Abstract: A printing cylinder mandrel (1) arranged to support a sleeve mounted on it and carrying the print characters, the mandrel (1) being surface-deformable and able to assume at least two configurations, in one of which the sleeve can be mounted on it and in the other of which the sleeve is torsionally locked to it, the mandrel (1) comprising a core (2) the surface of which is covered with a deformable element (8), between this latter and said core there being provided a plurality of intercommunicating perimetral chambers (10) containing an incompressible fluid; the mandrel (1) internally houses presser means (20) arranged to pressurize said fluid in order to achieve the surface deformation of the mandrel (1) and the torsional coupling and locking of the sleeve, said presser means (20) being guidedly movable within the mandrel (1) and being activated by feeding into this latter a pressurized fluid.

Abstract: A cylindrical stamp is capable of simply forming a stamp pattern inexpensively. The stamp device includes a ring-like member, an ink impregnated body provided around an outer periphery of the ring-like member and a perforated stencil provided around an outer periphery of the ink impregnated body. The stencil includes a stamp pattern having a portion permitting ink to permeate and a portion prohibiting ink from permeating. A pair of end caps secure the edges of the stencil to securely hold it in place and prevent ink seepage. The end caps easily snap into the ring-like member and provide a pair of axial shafts to assist in rotation.

Abstract: A rotary printing press cylinder mounting utilizes a bearing positioned in an annular bushing and separating the bushing into two chambers. A liquid lubricant is fed directly to the bearing by a feed pipe. A separating wall extends radially inwardly adjacent an inbound side of the bearing. Any lubricant that moves past the separating wall is collected in the inbound chamber and drains to the outboard chamber for return to a sump.

Abstract: An anti-ghosting roller having a main shaft, an inner race detachably mounted on the main shaft, a rotary bearing having movable bearing elements (e.g., needle bearings) positioned on the inner race, a roller core secured to the rotary bearing, and an end collar mounted to the shaft and spaced from an end of the roller core such that the roller core can both rotate and axially oscillate relative to the main shaft. The inner race extends beyond the end of the rotary bearing. An end collar is mounted to the end of the shaft. The end collar includes a spacer portion extending axially toward the roller core. The spacer portion is radially spaced from the main shaft so that it is free from interaction with the inner race.

Abstract: Transfer cylinder with an electromotive drive unit includes a common bearing for a rotor of the electromotive drive unit and for the transfer cylinder, the bearing being disposed in a unit of a printing press supporting the drive unit and the transfer cylinder.

Abstract: A flexographic printing cylinder comprises a hollow support cylinder with a supply of compressed air to within the hollow support cylinder. Nozzles pass through the support cylinder to convey the compressed air from the inside to the outside of the support cylinder. An interpolated sleeve tightly fits over the support cylinder, and a thin sleeve tightly fits over the interpolated sleeve. Nozzles extend through the interpolated sleeve in registry with the nozzles through the support cylinder to convey compressed air to the thin sleeve. Structure is provided for selectively opening and closing the nozzles of the interpolated sleeve.

Abstract: A cylinder in a rotary printing press is coupled to a driving wheel or gear by the engagement of two coupling disks. One of the disks is shiftable into coupling engagement with the other disk by application of a pressure medium to a work cylinder. A control valve is carried by the shiftable disk and limits the force of the pressure medium by use of a bleed passage that is closed only when coupling has been accomplished. The force of the pressure medium is at a higher level when coupling has been fully completed.

Abstract: A printing plate has an outer surface and an inner surface, the outer surface for receiving an image to be transferred to a printing blanket. The printing plate also includes a lead end and a tail end. A first bend and a second bend are formed at a first distance from the lead end of the printing plate, and a third bend is formed at a second distance from the lead end. A recessed portion is thereby formed between the second bend and the third bend, and an angular end portion is formed between the third bend and the lead end. The tail end of the printing plate is bonded to the recessed portion with an adhesive. In order to install the printing plate on the plate cylinder, the source of pressurized fluid is engaged to supply pressurized fluid, e.g. air, through the apertures of the plate cylinder. A press operator mounts an end of the printing plate onto the plate cylinder, aligning the angular end portion of the printing plate with the slot in the plate cylinder.

Abstract: A coloring device for transferring coloring materials from a writing or drawing instrument to a surface is disclosed. The coloring device includes a housing having a holder to hold a writing instrument, and, a roller connected to the housing for rotation about an axis. The roller is position to contact a writing instrument disposed in the holder to obtain coloring material therefrom and is further positioned to contact a surface to transfer the coloring material obtained from the writing instrument thereto as the roller rotates about the axis. In accordance with one optional aspect of the invention, the coloring device can be further provided with means for rotating the roller. These means may comprise a motor, a hand crank, or any other equivalent structure that can impart rotational motion to the roller. If the means for rotating is excluded, the roller is rotated by moving the coloring device such that the roller rolls against the surface to be marked.

Abstract: An offset rubber-blanket sleeve having a support sleeve in the form of a layered body. The layered body is produced from a plastic, preferably rubber, as a base material and the base material is reinforced by layer inserts embedded therein. Additionally, a rubber layer is vulcanized on the support sleeve.

Abstract: The hydrophilic properties of a printing-machine roller are adjusted with a coating applied on an outer surface of its cylindrical body. The coating contains at least 45% by weight of pure silicon, or it is formed exclusively of chemically pure silicon. The coating is between 0.2 and 2 mm thick and its surface roughness R.sub.z is no more than 5 .mu.m.

Abstract: An anti-ghosting roller having a main shaft, an inner race detachably mounted on the main shaft, a rotary bearing having movable bearing elements (e.g., needle bearings) positioned on the inner race, a roller core secured to the rotary bearing, and an end collar mounted to the shaft and spaced from an end of the roller core such that the roller core can both rotate and axially oscillate relative to the main shaft. The inner race extends beyond the end of the rotary bearing. An end collar is mounted to the end of the shaft. The end collar includes a spacer portion extending axially toward the roller core. The spacer portion is radially spaced from the main shaft so that it is free from interaction with the inner race.

Abstract: An attachment is made to a roller printer that indicates to a user of the roller printer that it is tracking a straight line on a vertical surface. The attachment in the best mode is a spirit level so positioned that it indicates whether the printing roller of the roller printer is horizontally oriented in use. A protractor or other form of angle indicator may be used with a pivotable spirit level to aid the user of a roller printer in producing a pattern that extends inclined to the vertical.

Abstract: An apparatus for reducing procession of a gapless tubular printing sleeve in an offset printing press caused by at least one fluid wave having a certain pressure trapped at an interface of the printing sleeve and a cylinder on which it is mounted. The apparatus includes a cylinder which is adapted to receive the printing sleeve for mounting on its circumferential surface. The cylinder has at least one path which connects an interface of the cylinder and the printing sleeve to a region of pressure lower than the pressure in the fluid wave. The path allows the fluid wave, which is trapped at the interface and advancing in front of a nip between the cylinder and an adjacent cylinder, to escape to the region of low pressure.

Abstract: A printing cylinder holding apparatus for a printing machine, includes a pair of bearing holding members arranged on one of a pair of frames which rotatably support a printing cylinder via a pair of bearing members, respectively. One of the frames has a first opening for allowing a cylindrical printing member to be put on and out of the printing cylinder. The bearing holding members are movable between a holding position wherein the bearing holding members hold one of the bearing members and an unholding position wherein the bearing holding members release the one of the bearing members to form a second opening which is associated with the first opening for allowing the cylindrical printing member to be put in and out of the printing cylinder.

Abstract: A printing mechanism for waterless offset printing including a form cylinder that carries a sleeve-shaped printing form and/or a transfer cylinder that carries a sleeve-shaped transfer form such that the forms can be slipped onto or removed from their respective cylinder. Both the transfer cylinder and the form cylinder having internal and external cooling arrangements.

Abstract: A printing sleeve including a nickel sleeve having an inner surface and an outer surface and opposite ends and a hard rubber layer bonded to the outer surface and having end portions extending beyond the opposite ends of the nickel sleeve, and an inner surface on the end portions of the hard rubber layer which are substantially in line with the inner surface of the nickel sleeve.

Abstract: A cylinder for a rotary press is removably supported between spaced flanges and journals. The cylinder has a body portion that is provided with axially retractable and extendable trunnions. These trunnions can be extended into engagement with the flanges or can be retracted into the cylinder body so that the cylinder body can be removed from between the flanges.

Abstract: A printing device (10) for a printing press (12) having a cylinder (14) having at least one journal (16 or 18) extending from an end (20 or 22) of the cylinder (14), and a bearing (30 or 32) on the journal (16 or 18) and having an inner edge (44 or 46) located in the range of 1/16 inches to 11/2 inches from the end (20 or 22) of the cylinder (14).

Abstract: A process and a device for register-correct positioning of printing form sleeves on printing cylinders of a rotary printing machine, each with a pressure gas cushion producible for shifting the elastically expandable printing form sleeve on the printing form cylinder. In order to provide quick register-correct positioning of the printing form sleeves without placing particular demands on the operating personnel, the positions of the printing form sleeves fitting tightly onto the printing cylinders are determined and then the printing form sleeves are individually set and released using the pressure gas cushion of the particular printing cylinder. Then the printing cylinder is turned relative to the printing form sleeve by its angular deviation relative to the register-correct position to be realized. Subsequently the printing form sleeve is again released as well as set relative to the printing cylinder by turning off of the pressure gas cushion.

Abstract: A process for producing a durable, readily-storable, cylindrically-shaped flexographic printing sleeve having inner and an outer cylindrically-shaped walls and a substantially constant cross-sectional inner and outer diameter is provided. The flexographic printing sleeve is readily axially mountable on and dismountable from a complementary cylindrically-shaped printing cylinder having an outer cylindrically shaped wall. The process comprises providing a sleeve body. A layer of a low temperature curable polymeric material is provided to the outer circumferential surface of the sleeve body. The low temperature curable polymeric material is then cured at a temperature not greater than about 150 degrees F. to form a hardened layer of the polymeric material having a substantially uniform degree of hardness without damaging or distorting the sleeve body. A portion of the hardened layer of the polymeric material is removed to produce a flexographic printing sleeve having a thickness of up to about 0.

Abstract: An apparatus for facilitating the movement of a printing sleeve with respect to a cylinder is provided which includes a manifold section having an air chamber therein in fluid communication with an air supply line. The manifold section has a plurality of air ports in fluid communication with the air chamber. An adapter ring is provided which surrounds the manifold section and has a plurality of air ports therein, corresponding in number to the air ports in the manifold section and adapted to be placed in fluid communication with the air ports in the manifold section. A locking collar for fixing the position of the manifold section on the shaft in contact with the cylinder and for fixing the adapter ring in contact with the printing sleeve is provided such that when pressurized air is introduced into said supply line, the air exits the air ports in the adapter ring and expands the sleeve thus allowing the sleeve to be moved with respect to the cylinder.

Abstract: In a lithographic printing press for printing on material in sheet or web form, a plate cylinder has a printing form mounted thereon. A gapless blanket cylinder is engageable with the plate cylinder and a tubular, removable blanket having a continuous surface is mounted on the blanket cylinder. Mechanisms to expand a cylindrical sleeve are provided as well as mechanisms to reduce cylinder distortion during rotation.

Abstract: A printing sleeve including a nickel sleeve having an inner surface and an outer surface and opposite end portions and opposite ends, and hard rubber rims bonded to the outer surface at the end portions and having rim portions extending beyond the opposite ends of the nickel sleeve and bonded thereto, and inner surfaces on the rim portions which are substantially in line with the inner surface of the nickel sleeve. A method of bonding a hard rubber rim onto each end of a nickel printing sleeve comprising the steps of applying an adhesive to each end and end portion of the sleeve, inserting a plug into each end of the sleeve, winding an unvulcanized rubber strip around each end portion of the sleeve and onto the play, and heating each rubber strip to cause it to cure and bond to the end portion of the sleeve.

Abstract: A plate cylinder for a sleeve-type printform, particularly an aluminum offset printform, with a ramp-like transition piece as a guide surface for the mechanical expansion of the sleeve-type printform onto the larger cylinder diameter. At least the surface area of the plate cylinder that is covered by the ramp-like transition piece has a highly wear-resistant and pressure-resistant slide surface of a material different from the remaining surface material of the plate cylinder to prevent abrasion when the printform is slipped onto the plate cylinder.

Abstract: In accordance with the invention, a magnetic cylinder and image plate or blanket carrier plate of magnetic material are provided for printing. The cylinder has a peripheral surface and the image plate or carrier plate is wrapped around the cylinder with an inner surface of the plate being in direct contact with the cylinder peripheral surface. The blanket and carrier plate are subject to circumferential movement around the cylinder as the blanket is subject to localized pressure from another cylinder in a nip, plus forces due to ink tack. The cylinder peripheral surface is defined by circumferentially spaced, axially extending ridges for suppressing local sliding by surface gripping with the plate inner surface.

Abstract: A new and improved printing cylinder or image carrier sleeve which is formed of either carbon fiber/particles or from a relatively thin flat sheet of metal. The flat sheet of metal, for example, stainless steel or tin, is rolled to form a cylinder of desired diameter and welded together along the longitudinal edges. The weld seam or spots may be filed to have a substantially flat and smooth surface. Also disclosed is a mandrel assembly having an outer expansion sleeve member with one or more yield or preferential expansion regions, for example, circumferential grooves for applying pressure to effect outward expansion of said outer sleeve member.

Abstract: A web transporting device usable in a rotary printing press or folder, includes a rotatably driven transport roller having a fixed axis and at least one engagable nip roller having an axis substantially parallel to the fixed axis and being engagable with the driven transport roller. The engagable nip roller has a length corresponding to a maximum width of the web processable in the printing press. A removable nip sleeve is provided which is axially mounted on the engagable nip roller. The removable nip sleeve has an least one ring-shaped annular gap disposed axially along its length which allows the web to ripple as it passes through the web transporting device without causing permanent wrinkles or creases to form in the web. A counterbalancing mechanism is also provided which stabilizes the engagable nip roller in a maintenance position as the removable nip sleeve is replaced.

Abstract: A rotary stamp including a casing having an opening, an impression wheel revolvably mounted within the casing and partially projected out of the opening of the casing and having an annular groove around the periphery, and an ink-absorbed absorptive belt stamp mounted around the annular groove of the impression wheel a slip joint and turned by the impression wheel over something to mark it.

Abstract: A printing group cylinder of a web-fed rotary printing machine is mounted by its journals on opposed side walls of the machine. A sleeve positioned on or about the cylinder may be slipped on or off of the cylinder through an opening in the side wall. During operation, the opening in the side wall is closed by placing a pair of sliding gates in their closed position. When it is desired to change the sleeve, the opening in the side wall is uncovered by displacing the sliding gates. In order to obtain good prim quality, the bearing is formed of multiple interengaging rings, of which at least one is eccentrically shaped. The eccentric shape of the ring causes the axis of the priming group cylinder to move into either a prim engagement or disengagement setting when the ring is slidably rotated. The eccentric ring is secured against turning when the sliding gates are opened.

Abstract: A sleeve-shaped printing sleeve for a form cylinder of a printing machine is fabricated from a blank of metallic material by cutting the blank to a width corresponding to the form cylinder and to an intermediate length which exceeds the circumference of the intended printing form cylinder. Additionally, the blank is provided with aligning indicia in the regions between each edge of the intermediate-length blank and the corresponding edge to be defined by cutting. Thus, these regions lie outside of the printing area. The blank is bent circularly, held in exact register in a bending/welding device, and cut to the length required for the intended form cylinder by laser beam cutters. As a result of this cutting operation, two waste pieces are produced. The waste pieces are removed and the now defined plate edges forming the beginning and end of the printing form are positioned opposite one another without overlap and welded together, preferably by a laser.

Abstract: An offset printing form comprising at least one printing form made up of at least one driving plate which is of metallic material and cut to size. The printing plate having starting and ending printing edges that are connected with one another so as to form a sleeve. A support for the printing plate is provided in the form of a slightly expandable hollow cylinder. The support is enclosed by an adhesive layer so that the printing plate can be placed on the adhesive layer so as to adhere thereto.

Abstract: A printing cylinder assembly comprises a cylinder shell with opposite open ends. Cylinder heads are received into the opposite open ends of the shell and include stub axle shafts which project outwardly in opposite directions. The shell open ends are reinforced by collet rings having an internally tapered collet face matched to receive a correspondingly tapered face on the cylinder heads. The opposite axle shafts are both bored coaxially to receive an end-to-end drawbolt. Internally, the cylinder heads have a sleeved socket to receive one end of respective graphite fiber tubes. At opposite ends, the graphite tubes are terminated into respective pin and socket joints. In assembly, the cylinder heads are faced to the sleeve collets with the graphite tube pin and socket joints meshed. The drawbolt is inserted along the axis length of the assembly and drawn tight by washer-nut fasteners.

Abstract: For the register of a sleeve-shaped offset priming form in which the beginning and end of the plate-shaped blank of the printing form are connected by a weld seam, a guide element in the form of a projection is provided for the sleeve at the inside of the sleeve. A form cylinder which can be used in combination with the sleeve has a groove extending along its entire width, which groove has a depth that is greater than the height of the projection. The projection can be inserted completely into the groove so that the sleeve can be secured on the form cylinder in the circumferential direction.

Abstract: Device for removing printing-unit cylinders from rotary printing presses having a transfer cylinder and a printing-unit cylinder, the rotary printing press including side walls formed with openings through which a bearing location of a printing-unit cylinder is accessible, includes surface portions defining one part of at least one opening of one of the side walls disposed concentrically to the axis of the transfer cylinder; the one opening including a removal region connected through the intermediary of a cutout to the bearing location of the printing-unit cylinder; the printing-unit cylinder, after removal of the transfer cylinder through the one opening which includes the removal region, being removable through the same one-opening removal region.

Abstract: A printing cylinder is disclosed comprising a four-piece mandrel assembly having spaced outer journal sections, a first cylindrical sleeve circumferentially mounted at its ends about a respective journal section, a second cylindrical sleeve having an inner diameter slightly larger than the outer diameter of said first cylindrical sleeve and being circumferentially mounted thereon by means, for example, circumferential welds, to provide a substantially uniform space circumferentially between said first and second sleeve members, said second sleeve member having one or more yield or preferential expansion regions, for example, circumferential grooves and a hydraulic system for applying pressure between said first and second sleeve members to thereby effect outward expansion of said second sleeve member.Another feature of the invention comprises the interchangeability of image carrier sleeves each having a selected thickness for mating operation with different inking rollers.

Abstract: The printing roller according to the invention comprises a core cylinder and a sleeve of plastic. The sleeve is built up from a tubular base body composed of a fiber-reinforced thermoplastic material and the base body is coated on its outer surface with a layer, produced by plasma-spraying, of copper or a copper alloy.

Abstract: A method for printing identity cards having blind hole-shaped recesses involves filling the recess at least partly with an element at the moment of printing so that the bottom of the recess is pressed against the printing surface. The elements are either firmly mounted on the back pressure surface of the apparatus or movably mounted in this surface. In the second case the elements can disappear into the back pressure surface if necessary.

Abstract: A tubular printing blanket for a blanket cylinder in an offset printing press comprises a cylindrical sleeve, a compressible layer over the sleeve, and an inextensible layer over the compressible layer. The cylindrical sleeve is movable telescopically over a blanket cylinder. The compressible layer comprises a first seamless tubular body of elastomeric material containing compressible microspheres. The inextensible layer comprises a second seamless tubular body of elastomeric material containing a tubular sublayer of circumferentially inextensible material. A seamless tubular printing layer over the inextensible layer has a continuous, gapless cylindrical printing surface. Methods of manufacturing the tubular printing blanket are also disclosed.

Abstract: An improved printing press includes a tubular-shaped printing blanket removably disposed on a blanket cylinder rotatably supported by a frame and having a continuous outer circumferential surface which is free of gaps. The printing blanket is disposed in rolling engagement with a conventional printing plate disposed on a plate cylinder having an axially extending gap in which opposite ends of the printing plate are secured. The printing blanket is removed by opening a portion of the frame and axially sliding the printing blanket off of the blanket cylinder. To assist in the removal or insertion of the printing blanket the blanket cylinder has passages which deliver a stream of air to the outer surface of the blanket cylinder which expands the inner circumferential surface of the printing blanket so that the blanket can be axially removed or inserted onto the blanket cylinder.

Abstract: A device for creating a printing pattern on an endless form sleeve utilizes a pattern forming head that is cooperatively positioned with an outer surface of an endless, sleeve. The sleeve has an inner ply of a ferromagnetic material and is supported in part by a support cylinder which may also be magnetic. A sleeve tensioning assembly is used to tension that part of the endless sleeve which is not supported by the cylinder.

Abstract: A rotatable rubber stamp device is disclosed which produces a special effect when the stamp is pressed against and/or rolled across a medium to be imprinted therewith. The special effects generated by the stamp can include audible (speech, sound and/or music), visual (light patterns and/or sequences, and displays). A cavity in the plastic handle of the housing of the stamp device contains the electronic circuitry necessary to provide the special effects messages. A sensor, such as a spring-metal, lever-action switch, is affixed within a support bracket for a translatable axle of the rotatable stamp device mount, so as to trigger the electronic circuitry to issue the special effects message in response to the imprinting of a visual image from the rubber stamp upon the desired medium.

Abstract: A Gravure printer comprises a mounting cylinder, an engraved printing sheet wound on the mounting cylinder, an ink supplier for supplying a surface of the printing sheet with ink, a doctor blade having a leading edge which scrapes the surface of the printing sheet to remove excess ink, and an impression cylinder for pressing a cut paper against the surface of the printing sheet. The feature of the invention is that the printing sheet is provided with an abrasive part to which the leading edge of the doctor contacts to be ground during rotation of the mounting cylinder.

Abstract: A circumferentially continuous printing plate, which has the advantage over clamp plates that a clamping arrangement and groove in a plate cylinder can be eliminated, is formed by rolling a flat printing plate into tubular or sleeve form and welding the end edges together, preferably by a neodymium-YAG laser weld, resulting in a narrow, less than 1 mm wide, weld seam (2) having upper and lower concave sides, or by adhering the end edges to an underlay saddle (9), the plate can be coated and imaged when flat or after having been rolled and installed on a plate cylinder (37) of a printing machine. Interengaging projection-and-recess elements (4, 6; 14, 16) are formed on the plate (1, 1') and on the cylinder (37), respectively, to ensure lateral and circumferential register.

Abstract: A printing apparatus comprises a printing roller (1) provided with a profile which containing (8) raised and lowered (9) parts in circumferential direction, a printing belt (3) provided at one side with a complementary profile, and an opposite roller (2) which together with the printing roller (1) determines a nip through which the printing belt (3) runs, in such a way that its profile side interacts with the printing roller, and its printing side interacts with the impression roller, which printing belt (3) is composed of an interlocked strip of plate material which is flexible as regards bending and is rigid as regards deformations in its plane, on one side of which a profiling of another, for instance rubbe-like, material is provided. Preferably, the profiling is carried out in the form of conical projections (6) distributed at regular intervals over the plate surface in question, and the printing roller (3) is provided with complementary recesses (9) distributed in a corresponding manner over its surface.

Abstract: In a rotary printing press with a printing cylinder and a counter roller, such as an impression cylinder, for example, and a print web guided between them, faultless print quality across the entire width is attained, even with an extremely wide print web and a correspondingly slim printing cylinder. The printing cylinder is provided with a fixed support and a jacket, which is rotatable around it, and is supported by a row of support elements with a printing pressure which is controlled individually or in groups. With this arrangement, a uniform printing pressure profile across the print web width and, simultaneously, a print gap which is generally uniform are attained. Deformations and displacements of the printing cylinder jacket cross-wise to the printing plane are avoided in that additional cross-bracing elements for exerting a restoring force on the printing cylinder jacket cross-wise to the printing plane are provided.

Abstract: A printing cylinder utilizes a magnetic surface to support a portion of a ferro-magnetic endless printing sleeve which has a circumferential length greater than that of the printing cylinder on which it is supported. A sleeve tightening assembly supports that part of the endless sleeve which is not in contact with the periphery of the printing cylinder.

Abstract: Flexographic press structure and operation which includes a plurality of decks each removably supporting a plate roll and an anilox roll with each roll including a sleeve rotatably mounted on a stationary mandrel and supported at the ends thereof, the press is equipped with a lifter at one end to free each roll from its support at the other end whereby the sleeve can be removed over the other end.

Abstract: A printing method and apparatus which use a sleeve-shaped printing form attached to a rotating body. The sleeve-shaped form conveniently permits the printing operation to be performed continuously and on both sides of the print career simultaneously. The sleeves preferably exhibit a number of process-specific functional layers. Exemplary layers are: (1) a supporting metal sleeve, (2) an intermediate metal layer for carrying the ink, and (3) a surface metal layer for carrying the water. Copper is an exemplary intermediate layer, and chromium is used as the surface metal layer.

Abstract: A printing unit (10) includes a blanket cylinder (20), a bearing assembly (56) and a door assembly (72). The blanket cylinder (20) carries a tubular printing blanket (36). The bearing assembly (56) includes a bearing housing (58) fixed to the stub shaft (50) on the end of the blanket cylinder (20). The door assembly (72) includes a door (82) which is supported for pivotal movement on a frame wall (22) of the printing unit (10). The door (82) has a closed position in which it extends across an opening (76) in the frame wall (22), and an open position in which it does not extend across the opening (76) in the frame wall (22). A clamping assembly clamps the bearing housing (58) on the door (82) when the blanket cylinder (20) rotates during a printing operation. The clamping assembly includes a first clamp (100) which fixed to the door (82) and a second clamp (102) which is supported on the door (82) for movement relative to the first clamp (100).