Abstract: An image forming apparatus includes an image carrier that is rotatable; a transfer member that is rotatably disposed so as to face the image carrier, the transfer member transferring an image carried by the image carrier to a sheet; a leading end gripping member that is attached to the transfer member, the leading end gripping member gripping a leading end of the sheet in the transport direction on an outer peripheral surface of the transfer member; a trailing end holding member that holds a trailing end of the sheet in the transport direction between the trailing end holding member and the outer peripheral surface of the transfer member; and a controller that changes a distance between the leading end gripping member and the trailing end holding member when holding the sheet on the basis of a length of the sheet in the transport direction.

Abstract: Provided is a quality inspection apparatus including: gripper units provided to each delivery chain, each gripper unit configured to hold an end portion of a sheet; an arc-shaped track portion provided in a part of a movement track of the gripper units and formed by the movement track; an inspection unit installed at an opposite side of the arc-shaped track portion from an arc center of the arc-shaped track portion; and a vacuum cylinder installed at the same side of the arc-shaped track portion as the arc center. In the apparatus, while running along the arc-shaped track portion, the sheet is inspected by the inspection unit under a guidance of the vacuum cylinder.

Abstract: An apparatus for turning a sheet during transport through a printing press provides better printed results as a result of improved sheet guidance. A transfer drum has gripper systems disposed in channels for holding the sheet at the leading and trailing sheet edge, and guide elements covering the channels.

Abstract: A sheet transfer system includes a register roller working for transfer of a one-side printed print sheet and a non-printed print sheet, a pair of first guide plates working to guide the one-side printed print sheet to the register, and a pair of second guide plates working to guide the non-printed print sheet to the register. The first guide plates make an opening angle ?1 in between greater than an opening ?2(?3) the second guide plates make in between.

Abstract: The invention relates to an automatic handling and transportation device for a printer housing. The device comprises a basic mobile unit movable on a first route and at least one handling unit mounted on the basic mobile unit. The handling unit includes a support for guiding and supporting housings born on a second route parallel to a housing-bearing assembly on a printing machine, able to be aligned with the same and an grasping/holding device, adapted to hold a housing and move it on the second route between a transferral position in which the grasping/holding device interacts with the housing installed on the housing-bearing assembly, and a transportation position in which the housing, held by the grasping/holding device is on the support, and vice-versa.

Abstract: In a balancing system and a method for balancing a drum of a printing plate exposer, at least one mass element is provided which can be moved substantially in the circumferential direction of the drum in order to reduce an imbalance of the drum. Previous devices and methods either needed the expertise and the knowledge of a user or external actuators which had to be driven by corresponding devices, for example computers, in order to compensate for an imbalance by moving the mass elements. The balancing system is simple and automatic balancing of the drum is achieved by a mass element being coupled to a positioning element and by its position being adjusted automatically on the basis of the circumferential extent of the printing form.

Abstract: A gripper for conveying a sheet through a printing machine makes it possible to increase speed. The gripper includes gripper fingers with finger tips disposed at a rotary articulation or joint.

Abstract: To record images accurately regardless of rigidity and size of a recording medium, each rear end clamp has a clamp rubber element for engaging a variable margin of the recording medium mounted peripherally of the recording drum. The margin is varied according to the rigidity of the recording medium. The margin is enlarged when the recording medium is highly rigid, and reduced when the recording medium is low in rigidity.

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: In a device for changing over a gripper control in a turning configuration of a sheet-processing machine, there is provided a slide to be guided axially displaceably by radial stops. The device changes over a gripper control from recto printing to verso printing on a transfer device such as a drum or a cylinder of a turning configuration in a sheet-processing machine.

Abstract: A method of varying a drum profile of a vario drum for transporting printing material sheets, in which shell segments of the vario drum are pivoted inward and outward. Sheet supporting elements assigned to the shell segments are reversibly deformed by pivoting the shell segments. A vario drum suitable for implementing the method and a machine containing the vario drum for processing printing material sheets contain the shell segments and the associated sheet supporting elements.

Abstract: In a method of operating a machine processing printing material sheets and having a sheet transport drum in various operating modes, drum circumferential shells are kept fixed on the sheet transport drum in an outer position in a first of the operating modes and in an inner position in a second of the operating modes. During a drum conversion to be carried out before the start of a third of the operating modes, the drum circumferential shells are removed from the sheet transport drum and, in this third operating mode, the sheet transport drum is rotated without the drum circumferential shells.

Abstract: A quality control device includes a suction box, at least one gripper which can be displaced along a suction surface of the suction box, and a CCD camera. A belt, which can be displaced in a sheet transport direction, is disposed on the suction surface of the suction box.

Abstract: The invention relates to a guiding device for metal sheet printing machines and metal sheet painting machines, which have at least two printing cylinders and a transfer drum situated therebetween. The guiding device is arranged on said transfer drum and, to be precise, is located close to the imaginary cylindrical outer surface of the transfer drum. The guiding device comprises at least one guiding element with an outwardly turned bearing surface for supporting the rear edge of the metal sheets. The guiding element is pivotally mounted by means of a swivel bearing whose pivotal axis is parallel to the axis of the transfer drum. The guiding element is coupled to a pivot drive by means of which its bearing surface can be adjusted to different pivoting angles (?) with regard to the tangent to the imaginary cylindrical outer surface of the transfer drum.

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 printing machine, which includes at least two printing unit groups having drives which are decoupled from one another and assigned, respectively, to one printing unit group, and having printing units with transfer cylinders, include compensation elements for compensating for speed differences and positional errors between two printing unit groups. The compensation elements are assigned to a printing unit group which is an accepting printing unit group, in order to compensate for transfer errors.

Abstract: A mechanism for correcting unbalance of a rotor that is caused at positions at which at least one of a leading edge chuck and a trailing edge chuck that hold a sheet member disposed on a peripheral surface of the rotor varying in accordance with the sheet size. The unbalance is corrected by disposing, at a predetermined distance from a rotary shaft, an anchor having a fixed weight. In a state where the unbalance is corrected, a main balancer is purposely attached to the rotor to cause an unbalanced state. According to the position at which the trailing edge chuck attaches to the peripheral surface of the rotor, a second arm is moved by mechanical interlocking to maintain an angle &thgr;2 with respect to a chuck holder. Consequently, unbalance is adjusted in accordance with the size of the sheet.

Abstract: A method of correcting a position of sheet material on conveying elements, the sheet material extending from a surface of a first sheet-conveying element to a surface of a second sheet-conveying element following downline from the first sheet-conveying element, as viewed in a conveying direction of the sheet material, which comprises detecting an actual position of a leading edge of the sheet material by at least one sensor element disposed on the first sheet-conveying element; by a control unit, making a comparison between a nominal and the actual position of the sheet material; and, if the actual position deviates from the nominal position of the sheet material, causing an actuator to fix the sheet material to the following second sheet-conveying element so as to perform a correction of the position deviation; a reversing or turning device in combination with the correction device; a printing unit having the correction device; and a multicolor printing machine in combination with the correction device.

Abstract: In a sheet-processing rotary printing machine operatable in recto printing and recto/verso printing modes, there is provided a device for reversing sheets, which includes a transfer drum bounded by two sheet-guiding cylinders, a reversing/storage drum and an additional transport element assigned to the transfer drum, the transfer drum being drivable in opposite directions of rotation in the recto printing and the recto/verso printing modes, and gripper systems actable in both directions of rotation of the transfer drum, the gripper systems being accommodated on an imaginary jacket surface of the transfer drum; a printing unit including the components of the device; and the printing machine being a multicolor printing machine.

Abstract: There is provided a double-sided printing press that includes a sheet-turning-over mechanism for turning sheets upside down at a sheet-turning-timing according to a set length of sheets, which has been previously set for the sheet-turning-over mechanism; and a sheet-length-detection means for detecting the length of sheets, which are fed to the sheet-turning-over mechanism; wherein where the length of sheets, which are fed to the sheet-turning-over mechanism and detected by the sheet-length-detection means, is deferent from the set length of sheets as a result of comparison therebetween, the sheets are stopped from being transferred to the sheet-turning-over mechanism.

Abstract: A sheet-fed rotary printing press has at least one unit which includes an impression cylinder and an additional cylinder assigned to the impression cylinder. The impression cylinder and the additional cylinder are relatively adjustable a spaced distance from one another. A sheet guiding device is disposed on the additional cylinder for keeping sheets of printing material, which have been transported by the impression cylinder past the additional cylinder, away from the additional cylinder, once the spaced distance between the impression cylinder and the additional cylinder has been set.

Abstract: A guiding device for an areal printing material, the guiding device having an areal structure with a guide surface facing towards the printing material, and wherein the areal structure includes a supporting layer, and a surface layer is provided for forming the guide surface and covering the supporting layer; and a rotary printing machine equipped with the guiding device.

Abstract: A feeder unit for a sheet-processing machine having a plurality of processing units is provided. The feeder unit includes a feeder, a feed table, and a feed drum. The feed drum is double-sized or larger in that it has a diameter at least twice that of the diameter of the plate or blanket cylinder of at least one of the processing units of the sheet-processing machine. The feed drum includes at least two gripper systems distributed symmetrically on a periphery of the feed drum. The feed drum is arranged with its rotational axis on or offset vertically above a horizontal plane formed by the rotational axes of the printing cylinders in the processing units. Each gripper system is pivotally supported on the feed drum and includes a gripper shaft, at least one gripper arranged on the gripper shaft, a gripper stop bar associated with the gripper, and a front guide arranged on the gripper stop bar.

Abstract: In a sheet-like object convey apparatus for a sheet-fed rotary printing press a cylinder shaft is rotatably supported between a pair of frames and rotatably driven during conveyance of a sheet-like object. Gripper pads and grippers grip an end of a sheet-like object conveyed from an upstream side of a sheet convey direction. A gripper pad bar and gripper shaft are supported by the cylinder shaft, to support the gripper pads and grippers in an axial direction of the cylinder shaft. A rod is rotatably supported parallel to the cylinder shaft and has an eccentric large-diameter portion. A lever, cam follower, and cam rotate the rod through a predetermined angle by rotation of the cylinder shaft. Press members are rotatably fitted on the large-diameter portion of the rod, to be displaced in a radial direction along with rotation of the rod.

Abstract: A suction gripper for transferring a trailing edge of a sheet guided on an upstream sheet-conveying cylinder to a downstream sheet-conveying cylinder of a turning device of a sheet-fed rotary printing machine includes a holding arm. The holding arm can be extended out of the circumferential surface of the downstream sheet-conveying cylinder, to which a suction head is movably fastened. The suction head is connected to the holding arm via a spring and its movement in a direction toward a circumferential surface of the upstream sheet conveying cylinder is limited by a stop.

Abstract: A stencil printing machine includes a printing drum having a flexible ink-permeable circumferential wall adapted to receive a perforated stencil sheet around an outer circumferential surface thereof, the printing drum being driven to rotate around a central axis thereof; a pressing device situated inside the printing drum for supplying ink to an inner surface of the circumferential wall, the pressing device being movable between a pressing position for pressing the circumferential wall to be deformed radially outwardly and a standing position for releasing the circumferential wall from deformation; an opposing drum disposed adjacent to the printing drum and driven to rotate in a direction opposite to that of the printing drum, the opposing drum having a recess formed in an outer circumferential surface thereof; a clamp disposed on an outer circumferential surface of the opposing drum and operating in synchronization with rotation of the opposing drum to hold a leading edge of a printing sheet supplied between

Abstract: In a reversing device of a sheet-fed rotary printing machine, there is provided a suction gripper for taking over a trailing edge of a sheet conveyed on an upline sheet-conveying cylinder, the suction gripper being movable out of a periphery of a downline sheet-conveying cylinder, gripping the sheet to be reversed in a region of the trailing edge thereof, and being movable back in a substantially radial direction towards the downline sheet-conveying cylinder for transferring thereat the trailing edge of the sheet to a further gripper device, including a device for converting the substantially radial return movement of the suction gripper into an axial movement of the suction gripper so as to tauten the sheet.

Abstract: A suction-air control device for controlling suction air applied to suction openings of a printing-press cylinder, having controllable valves by which the suction openings are connectable to a suction-air source, and a first pneumatic control device for timed or cyclically feeding the suction air, includes a second pneumatic control device for controlling the suction air in a manner dependent upon the format of the printing substrate, the valves being pneumatically controllable and being disposed on the cylinder.

Abstract: A drive system for an oscillating gripper of a sheet-fed printing machine has a main drive train and a controlled drive. The pregripper is mechanically coupled to the main drive train. The controlled drive supplies energy required to drive the pregripper in accordance with a position of the pregripper. The controlled drive at least approximately meets the discontinuous energy requirement of the pregripper.

Abstract: Device for laterally aligning sheets in a feeder of a sheet-fed rotary printing press wherein sheets having respective leading edges aligned at front lays of a feeder table are gripped by a gripper system of a pregripper in succession individually at an edge region thereof, and transferred with a swivelling or revolving movement to a gripper system of a revolvingly driven feed cylinder, includes motorized adjustment elements for laterally displacing at least one of the gripper systems transversely to sheet travel through the printing press, measuring elements for determining an actual position of a side edge of a respective sheet on the feeder table, and a setpoint- actual value comparator for comparing a setpoint position of the side edge of the respective sheet on the feeder table with the actual position of the side edge determined by the measuring elements, and for generating pulses for controlling the measuring elements in accordance with the comparison.

Abstract: A drive for a gripper mechanism of a feeding device for feeding separate products, for instance loose sheets, to a packaging or labelling machine, which gripper mechanism is arranged on a drivable drum (1) and comprises gripper elements (2) for gripping the products to be fed separately, wherein the drive of the gripper elements (2) comprises a toothed belt transmission (3, 4, 5), with the gripper elements (2) being connected to the driven pulley (3), and the driving pulley (5) being drivable by a double cam mechanism (6, 6', 7, 7', 8, 9).

Abstract: A rotatable gripper drum includes a seat mounted on the drum and a gripper supported on the drum for pivotal movement relative to the seat between an open position and a closed position. The seat is made from a resilient material and includes a body portion having first and second grip surfaces. The drum has a retaining pocket for receiving the body portion of the seat to secure the seat for rotation with the drum. The seat is selectively mountable in the retaining pocket with the body portion in a first orientation in which the first grip surface cooperates with the gripper to grip sheet material or in a second orientation in which the second grip surface cooperates with the gripper to grip sheet material.

Abstract: Point needles in a collecting cylinder are driven in a two stage extension process to initially needle or pierce the leading edge of a product web being cut. Once the cut has been made, the needle tips are moved further radially outwardly from the cylinder to secure the cut edge. As the signatures are transferred to a folding cylinder, the needle points are retracted along a single stage retraction curve which is different from the path traveled during the two stage extension process.

Abstract: A sheet reversing apparatus for a sheet-fed rotary press with a reversing mechanism includes a paper convey cylinder, gaps, a reversing mechanism, a paper trailing end holding member, a moving unit, and a pivoting unit. The moving unit performs a moving operation of the paper trailing end holding member which projects or retreats along an arc with respect to the outer surface of the paper convey cylinder in accordance with a pivotal movement of the paper convey cylinder. The pivoting unit performs a pivoting operation of the paper trailing end holding member in accordance with a movement of the paper trailing end holding member.

Abstract: A sheet transfer device for a sheet-fed rotary printing press includes a registration correction device. The registration correction device deforms the leading edge of the sheet using a deformable gripper bridge system. The gripper bridge system includes a gripper bridge which extends continuously over the width of the sheet transport path. The gripper bridge is supported at each of its two ends by a pivotable support to allow the gripper bridge to assume a deformed shape similar to that of a simply-supported beam.

Abstract: Gripper control for a cyclically rockingly driven pregripper for single-sheet feeding in a sheet-fed printing press, the pregripper being disposed at a free end of a rocker lever, which is swivelable about a rocker shaft fixed to a frame of the printing press, and having at least one sheet gripper forcibly movable by cams about an articulated shaft disposed parallel to the rocker shaft, for closing and opening the sheet gripper when the sheet is taken over and transferred, respectively, one of the cams being revolvable a single revolution, and another of the cams being disposed on a locally stationarily swivelable roller lever carrying a cam roller engaging with the one cam, the other cam being swivelable cyclically in the position thereof, the position of the cams determining the closing time and opening time of the gripper, includes an indexing mechanism for fixing the other cam on the locally stationarily swivelable roller lever, the other cam having a first gripper-closing cam region and a first gripper-o

Abstract: Device for avoiding registration errors at an oscillating pregripper of a sheet-processing machine includes a gripper bar deflectable in synchronism with the machine so that a respective sheet being processed therein undergoes stretching in a trailing region of the sheet. The gripper bar, in a middle region thereof, is guided and driven in a flexurally bending-resistant manner. A feeder cylinder carries thrust pads at both sides thereof for deflecting the gripper bar at the ends thereof in a sheet travel direction before a respective transfer of a sheet at the feeder cylinder, and for maintaining the deflection until sheet transfer has been completed.

Abstract: Suction-type grippers for a sheet-transfer drum includes a sheet-supporting element having a sheet-supporting surface formed with a plurality of suction-air openings disposed along a region thereof to be covered by at least one sheet edge, at least one flexible planar member disposed adjacent to said sheet-supporting element at a side thereof facing away from the sheet-supporting surface thereof, the flexible planar member having a member for sealing at least some of the suction-air openings.

Abstract: A sheet-conveying drum for use between units in a printing machine is provided with a plurality of gripper bridges arranged substantially circumferentially symmetrically on the drum surface. The gripper bridges hold the paper to the drum and include gripper impact strips that are adjustable radially relative to the drum in order to accommodate printing materials of different thickness. Each gripper impact strip is adjusted by means of a positioning device that is arranged on the drum radially inward of the gripper impact strip and mounted so that it can move axially relative to the drum and cam the gripper impact strip radially. The axial movement of each positioning device is brought about by an actuating device which is preferably a pneumatic cylinder and is disposed on the body of the drum at the free end of each positioning device. An energy supply sequentially actuates each actuating device resulting in the piston of each cylinder either extending or retracting.

Abstract: Device for register correction and for compensating for distorted sheets in a pregripper of a feeder for a sheet-fed rotary printing press has a frame-fixed brace disposed on a pregripper shaft and located approximately centrally between end supports on a gripper bar, the gripper bar being supported rigid against torsion at opposite ends thereof on the pregripper shaft and being capable of executing swivelling movements in a sheet-feeding direction and in a direction opposite thereto, the frame-fixed brace serving for elastically bending the gripper bar in the sheet-feeding direction before the sheet is gripped by sheet grippers which are disposed side by side on the gripper bar and are swivellable about an axis of the pregripper shaft, the brace including a cam roller by which it runs onto an adjustable cam having a frame-fixed support, and an articulated joint with an eccentric element having a lever arm connected thereto for carrying the cam roller spaced from a center of the eccentric element.

Abstract: A sheet transfer drum of a multi-color sheet-fed rotary printing press. A central drum body with flat portions carries at least one gripper system which extends over the sheet width. Jacket segments are mounted on the flat portions of the drum body. The jacket segments are exchangeably attached and they are formed with an inflatable interior. When they are deflated, the jacket segments fold into the flat portions of the drum body.

Abstract: An adjusting device has a pneumatically operating piston-cylinder unit pressurizable in an operating function thereof for actuating adjusting elements in a printing press. The piston-cylinder unit includes a cylinder housing formed with a cylinder chamber, a piston displaceable in the cylinder chamber, and an electromagnet for applying an activated holding force to the piston, the piston being subjectible pneumatically to a prepressurizing force in the cylinder chamber opposite to and less than the activated holding force.

Abstract: A folding cylinder for a web-fed rotary printing press is provided with signature end engaging point spurs. The cylinder is also provided with signature grippers which will engage the signature end or sides so that the point spurs can be retracted at a slower rate of speed to thereby avoid damaging the signature end.

Abstract: The device has a sheet-transfer cylinder (2) with a movable setting plate (3) which bears the sheet grippers (4) and whose lateral ends are individually adjustable during each revolution of the transfer cylinder (2) with the aid in each case of a roller lever (9) in the circumferential direction in such a way that the sheet transferred to the impression cylinder is in a position which corresponds to the precise printing register. For this purpose, each roller lever (9) mounted movably on the transfer cylinder (2) is guided in a guide path (15c), surrounding the cylinder axis (1) in an annular manner, of an actuator (15, 16) which is suspended pivotably above the cylinder axis (1). Said actuator is provided with individually adjustable stops (19a, 19b) which, by interaction with peripheral cams (24a to 24d) pivot the relevant actuator (15, 16) by a predeterminable amount during each revolution of the transfer cylinder (2) and thus displace the relevant end of the setting plate (3).

Abstract: Gripper control for a cyclically swingably driven pregripper for transporting single sheets in a sheet-fed printing press, the pregripper having at least one sheet gripper mounted on a free end of a swivel lever motorizingly pivotable about a frame-fixed swivel shaft, the gripper control including cams for forcibly moving the sheet gripper about an articulated shaft oriented parallel to the swivel shaft so as to close and open the sheet gripper upon sheet acceptance and sheet transfer, one of the cams being revolvable in a single revolution for cyclically shifting the other of the cams in the position thereof, the other of the cams being secured to a roller lever supported pivotally at a fixed location and having a cam roller resting on the one cam, relative positions of the cams being adjustable for determining the instants of closing and opening of the gripper, the other of the cams being a cam segment having two successive circular cam regions with radii of curvature of different length and a common center

Abstract: A sheet reversing apparatus for a sheet-fed rotary press with a reversing mechanism includes a paper convey cylinder, gaps, a reversing mechanism, a paper holding unit, a gripper moving unit, and a gripper pad moving unit. The gripper moving unit moves the gripper member of the paper holding unit from the gap to an outer surface of the paper convey cylinder in accordance with a pivotal movement of the paper convey cylinder. The gripper pad moving unit moves, in accordance with the pivotal movement of the paper convey cylinder, the gripper pad member of the paper holding unit between an operating position and a retreat position.

Abstract: Gripper control for sheet grippers on a sheet-guiding cylinder or the like in a printing press, wherein a stationary pressure generator for a pressure medium is connected by means of a coupling, through the intermediary of a motor-actuated servo-valve, to a sheet-gripper actuating system disposed on the cylinder or the like and, through a control system, being acted upon by the pressure medium in time with an operating cycle of the printing press, includes a piston-cylinder unit forming part of the actuating system, a displacement-measuring system connected to the piston-cylinder unit, respective elements for pivotally connecting the piston-cylinder unit, at one end thereof, to the sheet-guiding cylinder or the like and, at the other end thereof, to a lever connected to the sheet gripper, the control system including a programmable control computer connected by measuring lines to the displacement-measuring system and, via a position-control loop, being capable of controlling a motor-actuated positioning of th

Abstract: A delivery machine of a folder unit including endless transfer means disposed to pass in close proximity to a downstream side of a discharge portion of a folding machine for discharging, one-by-one, folded paper sheets while passing around guide wheels driven in synchronism with the operation of the folding machine. The delivery machine also includes an openable/closable folded paper sheet holding device sequentially disposed on the endless transfer means with predetermined gaps between them. A folded paper sheet holding operation device brings the folded paper sheet holding device at least from an open state to a closed state in close proximity to the downstream side of the discharge portion of the folding machine so as to allow them to hold one-by-one the folded paper sheets discharged sequentially from the discharge portion of the folding machine.

Abstract: Clamping and tensioning device for an inwardly bent trailing edge of a flexible printing plate disposed in an axial gap at the circumference of a plate cylinder adjustable in axial spacing and cooperating with a blanket cylinder, the printing plate being fixable at a leading edge thereof on the plate cylinder and being tensionable in circumferential direction on the plate cylinder, includes two clamping bars displaceably supported in the axial gap and forming therebetween a clamping slot for receiving therein an inwardly bent trailing edge of the printing plate, the two clamping bars extending axially in the gap within the cross-sectional contour of the plate cylinder and being loadable by reversible opposing clamping forces as well as by reversible tensioning forces in common in tensioning direction of the printing plate, and being respectively braced against the plate cylinder, the two clamping bars being formed with radially outer edges, the clamping and tensioning device being radially displaceably dispos

Abstract: Swivelling pre-gripper of a sheet-fed printing press having a sheet feeding table includes a swivel arm; a gripper carried by the swivel arm; a mutually cooperating roller lever and cam mechanism for, respectively, opening and closing the gripper; a device for cyclically swivelling the swivel arm of the pre-gripper to and away from the sheet feeding table; a device for cyclically opening and closing the gripper; a device for setting an instant of opening of the gripper for releasing a sheet gripped by the gripper in a closed condition thereof to a downline conveying device for accepting and transporting the released sheet; a device for setting, in a manner decoupled from the setting of the instant of opening, an instant of closing the gripper for gripping the sheet fed from the feeding table to the pre-gripper; one of the devices for setting the instant of opening and for setting the instant of closing of the gripper being disposed on the roller lever; and the other of the devices for setting the instant of c