Abstract: A disposable inking cartridge adapted to be removably connected to a mailing machine, the cartridge comprising: a generally rectangularly-shaped hollow housing having opposed side walls and having an edge wall extending between the side walls, the walls defining an aperture formed in the housing; an ink impregnated reservoir roller extending between the side walls and supported thereby for rotation about a first predetermined axis; an ink impregnated transfer roller extending between the side walls and supported thereby for rotation about a second predetermined axis extending parallel to the first axis; and the reservoir and transfer rollers respectively dimensioned for rolling engagement with each other to cause ink from the reservoir roller to be transferred to the transfer roller, and the transfer roller disposed within the housing to permit peripheral access thereto via the housing aperture.

Abstract: A roller holding apparatus for a printing press which holds bearing portions at two end portions of a roller includes an annular roller holding portion and a bolt. The annular roller holding portion is arranged at each of the two end portions and has a semicircular holder and a semicircular cap pivotally mounted on the semicircular holder and capable of being opened/closed. The bolt causes the holder and the cap of the roller holding portion to fix each of the bearing portions at the two end portions of the roller.

Abstract: A mailing machine including a base; a postage meter removably mountable on the base; the base and meter respectively including structure for guiding the meter in a path of travel to a predetermined position on the base when mounting the meter thereon; and a disposable inking cartridge having a generally rectangularly-shaped hollow housing movably connected to the base, the housing having opposed side walls and having an elongate perimeter edge wall extending between the side walls, each of the side walls including an arcuately-shaped cam surface oppositely spaced from the cam surface of the other side wall, the cam surfaces and edge wall defining a substantially arcuately-shaped aperture formed in the housing; and a transfer roller impregnated with printing ink and rotatably connected to the side walls so as to extend therebetween and be accessible via the housing aperture, the cam surfaces located in the path of travel of the meter for engagement thereby to move the housing out of the path of travel and carr

Abstract: A self-oscillating roller assembly (10, 10A, 10B, 10C, 10D) with an oscillating shaft (54) mounted on translational bearings (58, 60) to slide along a stationary shaft (48) and with a rotary shaft (55) mounted to the oscillating shaft (54) on rotational bearings (80, 82) to provide rotational movement. A key assembly (62, 63, 64, 66) restrains the relative longitudinal movement between the oscillating shaft (54) and the rotary shaft (55) while a pair of springs (68, 70) provides bias to return the rotary shaft (55) and oscillating shaft (54) to a preselected home position.

Abstract: A self-oscillating roller assembly (11, 13) and method of oscillating a roller in an offset printing press having an oscillating drive assembly (11) for oscillating a rotationally mounted roller (10, 12) with a source of pneumatic pressure (62) by alternatively applying pressure to pressure chambers (42A, 42B) on opposite sides of the roller (10, 12) to impart a longitudinal force on the oscillating roller (10, 12) from the source of pressure (62) in two opposite directions and a controller (47) for controlling the application of pressure (58, 62) to alternately move the rotationally mounted roller in two opposite directions.

Abstract: Apparatus for coating a webbing uses rollers in contact with each other. The coating is applied to a first roller and coating thickness is limited by a knife blade. The coating travels to a point of contact with the second roller about which the webbing is wound, and the coating is thereby transferred to the webbing. By controlling the relative speed between the two rollers, the knife blade can be raised or lowered with respect to the first roller to attain greater control over the coating operation.

Abstract: A dry offset printing process using a printing apparatus including a) at least one inker block, each block inking a relief plate corresponding to one color of the final motif to be reproduced on an object and including an inker and a succession of transfer rollers, and b) a central blanket which can be placed into contact with the object to be decorated. An ink of suitable tackiness is selected, and the temperature of the ink is regulated in the inker to a predetermined temperature between 15.degree. and 30.degree. C.

Abstract: An oscillating form roller in the inking mechanism of a printing press includes a roller casing which is rotatable and axially displaceable relative to a roller shaft. During its axial displacement the roller casing encounters set collars that are fastened to the roller shaft so as to be continuously adjustable. Friction surfaces are provided so that, in this contacting position, the set collars and the roller shaft are caused to rotate in synchronism with the roller casing.

Abstract: A roller for moving one of ink and water through a printing press is disclosed as an elastomeric covering on a solid journal. The elastomeric covering includes spiral lands and valleys adjacent the lands having depths ranging from 0.002 to 0.004 inch for ducting water, and ranging from 0.002 to 0.015 inch for ducting ink. At valley depths of greater than 0.015, ink is carried solely on the lands for the purpose of lubricating the ductor system. One embodiment includes reversed spiral land and valley end segments that direct ink inwardly from the ends of the rollers to prevent ink buildup at those positions on a ductor roller.

Abstract: A printing assembly comprises a counter-pressure cylinder (11) and an inking unit (17). The counter-pressure cylinder (11) or the inking unit (17) and/or the substrate (10) are divided axially into a plurality of thermal zones (Z1, Z2 . . . Zn) that may be independently heated or cooled so as to change the viscosity of the ink in this zone. Thereby, the amount of ink may be thermally influenced over the width of printing. The control of the ink amount may be effected in the axial direction during the printing operation without any changes in the mechanism of the machine.

Abstract: A roller 14 for use with a surface-scraping doctor blade to meter a fluid applied to an outer surface of the roller 14. The roller 14 has the following elements: a substantially cylindrical core 101 having a core surface; a coating 105 of a polymer material 102 on the core surface, the coating 105 having a predetermined thickness and having a predetermined percent by volume of substantially hard wear-resistant particles 103, the coating 105 also having a surface which is the outer surface of the roller 14; a plurality of cells 104 in the coating 105, each of the cells 104 having at least one cell wall oriented substantially perpendicular to the outer surface of the roller 14 and having an open end at the outer surface of the roller 14. A method for the manufacture of the roller 14 and a method for using the roller 14 are disclosed.

Abstract: A mechanism for axially oscillating a distribution roller in a printing, duplicating or like machine, in which a drive shaft extends generally coaxially of the distribution roller. The mechanism is operatively associated between the drive shaft and the roller and includes right hand and left hand threads axially spaced of the shaft. A teeter member extends axially of the shaft and is pivotally mounted intermediate its opposite ends on a pivot axis extending generally transverse to the shaft. The teeter member has portions for alternating engagement in the right hand and left hand threads for axially oscillating the distribution roller in response to rotation of the roller. The threads have risers to lift the teeter member out of a respective threads, and a detent device facilitates moving the teeter member into the respective opposite thread.

Abstract: A distributor roller for a printing press is usable to distribute fluids or inks by rotational and axial movement. The roller is driven by frictional engagement with a cooperating roller. Axial oscillatory movement of the roller with respect to its roller shaft is accomplished by preventing a drive housing from rotating with the roller body. The distributor roller may be used as an oscillating or non-oscillating ink transport roller.

Abstract: A roller for a printing machine is formed having oleophilic metal cells and hydrophilic ceramic cross pieces. The ceramic material is applied to the outer surface and is then ground away to again expose the metal. An upper portion of the metal is then removed to leave the elevated hydrophilic ceramic cross pieces.

Abstract: An ink metering roller for a keyless inking system which comprises a steel or aluminum roller core and an outer surface of highly wear-resistant hard particles imbedded in an oleophilic and hydrophobic bonding matrix, which matrix is subject to wear by contact with a coacting doctor blade, thereby creating gaps or interstices between the hard particles for conveying fixed amounts of input ink to the rotary press.

Abstract: A coating apparatus for use in a sheet-fed, offset rotary printing press to selectively apply a protective and/or decorative coating to the wet ink surface of freshly printed sheets and including a coating unit having a pick-up roller for supplying aqueous coating material from a reservoir to the surface of a delivery cylinder mounted on a press delivery drive shaft, the delivery cylinder performing the dual function of a coating applicator roller and a delivery cylinder during coating operations.

Abstract: A dampening system has a pan for containing dampening fluid, and transfer and metering rollers for bringing dampening fluid up out of the pan. A transition roller contacts one of the transfer and metering rollers. The transition roller is movable between first and second position. In the first position, the transition is off of the plate cylinder and dampening fluid is applied to the plate cylinder by ink form rollers. In the second position, the transition roller is on the plate cylinder. Another version of the dampening system has a bridge roller between the transition roller and a ink form roller, which bridge roller is movable between the third and fourth positions. In the third position, the bridge roller is on the transition roller. In the fourth position, the bridge roller is off of the transition roller. The dampening system can dampen the plate cylinder without the use of alcohol. The transition roller is rotated by a separate motor so that its speed is controlled independently of the other rollers.

Abstract: This roll mounting assembly (100) for mounting an anilox roll between opposed sideframes (12) includes an anilox roll (120) and opposed end bearings (124). Each sideframe (12) includes an open ended flanged slot (130) receiving an associated bearing (124) at each end and a screw clamping assembly (140) is disposed at the other end of the slot (130) to apply a predetermined pressure to bearing (124) through the medium of a clamping pad (148).

Abstract: An ink dispensing device is disclosed wherein the ink releasing member comprises two layers that serve different purposes. The layer which contacts a printing font is made of a porous material that has an open pore size of less than 30 microns and a porosity of 40% to 85%. The second layer is adjacent to the contact layer and is made from an elastic foam with larger pore size, in the range of 80 microns to 1000 microns and a porosity of greater than 70%. The second layer is impregnated with ink and acts as a reservoir for the first layer, the latter serving as a metering member.

Abstract: To associate the ink requirement of subject matter to be printed from a printing forme (6, 27) to the ink being supplied thereto by an ink application cylinder (5, 26), the ink application cylinder is provided with a jacket, sleeve or cover having a cellular surface, and in which the cell distribution or cell configuration of the surface is matched, at least approximately, and, for example, in zones or regions, to the subject matter to be printed from the forme. The ink can be transferred by an ink application roller, in which a plate cylinder carries the forme, and the ink application roller, the plate cylinder and the cylinder with the cellular surface cover all have essentially the same diameter and are all driven at the same speed.

Abstract: In a safety device for ink forming rollers, each of the rollers is supported on a frame through a moving shaft movable in an axial direction to remove the ink forming roller, a safety pin is provided which is urged and supported on the frame, the moving shaft is formed with a recess for engagement with the safety pin and guide surface for guiding the safety pin to the recess against the urging force of the safety pin. When the ink forming roller is mounted, the safety pin automatically engages to interrupt movement of the moving shaft, thereby preventing the ink forming roller from falling down due to an external cause such as a power stoppage or a misoperation, and the safety device being prevented from careless locking failure, thereby improving the safety of the printing machine.

Abstract: An inking roller or ink metering roller comprised of a base roller, a substantially continuous hard and wear-resistant microporous ceramic coated layer bonded to the base roller and an interdiffused and immobilized oleophilic and hydrophobic essentially organic polymeric based material affixed to the surfaces and interstices of the microporous layer.

Abstract: An oscillator apparatus for imparting axial oscillations to a roller (10). The roller (10) has at least a cylindrical outer core (12) rotatable about a stationary shaft (14), that is, the shaft (14) is stationary relative to the outer core (12) of the roller (10). The oscillator apparatus is connected to a supply (46) for providing a pressurized medium. The oscillator apparatus has at least one reciprocating assembly (30, 32) having a substantially stationary portion attached to the stationary shaft (14) and a moveable portion attached to the outer core (12), the reciprocating assembly (30, 32) also having at least first and second ports (52, 54) connected to the supply (46). The supply (46) alternately provides the pressurized medium to the first and second ports (52, 54) to activate the reciprocating assembly (30, 32).

Abstract: An inking roller or ink metering roller comprised of a base roller, a substantially continuous hard and wear-resistant microporous ceramic coated layer bonded to the base roller and an interdiffused and immobilized oleophilic and hydrophobic essentially organic polymeric based material affixed to the surfaces and interstices of the microporous layer.

Abstract: An oscillating forme roller which is unseable in an inking unit of a rotary printing machine has a rotatable and axially oscillating mantle tube carried on a roller axle. Stops are used at either end of the axle to prevent oscillation of the mantle tube. At least one of these stops is moveable axially to selectively prevent or allow the axial movement of the mantle tube.

Abstract: In an inking apparatus for a printing press, a rotary lever is rotated by adjusting means disposed between a roller arm and the rotary lever around an axis parallel to a swing shaft of the roller arm to move a cam follower mounted to the rotary lever, and a cam mounted coaxially with a plate cylinder is rotated by cam driving means to select pressing state and unpressing state of the ink form roller through the cam follower, thereby preventing the nip pressure from being varied by skewing adjustment of the plate cylinder.

Abstract: Printing machine with at least one printing unit having rotating cylinders, comprising an energy converter disposed at least partially in one of the cylinders for converting at least some rotational energy of the cylinder into electrical energy and an energy storage device also disposed in the cylinder for storing the electrical energy.

Abstract: According to a printing machine ink roller and a method of the invention for manufacturing the same, a surface layer (18) consisting of a synthetic resin or a rubber-like material, which has ink absorbency and which allows surface polishing, is arranged on a surface of a mandrel, a large number of substantially spherical particles are mixed in the surface layer (18), and a large number of independent projections (16) are formed by partially exposing predetermined substantial particles in a surface region (17) of the surface layer (18). The ink roller can maintain a function of transferring a predetermined amount of ink for a long period of time so that the performance of a printing machine can thus be improved, and such a printing machine can be very easily manufactured and repaired.

Abstract: Dampening unit for an offset printing machine includes a metering roller, a dampening form roller for applying dampening medium to a plate cylinder of the printing machine, the metering roller and the form roller being in mutually pressing engagement at a contact zone along respective axially parallel lines on respective casings of the rollers, a drive for rotating the metering roller and the form rolelr with circumferential speeds which are substantially in a downward direction in vicinity of the contact zone, a storage space for dampening medium located above the contact zone and defined by surfaces of the casings of the metering roller and the form roller and sealing elements located at respective ends of the metering roller and the form roller, and a traversing distributor roller disposed in direct friction contact with the metering roller.

Abstract: According to the invention, a surface layer consisting of a synthetic resin or rubber substance which has an ink suction property and can be subjected to surface grinding is formed on the surface of a core metal, a large number of substantially spherical grains and a recess forming substance are mixed in the surface layer, a predetermined amount of substantially spherical grains are partially exposed on a surface region of the surface layer to form a large number of mutually independent projections, and a large number of recesses are exposed on the surface layer by the recess forming substance. There are provided a printing machine ink roller which can maintain transfer function of a predetermined amount of ink for a long time period, can improve printing performance of a printing machine, and can be easily manufactured and repaired and a method of manufacturing the same.

Abstract: The invention relates to a liquid transfer article, such as a printing roll, having a laser-engraved coated surface comprised of wells adapted to receive a liquid and land areas adapted to be wiped free of any liquid prior to contacting a receiving surface so that only the liquid in the wells are transferred. The land areas of the coated surface have a density of greater than 95% theoretical and a roughness of less than 6 micro-inches R.sub.a to insure that any unwanted liquid on the land areas can be wiped clean prior to contacting a receiving surface. The invention also relates to a method for producing the liquid transfer article.

Abstract: A roller for distributing a coating material such as ink in a press is mounted on a shaft for sliding axially on and rotating on the shaft. First and second internally threaded sleeves are fixed internally of the roller coaxially with each other and concentric to the shaft. One of the threads has a left hand twist and the other has a right hand twist. Two follower plungers, one having left hand thread segments and the other having right hand thread segments are meshed alternately with the left and right hand twist square threads. A link spans between double armed levers which connect to the follower plungers, respectively. When one plunger is automatically forced out of engagement with its cooperating thread in the one sleeve, a force is transmitted through the link to the other lever which causes the other follower plunger and its thread segments to mesh with the internal threads on the other sleeve so the roller changes the direction of its axial movement.

Abstract: A pneumatic axially oscillated, frictionally rotated roller is disclosed and may be used in the ink or damping systems of a printing press. The roller features an internal air piston-cylinder construction that causes the axial motion but permits the roller to freely rotate. Further, several air cylinders can be stacked on each side of the roller to permit even a small diameter roller to be pneumatically oscillated. The roller, when used as an ink form roller, may be operated to oscillate in synchronization with an adjacent oscillating, vibrating roller to continually diagonally redistribute the ink so as to eliminate or minimize "ghosting". The foregoing is accomplished by controlling the oscillation of the form roller to move axially in a direction opposite of that of the vibrating roller. The lengths of the strokes of the two rollers may differ or be the same.

Abstract: An internal worm drive has a worm gear and a substantially hollow tubular worm with an outer surface and an inner surface. The inner surface has at least one internal worm thread mating the worm gear. The axis of the worm gear is substantially perpendicular to the longitudinal axis of the tubular worm. Utilizing the tubular worm with the threaded internal surface in conjunction with the mating worm gear is an oscillating roller assembly suitable for use as an ink roller in lithographic presses. The oscillating roller assembly has a shaft, and a bearing unit mounted along the shaft. A worm gear having a plurality of teeth is contained in a slotted space in the bearing unit and the shaft such that the rotational axis of the worm gear is substantially perpendicular to the longitudinal axis of the bearing unit and the shaft. The slotted space has first and second opposite longitudinal ends within the shaft.

Abstract: A moisture distribution roller assembly for use in a moisture feeding system of a printing, duplicating or like machine includes a shaft with a plurality of roller sections slidably mounted thereon. The roller sections are selectively positionable on the shaft at varying axial positions thereon to vary the effective surface area of the distribution roller assembly and, therefore, the amount of moisture carried by the composite roller assembly. As illustrated, the assembly has a central roller portion with stub shafts projecting axially outwardly from opposite ends therof, with the roller sections positionable on the stub shafts. Therefore, the central roller portion can be dimensioned axially to be substantially equal to the narrowest paper intended to be used in the machine.

Abstract: A replaceable ink cartridge provides a means for replacing an ink roller on an imprinting device without soiling ones hands or clothes. The replaceable ink cartridge includes an ink roller which is received within and contained by a molded containment member prior to its insertion on an imprinting device. In addition, an imprinting device utilizing the replaceable ink cartridge and a method for replacing a replaceable ink cartridge without soiling ones hands or clothing are also provided.

Abstract: A distributor roller for use in a printing press which includes an axial shaft member, a casing member surrounding the axial shaft member and being rotatably and axially slidably mounted with respect thereto, an interior surface of the casing member having a cross-section which, when taken tranverse to the axial shaft member, is eccentrically disposed with respect thereto, an arrangement for rotating the casing member about the axial shaft member, an oscillating body member disposed within the casing member and mounted for pivotal movement in a direction transverse to the longitudinal axial shaft member, the oscillating body member having an engagement surface for engaging the eccentrically disposed interior surface of the casing member, thereby the oscillating body member is caused to undergo a reciprocating movement in the direction transverse to the axial shaft member upon rotation of the casing member thereabout, and conversion means for converting the reciprocating movement of the oscillating body member

Abstract: A pitted roll for an offset litho press inking unit, more especially as part of a short inking unit, has a dual coating layer of which the inner layer is formed of a material such as copper comprising the application of a high affinity for ink and the outer layer is formed of ceramic material to give lands wiped by a doctor, preferably set at a negative angle, around the pits. A high wear resistance and a high accuracy may be achieved if the plain base member of the roll is coated with copper or the like and then with ceramic material, after which engraving takes place to penetrate the ceramic layer right into the copper or the material with an affinity for ink.

Abstract: A roller for use in lithography which comprises a surface layer of finely and uniformly mixed ultra-hard material and lipophilic material. The ultra-hard material is preferably tungsten carbide-cobalt and the lipophilic material is preferably aluminum bronze casting, the aluminum bronze casting being mixed with the tungsten carbide-cobalt in the ratio of 25-40% by weight.

Abstract: An unengraved metering roll made of porous ceramic material is described for depositing measured amounts of liquid as a coating on a substrate such as a metal can. The coating liquid is contained within the pores of the ceramic roll and deposited upon the object or a transfer roll without the use of metering cells which are ordinarily provided by engraving a pattern on the outer surface of the roll. The pores are of a substantially uniform size and are distributed substantially uniformly throughout the ceramic roll. The metering roll of porous ceramic material may be more easily resurfaced merely by grinding in a conventional manner to remove the original outer surface and replacing it with a new outer surface having pores which open to such outer surface for receipt of the coating liquid.

Abstract: Process for the production--using plasma spraying--of a coated product in which the coating consists of a ceramic fluorocarbon polymer-comprising coating, while between the surface of the product and the ceramic fluorocarbon polymer-comprising coating an adhesion layer completely of metal is applied. The adhesion layer consists in particular of at least two metals reacting exothermally with each other under plasma spraying conditions. In particular, the product to be coated is a thin-welled nickel, seamless cylinder with a wall thickness of 50-220 .mu.m. The invention also relates to an ink transfer roller in which a thin-walled seamless cylinder obtained by the process according to the invention is used.

Abstract: A liquid transfer article, such as an ink roll, and method for producing it, in which the article comprises a substrate coated with a ceramic or metallic carbide coating having engraved in its surface a pattern of wells adapted for receiving a metered quantity of a liquid, such as ink, and wherein the microporosities in the surface of the wells are filled with a film of a vapor-deposited polymer, such as parylene.

Abstract: An adjustable bearing arrangement for the cylinder of a rotary printing press provides a fine adjustment in which a step-down in the angle of rotation of the adjusting movement of an eccentric bushing relative to the rotation of a radially slotted cylinder mounting bracket is ensured. The locating pin of the cylinder mounting is rotatably mounted in the eccentric bushing and rotation-inhibiting means for the pin is formed by a groove in which one end of a rotation-inhibiting lever is guided after the fashion of a prismatic joint, the other end of the lever being so mounted fixedly to the frame that the lever can pivot around a knuckle joint disposed parallel to the pin. The anti-friction bearings of the cylinder are disposed on the journal of the cylinder with their outer race received in a totally enclosed bearing ring having a guide pin beveled to form two flat sides, the guide pin being introduced into a slot S of the cylinder mounting and being locked therein by a spring biased detent.

Abstract: An engraved printing roll is formed by sequential indentations in the roll surface by a stylus. Each indentation is a diamond shape with a longer axis of each indentation overlapping each circumferentially adjacent indentation but the shorter axis not overlapping any other indentation.

Abstract: To permit easy removal and/or engagement and disengagement of a chambered doctor blade unit (1) from an anilox roller (2), the chambered doctor blade unit is attached to a holder (4) which has axially extending projecting pins or bolts (6, 7). The pins or bolts (6, 7) engage in hook-like extensions (12, 13) depending from a cross member (9) extending between the side walls (8) of the printing machine. An eccentric clamping cam disk (10) is rotatable about the cross member (9) and bears, in dependence on the rotary position thereof, against an upper surface of the holder for the chambered doctor blade unit (1) to thereby ensure interengagement of the projecting pins or bolts (6, 7) in the hook-like extensions (12, 13) and on support as well as locating surfaces (14, 16; 17, 18) thereof, while permitting quick release of this interengagement permitting movement and easy removal of the chambered doctor blade unit (1).

Abstract: An inking system of postage and valuation stamping machines has an inking unit with an ink chamber and a portion covering the ink chamber. An inking unit cover has a stepped shape and a drip edge at a step thereof with a wedge-shaped cross section. The inking unit cover has a funnel disposed on the portion of the inking system covering the ink chamber for refilling the ink chamber with stamp ink. A stamp ink container is provided in the form of a cartridge. The funnel guides, retains and empties the cartridge.

Abstract: An ink dispensing roll comprises a generally cylindrical member having a plurality of holes communicating with an interior annular reservoir and a microporous ink impregnated sleeve mounted about the cylindrical member. The annular reservoir is in liquid communication with a larger reservoir charged with ink that flows by gravity into the annular reservoir and then into the microporous sleeve.

Abstract: An engraved micro-ceramic-coated cylinder and a coating process therefor, for use in converting industries, comprises a metal base cylinder having a metal layer disposed thereupon, having the metal layer engraved with a cell pattern and a protective/affinitive stratum of metal plated thereover, and having the surface of the protective/affinitive stratum abrasion treated and a ceramic coating applied thereover.

Abstract: A marking machine for automatically marking cartons passing on an intermittently moving conveyor includes a printing head cyclically moved by a pneumatic cylinder into engagement with the cartons. The motion of the printing head is controlled by guide elements extending from the printing head cooperating with slots in adjacent side plates. The printing head passes durng its cyclical movement across an ink roll disposed above the side plates. A backer plate drops behind the carton surface to be marked just before the printing stroke of the print head. The movement of the backer plate is provided by the guide elements extending from the printing head. The type face on the printing head can be oriented to face upwardly for marking the side of the cover of an egg carton or be oriented to face downwardly for marking a separator in a filler flat.

Abstract: An apparatus and method for oscillating the ink form rollers and dampening form roller in a lithographic printing press to apply a smooth, relatively uniform coating of ink to the ink-receptive areas of the lithographic printing plate and to prevent ink from being transferred from the dampening form roller to the ink-rejecting areas of the printing plate. The ink form rollers and the dampening form roller are each mounted on a shaft rotatable about its own axis. The shaft has at least one shaft key for mating with a complementary keyway in a bushing which is inserted at least partially into the central opening of the corresponding roller. The engagement between the shaft key and the bushing keyway allows the roller and bushing to engage the shaft for common rotation while permitting the roller and bushing to slide axially with resepct to the shaft.