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(11) | EP 0 003 051 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Method of mounting printing cylinders utilizing flexible metal sleeves and printing apparatus using such a printing cylinder |
| (57) Printing apparatus of the type utilizing flexible, readily collapsible, imperforate
thin metal sleeves wherein the sleeves are mounted in a device which maintains their
cylindrical configuration rigidified by introduction of fluid under pressure interior
of the sleeve during use. A method of mounting the sleeve (10) and several structures for supporting the sleeves are described. These include the provision of means in the printing press cooperating with the sleeves for maintainirg its interior pressure and for stopping the press if the pressure should drop below a predetermined value. The sleeves may carry an exterior coating of flexible, microcrystalline, wholly inorganic photoconductive material such as sputtered ultra-pure cadmium sulfide. |
[0001] The invention is concerned generally with printing apparatus which include cylinders for transferring of pigment to a substrate using electrostatic techniques.
[0002] The invention is advantageously utilizable in the printing of multicolor images on substrates which are either in long strip form or in the form of sheets of paper, fabric and the like.
[0003] Multicolor printing by conventional presses is a complex process from the point of making the color separations, forming the cylinders, operating the presses, providing the pigment or inks for the separate cylinders or other plates, etc.
[0004] Several developments in recent years have pointed to the use of electrostatic techniques for multicolor printing in printing presses using electrostatic techniques. As known, photoelectrostatic imaging is effected by charging the surface of a photoconductive coating in darkness, exposing the same to a light image, then toning the latent image with fine particles either in powder form or suspended in a solvent. The toned or developed image can either be transferred to a receptor or it can be fused in place directly onto the electrophotographic member of which the photoconductive coating is a part.
[0005] One of the coatings which has been evolved recently is a high gain, high resolution, easely charged, fully dischargeable, wholly inorganic, microcrystalline photoconductive material which has especially the property that it is rugged and extremely flexible when coated onto a thin flexible substrate. The material is disclosed in U.S. Patent 4.025.339. This coating is advantageous in addition to being flexible in that it can be imaged quickly in a high speed press and discharged readily by ambient light so that, as will be explained, it can be provided with an image of toner that is insulating and thereafter charged to apply a charge to the insulating toner while permitting the charge on the untoned areas to be dissipated in light. Secondary toner then can be adhered to the primary toned image and transferred to a substrate.
[0006] Thin-walled metal sleeves of electrodeposited nickel, copper, iron or other metal have been used in the fabric and other substrate printing field with success. Sleeves of plated metal may be used, such as for example, tin, chromium or other metals as nickel. These sleeves are a fraction of a millimeter thick and can be several meters long and as much as a third of a meter in diameter. They are seamless and are readily supported in printing machines.
[0007] One type of sleeve is disclosed in U.S. Patent 2.287.122. Such sleeve is foraminous in order to enable ink or other pigment to be expressed by doctor means through the walls of the cylinders onto the passing substrate. The walls are provided with suitable designs in the surface blocking certain of the holes and leaving others open.
[0008] For electrostatic use, these sleeves are sputtered with coatings of the photoconductive material which has been mentioned and are imperforate. An important advantage of this type of sleeve is that it is light in weight, it is quite strong and is collapsible so that packing and shipping the same is economical.
[0009] In using the sleeves, they must be mounted in cylindrical form on the printing press to receive and transfer the pigment, and must be supported on their interiors by using some readily installed or removed device to mainrain the sleeves in rigid cylindrical form during use.
[0010] Reference is made to Rothwell U.K. Patent 789.177, published January 15, 1958; Klemm W. German Auslegeschrift 1.231.258 published December 29, 1966; Zimmer Austria Patent 240.879 and Zimmer W. German Auslegeschrift 1.181.237, for a description of some devices wherein sleeves are pressurized by means of an inflatable tube. As evidenced by these publications the cylinders therein are described processed to have a pattern applied on their exterior (U.K. 789.177; DAS 1.181.237; Austria 240.879) or to produce a sleeve in a galvanic process (DAS 1.181.237). The U.S. Patent 3.312.801, March 12, 1968 may be referred to as concerned with the packing of flexible sleeves.
[0011] Considerable difficulties in providing structure for mounting such collapsible sleeves in a high speed printing press have deferred their use functionally in such press device, not withstanding the considerable advantage thereof as mentioned earlier herein.
[0012] Accordingly the invention provides a method of mounting an elongate flexible thinwalled metal sleeve on a frame for use in a rotary printing press, characterized by the steps of providing a rotatable framework including a device for shaping the sleeve into a cylinder; engaging the sleeve over the framework; forming the ends of the sleeve into circles; sealing the ends; containing the ends against axial movement and applying fluid pressure on the interior of the sleeve to inflate the same with uniform incremental internal pressure along said interior thereof.
[0013] Concurrently, the invention also provides the mounting method according to claim 1, characterized in that the sleeve is unsupported along the remaining length between the ends of said sleeve.
[0014] Further, the invention provides a printing press employing the said sleeve mounting and characterized by
A. an elongate framework including shaft means having opposite ends for connecting the framework into a printing press to be rotated thereby, a disc member at each end of the framework connected respectively to one of said shaft ends and each disc member adapted to have one end of a thin-walled metal sleeve coupled thereto and circularly shaped thereby and an axially extending spacer connected between said shaft ends for fixedly spacing the disc members apart and maintaining the spacing during the use of the apparatus,
B. the axially extending spacer being arranged to have such a length as to form the sleeve into cylindrical configuration in cooperation with the members and
C. means for applying a uniform pressure on the interior of the sleeve to every increment thereof over the entire area thereof between said ends in order to maintain its cylindrical configuration during use of the apparatus.
[0015] Additionally the invention provides the printing press further including the apparatus characterized in that the axially extending spacer means comprise an elongate rigid cylinder whose outer diameter is less than the inner diameter of the sleeve which is adapted to be supported by the apparatus whereby there will be a cylindrical space defined between the outer surface of the rigid cylinder and the inner surface of the sleeve when it is installed, the said pressure being supplied into said cylindrical space and the sleeve thereby being mechanically unsupported throughout its major length during use;
[0016] and also the apparatus, characterized in that said means for applying pressure include means for introducing fluid under pressure in the framework and transmitting the pressure to said cylindrical space when the sleeve is installed in place.
[0017] For a complete understanding of the invention preferred embodiments are described with reference to the accompanying drawings.
Figure 1 is a perspective view of a sleeve of the type which is to be mounted by means of the apparatus of the invention and held in a rigid cylindrical configuration to enable the same to be used as ink transfer means in a printing press;
Figure 2 is a sectional view through several of such sleeves showing the convenient manner in which they may be assembled for storing or transportation in small space;
Figure 3 is a highly diagrammatic view of a printing press having two of the cylinders of the invention associated therewith in order to show the environment of the invention;
Figure 5 is a similar view but partially exploded of a modified form of the invention;
Figure 6 is another similar view of a further modification of the invention;
Figure 7 is a sectional view similar to that of Figure 6 showing a variation of the structure of Figure 6;
Figure 8 is a median sectioned view through a printing apparatus taken generally along line 8-8 of Figure 9 and in the indicated direction, parts being taken away, and illustrating another modification of the invention;
Figure 9 is an endelevational view of the apparatus of Figure 8, view taken from the left hand side;
Figure 10 is a fragmentary detailed view of the sleeve clamping means of Figures 8 and 9 and
Figure 11 is a highly diagrammatic view of a printing press having the sleeve of the invention installed therein, there being means for utilizing a source of exterial pressure operable by exterial control means.
[0018] In Figure 1 there is illustrated in perspective view the type of cylinder 10 which is used with the invention, the same being based upon a sleeve 12 which has been formed by electrodeposition out of nickel, copper or the like, being quite thin - of the order of a small fraction of a millimeter and hence flexible or may comprise a naked sleeve plated with such metals as tin chromium or thus.
[0019] Upon this sleeve 12 there is sputtered a thin film coating 14 of a wholly inorganic, microcrystalline, highly sensitive, readily chargeable photoconductive material such as for example ultrapure cadmium sulfide. The characteristics of the material and the method of sputtering the same are disclosed in said U.S. Patent 4.025. 339. The techniques for the electrodeposition of the metal sleeve 12 and some of the characteristics thereof are described in said U.S. Patent 2.287.122 with the exception that the metal sleeve 12 is imperforate instead of foraminous as disclosed in said latter patent.
[0020] In the formation of the metal sleeve 12 the resulting product is normally cylindrical and likewise, in sputtering the coating 14 the configuration of the sleeve 12 will be maintained in cylindrical form. It is possible for the sputtering to be carried on with the metal sleeve 12 forming the substrate for the coating in an oval configuration.
[0021] In the mounting of the sleeve or cylinder 10, it will invariably be in a cylindrical configuration for high speed printing presses, especially multi-color presses. Nonetheless the sleeve 10 is to some extent collapsible without damage to either the substrate of metal or the coating of microcrystalline photoconductive material. The metal substrate comprising the sleeve 12 is stiff enough to handle, for example in a size which has a length of about two meters and a diameter which is about a sixth of a meter without axial collapsing or wrinkling, but can be readily compressed or collapsed laterally along its entire length to enable it to be shaped for example into oval form as shown in Figure 1. Likewise it can be partially rolled into reentrant shapes to occupy considerably less volume than when it is in its full cylindrical configuration as disclosed in U.S. Patent 3.372.801. This enables many of these sleeves to be packaged in a single small package as shown in Figure 2 in which there are two additional sleeves 10' and 10" within the sleeve 10. Abviously more than two such sleeves can be compressed into a single bundle.
[0022] Reference is made now to Figure 3 which illustrates the environment in which the sleeve 10 is intended to be used. Here as an example a printing presse 16 is shown, this being of a type which is intended to apply two colors of ink or dye carried in the fountains 18 and 20 in registration on a long strip-like substrate 22 of paper or the like. The substrate 22 is guided by means of the rolls 24, 26, 28 and 30 to pass around a back-up roll 32 against which the printing will occur. Two cylinders of the type described are shown at 10 and 10'''. The direction of rotation of the drum 32 is indicated by the arrows 34,.the direction of each of the cylinders 10 and 10''' being indicated by arrows marked on the cylinders.
[0023] In this apparatus 16, the cylinders 10 and 10''' will be presumed to have images carried on their outer surfaces as primary toned images. These can be applied while the cylinders 10 and 10''' are off the apparatus 16 and the cylinders thereafter installed in the apparatus.
[0024] In use the cylinders are charged by suitable corona means at 36 and 38, the charging occurring in light so that the charges on the photoconductive coatings are immediately dissipated leaving only the charges on the primary toner. The type of toner chosen is one which is insulating when developed, that is, fused. The fountains 18 and 20 contain the ink or dye which comprises the secondary toner. The polarity of the particles of the secondary toner is established as the opposite of that of the charge on the primary toner. This can be done electrophoretically or by triboelectric techniques. As the charged images pass the fountains 18 and 20 they will pick up the secondary toner from the respective fountains and apply the same to the surface of the substrate 22. Electrical bias can be used to assist in this transfer. Transfer will be done in registration.
[0025] After the transfer has been completed and the images pass the nip between the cylinders and the back-up roller 32 the printingcycle is repeated. Although not normally required, remaining secondary toner, if any, may be removed from the surfaces of the cylinders 10 and 10''' by suitable solvents or mechanical means at stations 40 and 42, with suitable solvents and/or mechanical means which do not affect the primary toner.
[0026] The cylinders 10 and 10''' could be provided with developed toned images and treated with suitable reagents or chemicals to render the toned surfaces hydrophobic and the untoned surfaces hydrophyllic to enable the cylinders to be used as printing cylinders with greasy ink in watered offset printing presses., The use of the cylinders in the type of printing apparatus operating by means of electrostatic techniques in preferred.
[0027] As heretofore mentioned, the cylinder 10 is required to be perfectly cylindrical and relatively rigid during its use and with its mounting or support, should be easily installed and removed from the printing press on which it is to be used. Likewise, it is required to be easily installed and removed from the mounting which carries it.
[0028] In Figure 4, there is illustrated (in section) a form of mounting upon which the cylinder 10 is arranged for use in a printing press. The mounting device 44 basically comprises a device in which the cylinder is suspended in cylindrical configuration and is kept inflated by means of a fluid such as oil or air or the like pumped into the interior of the cylinder 10 and maintained at a low pressure. It has been found that the cylinders 10 can be kept quite rigid and maintain their cylindrical configuration by means of pressures only slightly greater than atmospheric, say of the order of .5 to .7 of an atmosphere greater than ambient. This is considered a surprising result.
[0029] The cylinder ends must be tightly gripped in cylindrical configuration to prevent wrinkles and bulges.
[0030] In Figure 4 the mounting device is basically formed of two stub shafts 46 and 48, shaft 48 being solid and shaft 46 being hollow. A flanged disc 50 has an inwardly directed annular cup-like flange 52 whose interior diameter is very closely the outer diameter of the sleeve 10. A hub 54 mounts the web 51 of the disc 50 on the hollow shaft 46 non-rotatively, the center of the shaft 46 having a through bore 56 whose inner end may be plugged at 58 but which is provided with a lateral opening at 60 that connects with a radial passageway 62 passing through the hub 54 but located axially interior of the web 51 of the disc 50, the web 51 being imperforate.
[0031] The interior end of the shaft 46 also has a large washer 64 secured thereto as by welding, the washer 64 supporting an elongate rigid metal cylinder 66 and being secured thereto, also by welding, for example. This cylinder is included in the term axially extending spacer means as employed herinafter.
[0032] The opposite end of the cylinder 66 is attached to a second washer 68 that is welded to the shaft 48 so that both shafts 46 and 48 are aligned and rotate in unison. A second disc 70 has a central hub 72 that may be secured to the shaft 48 permanently or non-rotatable relative thereto but held in place by a nut such as 74. The body 76 of the disc is imperforate and has an inwardly directed cup-like annular flange 78 at its outer periphery having the same interior diameter as the flange 52.
[0033] Suitable packing is provided at 80 and 82 serving to prevent the leaking of fluid outwardly of the discs 50 and 70.
[0034] The disc 50 is held in place by the nut 81 engaging over the threaded end 83 of the shaft 46.
[0035] In use, a sleeve 10 is shaped into a cylinder and fitted into the interior of the flange 78 and cemented in place with a suitable adhesive, primarily to render the telescoping connection fluid tight. The flange 50 is not in place at this time. After installing the right hand end of the sleeve 10, the disc 50 is moved telecopically over the left hand end of the sleeve 10 and again the connection is effected with a coating of adhesive in place to provide a second fluid tight connection. When the adhesive has set, the entire assembly is installed in a printing press such as the apparatus 16 and a fluid such as air, hydraulic fluid or the like is admitted into the bore 56 through a suitable fitting attached to the left hand end of the shaft 46. This fitting is required to maintain the connection fluid tight while rotating, there being many such fittings known in the art. Such a fitting is indicated at 57, connected by line 59 to the fluid source 61.
[0036] The fluid is carried in the annular space between the central cylinder 66 and the sleeve 10 and it serves to maintain the sleeve 10 fully inflated and rigid during use. The presence of the inner sleeve enables a very small amount of fluid to be used to maintain the rigidity of the sleeve 10, and in the case of air or other gas being the fluid, the amount of pressure needed to maintain the inflated condition is lower than it would be if the shaft extended fully through the device and there was no cylinder 66. It is clear that the cylinder 66 functions to maintain the spacing between the discs 50 and 70 and to keep the shafts 46 and 48 in alignment and rotating together. The entire assembly is included in the term "framework" is used.
[0037] The internal pressure needed for keeping the cylinders inflated on a printing press is so low that readily available air pressure form commercial sources commonly provided in shops and factories will suffice. Further, since the method of transfer of ink to the substrate requires no mechanical pressure in the preferred structure in which the cylinders will be used, mechanical tension alone will be adequate to maintain the cylinders in their normal configuration in many instances.
[0038] Two other forms of the invention are illustrated, respectively in Figures 5 and 6, but the principals of construction and operation are basically the same for all of the cylinder supporting devices including that of Figure 4. Each has means for clamping or seizing the ends of the cylinder 10 in a fluid tight connection while shaping the same to form the cylindrical configuration, each has means for admitting a fluid to the interior of the cylinder to inflate it if required but at least to maintain it in rigid cylindrical configuration, and each has means for mounting the device onto a printing press. If should be understood that although the practical manner of introducing the fluid and maintaining the internal pressure is by having structure on the printing press which connects with the cylinder-supporting device while the cylinder is rotating, it is nevertheless possible to have the cylinder-supporting device provided with means that pumps the fluid into the interior of the cylinder and is sealed under some pressure so that the entire device is maintained in tis fully expanded condition independently of the printing machine.
[0039] The mounting devices 90 of Figure 5 differs primarily from that of Figure 4 in that the ends of the cylinder are held in place pneumatic or hydraulic expandable cushions. There is a pair of stub shafts 92 and 93 which have the interior rigid cylinder 94 secured to their inner ends, respectively, but both of these shafts are hollow. The right hand shaft 93 has a single bore 96 which connects to one or more radial passageways 98 in the washer end 100 of the cylinder 94 leanding to the interior of an inflatable elastomeric cushion 102 clamped to the end of the cylinder 94 by suitable bands 104. The securement can be effected by room temperature vulcanizing adhesive or other adhesive.
[0040] A similar cushion 106 shown in deflated condition is provided on the left hand end of the cylinder 94, since this end is shown in condition while it is being assembled. The shaft 92 differs from the shaft 93 and that of Figure 4 in that it has concentric passageways, there being a central bore or pipe 108 and a larger telescoping second bore 110, these being located within one another and being independent of one another. The central passageway formed by the bore 108 is connected through a fitting 112 by way of a short length of conduit 114 through the interior of the cylinder 94 to a lateral opening 116 to which it is connected by a suitable fitting 118. The outer bore 110 connects to one or more radial passageways 120 leading to the interior of the cushion 106.
[0041] Assembly is effected by moving the end cup-shaped discs 122 and 124 into telescoping engagement with the cylinder 10 taking up on the nuts 126 and 128, introducing a first fluid into the bores 96 and 108 to inflate the cushions 104 and 106 to clamp the sleeve 10 in place and thereafter introducing a second fluid into the interior pipe 108 to maintain the sleeve 10 as a rigid cylinder. The second fluid is held between the inner cylinder 94 and the interior of the sleeve 10. Shaft packing is not deemed necessary in the device 90.
[0042] In Figure 6 there is illustrated a device 140 which utilizes an elastomeric boot of cylindrical configuration to maintain the sleeve 10 rigid so that no fluid will be engaged against the interior of the sleeve and so that it is not essential that the engagement of the sleeve 10 in the end discs be fluid tight. In this device there is again an inner rigid cylinder 142 connected with a pair of end stub shafts 144 and 146 upon which there are engaged the discs 148 and 150 by means of the nuts 152 and 154, respectively. On the exterior of-the cylinder 142 there is mounted an elongate elastomeric sleeve-like boot 156 whose ends are tight clamped to the exterior of the cylinder 142 by any suitable means such as the annular band 158 and 160. The hollow bore 162 of the shaft 146 terminates axially within the cylinder 142 at 164 at which point it is connected by way of the conduits 166 connected at 168 to openings in the side wall of the cylinder 142, as for example at 170. Accordingsly passage for fluid from the exterior of the cylinder 142 is provided by way of the bore 162 to the chamber 172 formed on the interior of the boot 156 and the outer surface of the cylinder 142.
[0043] The assembly of the device 140 and the method of inflation are easily effected since everything may be in place at one end, say the right hand end, the sleeve 10 slipped in place into the cup of the disc 150 while no fluid is present, the second disc 148 telescopically engaged over the left hand end of the sleeve, the nut 152 screwed home and fluid applied. This inflates the boot 156 and rigidifies the sleeve 10. This will form a rather firm base for the sleeve 10 during use.
[0044] In Figure 7 another device 240 is illustrated in which the equivalent components of Figure 6 are designated by the same second and third numerals and the numeral "2" as the first. The principal differences between the devices 140 and 240 lie in the fact that the entire interior of the cylinder 242 carries the fluid, which in this case is a gas and the fact that the end washers of the cylinder 242 function both as such washers and the discs 148 and 150. Thus they carry reference numerals 248 and 250. The fluid is admitted by way of bore 262 in shaft 246 and finds its way into the chamber 172 through passageways 270.
[0045] The structure 240 is advantageous in eliminating parts comprising outer cup-shaped discs so that there need be no part of the device 240 protruding radially beyond the sleeve 10 itself. Thus the device is lighter in weight, simpler to construct, and more economical than the device 140.
[0046] In Figures 8 to 10 a modified embodiment of the inven tion is designated generally by reference character 300 and comprises a central hollow shaft 312 of metal having a plurality of lateral passageways 313 for air. Other fluids may be used, but for convenience only air will be referred to herinafter because it is most convenient to use the same in printing establishments.
[0047] The ends of the central shaft 312 are closed off by plugs 314 and 316 to which the shaft is welded as indicated at 318 and 320, respectively. A flanged disc is connected to each of these plugs by suitable means, the disc 322 being shown on the left and the desc 324 on the right. These discs 322 and 324 are identical and their construction and functions will be explained in detail later. At this point it is to be noted that the plugs 314 and 316 are generally cylindrical and that each of the discs 322 and 324 includes a hollow cylindrical hub shown at 326 and 328 which telecopically engages the respective plugs 314 and 316 on the exterior thereof, airtight connection being maintained by suitable packing such as 0-rings 330.
[0048] The discs 322 and 324 include internal radial strengthening ribs 332 and 334 integral with the web or body of each disc, the latter being imperforate to retain the air pressure which is to be maintained on the interior of the device 300.
[0049] As noted, the structures at opposite ends of the shaft 312 are different. These represent embodiments of the invention capable of being used together or separately. In other words, the structure at the left hand end may be used solely or duplicated at the right hand end; the structure at the right hand end may be used solely or duplicated at the left hand end; one of each structure may be used together at opposite ends.
[0050] Considering now the structure at the left hand end of the device 300, the plug 314 has a cylindrical axial recess formed in its outer end at 336 and a coaxial socket 338 in the center of the recess 336 in which there is disposed a simple air valve 340 of the so-called Schraeder type which communicates by way of the passageway 342 with the interior 344 of the hollow shaft 312. As explained, the shaft has the lateral passageways 313 by means of which the outer annular chamber 346 and the inner chamber 344 are in communication. As understood, a thin metal sleeve 348 of electrodeposited nickel or the like with an outer photo- conductuve coating is adapted to be clamped into cylindrical configuration on the device 300 and maintained in inflated condition by air pressure. This is effected by introducing air under pressure by way of the valve 340 into the chamber 344.
[0051] The disc 322 has an inwardly directed radial flange 349 which is engaged over the axial end of the plug 314 and provided with perforations and threaded sockets to aid in the assembly of the device. For example, in the device shown, there is a perforation in alignment with each of the ribs 322 thus providing six equally spaced perforations aligned with threaded sockets in the axial end of the plug 314. One such perforation is indicated at 350 and a threaded socket at 352.
[0052] These perforations and sockets receive machine screws 354 which pass through an outer cap or centering flange member 356 thereby securing the disc 322 to the plug 314.
[0053] The centering flange member 356 has a central spigot 358 which is cylindrical on its' exterior to fit into the recess 336 and is tapered on the interior as indicated at 360 and provided with a keyway at 362. There is also a radial flange portion 363 overlying the flange 349. The member 356 has the aligned perforations in the flange portion 363 for the screw 354 but in addition has several other perforations 364 which are intended to be aligned with threaded sockets 366 formed in the flange 349 to receive other machine screws 368 that pass through the flange portion 363. These screws 368 are only three in number as shown in Figure 9 and their function is to enable the proper alignment of the disc 322 and the flange member 356 but more importantly, to aid in assembly. The two parts 322 and 356 can be assembled together before the disc 322 is engaged onto the plug.
[0054] Looking now at Figure 12 which is an enlarged view of the outer section of the disc 322, there is an annular thickended rim 370 which has an interior (on the right hand face) axially extending annular seat or groove 372 formed fully around its circumference and coaxially centered. There is an elastomeric ring 374 seated in the bottom (left hand end) of the groove 372, the ring 374 being provided with spaced passageways 376 aligned with perforations 378 provided in the rim 370 and opening to an external shallow furrow 380 provided on the exterior of the rim 370. There is a pressure ring 382 of cylindrical configuration which has a plurality of threaded studs 384 secured into its left hand axial end in spaced circumferential position to align with the passageways 376 and perforations 378. The studs 384 extend through these passageways and perforations when the ring 382 is assembled to the disc 322 and are engaged by the nuts 386.
[0055] Before the nuts 386 are tightened, the assembly of the apparatus 300 with the sleeve 348 is effected, the sleeve 348 being easily slipped into place as the assembled disc 322, flange member 356 and ring 382, and properly positioned. Thereafter, taking up on the nuts 386 presses the ring 382 against the elastomeric ring 374 which expands in attempting to extrude out of the groove 372 thereby firmly clamping the sleeve 348 in place.
[0056] Assuming that the same structure and procedure has been utilized in assembly of the right hand end of the device 300, it can be pumped up to a pressure of say about half an atmosphere through the use of the valve 340 and installed in the printing press. The tapered socket 362 provides for centering and the keyway provides for positive driving of coupling of the device with suitable mechanical driving means associated with the printing press.
[0057] The right hand end of the device need not have a valve equivalent to the valve 340 but could have a blind end in the equivalent of the tapered socket 360 in the axial end of the plug 316. As a matter of fact, there need not be a second keyway at this location.
[0058] In the view of Figure 8, however, a second form of structure is illustrated which enables various functions to be effected by means of another valve.
[0059] Referring now to the right hand end of the device 300 shown in Figure 8, the only structural difference between that end and the left hand end lies in the valve device mounted at the right hand end. There is a valve housing 390 set into the right hand plug 316 which has a port 392 leading to the chamber 344. The movable valve 394 is seated at the right hand end of the chamber 396 by means of the 0-rings 398 against the axial intake port 400 and held there by a spring 402. The spring 402 is of a strength to maintain any pressure which is in the chamber 344 and 346 if the device 300 is removed from a press in which it is installed. When installed in a press, the stem 404 of the valve member 406 pushes the valve 394 off its seat and holds the port 400 open.
[0060] The valve member 406 has a coaxial passageway and itself is slidable in the port 400, being kept air tight therein by suitable 0-rings. Its external face 410 has 0-rings to enable it to make a frictional and air tight connection with a fitting that can supply external air pressure to the device 300. The fitting is not shown in Figure 8 but is symbolized by the fitting 412 in Figure 11 as a rotary air connection. The spring 402 keeps the valve member 406 in engagement with the fitting 412.
[0061] From this discription it is obvious that air can be maintained and supplied to the interior of the sleeve 348 through the valve member 406 from outside sources to pump up the sleeve 348 and maintain it in such condition.
[0062] Referring to Figure 11 a printing press is shown diagrammatically having the device 300 installed therein, the_structure being such as to utilize an external source of pressure. The other device of the invention previously described may be utilized so long as they utilize an external source of pressure. The device 300 is shown mounted on the frame 414 of a printing press 416, only a very small part of which is diagrammed. The substrate in the form of a web of paper 418 is being guided through the press 416 and may pass over idler and drive rollers, an idler roller being indicated at 420 and a drive roller being indicated at 422 mounted to the frame 414. The press drive 424 may be mechanical, electrical, pneumatic or a combination of these, suitably controlled as custormary with modern printing presses. The mechanical drive extending to the several rotary parts is indicated by the broken lines 426.
[0063] A pressure source is shown at 428 supplying pressure to the fitting 412 by way of the pressure regulator 430 and the air line 432 and 434. The exact pressure within the sleeve 348 will be controlled by the pressure regulator 430 whose set value may be established manually as by a control 436 or may be varied automatically for certain purposes by way of the line 438.
[0064] The pressure switch 440 is sensitive to sudden changes in the pressure in the line 434, being connected to the line 434 by a conduit 442. A large hole suddenly occurring in the sleeve 348 or the bursting thereof will cause a sudden dropping of pressure in the chamber 346. The drop will be experienced by the line 434 and the regulator will attempt to equalize the pressure. This radical change sensed by the switch 440 can be made to operate the switch to turn off the press drive and prevent damage.
[0065] Slight air leaks in the chamber 346 can be taken care of by the regulator 430 as a routine matter.
[0066] The press 416 will normally have some form of transducer system (not shown) to indicate registration of multiple impressions and a signal from such system can be picked up and transmitted by a line, electrical or pneumatic, as shown at 444 to a sensor 446. This sensor 446 may in turn provide a signal which operates a register adjusting device 448 which is nothing more than an automatic adjustment for the set point of the pressure regulator. It has been found that since the sleeve 448 is made out of metal that is very thin, it is capable of being inflated slightly beyond its normal diameter by a small amount, say a few thousandths of a millimeter. Registration can be affected by this means, to augment ordinary registration control means rather than to replace the same.
1. A method of mounting an elongate flexible thin- walled metal sleeve on a frame
for use in a rotary printing press, characterized by the steps of providing a rotatable
framework including a device for shaping the sleeve into a cylinder; engaging the
sleeve over the framework; formind the ends of the sleeve into circles; sealing the
ends; containing the ends against axial movement and applying fluid pressure on the
interior of the sleeve to inflate the same with uniform incremental internal pressure
along said interior thereof.
2. The mounting method according to claim 1, characterized in that the sleeve is unsupported
along the remaining length between the ends of said sleeve.
3. The mounting method according to claim 1 or 2, characterized in that the fluid
pressure is applied directly to the interior of the sleeve.
4. The mounting method according to claim 1 or 2, characterized in that the fluid
pressure is applied indirectly to the interior of the sleeve by introducing an inflatable
body within the sleeve and introducing fluid under pressure to said inflatable body
whereby to apply pressure to said sleeve interior sufficient to rigidify the same.
5. A printing apparatus including a support for an imperforate thin-walled metal sleeve
for use as an ink transfer device, the sleeve being flexible and collapsible when
unsupported, characterized by.
A. an elongate framework including shaft means having opposite ends for connecting the frame- wirk into a printing press to be rotated thereby, a disc member at each end of the framework connected respectively to one of said shaft ends and each disc member adapted to have one end of a thin-walled metal sleeve coupled thereto and circularly shaped thereby and an axially extending spacer connected between said shaft ends for fixedly spacing the disc members apart and maintaining the spacing during the use of the apparatus,
B. the axially extending spacer being arranged to have such a length as to form the sleeve into cylindrical configuration in cooperation with the disc members and
C. means for applying a uniform pressure on the interior of the sleeve every increment thereof over the entire area thereof between said ends in order to maintain its cylindrical configuration during use of the apparatus.
6. The apparatus according to claim 5, characterized in that the axially extending
spacer means comprise an elongate rigid cylinder whose outer diameter is less than
the inner diameter of the sleeve which is adapted to be supported by the apparatus
whereby there will be a cylindrical space defined between the outer surface of the
rigid cylinder and the inner surface of the sleeve when it is installed, the said
pressure being supplied into said cylindrical space and the sleeve thereby being mechanically
unsupported throughout its major length during use.
7. The apparatus according to claim 6, characterized in that said means for applying
pressure include means for introducing fluid under pressure in the framework and transmitting
the pressure to said cylindrical space when the sleeve is installed in place.
8. The apparatus according to claim 5 or 6, characterized in that the means for introducing
pressure include at least one passageway through the shaft means and connecting conduit
means between said passageway and the interior of said sleeve for applying said pressure
on the interior wall of said sleeve.
9. The apparatus according to claim 5 or 6, characterized in that the means for introducing
pressure include at least one passageway through the shaft means and means for establishing
a connection between said passageway and an external source of fluid under pressure.
10. The apparatus according to claim 6 or 7, characterized in that there is a generally
cylindrical inflatable boot sealed to said rigid cylinder and the means for applying
pressure include a conduit for leading fluid to the interior of the boot to expand
same into engagement with the interior of the sleeve.
11. The apparatus according to claims 6 or 7, characterized in that the opposite ends
of the rigid cylinder are provided with respective inflatable cushions adapted to
be inflated into engagement with the ends of the sleeve to seal and clamp said sleeve
ends between the rigid cylinder and the shaft having a first passageway means for
introducing a first fluid under pressure to the interiors of said cushions.
12. The apparatus according to claim 6 or 7, characterized in that there is a coaxial
inflatable boot disposed in the framework telecopically located on the interior of
the sleeve and sealed at its ends and structure for leading the fluid to the interior
of the boot to inflate the same against the inside surface of the sleeve.
13. The apparatus according to claim 5 or 6, characterized in that there is at least
one passageway coaxial with and through said shaft, habing its inner end terminating
in the interior of the sleeve and its outer end terminating at one of said shaft means
ends, a fluid tight connection coupling said sleeve ends, structure for leading fluid
under pressure to one shaft means end and into said passageway from the exterior of
the framework.
14. The apparatus according to claim 6 or 7, characterized in that the ends of the
cylinder have washers closing same off, the shaft means are coaxial with the washers,
the disc members are mounted on the shaft means, and the fluid bypasses the cylinder
on the exterior thereof.
15. The apparatus according to claim 14, characterized in that the disc members have
inwardly directed axially extending annular flanges and the sleeve is capable of being
secured on the interior of the flanges.
16. The apparatus according to claim 15, characterized in that said shaft includes
a second passageway means independent of the said one passageway means to enable introducing
a second fluid under pressure in the said annular space to inflate said sleeve when
installed.
17. The apparatus according to claim 5 or 6, characterized in that there are means
for mounting said apparatus for rotation, an external source of fluid under pressure
and means extablishing a rotatable fluid coupling leading from said external source
of fluid under pressure to said interior whereby to apply fluid pressure thereto during
rotation.
18. The apparatus according to claim 5 or 6, characterized in that the sleeve ends
are in coupled "B" relationship with the respective disc members.
19. The apparatus according to claim 5, characterized in that said elongate framework
includes arigid hollow cylinder having end washers closing the same and said shaft
means ends respectively are connected to the respective washers and are axially extending
outwardly relative to said cylinder a coupling on the shaft ends for effecting the
rotatable connection into the printing press, said framework including a disc member
at each end of the calinder connected respectively to the shafts and capable for rotation
with said framework, each disc member having a peripheral, annular, axially extending
relatively short flange with the flanges and discs forming cup-like formations opening
toward one another and having the inner diameter thereof larger than the exterior
diameter of said cylinder, at least one of the discs being movable axially relative
to the other disc and capable of being secured in a predetermined axial position each
cup-like formation adapted to have one end of said sleeve coupled thereto for circularly
shaping same thereby the position of the movable disc at a location relative to the
other disc and the cylinder being fixed when the sleeve is in place so that the sleeve
will form a second hollow cylinder coaxial of the first cylinder and surrounding the
same and further including a pressurized fluid source, at least one end of said shaft
means including a passageway leading fron said shaft means to a space between cylinders
at a location axially outward said cylinders.
20. The apparatus as claimed in claim 19 characterized in that a passageway formed
through said shaft, an external source of fluid under pressure and a connection between
said source and said passageway communicate internally with the interior of the sleeve
when said sleeve is so mounted and coupled.
21. Apparatus according to claim 5 or 6, characterized in that each disc member has
the ends thereof sealybly mounted and coupled to said respective ends of said sleeve,
there being no mechanical support provides for said sleeve between its ends when said
sleeve is so coupled, said a spacer being connected between the shaft ends for fixedly
spacing the disc members apart and maintaining the spacing during the use of the apparatus.
22. The apparatus according to in any one of claim 5 to 21, characterized in that
thin-walled metal sleeve has its ends adhesively engaged with said disc members in
stretched condition.
23. The apparatus according to any one of claim 1 to 22, characterized in that the
sleeve has an exterior thin film coating of a microcrystalline flexible photoconductive
material.
24. Apparatus for supporting an imperforate thin walled metal sleeve which is flexible
and collapsible when unsupported, for use as an ink transfer device in a printing
press or the like characterized by :
A. an elongate hollow shaft having a plug at opposite ends thereafter and lateral passageways through the shaft wall between the ends thereof,
B. each of the plugs having structure to enable the apparatus to be removably coupled to a printing press and be rotated by the press drive on an axis defined by the axis of the hollow shaft,
C. an imperforate disc connected to each of the plugs coaxial with said shaft and having a circumferential groove on its face located radially inward of its outer edge, the diameter of the grooves being sub- standially greater than the outer diameter of the hollow shaft, said grooves facing one another axially and providing seats for the ends of said thin walled metal sleeve adapted to be engaged therein and extending between said discs spaced outwardly of said hollow shaft,
D. an elastomeric 0-ring engaged in each groove and a locking ring also axially movable into said groove and adapted to engage said 0-ring and press same into its groove whereby to clamp the ends of the thin-walled sleeve into the respective grooves while forming said ends into circles coaxial with said shaft,
E. said apparatus providing no support for the said sleeve when so installed between the clamped ends thereof other than fluid pressure,
F. means for securing the locking rings in said clamped engagement and
G. a valve in at least one of said plugs to enable the admission of fluid under pressure into the interior of the sleeve when said sleeve is so mounted in said apparatus, the valve bein arranged to retain the fluid pressure in the apparatus.
25. The apparatus as claimed in claim 24, characterized in that the valve is capable
of being opened to connect the apparatus to an external source of pressure while mounted
in a printing press and rotating.
26. The apparatus as claimed in claim 25, characterized in that the valve is arranged
automatically to close but retain said pressure if the apparatus is removed from said
printing press.
27. The apparatus as claimed in claim 26, characterized in that the means for securing
the locking rings comprise bolts extending through said discs from the exterior faces
thereof and into engagement with the clamping rings on the interior of said grooves.
28. The apparatus as claimed in claim 27, characterized in that the said structure
to enable coupling of said apparatus to a printing press comprise tapered sockets
formed in each respective plug coaxial with said shaft and at least one of said sockets
having key means, said sockets adapted to be engaged with male members connected with
said printing press, at least the keyed socket adapted to be engaged with a male member
that is rotary.