, wherein the controller reversely rotates the DC blushless motor for a predetermined time after performing brake control of the DC blushless motor for a predetermined time, at predetermined timing.

Abstract: An image forming apparatus which can suppress the occurrence of noises without reducing productivity. Sheet transporting units are provided in a paper supply transport section for transporting a sheet to an image forming section, and in a paper ejection transport section for transporting the sheet, on which an image has been formed in the image forming section, to a paper ejection section. When an image is formed on a predetermined sheet, a speed control unit controls a sheet transport speed of at least one of the sheet transporting units provided in the paper supply transport section and the paper ejection transport section to be higher than that in the image forming section.

Abstract: A document feeder which picks up documents from a tray, separates/feeds a document with a feed roller and a separation roller and transports the document on a reading position with read rollers. The speed of feeding a document by the feed roller is higher than the speed of transporting a document by the read rollers. The reading position is at a distance from the nip portion between the feed roller and the separation roller, the distance being longer than the length in the document feeding direction of the document.

Abstract: Referring to the table of the count values corresponding to the aligning speeds stored in a ROM, the main control unit sets an aligning speed value (Kd: default value) in the aligning motor speed control circuit 193 and calculates the equation K1=Kd/(−Ta/Tb+(2+&agr;))−1 measured by the aligning speed adjustment sequence and a new target value Ka=(Kd+K1)/2+C. At this time, if |Kd−K1|≦10, the main control unit substitutes C=0; if 20≧|Kd−K1|>10, it substitutes C=2 when Kd<K1 and C=−2 when Kd>K1; and if |Kd−K1|>20, it substitutes C=4 when Kd<K1 and C=−8 when Kd>K1.

Abstract: A method of media-to-image registration sets a top writing line margin on a print medium within an electrophotographic machine. Movement of a substantially stationary sheet of print medium along a print medium path within the electrophotographic machine is initiated. An image associated with the sheet of print medium is scanned onto a developing unit. The scanning step commences before the initiating step. Toner is adhered to the image on the developing unit. The toner is transferred from the developing unit to a moving toner transfer medium. The electrophotographic machine is provided with a toner transfer area in which the toner can be transferred to the moving sheet of print medium. A speed of the movement of the sheet of print medium is adjusted such that the toner is transferred from the moving toner transfer medium to a desired area on the sheet of print medium within the toner transfer area.

Abstract: An image forming apparatus of an electrophotographic type including a paper feeding device for separating and feeding piled recording paper, an image forming device for forming the image in order on the fed recording paper, a paper turning-over device for switching back the recording paper and turning over the front and rear tip ends of the recording paper, and a paper re-feeding device for re-feeding the recording paper having the image on one-side surface. In such an apparatus, the both-surfaces image formation can be practiced at the same paper distance, keeping the image forming apparatus small in size and low cost. Furthermore, a conveying roller for switching back the paper and sending out the paper to a printer engine is provided such that the rear tip end of the paper accommodated in the switching-back path becomes the front tip end thereof, and a jogger for performing compensation of lateral registration for the paper is provided in the switch-back path.

Abstract: A mounting device for an image forming apparatus comprises a mounting rack for mounting an image forming apparatus for forming an image at a predetermined speed, a feeding section provided within the mounting rack for feeding a medium into the image forming apparatus, and a changing section for changing a medium feeding speed of the feeding section in accordance with an image forming speed of the image forming apparatus. The changing section comprises a movable gear having coaxially-arranged large and small gear portions different in the number of teeth and rotating upon receipt of driving force, and first and second power transmitting sections for transmitting power to the feeding section when the large and small gear portions are selectively connected by shifting the movable gear, to thereby drive the feeding means at a different speed.

Abstract: A method of decreasing wait time for a printed page and an image forming device implementing the method which includes an output transport mechanism configured to provide a higher linear velocity for print media than the linear velocity at which the media is transported through the rest of the image forming device. The rollers or other motion imparting apparatus of the output transport mechanism are driven at a higher linear velocity, but connected to their drive source using a slip drive mechanism. The slip drive mechanism maintains a predetermined tension on the media so that the media cannot be deformed before it has completely exited from the print engine. The overall time needed to deliver a printed image to the user is significantly shortened.

Abstract: A color image forming apparatus is capable of color printing and monochrome printing in accordance with print data. The apparatus has a plurality of image-forming sections that print toner images of corresponding different colors. The plurality of image-forming sections are aligned in a direction of travel of a recording medium, and print the respective toner images on the recording medium in superposition. The toner images are subsequently fixed at a fixing unit. The apparatus includes a data-identifying section and a mode-selecting section. The data-identifying section identifies the print data as to whether the print data is for color printing or for monochrome printing. The mode-selecting section selects a multi-color mode if the print data is for color printing and a mono-color mode if the print data is for mono-color printing. A printing operation is performed at a higher speed in the mono-color mode than in the multi-color mode.

Abstract: An image forming apparatus is provided with a plurality of storing units for storing respective recording materials of various sizes; a plurality of feeding members for feeding out the recording materials from each of the storing units; a conveyance path along which the recording materials being fed out by each of the feeding members are conveyed; a plurality of conveying members for conveying the recording materials along the conveyance path; an image forming section for forming an image on the recording materials conveyed along the conveyance path; and a plurality of first regulators provided at respective predetermined positions with respect to corresponding ones of each of the storing units for regulating at least a maximum size of the various sizes of the recording materials while at least at a part of each of the recording materials is fed out from the respective corresponding storing units.

Abstract: There is provided an image recording apparatus which does not cause a print shift or a color drift caused by vibration and a widthwise shift due to speed variation in a conveying direction of a continuous sheet such as rolled paper or folded paper, in which a variation in speed is prevented by rollers which wind and clamp the sheet on and between an upper and a lower roller which are driven by the conveying force of the sheet, so as to prevent occurrence of vibration in the conveying direction, and a guide roller having pins adapted to be engaged in sprocket holes of the sheet are provided between the set-up positions of the tractors.

Abstract: An image formation system includes: a paper transport unit transporting paper along a paper transport passage; an image formation unit forming an image on an image carry belt; an image sense unit sensing a position of the image formed on the image carry belt; a transfer unit transferring the image formed on the image carry belt to the paper transported by the paper transport unit; a paper passage sense unit sensing paper passage on the paper transport passage, the paper passage sense unit being disposed upstream from a position where the image is transferred by the transfer unit; and a control unit controlling paper transport speed of the paper transport unit based on the sense results of the image sense unit and the paper passage sense unit.

Abstract: A method of control to synchronize the arrival of images and copy sheets at a transfer station by sensing delay of a copy sheet arrival at the transfer station. There is then a determination that the delay of arrival is incapable of being corrected to synchronize with a given image. In response, the control decides to rewrite the given image on the receiving medium or further delay the arrival of the copy sheet, or a combination of rewrite and delay, in order that the arrival of a given image and copy sheet is synchronized.

Abstract: A system capable of suppressing the variation of a conveyance speed of a medium occurring when the rear end of the medium gets away from between a pair of rollers to surely and stably conduct the processing (transfer of a visible image) for the medium in a processing section (a transfer position). Accordingly, this system includes a position detecting section for detecting a position of the medium conveyed, and a control section for, when the position detecting section detects the fact that the rear end of the medium exists at a position immediately before getting away from between resist rollers, executing control so that a medium conveyance speed by the resist rollers becomes equal or substantially equal to a medium conveyance speed by conveyance rollers. This system is applicable to printers including an electrophotographic system.

Abstract: An image forming apparatus includes an image transfer unit disposed along a sheet feed path. A sheet feed roller feeds a sheet toward an image transfer position where an image can be transferred by the image transfer unit. A sheet detect unit detects the sheet fed by the sheet feed roller and a control unit controls the rotational operation of the sheet feed roller in accordance with a detection result of the sheet detect unit. As such, a sheet feed path length, which extends between the image transfer position and a detection position where the sheet is detected by the sheet detect unit, is set at an integer multiple of a circumferential length of the sheet feed roller.

Abstract: An apparatus has a first conveyor for conveying a recording medium into an image forming unit which forms an image on a recording medium, a second conveyor for re-conveying the recording medium having an image formed thereon by the image forming unit to the second conveyor, and a curl straightener, formed by a plurality of rollers forming a bent path within the second conveyor, for straightening the curl on the recording medium. The conveyance speed of the second conveyor is switchable between a first speed equal to the conveyance speed of the first conveyor and a second speed which is greater than the first speed. The first speed is the speed of the recording medium until at least a predetermined length of the recording medium passes the curl straightener, and the second speed is the speed of the recording medium after passage therethrough.

Abstract: An image forming apparatus includes a color difference detection pattern output device that outputs an image signal to produce a color difference detection pattern for detecting periodic rotational variations arising in the image forming apparatus, a pattern detection device for detecting the color difference detection pattern formed on an endless carrier; phase detection device for detecting the phase of rotation of at least one of the image carriers of the image forming apparatus on the basis of a detection signal received from the pattern detection device; and a rotational phase control device for individually controlling the phase of rotation of at least one of the image carriers of the image forming apparatus and the endless carrier on the basis of the phase information detected by the phase detection device. The phase detection device calculates the mean value of the rotational variations of the rotational phases.

Abstract: A continuous web substrate printing system which can utilize a single otherwise conventional or existing xerographic print engine (normally printing conventional cut sheet print substrates) having an endless photoreceptor belt with a belt seam requiring a section of that belt to be unimaged in each belt rotation, yet provide continuous directly abutting images on the printed web, to avoid paper scrap. A special simplex or duplex continuous web printing substrate supply module may be docked with the cut sheet print engine to form an integral web printing system. It has a web feeding and image transfer system for appropriately feeding the continuous web printing substrate uncut into the print engine for image transfers to one or both sides of the web from the imaging surface of the print engine.

Abstract: A method for tracking the position of a sheet through a paper path being translated by a plurality of feed mechanisms within a printing machine is provided.

Abstract: A paper feeding unit for an electrophotographic printing apparatus which can prevent print media from being drawn to the right or left during conveyance.

Abstract: An image forming apparatus includes a sheet transport channel including a registration roller for supplying a sheet that is fed from a tray to an image recording section at predetermined timing. A brake forcibly stops rotation of the registration roller. A sensor senses the occurrence of an abnormality in the paper transport channel during transport of the sheet. A controller activates the brake when the sensor has detected the abnormality. Therefore, when a POP jam occurs, sheet rushing into the cleaner due to an overrun can be reliably prevented. Also, in the case of feeding a sheet to prevent a guillotine jam, sheet rushing into the image recording section due to idle rotation of the registration roller can be prevented reliably.

Abstract: A continuous forms printer utilizing paper without pinholes along each edge is provided with a first paper transfer device on the input side of the printing station and a second paper transfer device on the output side of the printing station. The two paper transfer devices are operated at slightly different speeds in order to place tension in the continuous forms at the printing station in order to control registration and magnification problems. For example, a vacuum transport belt is placed on the output side and operated at a slightly greater speed than the printer. The belt is provided with friction characteristics and operated at a vacuum pressure to allow slippage of the belt and paper at the desired tension. By placing positive paper control on the output side, the directional stability of the continuous forms is improved thus avoiding skew control problems.

Abstract: An electrophotographic apparatus is provided in which toner stick hardly occurs by improving the cooling effect on the strip of paper sheets after they are heat-fixed. This electrophotographic apparatus includes a fixing unit for heating toner transferred on a continuous strip of paper sheets and fixing the toner, and a folding unit for supplying a folding force to the continuous strip of paper sheets. A conveyer unit is arranged in the back stage of the electrophotographic apparatus for transferring the continuous strip of paper sheets, received from folding unit, in the horizontal direction.

Abstract: A feed apparatus for feeding a recorded image or film (scanned medium) in a reading or recording apparatus has a feed drum for feeding the scanned medium and a motor for rotating the feed drum. The rotating states of the feed drum and the motor are detected respectively by a rotary encoder and a frequency generator for feedback control of the feed drum and the motor. The eccentricity of the feed drum is limited to a predetermined value which is calculated according to the following equation:.DELTA.D=1/2{(T+D).DELTA.L/L-2.DELTA.T}where .DELTA.D represents the predetermined value, L the length of the scanned medium in the auxiliary scanning direction, .DELTA.L the allowable feed error of the scanned medium in the auxiliary scanning direction, T the thickness of the scanned medium, and .DELTA.L the thickness variation of the scanned medium.

Abstract: An image recording apparatus according to the present invention has a photosensitive drum, a pre-transfer roller, and a fixing roller. The photosensitive drum, the pre-transfer roller and the fixing roller are generally rotated at an equal peripheral speed. Particularly, the peripheral speed of the photosensitive drum and the peripheral speed of the fixing roller are equal to each other, whereby there is no problem that an image transferred to a rolled-paper sheet from the photosensitive drum extends due to the leading end of the rolled-paper sheet being pulled after reaching the fixing roller. On the other hand, after the leading end of the rolled-paper sheet reaches the fixing roller, the peripheral speed of the pre-transfer roller is so controlled as to be lower than the peripheral speed of the photosensitive drum during a predetermined time period.

Abstract: An image forming apparatus which sequentially transfers and superimposes sequentially formed electrostatic latent images onto a sheet wound around a sheet support. The image forming apparatus have either a photoconductor where the electrostatic latent images are sequentially formed on the surface or a plurality of photoconductors where the electrostatic latent images are formed respectively and sequentially. The quantity of print dot misregister is detected by forming reference patterns on a sheet and by reading the formed reference patterns. The rotational speed of conveying rollers for delivering a sheet to the sheet support is switched over in response to the quantity of the print dot misregister. The rotational speed of the conveying rollers can also be switched over in response to the thickness of a sheet. In the case that the image forming apparatus is a full-color copying machine, the electrostatic latent images are of four types for cyan, magenta, yellow and black.

Abstract: An apparatus and method for control of a stepper motor drive for controlling movement of a receiver sheet into transfer relationship with an image-bearing member that supports an image to be transferred to the receiver sheet. Initially, the stepper motor is driven by drive pulses generated in response to clock pulses not synched with movement of the member. However, in order to ensure accurate registration, stepper motor drive pulses are subsequently generated that are in sync with encoder clock pulses that are generated in response to movement of the member. The transition of generation of the drive pulses is determined by establishing a condition of concurrence of a non-synched stepper motor drive pulses with an edge of an encoder pulse. The term condition of concurrence may be established by generating a timing control pulse of relatively short pulsewidth to define an allowed period for determining the condition of concurrence.

Abstract: A scanner device, and the method it embodies, for scanning a document. The scanning includes a pre-scan and a subsequent main scan, with the pre-scan generating data related to the document. The scanner device includes: a scanning assembly having a platen against which the document is positioned and a mobile portion movable along the platen; a document moving device for moving a document in a first direction onto the platen; a mobile-portion-moving device for moving the mobile portion of the scanning assembly in a second direction opposite to the first direction; and a controller for controlling the document moving device and the mp-moving device, and for controlling the scanning assembly to scan the document while the document and the portion of the scanning assembly are both moving. This, for example, substantially reduces instances in which the mobile portion is moving without scanning taking place.

Abstract: A copying machine that is capable of copying a large-size document original on a transfer sheet is provided in which the transfer sheet is prevented from being skewed from the desired transport path. In one embodiment, this bypass transportation path for a cut-sheet extends to a photoreceptor drum and is provided with a resist roller and a downstream transportation roller. A cut-sheet inserted from a manual sheet feeding section is stopped with its leading edge abutting against the resist roller, so that the leading edge of the cut-sheet is aligned with a line perpendicular to a transportation direction of the sheet. The cut-sheet is then transported by the resist roller and the transportation roller. At this time, the circumferential speed of the resist roller is slower by a predetermined degree than the circumferential speed of the transportation roller.

Abstract: A stalled roll registration device that minimizes or prevents creasing of a sheet as it is fed through the device. The rolls that register the sheet are not perfectly cylindrical and have a larger radius toward the outside edges of the sheetpath. After the sheet is stalled and then started through the registration pair, the velocity difference caused by the noncylindrical rolls causes the edges of the sheet to be urged toward the edges of the sheetpath thereby minimizing the risk of wrinkling the sheet.

Abstract: Image-forming apparatus includes a finite length image member such as a seamed photoconductive loop. Images are formed on the image member in one of three different sized image frames, the first image frame being 1/2 the in-track length of the third image frame and the second image frame having an intermediate length. Relatively small size images, for example letter size images are formed in the first size frames while relatively large sized images, for example, ledger sized images are formed in the third size frames. Intermediate sized images, for example images for B-4 receiving sheets are formed in the second or intermediate size image frames. Receiving sheets in duplex are passed through a finite length duplex path which has a speed profile which is substantially the same for receiving sheets bearing images formed in the first and third frame lengths but is different, for example faster, for images formed in the second size image frame while use of the same duplex path for the three frame sizes.

Abstract: A fuser roll nip sheet sensing scheme detects the torque spike of a fuser roll motor when paper is entering the nip region and uses that spike to signal a speed change to the motor to thereby control the motion of the paper. The nip sheet sensing scheme is used for paper position/timing and for single pass duplex fusing.