Abstract: An application apparatus includes a first roller configured to apply a treatment liquid to a recording medium conveyed; and a second roller disposed in contact with the first roller and forming, with the first roller, a conveyance nip in which the recording medium is nipped. The application apparatus further includes a third roller disposed in contact with the first roller at a position different from the conveyance nip, and a fourth roller disposed in contact with the second roller at a position different from the conveyance nip. The third roller has a rigidity higher than a rigidity of the first roller, and the fourth roller has rigidity higher than a rigidity of the second roller.

Abstract: An image recording apparatus, including a body including a path to convey a sheet from a feeder tray to an ejection tray; a conveyer unit to convey the sheet; a recording unit to record an image on the sheet; and a controller to control the conveyer unit and the recording unit, is provided. The controller is configured to execute a ejection request accepting process, in which the controller accepts a request for executing a sheet ejection job being a single job to eject the sheet without causing a recording action in the recording unit; and a sheet ejecting process, in which, after accepting the request for executing the sheet ejection job, the controller controls the conveyer unit to convey the sheet from the feeder tray to the ejection tray without causing the recording action in the recording unit.

Abstract: A machine arrangement, that sequentially processes sheet-type substrates, includes a plurality of different processing stations, one of which includes a non-impact printing device that prints the substrates. Further processing stations are a primer application device that primes the substrates and a dryer for drying the primer applied to the substrates. The primer application device and the dryer precede the non-impact printing device, in the direction of travel of the substrates. The processing station including the non-impact printing device, also includes a printing cylinder, on the circumference of which, the non-impact printing device that prints the substrates is arranged.

Abstract: A delivery drum includes at least one supporting shell for supporting a printed sheet and for producing a vacuum region between the supporting shell and the printed sheet. The supporting shell extends over the entire width of the printed sheet. A circumferential length, which is at least one quarter of the sheet length of the printed sheet, is disposed between the sheet start of the printed sheet and the start of the vacuum region.

Abstract: A sheet-fed offset printing press for printing on both sides of sheets has a compact construction and permits a number of color separations to be printed over one another in recto printing or recto and verso printing in a flexible manner and with high print quality. A plurality of printing units, which are disposed behind one another, each include at least one form cylinder, a transfer cylinder, a first impression cylinder and an inking unit having at least one ink applicator roll associated with the form cylinder. A second impression cylinder, which interacts with the transfer cylinder and the first impression cylinder, is provided in at least one printing unit.

Abstract: There is described a sheet inspection system for a sheet-fed recto-verso printing press of the type comprising two printing cylinders (10, 20) for carrying out simultaneous recto-verso printing of the sheets, said sheet inspection system comprising at least a first inspection device (100) for taking an image of a first side of the printed sheets. The first inspection device (100) comprises a first line image sensor (110) for performing line-scanning image acquisition of the first side of the printed sheets, and the first inspection device (100) is disposed in such a way that the first line image sensor visually acquires an image of a printed sheet while the said printed sheet is still adhering onto the surface of a first one (10) of the two printing cylinders (10, 20) of the printing press and immediately before the said printed sheet is transferred to a chain gripper system (5) of the printing press. Also described is a printing press equipped with the inspection system.

Abstract: A superstructure of a printing press includes a turning tower with at least one turner bar that is usable to deflect a web section from a transport direction by 90°. A second turner bar, that is shorter than the first turner bar, is also used to deflect a web section from the transport direction by 90° in the same direction as the first web section. These first and second turner bars are offset vertically in relation to one another in the same turning tower. The first turner bar is supported at both ends on at least one first lateral support and at least one second lateral support. The second turner bar is supported only on one end on the lateral support in a floating manner. The second support side of the second turner bar is provided with access from that support side into the interior of the turning tower.

Abstract: A printing state automatic switching apparatus includes a printing state switching unit, abnormal end detection unit, and error recovery unit. The printing state switching unit automatically switches the printing state of a printing press from a first printing state to a second printing state through a plurality of switching steps. The abnormal end detection unit detects an abnormal end of each switching step of automatic switching from the first printing state to the second printing state. When the abnormal end detection unit detects an abnormal end of a switching step, the error recovery unit receives an error recovery instruction and eliminates the error of the switching step. A printing state automatic switching method is also disclosed.

Abstract: A sheet-fed offset printing press for printing multiple colors on both sides of sheets, preferably on sheets of paper, includes a first row of in-line printing units for printing a first side of the sheet, followed by a reversing device, followed by a second row of in-line printing units for printing the other side of the sheets, and followed by one or more varnishing units that are disposed in such a way, or include varnishing blanket cylinders that are disposed in such a way, that the front sides and the back sides of the passing sheets are varnished. A further reversing device is inserted between two varnishing units. A method of printing multiple colors on both sides of sheets is also provided.

Abstract: In one embodiment, a method includes applying at least one invisible mark to media, sensing the at least one invisible mark with separate sensors, and determining a speed of the media from signals of the separate sensors.

Abstract: A card sheet including a top material having punched lines, the front side of the top material being printable. A carrier material of at least one polymer layer is directly applied as by extruding to the back side of the top material. The polymer has a stress-at-break in the range of 10 to 30 MPa and an elongation at break in the range of 10 to 120%. From the card sheet individual cards may be broken out to form high quality calling (business) cards, photograph cards, post cards or the like.

Abstract: An apparatus for carrying or guiding a printing material sheet on an air cushion between a nozzle surface and the printing material sheet. The apparatus has first nozzle pairs which are arranged in a first row and second nozzle pairs which are arranged in a second row for generating the air cushion. The first nozzle pairs and the second nozzle pairs in each case have a blower nozzle and a suction nozzle, which are paired in such a way that one and the same air flow is blown out by the respective blower nozzle and is aspirated, at least predominantly, by the suction nozzle that is paired with the blower nozzle. The suction nozzles of the first nozzle pairs are arranged in such a way between the blower nozzles of the second nozzle pairs and the suction nozzles of the second nozzle pairs such that the air flows of the second nozzle pairs flow past the suction nozzles of the first nozzle pairs.

Abstract: A delivery drum includes at least one supporting shell for supporting a printed sheet and for producing a vacuum region between the supporting shell and the printed sheet. The supporting shell extends over the entire width of the printed sheet. A circumferential length, which is at least one quarter of the sheet length of the printed sheet, is disposed between the sheet start of the printed sheet and the start of the vacuum region.

Abstract: A duplex printing apparatus capable of printing by performing a slow-up operation on the printing speed so that it increases from a low speed to a set speed at the time of duplex printing. Control means controls, on the basis of a drum rotation position signal and a drum speed signal from a home position sensor and an unshown encoder sensor, a sheet feeding unit, printing unit, sheet discharge unit, sheet re-feeding means and switching member, such that the printing speed (drum speed) slows up from a low speed to a set speed in each rotation of a plate cylinder, which corresponds to feeding of each sheet to the printing unit when duplex printing is started, and further controls a stepping motor of the sheet re-feeding means such that conveyance speed of a sheet receiving board synchronizes with the printing speed.

Abstract: A sheet-fed rotary printing press for selective recto printing and recto and verso printing includes a three-drum reversing device having three cylinders cooperatively disposed behind one another between respective impression cylinders of two adjacent printing units. The three cylinders include one at least double-size transfer cylinder, one at least double-size storage drum, and one at least single-size reversing drum. Grippers prescribe a circular periphery of the transfer cylinder. The transfer cylinder has an outer contour smaller than the circular periphery prescribed by the grippers of the transfer cylinder. Other grippers prescribe a circular periphery of the reversing drum. The reversing drum has an outer contour smaller than the circular periphery prescribed by the grippers of the reversing drum. A method of operating the three-drum reversing device is also provided.

Abstract: Disclosed is a duplex printer which is capable of performing simplex printing without wasting a master and providing a print output with a satisfactory image quality at the time of duplex printing, and which is capable of suppressing an increase in installation space while effecting adjustment on the print image position in the sheet conveyance direction. The duplex printer includes a printing section, a sheet feeding section, a sheet discharging section, an auxiliary tray, refeeding means for refeeding a sheet having an image printed on its front side, and a path selector that steers the sheet to one of the auxiliary tray and the sheet discharging section. In a duplex printing mode, a master having first and second perforated images formed thereon side by side is wound around a print drum, thereby performing duplex printing.

Abstract: Apparatus for duplex printing comprising: a first impression roller (24) on which a first side of a sheet (22) having a leading edge and a trailing edge is printed referenced to the leading edge; a second impression roller (26) on which a second side of the sheet is printed; and a transport system (20) that removes a printed sheet from the first impression roller (24) and transports it to the second impression roller (26), the transport system comprising a perfector (32) that receives the sheet and grips it along both the leading and trailing edges of the sheet, which perfector turns the sheet over and transfers the sheet trailing edge first towards the second impression roller.

Abstract: A sheet guide apparatus comprises gripper devices for holding and transporting a printed sheet, an impression cylinder and a transfer cylinder for holding and transporting the printed sheet received from the gripper device, and a first guide device for guiding the printed sheet being transported. A front end portion of the first guide device is located upstream, in the flow direction of the printed sheet, from a transfer position, where the printed sheet is transferred from the gripper device to the impression cylinder, and the front end portion of the first guide device is also located near the transfer position. Suction holes opening in a front end portion of a plate-shaped guide of the first guide device are provided for sucking air. The sheet guide apparatus suppresses fluttering or instability of the sheet.

Abstract: A quality inspection apparatus for a double-sided printing machine which includes a rubber impression cylinder and a rubber cylinder; inking unite for supplying ink to the rubber impression cylinder and the rubber cylinder; and a transport mechanism for transporting the printed paper to a delivery unit. The transport mechanism includes first through third transport cylinders for transporting the paper from the first delivery chain, and a delivery chain for transporting the paper from the first through third transport cylinders. The quality inspection apparatus includes an inspection camera for detecting a status of printing on one face of the paper when transported by the first transport cylinder, and an inspection camera for detecting a status of printing on the other face of the paper when transported by the second transport cylinder.

Abstract: A printing press for one-sided or two-sided printing of a sheet includes a transfer cylinder disposed in a travel direction of the sheet between a first and a second impression cylinder, respectively, of two printing units, and a sheet support assigned to the transfer cylinder for receiving the sheet thereon before the sheet is transferred to the second impression cylinder, an inverting drum disposed in the travel direction of the sheet between the sheet support and the second impression cylinder, the inverting drum serving for picking up the sheet from the sheet support and transporting the sheet to the second impression cylinder; and a method of operation.

Abstract: A vacuum platen assembly for a fluid-ejection device of one embodiment of the invention is disclosed that includes a platen that has a number of vacuum holes, and one or more aerosol-collection recesses. A number of ribs extend from the platen, against which position of media is maintained by suction effect from the vacuum holes.

Abstract: A device for changing an operating state of a gripper-control device in a sheet-reversing device of a sheet-processing machine including a cylinder having an actuating shaft accommodated therein, includes an activating element cooperatively engaging with the actuating shaft for changing the operating state of the gripper control device. An actuating element is coupled mechanically with the actuating shaft. An adjusting element is movable relative to the cylinder. The adjusting element is disposed externally to the cylinder and cooperatively engages with the actuating element for moving the actuating element at least approximately synchronously with the cylinder during operation of the sheet-processing machine while the actuating shaft remains in a prescribed position with respect to the cylinder. The actuating element is changeable in position relative to the cylinder by the adjusting element, whenever the operating state is changed.

Abstract: A tandem printer with a mechanism for fine substrate-position correction, comprising: a first printing station; a second printing station; a rotatable element, rotating at a given rotation rate, that receives the substrate after printing thereon by the first printing station and transfer the substrate toward the second printing station; a sensor which measure the position of an edge of the substrate during its transfer from the first printing station to the second printing station; and a controller, which applies a corrective step change in angular position of the rotatable element responsive to the measurements of the sensor, without changing the general rotation rate of the rotatable element.

Abstract: A dual-speed printer drive mechanism is disclosed. The drive mechanism includes a drive motor, a drive roller for feeding a media sheet toward and through a printing area and a drive transmission for coupling the drive roller to the drive motor for turning the drive roller with different gear reduction ratios. The drive mechanism further includes a gear reduction ratio selector disposed in the drive transmission for selectively turning the drive roller at a first gear reduction ratio for feeding the media sheet to the printing area, and for selectively turning the drive roller at a second gear reduction ratio for feeding the media sheet with precision for image printing while in the printing area.

Abstract: A satellite printing machine for printing sheets includes a single central common counter-pressure cylinder and at least four satellite printing groups arranged in a peripherally distributed manner about the counter-pressure cylinder in a rotational direction thereof from a feed cylinder to an output cylinder. The counter-pressure cylinder is provided in the form of a rubber blanket cylinder. At least one additional satellite printing group cooperates with the counter-pressure cylinder for at least single-color back side printing, and is disposed in the rotational direction of the counter-pressure cylinder before the feed system and after the output cylinder.

Abstract: The tension of a web in a rotary printing machine is monitored and adjusted. The web runs through at least one printing group in the rotary printing machine. Any change in the stretch of the web during the production run is determined by noting any difference between first and second speeds of the web. The change in stretch is compensated for by a change in the tension of the web before the first printing group.

Abstract: In a varnish coating apparatus, a first varnish film forming cylinder has a first supply surface to which varnish is supplied. A second varnish film forming cylinder has a second supply surface to which varnish is supplied. A first blanket cylinder has a first transfer surface and first opposing surface. A second blanket cylinder has a second transfer surface and second opposing surface. When a sheet passes through a contact point between the first and second blanket cylinders, the first transfer surface of the first blanket cylinder opposes the second opposing surface of the second blanket cylinder to perform varnish coating on a first surface of the sheet, and the second transfer surface of the second blanket cylinder opposes the first opposing surface of the first blanket cylinder so as to perform varnish coating on a second surface of the sheet.

Abstract: The circumferential register of a web passing through printing units of a web-fed rotary press is accomplished by determining an actual value of the tension in the web. An angular position or an angular velocity of a cylinder of a first print unit, with respect to a cylinder of a second print unit, is varied based on this determined tension. This corrects any register offset without the need to control web tension and without the use of an optical recognition system. The value of the needed change for the cylinder angular position or velocity is determined as a function of the measured tension of the web.

Abstract: A signature transfer device includes a rotating arm rotating about a first axis and a first gripper rotatably mounted on the rotating arm about a second axis, the first and second axes being parallel, the first gripper having a first gripper finger and a second gripper finger. An actuator is connected to the first gripper for opening and closing the first gripper as a function of the angle of the rotating arm about the first axis, and a compression spring connects the first gripper finger and the second gripper finger, the compression spring being compressed when the first gripper and the second gripper finger are apart.

Abstract: A device for turning sheet-like material from a printed side onto an unprinted side uses an impression cylinder which guides the sheet-like material and which is preceded by a transfer cylinder and followed by a further transfer cylinder. The sheet-like, flexurally rigid material is received on the outer surface of the impression cylinder and can be printed with a transmission cylinder. In the gusset between the outer surfaces of the impression cylinder and the preceding transfer cylinder, a contactlessly acting throw-on device is provided which forces the sheet-like material into a curved position corresponding to the curvature of the outer surface of the impression cylinder such that the sheet-like material is curved even in the gusset region. A printing press and a multicolor rotary printing press are also provided.

Abstract: A printer with a duplex printing capability of the present invention includes a printing section. In a duplex print mode, the printing section prints either one of a first and a second image formed in a master side by side on the front side of a first sheet. A path selector steers the first sheet coming out of the printing section toward an auxiliary tray. The printing section prints either one of the first and second images on the front side of a second sheet while refeeding means again feeds the first sheet to the printing section to thereby form either one of the first and second images on the reverse side of the first sheet. The path selector steers the first and second sheets toward a sheet discharging section and the auxiliary tray, respectively.

Abstract: To stably transport an elongated web-like print paper so as not to move in the widthwise direction of the print paper, a first sensor is disposed at a first position in a paper conveying path and a second sensor at a second position downstream of the first position with respect to the paper conveying direction. Both the first and second sensors detect a position of a side edge or the print paper. A difference between the outputs from the first and second sensors is computed while taking a travel time of the edge detected by the first sensor to reach the second sensor into account. A main controller generates a drive signal based on the difference computed and controls a mechanism for moving the print paper in the widthwise direction in accordance with the drive signal.

Abstract: An apparatus for guiding and transferring a sheet in a printing machine from a first cylinder to a gripper of a second cylinder in which the apparatus has a guide device for a holding element, which is held outside the first and second cylinder. In this way, the design of the guide apparatus can be independent of the first and second cylinders. In addition, a longer time period is available for gripping, tensioning and transferring the sheet. The apparatus can be used both in a recto printing machine and in a turner device in recto and verso printing.

Abstract: There is provided a printing press with a sheet-turning-over-mechanism for turning over a printing sheet, enabling the printing press to be selectively operable in a one-sided printing mode and a double-sided printing mode. The printing press includes a controller which, when any failure stops any one of steps of a mode switching operation for switching the printing press from the one-sided printing mode to the double-sided printing mode or vice versa, stores the information representative of a state of the mode switching operation at the moment of the stop due to the failure, and when a normal operable state is restored from the failure, resumes the mode switching operation from a step of the mode switching operation indicated by the operational state stored therein.

Abstract: A device for aligning sheets on a feeder of a sheet-processing machine includes a plurality of pivotably disposed front lays and a plurality of pivotably disposed top lays, the top lays being vertically adjustable. The front lays and the top lays are respectively assigned to and combined with one another and have a common pivoting drive. A push rod vertically adjusts the top lays, and a wedge-like slide actuates the push rod.

Abstract: Provided, in combination, is a device for turning sheet-like material, with an impression cylinder for guiding the sheet-like material, the impression cylinder being preceded by a first transfer cylinder and followed by a second transfer cylinder, the sheet-like material being receivable on an outer jacket surface of the impression cylinder so as to be printable by a third transfer cylinder, and further included are a storage device, and a device for imparting a deformation in the sheet-like material during entry thereof into the storage device and while the sheet-like material is gripped at an edge thereof; and a printing unit and a multicolor rotary printing machine, respectively, provided with the combination.

Abstract: A sheet processing device is provided in a sheet-fed printing press. Sheets are conveyed to a sheet transport cylinder and are processed on the sheet transport cylinder. The sheets are each removed twice from the sheet transport cylinder.

Abstract: A machine for processing sheets, in particular a sheet-fed rotary printing machine, includes a transporting cylinder for transporting the sheets and having air nozzles disposed offset in relation to one another in a direction other than an axis-parallel direction of the transporting cylinder, and having a directing configuration for directing the sheets and having air nozzles, the configuration being assigned to the transporting cylinder. The machine is distinguished in that the air nozzles include throttled air nozzles and unthrottled air nozzles.

Abstract: A guiding device in a machine for processing sheets of printing material includes unthrottled air nozzles for contact-free guidance of the sheets, and throttled air nozzles arranged at locations which are prone to contact by the sheets; and a machine for processing sheets of printing material and a sheet-fed rotary printing machine, respectively, having the guiding device.

Abstract: A sheet processing device is provided in a sheet-fed printing press. Sheets are conveyed to a sheet transport cylinder and are processed on the sheet transport cylinder. The sheets are each removed twice from the sheet transport cylinder.

Abstract: A multi-color, web-fed rotary printing press provides a shortened construction. A web passes vertically downwardly through a plurality of bridge printing units which are arranged one above the other. A lowermost one of these bridge printing units has a transfer cylinder that changes the path of web travel from a generally vertical direction to a generally horizontal direction in route to a downstream located device, such as a drying device.

Abstract: The present invention is an apparatus and method for duplex printing of a sheet-like substrate in a continuous single-pass flat printing process. The device comprises a first conveyor unit in communication with a feeder and a second conveyor unit in communication with a delivery. Each conveyor unit has a printing device and a drying/curing device disposed adjacent to the conveyor unit for applying a printed material to the substrate. A transfer device is disposed between the two conveyor units for transferring the substrate from the first conveyor unit to the second conveyor unit and turning the substrate, thereby allowing both sides of the substrate to be printed. Alternative embodiments may include any number of conveyor units and transfer units.

Abstract: A paper guide apparatus of a perfecting press is disclosed. The perfecting press comprises a blanketed impression cylinder which has a holding device for holding paper and prints one side of the paper, and a blanket cylinder which is in contact with the blanketed impression cylinder and prints the other side of the paper. The blanketed impression cylinder and the blanket cylinder are arranged nearly horizontally. In the paper guide apparatus, suction chambers for sucking and guiding the paper transported by the blanketed impression cylinder are provided between a transfer cylinder located directly ahead of the blanketed impression cylinder and the blanket cylinder, and an air nozzle is provided for blowing air between the paper transferred from the transfer cylinder to the blanketed impression cylinder and the circumferential surface of the blanketed impression cylinder.

Abstract: Four impression cylinders of first and second face-side coating units and first and second back-side coating units, and two transfer cylinders of a face-side drying unit and a back-side drying unit are arranged adjacently and nearly linearly in a paper flow direction. Above circumferential surfaces of the odd-numbered cylinders of these cylinders, the first face-side coating unit, the second face-side coating unit, and the face-side drying unit are arranged. Below circumferential surfaces of the even-numbered cylinders, the first back-side coating unit, the second back-side coating unit, and the back-side drying unit are arranged. Above the circumferential surfaces of the odd-numbered cylinders, a first face-side drying device and a second face-side drying device, each of which has one dryer, are disposed downstream of the first face-side coating unit and the second face-side coating unit, respectively.

Abstract: A sheet processing device is provided in a sheet-fed printing press. Sheets are conveyed to a sheet transport cylinder and are processed on the sheet transport cylinder. The sheets are each removed twice from the sheet transport cylinder.

Abstract: A vacuum assisted sheet transfer assembly has an array of support bars which support the unprinted side of a freshly printed sheet along a sheet transfer path. The support bars overlie the airflow inlet of a manifold housing, with the longitudinal axis of each support bar extending across the sheet transfer path. The support bars provide smooth surfaces for engaging and supporting the unprinted side of the sheet material as it is pulled along the transfer path while simultaneously limiting the flow of inlet air through elongated inlet apertures. As air is drawn through the inlet apertures, the unprinted side of the sheet is sucked into engagement with the support bars as it moves along the sheet transfer path. The sheet transfer assembly eliminates the need for conventional skeleton wheels and the like. Marking, smearing and smudging are prevented since the printed side of the sheet is not handled or contacted in any way as the sheet is conveyed along the sheet transfer path.

Abstract: A printing apparatus (1001) having a plurality of blanket cylinders (1051 to 1054) normally-contacting to impression cylinders (1031, 1032), plate cylinders (1041 to 1044) normally-contacting to the respective blanket cylinders, and a ink coating apparatus (1061 to 1064), a printing apparatus, an imaging apparatus, an imaging method, an imaging medium, a printing system, and a printing method. In the printing apparatus (1001), a plurality of ink coating apparatus (1061 to 1064) is arranged in a substantially gravity direction, a feeding apparatus (1020) of sheets of recording mediums to the printing apparatus and a discharging apparatus (1070) are provided at a side opposite to a setting side of the ink coating apparatus with respect to the blanket cylinders. The printing apparatus can execute a back face printing easily, and has good workability.

Abstract: A printing device for duplex printing of a sheet, comprising a feed path for feeding an unprinted sheet and a return path for returning a sheet printed on one side in an inverted orientation to a part of the feed path which is provided with an aligning station for aligning a supplied unprinted sheet and a returned sheet printed on one side. The aligning station comprises two aligning mechanisms which are disposed in spaced relationship in the feed direction and which each comprise two activatable transport nips which, as considered in a direction transversely of the feed direction, are situated a short distance apart so that a sheet fed between the nips can be aligned against one of each of the two transport nips by lateral transport and turning.

Abstract: The impression cylinder (2), which together with the cylinder (1) that prints the image, forms the printing nip, co-operates with two transfer cylinders (3, 4) which feed or remove the sheets, and has an essentially closed cylindrical circumferential surface, into which, at the beginning of each impression segment, a suction strip (5, 6) is inset to apply suction to the front edge of a sheet. The two transfer cylinders (3, 4) are similarly provided with suction strips (7, 8; 13, 14) which are arranged in good register with the suction strips (5, 6) of the impression cylinder (2), and moreover have dipping grippers (10, 12; 16, 18), which are located in gaps in the dipping strips. Sheet transfer to and from the impression cylinder (2) is effected by alternately switching on and off the suction air at the relevant suction strips.

Abstract: During first side printing, a media sheet is fed along a feed roller over a refeed guide toward a metering roller and into a print zone. As the trailing edge approaches a metering pinch line, the metering roller stops. After a drying time, the rollers reverse direction. The refeed guide directs the media sheet around the metering roller onto an inner guide having a reversible roller. When the trailing edge of the media sheet clears the refeed guide, the reversible roller is moved into contact with the metering roller causing such roller to reverse direction. The media sheet now moves back along the inner guide onto the feed roller. When the media sheet trailing edge is detected at the feed roller, the feed roller and metering roller change direction back to the original direction. The media sheet now is fed through the print zone for second side printing.